Thin-Film Nanocomposite Membrane with the Minimum Amount of MOF by the Langmuir-Schaefer Technique for Nanofiltration.

PubMed

Navarro, Marta; Benito, Javier; Paseta, Lorena; Gascón, Ignacio; Coronas, Joaquín; Téllez, Carlos

2018-01-10

An innovative procedure for positioning a monolayer of hydrophilic metal organic framework (MOF) MIL-101(Cr) (MIL, Materials of Institute Lavoisier) nanoparticles (NPs) in thin-film nanocomposite (TFN) membranes has been implemented by transferring a Langmuir-Schaefer (LS) film of the MOF in between the polyamide thin layer at the top and the cross-linked asymmetric polyimide (P84) support at the bottom. The presence and layout of the LS-MIL-101(Cr) monolayer in the TFN membrane was confirmed by scanning transmission electron microscopy imaging with a high-angle annular dark-field detector images and X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy, and atomic force microscopy analyses. This methodology requires the smallest amount of MOF reported to date, 3.8 μg cm -2 , and promotes the formation of a defect-free ultrathin MOF film. Although conventional TFN membranes tend to show MOF agglomerates that could contribute to the formation of unselective defects, LS-TFN membranes, characterized by a homogeneous and continuous MOF coating, exhibit an optimal membrane performance, without a significant decrease in selectivity. Outstanding methanol permeances, one of the best results reported to date, of 10.1 ± 0.5 L m -2 h -1 bar -1 when filtering sunset yellow and of 9.5 ± 2.1 L m -2 h -1 bar -1 when filtering rose bengal have been achieved in LS-TFN membranes with a rejection higher than 90% in all cases. Methanol permeates through the polyamide and the LS-MIL-101(Cr) monolayer, greatly enhanced by the MOF pore system, in comparison to thin-film composite and conventional TFN membranes (7.5 ± 0.7 and 7.7 ± 1.1 L m -2 h -1 bar -1 when filtering sunset yellow), respectively, in which polyamide areas free of MOF NPs are present.

Fe-MIL-101 exhibits selective cytotoxicity and inhibition of angiogenesis in ovarian cancer cells via downregulation of MMP

PubMed Central

Wang, Jiaqiang; Chen, Daomei; Li, Bin; He, Jiao; Duan, Deliang; Shao, Dandan; Nie, Minfang

2016-01-01

Though metal-organic frameworks (MOFs) have inspired potential applications in biomedicine, cytotoxicity studies of MOFs have been relatively rare. Here we demonstrate for the first time that an easily available MOF, Fe-MIL-101, possesses intrinsic activity against human SKOV3 ovarian cancer cells and suppress the proliferation of SKOV3 cells (IC50 = 23.6 μg mL−1) and normal mouse embryonic fibroblasts (BABL-3T3, IC50 = 78.3 μg mL−1) cells. It was more effective against SKOV3 cells than typical anticancer drugs such as artesunate (ART, IC50 = 96.9 μg mL−1) and oxaliplatin (OXA, IC50 = 64.4 μg mL−1), but had less effect on normal BABL-3T3 cells compared with ART (IC50 = 36.6 μg mL−1) and OXA (IC50 = 13.8 μg mL−1). Fe-MIL-101 induced apoptosis of human umbilical vein endothelial cells (HUVECs) via G0/G1 cell cycle arrest and decreased the mitochondrial membrane potential in HUVECs and induced apoptosis. Furthermore, Fe-MIL-101 exhibited stronger antiangiogenic effects in HUVEC cells than antiangiogenic inhibitor (SU5416) via downregulation the expression of MMP-2/9. Our results reveal a new role of Fe-MIL-101 as a novel, non-toxic anti-angiogenic agent that restricted ovarian tumour growth. These findings could open a new avenue of using MOFs as potential therapeutics in angiogenesis-dependent diseases, including ovarian cancer. PMID:27188337

Water Adsorption on Various Metal Organic Framework

NASA Astrophysics Data System (ADS)

Teo, H. W. B.; Chakraborty, A.

2017-12-01

In this paper, Metal Organic Framework (MOF) undergoes N2 and water adsorption experiment to observe how the material properties affects the water sorption performance. The achieved N2 isotherms is used to estimate the BET surface area, pore volume and, most importantly, the pore size distribution of the adsorbent material. It is noted that Aluminium Fumarate and CAU-10 has pore distribution of about 6Å while MIL-101(Cr) has 16 Å. The water adsorption isotherms at 25°C shows MIL-101(Cr) has a long hydrophobic length from relative pressure of 0 ≤ P/Ps ≤ 0.4 with a maximum water uptake of 1kg/kg sorbent. Alkali metal ions doped MIL-101(Cr) reduced the hydrophobic length and maximum water uptake of original MIL-101(Cr). Aluminium Fumarate and CAU-10 has lower water uptake, but the hydrophobic length of both materials is within relative pressure of P/Ps ≤ 0.2. The kinetic behaviour of doped MIL-101(Cr), Aluminium Fumarate and CAU-10 are faster than MIL-101(Cr).

The Preparation of Porous Sol-Gel Silica with Metal Organic Framework MIL-101(Cr) by Microwave-Assisted Hydrothermal Method for Adsorption Chillers

PubMed Central

Uma, Kasimayan; Pan, Guan-Ting; Yang, Thomas C.-K.

2017-01-01

Metal organic framework (MOF) of MIL-101(Cr)-Silica (SiO2) composites with highly mesoporous and uniform dispersions were synthesized by a microwave-assisted hydrothermal method followed by the sol-gel technique. Water vapor adsorption experiments were conducted on the MIL-101(Cr)-SiO2 composites for industrial adsorption chiller applications. The effects of MIL-101(Cr)-SiO2 mixing ratios (ranging from 0% to 52%), the surface area and amount of Lewis and Brønsted sites were comprehensively determined through water vapor adsorption experiments and the adsorption mechanism is also explained. The BET and Langmuir results indicate that the adsorption isotherms associated with the various MIL-101(Cr)-SiO2 ratios demonstrated Type I and IV adsorption behavior, due to the mesoporous structure of the MIL-101(Cr)-SiO2. It was observed that the increase in the amount of Lewis and Brønsted sites on the MIL-101(Cr)-SiO2 composites significantly improves the water vapor adsorption efficiency, for greater stability during the water vapor adsorption experiments. PMID:28772969

Mn-salen@MIL101(Al): a heterogeneous, enantioselective catalyst synthesized using a 'bottle around the ship' approach.

PubMed

Bogaerts, Thomas; Van Yperen-De Deyne, Andy; Liu, Ying-Ya; Lynen, Frederic; Van Speybroeck, Veronique; Van Der Voort, Pascal

2013-09-21

An enantioselective catalyst, consisting of a chiral Mn(III)salen complex entrapped in the MIL-101 metal organic framework, is reported. For the first time, we assemble a robust MOF-cage around a chiral complex. The heterogeneous catalyst shows the same selectivity as the homogeneous complex and is fully recyclable. Theoretical calculations provide insight into this retention of selectivity.

Polydimethylsiloxane/metal-organic frameworks coated fiber for solid-phase microextraction of polycyclic aromatic hydrocarbons in river and lake water samples.

PubMed

Zhang, Guijiang; Zang, Xiaohuan; Li, Zhi; Wang, Chun; Wang, Zhi

2014-11-01

In this study, polydimethylsiloxane/metal-organic frameworks (PDMS/MOFs), including PDMS/MIL-101 and PDMS/MOF-199, were immobilized onto a stainless steel wire through sol-gel technique as solid-phase microextraction (SPME) fiber coating. The prepared fibers were used for the extraction of some polycyclic aromatic hydrocarbons (PAHs) from water samples prior to gas chromatography-mass spectrometry (GC-MS) analysis. Under the optimized experiment conditions, the PDMS/MIL-101 coated fiber exhibited higher extraction efficiency towards PAHs than that of PDMS/MOF-199. Several parameters affecting the extraction of PAHs by SPME with PDMS/MIL-101 fiber, including the extraction temperature, extraction time, sample volume, salt addition and desorption conditions, were investigated. The limits of detection (LODs) were less than 4.0 ng L(-1) and the linearity was observed in the range from 0.01 to 2.0 µg L(-1) with the correlation coefficients (r) ranging from 0.9940 to 0.9986. The recoveries of the method for the PAHs from water samples at spiking levels of 0.05 and 0.2 µg L(-1) ranged from 78.2% to 110.3%. Single fiber repeatability and fiber-to-fiber reproducibility were less than 9.3% and 13.8%, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

A Combined Experimental and Computational Study on the Stability of Nanofluids Containing Metal Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annapureddy, Harsha Vardhan Reddy; Nune, Satish K.; Motkuri, Radha K.

2015-01-08

Computational studies on nanofluids composed of metal organic frameworks (MOFs) were performed using molecular modeling techniques. Grand Canonical Monte Carlo (GCMC) simulations were used to study adsorption behavior of 1,1,1,3,3-pentafluoropropane (R-245fa) in a MIL-101 MOF at various temperatures. To understand the stability of the nanofluid composed of MIL-101 particles, we performed molecular dynamics simulations to compute potentials of mean force between hypothetical MIL-101 fragments terminated with two different kinds of modulators in R-245fa and water. Our computed potentials of mean force results indicate that the MOF particles tend to disperse better in water than in R-245fa. The reasons for thismore » observation were analyzed and discussed. Our results agree with experimental results indicating that the employed potential models and modeling approaches provide good description of molecular interactions and the reliabilities. Work performed by LXD was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Work performed by HVRA, SKN, RKM, and PBM was supported by the Office of Energy Efficiency and Renewable Energy, Geothermal Technologies Program. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for DOE by Battelle.« less

Fe-based MOFs for efficient adsorption and degradation of acid orange 7 in aqueous solution via persulfate activation

NASA Astrophysics Data System (ADS)

Li, Xianghui; Guo, Weilin; Liu, Zhonghua; Wang, Ruiqin; Liu, Hua

2016-04-01

Fe-based metal-organic frameworks (MOFs) including MIL-101(Fe), MIL-100(Fe), MIL-53(Fe), and MIL-88B(Fe) prepared via a facile solvothermal process were introduced as both adsorbents and catalysts to generate powerful radicals from persulfate for acid orange 7 (AO7) removal in aqueous solution. Various catalysts were described and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectra. Because of the high specific surface area of the materials, we studied the adsorption isotherms of the four MILs by the fitting of Langmuir adsorption isotherm. Meanwhile, the catalytic activities in persulfate oxidation system were investigated. The results showed that the sequence of the materials ability in the combination of adsorption and degradation was MIL-101(Fe) > MIL-100(Fe) > MIL-53(Fe) > MIL-88B(Fe), which had a close connection with the activity of metal ion in active site of the catalysts and their different cages in size. Moreover, the reactive species in MILs/persulfate system were identified as sulfate radicals and hydroxyl radicals. The reaction mechanism for persulfate activation over MILs was also studied.

Functionalized MIL-101 with imidazolium-based ionic liquids for the cycloaddition of CO2 and epoxides under mild condition

NASA Astrophysics Data System (ADS)

Liu, Dan; Li, Gang; Liu, Haiou

2018-01-01

A kind of multi-functional sites metal-organic framework (MOF) composite (MIL-101-IMBr) was successfully prepared by post-synthesis modification of MIL-101 with imidazolium-based ionic liquids. The ionic liquids not only functionalize as basic sites but also provide halide anions, which serve as a nucleophile in cycloaddition reaction. The prepared functional MOF materials were characterized by X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, N2 adsorption-desorption and CO2 temperature programmed desorption. The results of fourier transform infrared spectroscopy and energy dispersive spectroscopy show that the MIL-101-IMBr composite was successfully synthesized. The N2 adsorption-desorption results clearly demonstrated that the modified composites still preserve high BET surface area and total pore volume. The composite exhibits high catalytic activity for the cycloaddition of CO2 with epoxides under mild and co-catalyst free conditions. The conversion of propylene oxide was 95.8% and the selectivity of cyclic carbonate was 97.6% under 0.8 MPa at 80 °C for 4 h. Moreover, the catalyst can be used for at least five times.

Immobilizing Highly Catalytically Active Pt Nanoparticles inside the Pores of Metal-Organic Framework: A Double Solvents Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aijaz, Arshad; Karkamkar, Abhijeet J.; Choi, Young Joon

2012-08-29

Ultrafine Pt nanoparticles were successfully immobilized inside the pores of a metal-organic framework MIL-101 without deposition of Pt nanoparticles on the external surfaces of framework by using a 'double solvents' method. The resulting Pt@MIL-101 composites with different Pt loadings represent the first highly active MOF-immobilized metal nanocatalysts for catalytic reactions in all three phases: liquid-phase ammonia borane hydrolysis; solid-phase ammonia borane thermal dehy-drogenation and gas-phase CO oxidation. The observed excellent catalytic performances are at-tributed to the small Pt nanoparticles within the pores of MIL-101. 'We are thankful to AIST and METI for financial support. TA & AK are thankful formore » support from the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. PNNL is operated by Battelle.'« less

Metal-organic framework MIL-101(Cr) as a sorbent of porous membrane-protected micro-solid-phase extraction for the analysis of six phthalate esters from drinking water: a combination of experimental and computational study.

PubMed

Wang, Ting; Wang, Jian; Zhang, Conglu; Yang, Zhao; Dai, Xinpeng; Cheng, Maosheng; Hou, Xiaohong

2015-08-07

An attractive metal-organic framework (MOF) MIL-101(Cr) material was synthesized at the nanoscale and applied as a sorbent in the porous membrane-protected micro-solid-phase extraction (μ-SPE) device for the pre-concentration of phthalate esters (PAEs) in drinking water samples for the first time. Parameters influencing the extraction efficiency, such as the selection of sorbent materials, pH adjustment, the effect of salt, magnetic-stirring extraction time, the desorption solvent and the desorption time, were investigated. Under the optimum conditions, the limits of detection from gas chromatography-mass spectrometric analysis for PAEs varied from 0.004 to 0.02 μg L(-1). The linear ranges were from 0.1 to 50 μg L(-1) or from 0.2 to 50 μg L(-1) for the analytes with the relative standard deviations fluctuating from 0.8 to 10.9% (n = 5). The enrichment factors (EFs) for the target PAEs were varied from 143 to 187. MIL-101(Cr) exhibited remarkable advantages compared to activated carbon and MIL-100(Fe). On the other hand, the computational method was first used to predict the adsorption of MIL-101(Cr) towards PAEs. The molecular interactions and the free binding energies between MIL-101(Cr) and PAEs were observed and calculated in terms of the molecular modeling method. MIL-101(Cr) showed high potential in the analysis of PAEs at trace levels in drinking water. The computational result was consistent with the detected enrichment factors. The computational modeling accurately predicted the extraction efficiency of MOF-based material towards the target analytes. Therefore, the combination of experimental and computational study provided a new strategy on the trace contaminant analysis.

Strategies for Enhancing the Catalytic Performance of Metal-Organic Frameworks in the Fixation of CO2 into Cyclic Carbonates.

PubMed

Taherimehr, Masoumeh; Van de Voorde, Ben; Wee, Lik H; Martens, Johan A; De Vos, Dirk E; Pescarmona, Paolo P

2017-03-22

Metal-organic frameworks (MOFs) with accessible Lewis acid sites are finding increasing application in the field of heterogeneous catalysis. However, the structural instability of MOFs when they are exposed to high temperature and/or high pressure often limits their applicability. In this study, two strategies were applied to achieve a MOF catalyst with high stability, activity and selectivity in the reaction of CO 2 with styrene oxide to produce styrene carbonate. In the first approach, a MOF with linkers with high connectivity as MIL-100(Cr) was studied, leading to promising activity and recyclability in consecutive catalytic runs without loss of activity. In the second strategy, a MOF with linkers with lower connectivity but with encapsulated Keggin phosphotungstic acid (MIL-101(Cr)[PTA]) was prepared. However, the activity of this catalyst decreased upon reuse as a consequence of deterioration of the MOF. Further investigations were dedicated to the enhancement of the catalytic performance of MIL-100 and included the variation of the metal centre as well as the type and loading of organic salt acting as nucleophile source. This allowed tuning the nature of the organic halide to the specific porous structure of MIL-100(Cr) to prevent diffusion limitations. The best catalytic performance was obtained for MIL-100(Cr) in combination with EMIMBr ionic liquid, which gave very high styrene carbonate yield (94 %) with complete selectivity after 18 h of reaction at mild temperature (60 °C). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal-Organic Framework-Polymer Composite as a Highly Efficient Sorbent for Sulfonamide Adsorption and Desorption: Effect of Coordinatively Unsaturated Metal Site and Topology.

PubMed

Shih, Yung-Han; Wang, Kuen-Yun; Singco, Brenda; Lin, Chia-Her; Huang, Hsi-Ya

2016-11-08

In this study, we first demonstrated the effect of two types of metal-organic framework-polymer (MOF-polymer) monoliths on in-tube solid-phase microextraction (IT-SPME) of sulfonamides. Sulfonamides were successfully adsorbed onto MIL-101(Cr)-polymer but were difficult to elute due to these sulfonamides could interact via Lewis acid-base interaction with the presence of Cr(III) coordinatively unsaturated metal sites (CUS). Moreover, the cage-type topology of MIL-101(Cr) that could produce multiple pathways thus complicates the desorption of the test analytes from the sorbent. Contrastingly, MIL-53(Al)-polymer provided weaker Al(III) CUS, and its one-dimensional channel pore structure could provide an unhindered pathway for sulfonamides transfer during elution. After optimizing the IT-SPME condition such as MOF content, pH of sample matrix, column length, extraction flow rate, and elution volume, the calculated extraction recovery of sulfonamides in MIL-53(Al)-polymer as analyzed by microemulsion electrokinetic chromatography (MEEKC) were in the range of 40%-90% with relative standard deviations (RSDs) below 5% and a reusability of at least 30 times.

Heterogeneous epoxide carbonylation by cooperative ion-pair catalysis in Co(CO) 4 –-incorporated Cr-MIL-101

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Hoyoung D.; Dinca, Mircea; Roman-Leshkov, Yuriy

Here, despite the commercial desirability of epoxide carbonylation to β-lactones, the reliance of this process on homogeneous catalysts makes its industrial application challenging. Here we report the preparation and use of a Co(CO) 4 –-incorporated Cr-MIL-101 (Co(CO) 4cCr-MIL-101, Cr-MIL-101 = Cr 3O(BDC) 3F, H2BDC = 1,4-benzenedicarboxylic acid) heterogeneous catalyst for the ring-expansion carbonylation of epoxides, whose activity, selectivity, and substrate scope are on par with those of the reported homogeneous catalysts. We ascribe the observed performance to the unique cooperativity between the postsynthetically introduced Co(CO) 4 – and the site-isolated Lewis acidic Cr(III) centers in the metal–organic framework (MOF). Themore » heterogeneous nature of Co(CO) 4cCr-MIL-101 allows the first demonstration of gas-phase continuous-flow production of β-lactones from epoxides, attesting to the potential applicability of the heterogeneous epoxide carbonylation strategy.« less

Heterogeneous epoxide carbonylation by cooperative ion-pair catalysis in Co(CO) 4 –-incorporated Cr-MIL-101

DOE PAGES

Park, Hoyoung D.; Dinca, Mircea; Roman-Leshkov, Yuriy

2017-03-21

Here, despite the commercial desirability of epoxide carbonylation to β-lactones, the reliance of this process on homogeneous catalysts makes its industrial application challenging. Here we report the preparation and use of a Co(CO) 4 –-incorporated Cr-MIL-101 (Co(CO) 4cCr-MIL-101, Cr-MIL-101 = Cr 3O(BDC) 3F, H2BDC = 1,4-benzenedicarboxylic acid) heterogeneous catalyst for the ring-expansion carbonylation of epoxides, whose activity, selectivity, and substrate scope are on par with those of the reported homogeneous catalysts. We ascribe the observed performance to the unique cooperativity between the postsynthetically introduced Co(CO) 4 – and the site-isolated Lewis acidic Cr(III) centers in the metal–organic framework (MOF). Themore » heterogeneous nature of Co(CO) 4cCr-MIL-101 allows the first demonstration of gas-phase continuous-flow production of β-lactones from epoxides, attesting to the potential applicability of the heterogeneous epoxide carbonylation strategy.« less

An efficient and sensitive fluorescent pH sensor based on amino functional metal-organic frameworks in aqueous environment.

PubMed

Xu, Xiao-Yu; Yan, Bing

2016-04-28

A pH sensor is fabricated via a reaction between an Al(III) salt and 2-aminoterephthalic acid in DMF which leads to a MOF (Al-MIL-101-NH2) with free amino groups. The Al-MIL-101-NH2 samples show good luminescence and an intact structure in aqueous solutions with pH ranging from 4.0 to 7.7. Given its exceptional stability and pH-dependent fluorescence intensity, Al-MIL-101-NH2 has been applied to fluorescent pH sensing. Significantly, in the whole experimental pH range (4.0-7.7), the fluorescence intensity almost increases with increasing pH (R(2) = 0.99688) which can be rationalized using a linear equation: I = 2.33 pH + 26.04. In addition, error analysis and cycling experiments have demonstrated the accuracy and utilizability of the sensor. In practical applications (PBS and lake water), Al-MIL-101-NH2 also manifests its analytical efficiency in pH sensing. And the samples can be easily isolated from an aqueous solution by incorporating Fe3O4 nanoparticles. Moreover, the possible sensing mechanism based on amino protonation is discussed in detail. This work is on of the few cases for integrated pH sensing systems in aqueous solution based on luminescent MOFs.

A combination of computational-experimental study on metal-organic frameworks MIL-53(Al) as sorbent for simultaneous determination of estrogens and glucocorticoids in water and urine samples by dispersive micro-solid-phase extraction coupled to UPLC-MS/MS.

PubMed

Gao, Guihua; Li, Sijia; Li, Shuo; Wang, Yudan; Zhao, Pan; Zhang, Xiangyu; Hou, Xiaohong

2018-04-01

In this work, computational and experimental methods were used to study the adsorption of estrogens and glucocorticoids on metal-organic frameworks (MOFs). Computer-aided molecular simulation was applied to predict the adsorption of eight analytes on four MOFs (MIL-101(Cr), MIL-100(Fe), MIL-53(Al), and UiO-66(Zr)) by examining molecular interactions and calculating free binding energies. Subsequently, the four water-stable MOFs were synthesized and evaluated as adsorbents for the target hormones in aqueous solution. As the MOF exhibiting the highest adsorption capacity in both computations and experiments, MIL-53(Al) was chosen as a sorbent to develop a dispersive micro-solid-phase extraction procedure coupled to ultra-performance liquid chromatography tandem mass spectrometry for simultaneous determination of the target analytes in water and human urine samples. Experimental parameters affecting the extraction recoveries, including pH, ionic strength, MIL-53(Al) amount, extraction time, desorption time, and desorption solvent, were optimized. The optimized method provided a linear range of 0.005025-368.6μg/L with good correlation coefficients (0.9982 ≤ r 2 ≤ 0.9992), and limits of detection (S/N = 3) and quantification (S/N = 10) of 0.0015-1.0μg/L and 0.005-1.8μg/L, respectively. The analyte recoveries were in the range of 80.6-98.4% in water samples and 88.4-93.2% in urine samples. Furthermore, MIL-53(Al) showed good stability over 10 extraction cycles (RSD < 10.0%). Good agreement between experimental measurements and computational results showed the potential of this approach for elucidating adsorption mechanisms and predicating extraction efficiencies for MOFs and targets, providing new directions for the development and utilization of MOFs. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficient detection of hazardous catechol and hydroquinone with MOF-rGO modified carbon paste electrode.

PubMed

Wang, Hailong; Hu, Quanqin; Meng, Yuan; Jin, Zier; Fang, Zilin; Fu, Qinrui; Gao, Wenhua; Xu, Liang; Song, Yibing; Lu, Fushen

2018-02-19

Reduced graphite oxide (rGO) was incorporated into a metal organic framework (MOF) MIL-101(Cr) for the modification of carbon paste electrode. Taking advantages of the large surface area of MOF and the electrical conductivity of rGO, the resulted electrodes exhibited high sensitivity and reliability in the simultaneous electrochemical identification and quantification of catechol (CC) and hydroquinone (HQ). Specifically, in the mixture solution of catechol and hydroquinone (constant concentration of an analyte), the linear response ranges for catechol and hydroquinone were 10-1400 μM and 4-1000 μM, and detection limits were 4 μM and 0.66 μM (S/N = 3) for individual catechol and hydroquinone, respectively. Therefore, the relatively easy fabrication of modified CPE and its fascinating reliability towards HQ and CC detection may simulate more research interest in the applications of MIL-101(Cr)-rGO composites for electrochemical sensors. Copyright © 2018 Elsevier B.V. All rights reserved.

Adsorptive removal of naproxen and clofibric acid from water using metal-organic frameworks.

PubMed

Hasan, Zubair; Jeon, Jaewoo; Jhung, Sung Hwa

2012-03-30

Adsorptive removal of naproxen and clofibric acid, two typical PPCPs (pharmaceuticals and personal care products), has been studied using metal-organic frameworks (MOFs) for the first time. The removal efficiency decreases in the order of MIL-101>MIL-100-Fe>activated carbon both in adsorption rate and adsorption capacity. The adsorption kinetics and capacity of PPCPs generally depend on the average pore size and surface area (or pore volume), respectively, of the adsorbents. The adsorption mechanism may be explained with a simple electrostatic interaction between PPCPs and the adsorbent. Finally, it can be suggested that MOFs having high porosity and large pore size can be potential adsorbents to remove harmful PPCPs in contaminated water. Copyright © 2012 Elsevier B.V. All rights reserved.

Salen- Zr(IV) complex grafted into amine-tagged MIL-101(Cr) as a robust multifunctional catalyst for biodiesel production and organic transformation reactions

NASA Astrophysics Data System (ADS)

Hassan, Hassan M. A.; Betiha, Mohamed A.; Mohamed, Shaimaa K.; El-Sharkawy, E. A.; Ahmed, Emad A.

2017-08-01

The synthesis of metal-organic frameworks (MOFs), porous coordination polymers with functional groups has received immense interest due to the functional groups can offer desirable properties and allow post-synthetic modification. Herein, for the first time, Zr(IV)-Sal Schiff base complex incorporated into amino-functionalized MIL-101(Cr) framework by salicylaldehyde condensing to amino group, and coordinating Zr(IV) ion have been successfully synthesized. The worthiness of the synthesized material as a catalyst has been examined for the esterification of oleic acid (free fatty acid) with methanol producing biodiesel (methyl oleate), Knoveonagel condensation reaction of aldehydes and Friedel-Crafts acylation of anisole. Our findings demonstrated that Salen-Zr(IV) grafted to framework of NH2-MIL-101(Cr) as a solid acid catalyst exhibited distinct catalytic performance for the production of biodiesel by esterification of oleic acid with methanol, Knoveonagel condensation and Friedel-Crafts acylation. These could be attributed to high surface area which allow high distribution of Zr(IV) species lead to a sufficient contact with the reactants species. Furthermore, the catalyst showed excellent recycling efficiency due to the strong interaction between the Zr(IV) ions and chelating groups in the NH2-MIL-101(Cr)-Sal.

Photothermal Activation of Metal-Organic Frameworks Using a UV-Vis Light Source.

PubMed

Espín, Jordi; Garzón-Tovar, Luis; Carné-Sánchez, Arnau; Imaz, Inhar; Maspoch, Daniel

2018-03-21

Metal-organic frameworks (MOFs) usually require meticulous removal of the solvent molecules to unlock their potential porosity. Herein, we report a novel one-step method for activating MOFs based on the photothermal effect induced by directly irradiating them with a UV-vis lamp. The localized light-to-heat conversion produced in the MOF crystals upon irradiation enables a very fast solvent removal, thereby significantly reducing the activation time to as low as 30 min and suppressing the need for time-consuming solvent-exchange procedures and vacuum conditions. This approach is successful for a broad range of MOFs, including HKUST-1, UiO-66-NH 2 , ZIF-67, CPO-27-M (M = Zn, Ni, and Mg), Fe-MIL-101-NH 2 , and IRMOF-3, all of which exhibit absorption bands in the light emission range. In addition, we anticipate that this photothermal activation can also be used to activate covalent organic frameworks (COFs).

Isotropic and Anisotropic Growth of Metal-Organic Framework (MOF) on MOF: Logical Inference on MOF Structure Based on Growth Behavior and Morphological Feature.

PubMed

Choi, Sora; Kim, Taeho; Ji, Hoyeon; Lee, Hee Jung; Oh, Moonhyun

2016-11-02

The growth of one metal-organic framework (MOF) on another MOF for constructing a heterocompositional hybrid MOF is an interesting research topic because of the curiosity regarding the occurrence of this phenomenon and the value of hybrid MOFs as multifunctional materials or routes for fine-tuning MOF properties. In particular, the anisotropic growth of MOF on MOF is fascinating for the development of MOFs possessing atypical shapes and heterostructures or abnormal properties. Herein, we clarify the understanding of growth behavior of a secondary MOF on an initial MOF template, such as isotropic or anisotropic ways associated with their cell parameters. The isotropic growth of MIL-68-Br on the MIL-68 template results in the formation of core-shell-type MIL-68@MIL-68-Br. However, the unique anisotropic growth of a secondary MOF (MOF-NDC) on the MIL-68 template results in semitubular particles, and structural features of this unknown secondary MOF are successfully speculated for the first time on the basis of its unique growth behavior and morphological characteristics. Finally, the validation of this structural speculation is verified by the powder X-ray diffraction and the selected area electron diffraction studies. The results suggests that the growth behavior and morphological features of MOFs should be considered to be important factors for understanding the MOFs' structures.

Elaboration and properties of hierarchically structured optical thin films of MIL-101(Cr).

PubMed

Demessence, Aude; Horcajada, Patricia; Serre, Christian; Boissière, Cédric; Grosso, David; Sanchez, Clément; Férey, Gérard

2009-12-14

Stable nanoparticles dispersions of the porous hybrid MIL-101(Cr) allow dip-coating of high quality optical thin films with dual hierarchical porous structure. Moreover, for the first time, mechanical and sorption properties of mesoporous MOFs based thin films are evaluated.

Highly Selective Adsorption of Ethylene over Ethane in a MOF Featuring the Combination of Open Metal Site and -Complexation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yiming; Li, Baiyan; Wu, Zili

The introduction of the combination of open metal site (OMS) and -complexation into MOF has led to very high ethylene/ethane adsorption selectivity at 318K, as illustrated in the context of MIL-101-Cr-SO 3Ag. The interactions with ethylene from both OMS and -complexation in MIL-101-Cr-SO 3Ag have been investigated by in situ IR spectroscopic studies and computational calculations, which suggest -complexation contributes dominantly to the high ethylene/ethane adsorption selectivity.

Highly Selective Adsorption of Ethylene over Ethane in a MOF Featuring the Combination of Open Metal Site and -Complexation

DOE PAGES

Zhang, Yiming; Li, Baiyan; Wu, Zili; ...

2015-01-09

The introduction of the combination of open metal site (OMS) and -complexation into MOF has led to very high ethylene/ethane adsorption selectivity at 318K, as illustrated in the context of MIL-101-Cr-SO 3Ag. The interactions with ethylene from both OMS and -complexation in MIL-101-Cr-SO 3Ag have been investigated by in situ IR spectroscopic studies and computational calculations, which suggest -complexation contributes dominantly to the high ethylene/ethane adsorption selectivity.

Formation mechanism of the secondary building unit in a chromium terephthalate metal-organic framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cantu Cantu, David; McGrail, B. Peter; Glezakou, Vassiliki Alexandra

2014-09-18

Based on density functional theory calculations and simulation, a detailed mechanism is presented on the formation of the secondary building unit (SBU) of MIL-101, a chromium terephthalate metal-organic framework (MOF). SBU formation is key to MOF nucleation, the rate-limiting step in the formation process of many MOFs. A series of reactions that lead to the formation of the SBU of MIL-101 is proposed in this work. Initial rate-limiting reactions form the metal cluster with three chromium (III) atoms linked to a central bridging oxygen. Terephthalate linkers play a key role as chromium (III) atoms are joined to linker carboxylate groupsmore » prior to the placement of the central bridging oxygen. Multiple linker addition reactions, which follow in different paths due to structural isomers, are limited by the removal of water molecules in the first chromium coordination shell. The least energy path is identified were all linkers on one face of the metal center plane are added first. A simple kinetic model based on transition state theory shows the rate of secondary building unit formation similar to the rate metal-organic framework nucleation. The authors are thankful to Dr. R. Rousseau for a critical reading of the manuscript. This research would not have been possible without the support of the Office of Fossil Energy, U.S. Department of Energy. This research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and the PNNL Institutional Computing (PIC) program located at Pacific Northwest National Laboratory.« less

Magnetic solid-phase extraction of triazine herbicides from rice using metal-organic framework MIL-101(Cr) functionalized magnetic particles.

PubMed

Liang, Li; Wang, Xinghua; Sun, Ying; Ma, Pinyi; Li, Xinpei; Piao, Huilan; Jiang, Yanxiao; Song, Daqian

2018-03-01

The metal-organic framework (MOF) functionalized magnetic graphene oxide/mesoporous silica composites (Fe 3 O 4 @SiO 2 -GO/MIL-101(Cr)) were synthesized and utilized as magnetic solid-phase extraction (MSPE) adsorbent for the extraction of seven triazine herbicides (terbuthylazine, secbumeton, terbumeton, atraton, atrazine, prometon and trietazine) in rice samples. Several experimental parameters, including type and volume of extraction solvent, amount of MIL-101(Cr), extraction time, volume of desorption solvent and desorption time were investigated and optimized. The limits of detection (LODs) of seven triazine herbicides obtained by using the proposed MSPE method combined with high performance liquid chromatography (HPLC) were in the range of 0.010-0.080µgkg -1 . The recoveries of the triazine herbicides in spiked rice samples ranged from of 83.9-103.5% with the relative standard deviations lower than 8.7%. The intra and inter-day (n = 6) precisions for all triazine herbicides at the spiked level of 100.0µgkg -1 were 1.4-5.9% and 2.6-7.8%, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular Level Characterization of the Structure and Interactions in Peptide-Functionalized Metal-Organic Frameworks.

PubMed

Todorova, Tanya K; Rozanska, Xavier; Gervais, Christel; Legrand, Alexandre; Ho, Linh N; Berruyer, Pierrick; Lesage, Anne; Emsley, Lyndon; Farrusseng, David; Canivet, Jérôme; Mellot-Draznieks, Caroline

2016-11-07

We use density functional theory, newly parameterized molecular dynamics simulations, and last generation 15 N dynamic nuclear polarization surface enhanced solid-state NMR spectroscopy (DNP SENS) to understand graft-host interactions and effects imposed by the metal-organic framework (MOF) host on peptide conformations in a peptide-functionalized MOF. Focusing on two grafts typified by MIL-68-proline (-Pro) and MIL-68-glycine-proline (-Gly-Pro), we identified the most likely peptide conformations adopted in the functionalized hybrid frameworks. We found that hydrogen bond interactions between the graft and the surface hydroxyl groups of the MOF are essential in determining the peptides conformation(s). DNP SENS methodology shows unprecedented signal enhancements when applied to these peptide-functionalized MOFs. The calculated chemical shifts of selected MIL-68-NH-Pro and MIL-68-NH-Gly-Pro conformations are in a good agreement with the experimentally obtained 15 N NMR signals. The study shows that the conformations of peptides when grafted in a MOF host are unlikely to be freely distributed, and conformational selection is directed by strong host-guest interactions. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A multifunctional metal-organic framework based tumor targeting drug delivery system for cancer therapy

NASA Astrophysics Data System (ADS)

Wang, Xiao-Gang; Dong, Zhi-Yue; Cheng, Hong; Wan, Shuang-Shuang; Chen, Wei-Hai; Zou, Mei-Zhen; Huo, Jia-Wei; Deng, He-Xiang; Zhang, Xian-Zheng

2015-09-01

Drug delivery systems (DDSs) with biocompatibility and precise drug delivery are eagerly needed to overcome the paradox in chemotherapy that high drug doses are required to compensate for the poor biodistribution of drugs with frequent dose-related side effects. In this work, we reported a metal-organic framework (MOF) based tumor targeting DDS developed by a one-pot, and organic solvent-free ``green'' post-synthetic surface modification procedure, starting from the nanoscale MOF MIL-101. Owing to the multifunctional surface coating, premature drug release from this DDS was prevented. Due to the pH responsive benzoic imine bond and the redox responsive disulfide bond at the modified surface, this DDS exhibited tumor acid environment enhanced cellular uptake and intracellular reducing environment triggered drug release. In vitro and in vivo results showed that DOX loaded into this DDS exhibited effective cancer cell inhibition with much reduced side effects.Drug delivery systems (DDSs) with biocompatibility and precise drug delivery are eagerly needed to overcome the paradox in chemotherapy that high drug doses are required to compensate for the poor biodistribution of drugs with frequent dose-related side effects. In this work, we reported a metal-organic framework (MOF) based tumor targeting DDS developed by a one-pot, and organic solvent-free ``green'' post-synthetic surface modification procedure, starting from the nanoscale MOF MIL-101. Owing to the multifunctional surface coating, premature drug release from this DDS was prevented. Due to the pH responsive benzoic imine bond and the redox responsive disulfide bond at the modified surface, this DDS exhibited tumor acid environment enhanced cellular uptake and intracellular reducing environment triggered drug release. In vitro and in vivo results showed that DOX loaded into this DDS exhibited effective cancer cell inhibition with much reduced side effects. Electronic supplementary information (ESI) available: Synthesis procedure, 1HNMR, ESI-MS and additional data. See DOI: 10.1039/c5nr04045k

Photoreactivity of Metal-Organic Frameworks in Aqueous Solutions: Metal Dependence of Reactive Oxygen Species Production.

PubMed

Liu, Kai; Gao, Yanxin; Liu, Jing; Wen, Yifan; Zhao, Yingcan; Zhang, Kunyang; Yu, Gang

2016-04-05

Promising applications of metal-organic frameworks (MOFs) in various fields have raised concern over their environmental fate and safety upon inevitable discharge into aqueous environments. Currently, no information regarding the transformation processes of MOFs is available. Due to the presence of repetitive π-bond structure and semiconductive property, photochemical transformations are an important fate process that affects the performance of MOFs in practical applications. In the current study, the generation of reactive oxygen species (ROS) in isoreticular MIL-53s was studied. Scavengers were employed to probe the production of (1)O2, O2(•-), and •OH, respectively. In general, MIL-53(Cr) and MIL-53(Fe) are dominated by type I and II photosensitization reactions, respectively, and MIL-53(Al) appears to be less photoreactive. The generation of ROS in MIL-53(Fe) may be underestimated due to dismutation. Further investigation of MIL-53(Fe) encapsulated diclofenac transformation revealed that diclofenac can be easily transformed by MIL-53(Fe) generated ROS. However, the cytotoxicity results implied that the ROS generated from MIL-53s have little effect on the viability of the human hepatocyte (HepG2) cell line. These results suggest that the photogeneration of ROS by MOFs may be metal-node dependent, and the application of MIL-53s as drug carriers needs to be carefully considered due to their high photoreactivity.

Metal organic frameworks (MOFs) for magnetic solid-phase extraction of pyrazole/pyrrole pesticides in environmental water samples followed by HPLC-DAD determination.

PubMed

Ma, Jiping; Yao, Zhidan; Hou, Liwei; Lu, Wenhui; Yang, Qipeng; Li, Jinhua; Chen, Lingxin

2016-12-01

Magnetic metal-organic frameworks (MOFs, [MIL-101]) were prepared and used as magnetic solid-phase extraction (MSPE) adsorbents for preconcentration of four kinds of pyrazole/pyrrole pesticides (flusilazole, fipronil, chlorfenapyr, and fenpyroximate) in environmental water samples, followed by high-performance liquid chromatography-diode-array detector (HPLC-DAD) determination. Several variables affecting MSPE efficiency were systematically investigated, including amount of MIL-101, extraction time, sample pH, salt concentration, type of desorption solvent and desorption number of times. Under optimized conditions, excellent linearity was achieved in the range of 5.0-200.0μg/L for flusilazole and fipronil, and 2.0-200.0μg/L for chlorfenapyr and fenpyroximate, with correlation coefficients r>0.9911. Limits of detection and quantification were 0.3-1.5μg/L and 1.0-5.0μg/L, respectively. The intra-day and inter-day precision (relative standard deviation, n=6, %) at three spiked levels were 1.1-5.4% and 3.9-7.8% in terms of peak area, respectively. The method recoveries at three fortified concentration levels ranged from 81.8% to 107.5% for reservoir water samples, 81.0-99.5% for river water samples, and 80.2-106.5% for seawater samples. The developed MOFs based MSPE coupled with HPLC method proved to be a convenient, rapid and eco-friendly alternative to the sensitive determination of pyrazole/pyrrole pesticides with high repeatability and excellent practical applicability. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of Heterogeneous Metal-Organic Framework Organocatalysts Prepared by Postsynthetic Modification

PubMed Central

Garibay, Sergio J.; Wang, Zhenqiang; Cohen, Seth M.

2010-01-01

A metal-organic framework (MOF) containing 2-amino-1,4-benzenedicarboxylate (NH2-BDC) as a building block is shown to undergo chemical modification with a set of cyclic anhydrides. The modification of the aluminum-based MOF known as MIL-53(Al)-NH2 (MIL = Matérial Institut Lavoisier) by these reagents is demonstrated by using a variety of methods, including NMR and ESI-MS, and the structural integrity of the modified MOFs has been confirmed by TGA, PXRD, and gas sorption analysis. Reaction with these cyclic anhydrides produces MOFs that display carboxylic acid functional groups within their pores. Furthermore, it is shown that maleic acid functionalized MIL-53(Al)-AMMal can act as a Brønsted acid catalyst and facilitate the methanolysis of several small epoxides. Experiments show that MIL-53(Al)-AMMal acts in a heterogeneous manner and is recyclable with consistent activity over at least three catalytic cycles. The findings presented here demonstrate several important features of covalent postsynthetic modification (PSM) on MOFs, including: 1) facile introduction of catalytic functionality using simple organic reagents (e.g. anhydrides); 2) the ability to utilize and recycle organocatalytic MOFs; 3) control of catalytic activity through choice of functional group. The findings clearly illustrate that covalent postsynthetic modification represents a powerful means to access new MOF compounds that serve as organocatalytic materials. PMID:20698561

The metal-organic framework MIL-101(Cr) as efficient adsorbent in a vortex-assisted dispersive solid-phase extraction of imatinib mesylate in rat plasma coupled with ultra-performance liquid chromatography/mass spectrometry: Application to a pharmacokinetic study.

PubMed

Qi, Chao; Cai, Qianqian; Zhao, Pan; Jia, Xiuna; Lu, Nan; He, Lu; Hou, Xiaohong

2016-06-03

Metal-organic framework MIL-101(Cr) was successfully used as an efficient sorbent in a vortex-assisted dispersive solid-phase extraction (VA-DSPE) and applied for the determination and the pharmacokinetic of imatinib mesylate in rat plasma by UPLC-MS/MS. In the enrichment of imatinib from rat plasma, the analyte was efficiently adsorbed on MIL-101(Cr) and simply recovered by using initial mobile phase (0.1% formic acid-methanol (6:4 v/v)) as elution solvent. Meanwhile, the protein in the plasma samples was excluded from the porous structure of MIL-101(Cr), leading to direct extraction of drug molecule from protein-rich biological samples without any other pretreatment procedure. After being removed, the supernatant was filtered and directly injected into the UPLC-MS/MS for the analysis of the target. The experimental parameters, including nature of MOFs, amount of MIL-101(Cr), pH value of aqueous solution, extraction time, type and volume of elution solvent, were systematically optimized. After VA-DSPE, chromatographic separation was performed on an ACQUITY UPLC(®) BEH C18 column (2.1mm×100mm, 1.7μm) with a 3min gradient elution using 0.1% formic acid and methanol as mobile phase at a flow rate of 0.3mL/min. The detection was accomplished on a tandem mass spectrometer via an electrospray ionization (ESI) source by multiple reaction monitoring (MRM) in the positive ionization mode. The lower limit of quantification of 1ng/mL was achieved and the mean recovery of the analyte was higher than 81.2%. Moreover, computational simulation was primarily applied to predict the adsorption behavior and revealed the molecular interactions and free binding energies between MIL-101(Cr) and imatinib with the molecular modeling method, providing certain explanation of the adsorption mechanism. The originally established pretreatment and detection method has some merits, such as less solvent consumption, easy operation, higher sensitivity and lower matrix effect. And the MIL-101(Cr) exhibited a potential as an efficient sorbent in the enrichment of the analyte from complex biosamples. Copyright © 2016 Elsevier B.V. All rights reserved.

Aluminum based metal-organic framework-polymer monolith in solid-phase microextraction of penicillins in river water and milk samples.

PubMed

Lirio, Stephen; Liu, Wan-Ling; Lin, Chen-Lan; Lin, Chia-Her; Huang, Hsi-Ya

2016-01-08

In this study, aluminum based metal-organic framework (Al-MOF)-organic polymer monoliths were prepared via microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA) with different weight percentages of Al-MOF (MIL-53; 37.5-62.5%) and subsequently utilized as sorbent in solid-phase microextraction (SPME) of penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin). The Al-MOF-polymer was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-energy-dispersive X-ray spectroscopy (SEM-EDS) to clarify the retained crystalline structure well as the homogeneous dispersion of Al-MOF (MIL-53) in polymer monolith. The developed Al-MOF-polymer (MIL-53) monolithic column was evaluated according to its extraction recovery of penicillins. Several parameters affecting the extraction recoveries of penicillins using fabricated Al-MOF-polymer (MIL-53) monolithic column including different MIL-53 weight percentages, column length, pH, desorption solvent, and mobile phase flow rate were investigated. For comparison, different Al-based MOFs (MIL-68, CYCU-4 and DUT-5) were fabricated using the optimized condition for MIL-53-polymer (sample matrix at pH 3, 200μL desorption volume using methanol, 37.5% of MOF, 4-cm column length at 0.100mLmin(-1) flow rate). Among all the Al-MOF-polymers, MIL-53(Al)-polymer still afforded the best extraction recovery for penicillins ranging from 90.5 to 95.7% for intra-day with less than 3.5% relative standard deviations (RSDs) and inter-day precision were in the range of 90.7-97.6% with less than 4.2% RSDs. Meanwhile, the recoveries for column-to-column were in the range of 89.5-93.5% (<3.4% RSDs) while 88.5-90.5% (<5.8% RSDs) for batch-to-batch (n=3). Under the optimal conditions, the limit of detections were in the range of 0.06-0.26μgL(-1) and limit of quantifications between 0.20 and 0.87μgL(-1). Finally, the MIL-53-polymer was applied for the extraction of penicillin in river water and milk by spiking trace-level penicillin for as low as 50μgL(-1) and 100μgL(-1) with recoveries ranging from 80.8% to 90.9% (<6.7% RSDs) in river water and 81.1% to 100.7% (<7.1% RSDs) in milk sample, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Iron Containing Metal-Organic Frameworks: Structure, Synthesis, and Applications in Environmental Remediation.

PubMed

Liu, Xiaocheng; Zhou, Yaoyu; Zhang, Jiachao; Tang, Lin; Luo, Lin; Zeng, Guangming

2017-06-21

Metal-organic frameworks (MOFs) with Fe content are gradually developing into an independent branch in environmental remediation, requiring economical, effective, low-toxicity strategies to the complete procedure. In this review, recent advancements in the structure, synthesis, and environmental application focusing on the mechanism are presented. The unique structure of novel design proposed specific characteristics of different iron-containing MOFs with potential innovation. Synthesis of typical MILs, NH 2 -MILs and MILs based materials reveal the basis and defect of the current method, indicating the optimal means for the actual requirements. The adsorption of various contamination with multiple interaction as well as the catalytic degradation over radicals or electron-hole pairs are reviewed. This review implied considerable prospects of iron-containing MOFs in the field of environment and a more comprehensive cognition into the challenges and potential improvement.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buragohain, Amlan; Couck, Sarah; Van Der Voort, Pascal

Four existing and three new functionalized chromium terephthalates having MIL-101 topology and denoted as Cr-MIL-101-X (existing ones with X=–F, 1-F; –Cl, 2-Cl; –Br, 3-Br; –CH{sub 3}, 4-CH{sub 3}; new ones with X=–C{sub 6}H{sub 4}, 5-C{sub 6}H{sub 4}; –F{sub 2}, 6-F{sub 2}, –(CH{sub 3}){sub 2}, 7-(CH{sub 3}){sub 2}) were synthesized under hydrothermal conditions. All the materials except 5-C{sub 6}H{sub 4} could be prepared by a general synthetic route, in which the mixtures of CrO{sub 3}, H{sub 2}BDC-X (BDC=1,4-benzenedicarboxylate) linkers, conc. HCl and water with a molar ratio of 1:1:3.9:222.2 were reacted at 180 °C for 144 h. Compared to the 144more » h of synthesis time, three of the compounds, namely 1-Cl, 2-Br and 5-C{sub 6}H{sub 4}, could be prepared in much shorter reaction times (12–18 h at 180–210 °C). The materials possess high thermal stability up to 270–300 °C in an air atmosphere. The activated compounds exhibit significant porosity (S{sub BET} range: 1273–2135 m{sup 2} g{sup −1}). At 0 °C and 1 bar, the CO{sub 2} adsorption capacities of the compounds fall in the 1.7–2.9 mmol g{sup −1} range. Compounds 1-F and 6-F{sub 2} showed enhanced CO{sub 2} uptake values compared to parent Cr-MIL-101. The benzene adsorption capacities of the compounds lie in the range of 66.2–139.5 molecules per unit cell at 50 °C and p/p{sub 0}=0.35. The increased benzene uptake value of 1-F compared to un-functionalized Cr-MIL-101 and 4-CH{sub 3} suggests that the fluorination has induced more hydrophobicity in Cr-MIL-101 as compared to the methylation. - Graphical abstract: Benzene adsorption by seven functionalized Cr-MIL-101-X metal-organic framework (MOF) materials Display Omitted - Highlights: • Seven functionalized Cr-MIL-101-X materials were synthesized solvothermally. • All Cr-MIL-101-X materials exhibited high thermal stability up to 270–300 °C in air. • All Cr-MIL-101-X compounds displayed considerable porosity towards N{sub 2}, CO{sub 2} and benzene. • Mono- and di-fluorinated Cr-MIL-101 materials showed enhanced CO{sub 2} adsorption capacities. • Cr-MIL-101-F adsorbed more benzene than non- and methyl-functionalized Cr-MIL-101.« less

Metal-organic frameworks as potential shock absorbers: the case of the highly flexible MIL-53(Al).

PubMed

Yot, Pascal G; Boudene, Zoubeyr; Macia, Jasmine; Granier, Dominique; Vanduyfhuys, Louis; Verstraelen, Toon; Van Speybroeck, Veronique; Devic, Thomas; Serre, Christian; Férey, Gérard; Stock, Norbert; Maurin, Guillaume

2014-08-28

The mechanical energy absorption ability of the highly flexible MIL-53(Al) MOF material was explored using a combination of experiments and molecular simulations. A pressure-induced transition between the large pore and the closed pore forms of this solid was revealed to be irreversible and associated with a relatively large energy absorption capacity. Both features make MIL-53(Al) the first potential MOF candidate for further use as a shock absorber.

Protonated graphitic carbon nitride coated metal-organic frameworks with enhanced visible-light photocatalytic activity for contaminants degradation

NASA Astrophysics Data System (ADS)

Huang, Jie; Zhang, Xibiao; Song, Haiyan; Chen, Chunxia; Han, Fuqin; Wen, Congcong

2018-05-01

Most of the reported composites of g-C3N4/metal-organic frameworks (MOFs) were obtained via exfoliation of g-C3N4 and wrapping the nanosheets on MOFs with weak interaction. In this work, chemical protonation of g-C3N4 and dip-coating was adopted as a feasible pathway to achieve the real combination of g-C3N4 derivatives with a familiar MOF material MIL-100(Fe). Structural, chemical and photophysical properties of the novel hybrid photocatalysts were characterized and compared to those of the parent materials. It was verified that the protonated g-C3N4 species of appropriate content were uniformly coated along the frameworks of MIL-100(Fe) with strong interaction. The optimal materials maintained the intact framework structure, surface property and porosity of MIL-100(Fe), as well as the inherent structural units and physicochemical properties of C3N4. In comparison to the parent materials, the protonated g-C3N4 coated MIL-100(Fe) materials exhibited enhanced photocatalytic activity in degradation of rhodamine B or methylene blue dye, as well as in oxidative denitrogenation for pyridine by molecular oxygen under visible light. Introduction of protonated g-C3N4 on MOFs improved the adsorption ability for contaminant molecules. Furthermore, coating effect provided a platform for rapid photoexcited electrons transfer and superior separation of photogenerated electron-hole pairs. Photocatalytic conversion of the three contaminants followed different mechanisms.

Glucose recovery from aqueous solutions by adsorption in metal–organic framework MIL-101: a molecular simulation study

PubMed Central

Gupta, Krishna M.; Zhang, Kang; Jiang, Jianwen

2015-01-01

A molecular simulation study is reported on glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101. The F atom of MIL-101 is identified to be the most favorable adsorption site. Among three MIL-101-X (X = H, NH2 or CH3), the parent MIL-101 exhibits the highest adsorption capacity and recovery efficacy. Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose. The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility. Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed. The simulation study provides useful structural and dynamic properties of glucose in MIL-101, and it suggests that MIL-101 might be a potential candidate for glucose recovery. PMID:26242874

Glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101: a molecular simulation study

NASA Astrophysics Data System (ADS)

Gupta, Krishna M.; Zhang, Kang; Jiang, Jianwen

2015-08-01

A molecular simulation study is reported on glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101. The F atom of MIL-101 is identified to be the most favorable adsorption site. Among three MIL-101-X (X = H, NH2 or CH3), the parent MIL-101 exhibits the highest adsorption capacity and recovery efficacy. Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose. The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility. Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed. The simulation study provides useful structural and dynamic properties of glucose in MIL-101, and it suggests that MIL-101 might be a potential candidate for glucose recovery.

The studies on gas adsorption properties of MIL-53 series MOFs materials

NASA Astrophysics Data System (ADS)

Jiao, Yuqiu; Li, Zhenyu; Ma, Yue; Zhou, Guanggang; Wang, Shuangxi; Lu, Guiwu

2017-08-01

Molecular dynamics (MD), grand canonical Monte Carlo (GCMC) and ideal adsorbed solution theory (IAST) were used to study the structures and gas adsorption properties of MIL-53(M)[M=Cr, Fe, Sc, Al] metal organic framework (MOF) materials. The results show that the volumes of those MOF materials increase significantly at high temperature. By analyzing the adsorption isotherms, we found that the temperature had a paramount effect on the gas adsorption behaviors of these MOF materials. For MIL-53(Cr), the orders of the quantities of adsorbed gases were CH4>N2>CO2>H2S, CH4>H2S>CO2>N2 and CH4>CO2>H2S>N2 at 100K, 293K and 623K, respectively. We also calculated the adsorption of several combinations of two gases by MIL-53(Cr) at 293K, the results indicate that the material had selective adsorption of CH4 over CO2, H2S and N2. Our calculations provide microscopic insights into the gas adsorption performances of these MOFs and may further guide the practice of gas separation.

Influence of Filler Pore Structure and Polymer on the Performance of MOF-Based Mixed-Matrix Membranes for CO2 Capture.

PubMed

Sabetghadam, Anahid; Liu, Xinlei; Benzaqui, Marvin; Gkaniatsou, Effrosyni; Orsi, Angelica; Lozinska, Magdalena M; Sicard, Clemence; Johnson, Timothy; Steunou, Nathalie; Wright, Paul A; Serre, Christian; Gascon, Jorge; Kapteijn, Freek

2018-06-04

To gain insight into the influence of metal-organic framework (MOF) fillers and polymers on membrane performance, eight different composites were studied by combining four MOFs and two polymers. MOF materials (NH 2 -MIL-53(Al), MIL-69(Al), MIL-96(Al) and ZIF-94) with various chemical functionalities, topologies, and dimensionalities of porosity were employed as fillers, and two typical polymers with different permeability-selectivity properties (6FDA-DAM and Pebax) were selected as matrices. The best-performing MOF-polymer composites were prepared by loading 25 wt % of MIL-96(Al) as filler, which improved the permeability and selectivity of 6FDA-DAM to 32 and 10 %, while for Pebax they were enhanced to 25 and 18 %, respectively. The observed differences in membrane performance in the separation of CO 2 from N 2 are explained on the basis of gas solubility, diffusivity properties, and compatibility between the filler and polymer phases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controllable Synthesis of a Smart Multifunctional Nanoscale Metal-Organic Framework for Magnetic Resonance/Optical Imaging and Targeted Drug Delivery.

PubMed

Gao, Xuechuan; Zhai, Manjue; Guan, Weihua; Liu, Jingjuan; Liu, Zhiliang; Damirin, Alatangaole

2017-02-01

As a result of their extraordinarily large surfaces and well-defined pores, the design of a multifunctional metal-organic framework (MOF) is crucial for drug delivery but has rarely been reported. In this paper, a novel drug delivery system (DDS) based on nanoscale MOF was developed for use in cancer diagnosis and therapy. This MOF-based tumor targeting DDS was fabricated by a simple postsynthetic surface modification process. First, magnetic mesoporous nanomaterial Fe-MIL-53-NH 2 was used for encapsulating the drug and served as a magnetic resonance contrast agent. Moreover, the Fe-MIL-53-NH 2 nanomaterial exhibited a high loading capacity for the model anticancer drug 5-fluorouracil (5-FU). Subsequently, the fluorescence imaging agent 5-carboxyfluorescein (5-FAM) and the targeting reagent folic acid (FA) were conjugated to the 5-FU-loaded Fe-MIL-53-NH 2 , resulting in the advanced DDS Fe-MIL-53-NH 2 -FA-5-FAM/5-FU. Owing to the multifunctional surface modification, the obtained DDS Fe-MIL-53-NH 2 -FA-5-FAM/5-FU shows good biocompatibility, tumor enhanced cellular uptake, strong cancer cell growth inhibitory effect, excellent fluorescence imaging, and outstanding magnetic resonance imaging capability. Taken together, this study integrates diagnostic and treatment aspects into a single platform by a simple and efficient strategy, aiming for facilitating new possibilities for MOF use for multifunctional drug delivery.

Polydimethylsiloxane/metal-organic frameworks coated stir bar sorptive extraction coupled to gas chromatography-flame photometric detection for the determination of organophosphorus pesticides in environmental water samples.

PubMed

Xiao, Zuowei; He, Man; Chen, Beibei; Hu, Bin

2016-08-15

In this work, the metal-organic frameworks (MOFs), MIL-101-Cr-NH2 was synthesized via a direct hydrothermal method, and a polydimethylsiloxane (PDMS)/MIL-101-Cr-NH2 coated stir bar was prepared by sol-gel technique. Good reproducibility was obtained for the preparation of PDMS/MIL-101-Cr-NH2 coated stir bar with the relative standard deviations (RSDs) ranging from 3.7 to 5.2% (n=7) in one batch, and from 5.4 to 9.2% (n=7) among different batches. With the high surface area and rich benzene ring structure of MIL-101-Cr-NH2, the prepared PDMS/MIL-101-Cr-NH2 coated stir bar presented higher extraction efficiency for target organophosphorus pesticides (OPPs, including phorate, diazinon, malathion, fenthion, quinalphos and ethion) over PDMS coated stir bar. Based on it, a new method of PDMS/MIL-101-Cr-NH2 coated stir bar sorptive extraction (SBSE) coupled to gas chromatography-flame photometric detection (GC-FPD) was proposed for the determination of six OPPs in environmental water samples. The operation parameters affecting the extraction efficiency of SBSE, including extraction time, stirring rate, desorption time and ionic strength, were investigated. Under the optimal conditions, the limits of detection (S/N=3) were found to be in the range of 0.043-0.085μgL(-1) for the six target OPPs, and the linear range was 0.5-100μgL(-1) for malathion and 0.2-100μgL(-1) for other five OPPs. The RSDs of the proposed method evaluated at 1µgL(-1) for each OPP were in the range of 5.9-8.7% (intra-day, n=7) and 6.1-10.7% (inter-day, n=5), respectively. The enrichment factors were varied from 110 to 151-fold (theoretical enrichment factor was 200-fold). The proposed method was applied to the analysis of OPPs in East Lake and pond water samples with recoveries in the range of 89.3-115% and 80.0-113% for the spiked East Lake and pond water samples, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced proton conductivity of proton exchange membranes by incorporating sulfonated metal-organic frameworks

NASA Astrophysics Data System (ADS)

Li, Zhen; He, Guangwei; Zhao, Yuning; Cao, Ying; Wu, Hong; Li, Yifan; Jiang, Zhongyi

2014-09-01

In this study, octahedral crystal MIL101(Cr) with a uniform size of ∼400 nm is synthesized via hydrothermal reaction. It is then functionalized with sulfonic acid groups by concentrated sulfuric acid and trifluoromethanesulfonic anhydride in nitromethane. The sulfonated MIL101(Cr) are homogeneously incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare hybrid membranes. The performances of hybrid membranes are evaluated by proton conductivity, methanol permeability, water uptake and swelling property, and thermal stability. The methanol permeability increased slightly from 6.12 × 10-7 to 7.39 × 10-7 cm2 s-1 with the filler contents increasing from 0 to 10 wt. %. However, the proton conductivity of the hybrid membranes increased significantly. The proton conductivity is increased up to 0.306 S cm-1 at 75 °C and 100% RH, which is 96.2% higher than that of pristine membranes (0.156 S cm-1). The increment of proton conductivity is attributed to the following multiple functionalities of the sulfonated MIL101(Cr) in hybrid membranes: i) providing sulfonic acid groups as facile proton hopping sites; ii) forming additional proton-transport pathways at the interfaces of polymer and MOFs; iii) constructing hydrogen-bonded networks for proton conduction via -OH provided by the hydrolysis of coordinatively unsaturated metal sites.

MIL-53 frameworks in mixed-matrix membranes and cross-linked ZIF-8/matrimidRTM mixed-matrix membranes for gas separation

NASA Astrophysics Data System (ADS)

Hsieh, Josephine Ordonez

Mixed matrix membranes (MMMs) are hybrid materials consisting of two phases: an inorganic nanoscale particle as the discrete phase, and a polymeric material as the continuous phase. The incorporation of inorganic particles into a polymer can improve a membrane's overall separation performance. MMMs incorporating metal-organic frameworks (MOFs) have exhibited promising gas separation performance. MOFs are inorganic-organic crystals constructed from metal ions that are linked by polydentate ligands. Zeolitic imidazolate frameworks (ZIFs) are a sub-class of MOFs that uses imidazole analogues as ligands. In these studies, the MOF MIL-53 and ZIF-8 were successfully synthesized and characterized by a battery of analytical techniques including XRD, FTIR, TGA, N2 adsorption, and SEM, and were incorporated into MMMs with Matrimid® polymer. In chapter 1, MIL-53/Matrimid® MMMs containing MIL-53-ht (open-pore form) were fabricated, characterized and obtained permeability values higher than Matrimid®. Selectivities decreased for the gas pairs of O2/N2, H2/O2, H2/CO2, and H2/N2. However, slight enhancement of the CO2/CH4 selectivity was observed for the MIL-53-ht/Matrimid® compared to that of Matrimid ®. The MIL-53-as/Matrimid® MMM also showed an increase in permeability as well as an increase in selectivity for the gas pairs H2/O2, CO2/CH4, H 2/CH4, and H2/N2. The MIL-53-lt/Matrimid ® MMM showed that it does not retain its closed-pore form in the MMM due to chloroform solvent opening the pores and eventually polymer confinement of the MIL 53 framework in the MMM. In chapter 2, easy synthesis and fabrication of the MIL-53 MOF membrane was realized using a seeded growth method with a commercially available alumina TLC plate. The MOF membrane had a well-intergrown and dense layer of MIL-53 crystals on the surface of the alumina substrate. The MIL-53 crystals were also converted to the MIL-53-lt (closed-pore form) after heating at 330 °C and cooling to room temperature, which confirms the breathing ability of the MOF. In chapter 3, a comprehensive approach for membrane materials in order to achieve high productivity and separation efficiency was applied by incorporating additives into polymers and cross-linking the resulting MMM that could lead to increase and simultaneous selectivity enhancement. ZIF-8 was used as an additive in these MMMs. ZIF-8 can readily absorb small gases such, as H 2 and CO2 due to its 3.4 Å pore aperture. ZIF-8/Matrimid ® MMMs were fabricated with a spin-coated Matrimid® layer on one surface and cross-linked with EDA vapor. This membrane morphology could lead to enhanced selectivities due to the cross-linked layer, at the same time maintain the high permeability of the bulk MMM. The permeabilities decreased for the cross-linked, spin-coated Matrimid® ZIF-8/Matrimid ® MMMs. However, there was enhancement in selectivities for H 2/CO2, H2/N2, H2/O 2 and H2/CH4 gas pairs, which can be due to reduction of diffusive pathways for larger gas molecules. Compared to uncross-linked ZIF-8/Matrimid® MMMs, the cross-linked, spin-coated Matrimid ® ZIF-8/Matrimid® MMMs lie close to the Robeson's upper bound for H2/CO2 suggesting its potential for this gas pair separation.

DNA Detection by Flow Cytometry using PNA-Modified Metal-Organic Framework Particles.

PubMed

Mejia-Ariza, Raquel; Rosselli, Jessica; Breukers, Christian; Manicardi, Alex; Terstappen, Leon W M M; Corradini, Roberto; Huskens, Jurriaan

2017-03-23

A DNA-sensing platform is developed by exploiting the easy surface functionalization of metal-organic framework (MOF) particles and their highly parallelized fluorescence detection by flow cytometry. Two strategies were employed to functionalize the surface of MIL-88A, using either covalent or non-covalent interactions, resulting in alkyne-modified and biotin-modified MIL-88A, respectively. Covalent surface coupling of an azide-dye and the alkyne-MIL-88A was achieved by means of a click reaction. Non-covalent streptavidin-biotin interactions were employed to link biotin-PNA to biotin-MIL-88A particles mediated by streptavidin. Characterization by confocal imaging and flow cytometry demonstrated that DNA can be bound selectively to the MOF surface. Flow cytometry provided quantitative data of the interaction with DNA. Making use of the large numbers of particles that can be simultaneously processed by flow cytometry, this MOF platform was able to discriminate between fully complementary, single-base mismatched, and randomized DNA targets. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Highly functionalized biaryls via Suzuki-Miyaura cross-coupling catalyzed by Pd@MOF under batch and continuous flow regimes.

PubMed

Pascanu, Vlad; Hansen, Peter R; Bermejo Gómez, Antonio; Ayats, Carles; Platero-Prats, Ana E; Johansson, Magnus J; Pericàs, Miquel À; Martín-Matute, Belén

2015-01-01

A diverse set of more than 40 highly functionalized biaryls was synthesized successfully through the Suzuki-Miyaura cross-coupling reaction catalyzed by Pd nanoparticles supported in a functionalized mesoporous MOF (8 wt % Pd@MIL-101(Cr)-NH2 ). This could be achieved under some of the mildest conditions reported to date and a strong control over the leaching of metallic species could be maintained, despite the presence of diverse functional groups and/or several heteroatoms. Some of the targeted molecules are important intermediates in the synthesis of pharmaceuticals and we clearly exemplify the versatility of this catalytic system, which affords better yields than currently existing commercial procedures. Most importantly, Pd@MIL-101-NH2 was packed in a micro-flow reactor, which represents the first report of metallic nanoparticles supported on MOFs employed in flow chemistry for catalytic applications. A small library of 11 isolated compounds was created in a continuous experiment without replacing the catalyst, demonstrating the potential of the catalyst for large-scale applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Computational discovery of metal-organic frameworks with high gas deliverable capacity

NASA Astrophysics Data System (ADS)

Bao, Yi

Metal-organic frameworks (MOFs) are a rapidly emerging class of nanoporous materials with largely tunable chemistry and diverse applications in gas storage, gas purification, catalysis, sensing and drug delivery. Efforts have been made to develop new MOFs with desirable properties both experimentally and computationally for decades. To guide experimental synthesis, we here develop a computational methodology to explore MOFs with high gas deliverable capacity. This de novo design procedure applies known chemical reactions, considers synthesizability and geometric requirements of organic linkers, and efficiently evolves a population of MOFs to optimize a desirable property. We identify 48 MOFs with higher methane deliverable capacity at 65-5.8 bar condition than the MOF-5 reference in nine networks. In a more comprehensive work, we predict two sets of MOFs with high methane deliverable capacity at a 65-5.8 bar loading-delivery condition or a 35-5.8 bar loading-delivery condition. We also optimize a set of MOFs with high methane accessible internal surface area to investigate the relationship between deliverable capacities and internal surface area. This methodology can be extended to MOFs with multiple types of linkers and multiple SBUs. Flexibile MOFs may allow for sophisticated heat management strategies and also provide higher gas deliverable capacity than rigid frameworks. We investigate flexible MOFs, such as MIL-53 families, and Fe(bdp) and Co(bdp) analogs, to understand the structural phase transition of frameworks and the resulting influence on heat of adsorption. Challenges of simulating a system with a flexible host structure and incoming guest molecules are discussed. Preliminary results from isotherm simulation using the hybrid MC/MD simulation scheme on MIL-53(Cr) are presented. Suggestions for proceeding to understand the free energy profile of flexible MOFs are provided.

Transforming MOFs for Energy Applications Using the Guest@MOF Concept.

PubMed

Ullman, Andrew M; Brown, Jonathan W; Foster, Michael E; Léonard, François; Leong, Kirsty; Stavila, Vitalie; Allendorf, Mark D

2016-08-01

As the world transitions from fossil fuels to clean energy sources in the coming decades, many technological challenges will require chemists and material scientists to develop new materials for applications related to energy conversion, storage, and efficiency. Because of their unprecedented adaptability, metal-organic frameworks (MOFs) will factor strongly in this portfolio. By utilizing the broad synthetic toolkit provided by the fields of organic and inorganic chemistry, MOF pores can be customized to suit a particular application. Of particular importance is the ability to tune the strength of the interaction between the MOF pores and guest molecules. By cleverly controlling these MOF-guest interactions, the chemist may impart new function into the Guest@MOF materials otherwise lacking in vacant MOF. Herein, we highlight the concept of the Guest@MOF as it relates to our efforts to develop these materials for energy-related applicatons. Our work in the areas of H2 and noble gas storage, hydrogenolysis of biomass, light-harvesting, and conductive materials will be discussed. Of relevance to light-harvesting applications, we report for the first time a postsynthetic modification strategy for increasing the loading of a light-sensitive electron-donor molecule in the pores of a functionalized MIL-101 structure. Through the demonstrated versatility of these approaches, we show that, by treating guest molecules as integral design elements for new MOF constructs, MOF science can have a significant impact on the advancement of clean energy technologies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ullman, Andrew M.; Brown, Jonathan W.; Foster, Michael E.

As the world transitions from fossil fuels to clean energy sources in the coming decades, many technological challenges will require chemists and material scientists to develop new materials for applications related to energy conversion, storage, and efficiency. Because of their unprecedented adaptability, metal–organic frameworks (MOFs) will factor strongly in this portfolio. By utilizing the broad synthetic toolkit provided by the fields of organic and inorganic chemistry, MOF pores can be customized to suit a particular application. Of particular importance is the ability to tune the strength of the interaction between the MOF pores and guest molecules. By cleverly controlling thesemore » MOF–guest interactions, the chemist may impart new function into the Guest@MOF materials otherwise lacking in vacant MOF. Herein, we highlight the concept of the Guest@MOF as it relates to our efforts to develop these materials for energy-related applicatons. Additionally, our work in the areas of H 2 and noble gas storage, hydrogenolysis of biomass, light-harvesting, and conductive materials will be discussed. Of relevance to light-harvesting applications, we report for the first time a postsynthetic modification strategy for increasing the loading of a light-sensitive electron-donor molecule in the pores of a functionalized MIL-101 structure. Through the demonstrated versatility of these approaches, we show that, by treating guest molecules as integral design elements for new MOF constructs, MOF science can have a significant impact on the advancement of clean energy technologies.« less

Fe II/Fe III mixed-valence state induced by Li-insertion into the metal-organic-framework Mil53(Fe): A DFT+U study

NASA Astrophysics Data System (ADS)

Combelles, C.; Ben Yahia, M.; Pedesseau, L.; Doublet, M.-L.

The iron-based metal-organic-framework MIL53(Fe) has recently been tested as a cathode materials for Li-Ion batteries, leading to promising cycling life and rate capability. Despite a poor capacity of 70 mAh g -1 associated with the exchange of almost 0.5Li/Fe, this result is the first evidence of a reversible lithium insertion never observed in a MOF system. In the present study, the MIL53(Fe) redox mechanism is investigated through first-principles DFT+U calculations. The results show that MIL53(Fe) is a weak antiferromagnetic charge transfer insulator at T = 0 K, with iron ions in the high-spin S = 5/2 state. Its reactivity vs elemental lithium is then investigated as a function of lithium composition and distribution over the most probable Li-sites of the MOF structure. The redox mechanism is fully interpreted as a two-step insertion/conversion mechanism, associated with the stabilization of the Fe 3+/Fe 2+ mixed-valence state prior to the complete decomposition of the inorganic-organic interactions within the porous MOF architecture.

Fabrication of core-shell Fe{sub 3}O{sub 4}@MIL-100(Fe) magnetic microspheres for the removal of Cr(VI) in aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qingxiang, E-mail: qxyangzz@163.com; Zhao, Qianqian; Ren, ShuangShuang

Facile regeneration of an adsorbent is very important for commercial feasibility. One typical highly porous metal-organic framework (MOF) materials based on MIL-100(Fe) and magnetic iron oxide particles (denoted as MMCs) with diameter about of 350 nm were successfully synthesized. The growth of MIL-100(Fe) shell on the surface of Fe{sub 3}O{sub 4} was utilized precursor as crystal seed via in-situ step hydrothermal reaction. It is a simple way to obtain well organized core-shell MOF composites, compared to the step-by-step method. MMCs were firstly used to uptake of Cr(VI) anions in aqueous solution. Adsorption experiments were carried out in batch sorption mode investigatingmore » with the factors of contact time (0–1000 min), pH (from 2 to 12), dose of adsorbent (4–25 mg), and initial Cr(VI) concentration (range from 10 to 100 ppm). - Graphical abstract: One typical highly porous metal-organic framework (MOF) materials based on MIL-100(Fe) and magnetic iron oxide particles (denoted as MMCs) were successfully synthesized. Utilizing Fe{sub 3}O{sub 4} precursor as crystal seed to grow MIL-100(Fe) shell by in-situ step hydrothermal reaction. It is a simple way to obtain core-shell MOF composites. MMCs could effectively uptake of Cr(VI) anions in aqueous solution. - Highlights: • Fe{sub 3}O{sub 4}@MIL-100(Fe) composites with core-shell structure were successfully prepared through a simple method. • The influence factors on Cr(VI) adsorption by Fe{sub 3}O{sub 4}@MIL-100(Fe) were investigated. • Cr(VI) can efficiently adsorbed by Fe{sub 3}O{sub 4}@MIL-100(Fe) composites from aqueous solution.« less

Experimental and molecular docking investigation on metal-organic framework MIL-101(Cr) as a sorbent for vortex assisted dispersive micro-solid-phase extraction of trace 5-nitroimidazole residues in environmental water samples prior to UPLC-MS/MS analysis.

PubMed

Lu, Nan; Wang, Ting; Zhao, Pan; Zhang, Lianjun; Lun, Xiaowen; Zhang, Xueli; Hou, Xiaohong

2016-11-01

In the presented work, metal-organic framework (MOF) material MIL-101(Cr) (MIL, Matérial Institute Lavoisier) was used as a sorbent for vortex assisted dispersive micro-solid-phase extraction (VA-D-μ-SPE) of trace amount of metronidazole (MNZ), ronidazole (RNZ), secnidazole (SNZ), dimetridazole (DMZ), tinidazole (TNZ), and ornidazole (ONZ) in different environmental water samples. Ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was used to quantify the target analytes. The extraction conditions, including type of sorbents, amount of MIL-101(Cr), solution pH, extraction method, extraction time, effect of salt, and elution conditions were investigated. Upon the optimal conditions, the developed method showed an excellent extraction performance with the average recovery ranging from 75.2 to 98.8 %. Good sensitivity levels were achieved with the detection limits of 0.03∼0.06 μg/L and the quantitation limits of 0.09∼0.20 μg/L. The linear ranges were varied from 0.1 to 20 for SNZ and ONZ and from 0.2 to 40 μg/L for MNZ, RNZ, DMZ, and TNZ (r 2  > 0.992), and repeatability of the method was satisfactory with the relative standard deviations (RSD) <8 %. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of 5-nitroimidazoles (5-NDZs) in 12 real water samples, showing the positive findings of MNZ and TNZ ranging from 0.3 to 1.0 μg/L. Furthermore, molecular docking was applied to explain the molecular interactions and free binding energies between MIL-101(Cr) and 5-NDZs, providing a deep insight into the adsorption mechanism. The proposed method exhibited the advantages of simplicity, rapidly, less solvent consumption, ease of operation, higher sensitivity, and lower matrix effect. Graphical abstract Schematic diagram of the extraction process and molecular docking investigation.

Transforming MOFs for energy applications using the guest@MOF concept

DOE PAGES

Ullman, Andrew M.; Brown, Jonathan W.; Foster, Michael E.; ...

2016-07-11

As the world transitions from fossil fuels to clean energy sources in the coming decades, many technological challenges will require chemists and material scientists to develop new materials for applications related to energy conversion, storage, and efficiency. Because of their unprecedented adaptability, metal–organic frameworks (MOFs) will factor strongly in this portfolio. By utilizing the broad synthetic toolkit provided by the fields of organic and inorganic chemistry, MOF pores can be customized to suit a particular application. Of particular importance is the ability to tune the strength of the interaction between the MOF pores and guest molecules. By cleverly controlling thesemore » MOF–guest interactions, the chemist may impart new function into the Guest@MOF materials otherwise lacking in vacant MOF. Herein, we highlight the concept of the Guest@MOF as it relates to our efforts to develop these materials for energy-related applicatons. Additionally, our work in the areas of H 2 and noble gas storage, hydrogenolysis of biomass, light-harvesting, and conductive materials will be discussed. Of relevance to light-harvesting applications, we report for the first time a postsynthetic modification strategy for increasing the loading of a light-sensitive electron-donor molecule in the pores of a functionalized MIL-101 structure. Through the demonstrated versatility of these approaches, we show that, by treating guest molecules as integral design elements for new MOF constructs, MOF science can have a significant impact on the advancement of clean energy technologies.« less

Chelating agent-free, vapor-assisted crystallization method to synthesize hierarchical microporous/mesoporous MIL-125 (Ti).

PubMed

McNamara, Nicholas D; Hicks, Jason C

2015-03-11

Titanium-based microporous heterogeneous catalysts are widely studied but are often limited by the accessibility of reactants to active sites. Metal-organic frameworks (MOFs), such as MIL-125 (Ti), exhibit enhanced surface areas due to their high intrinsic microporosity, but the pore diameters of most microporous MOFs are often too small to allow for the diffusion of larger reactants (>7 Å) relevant to petroleum and biomass upgrading. In this work, hierarchical microporous MIL-125 exhibiting significantly enhanced interparticle mesoporosity was synthesized using a chelating-free, vapor-assisted crystallization method. The resulting hierarchical MOF was examined as an active catalyst for the oxidation of dibenzothiophene (DBT) with tert-butyl hydroperoxide and outperformed the solely microporous analogue. This was attributed to greater access of the substrate to surface active sites, as the pores in the microporous analogues were of inadequate size to accommodate DBT. Moreover, thiophene adsorption studies suggested the mesoporous MOF contained larger amounts of unsaturated metal sites that could enhance the observed catalytic activity.

Metal-organic frameworks for analytical chemistry: from sample collection to chromatographic separation.

PubMed

Gu, Zhi-Yuan; Yang, Cheng-Xiong; Chang, Na; Yan, Xiu-Ping

2012-05-15

In modern analytical chemistry researchers pursue novel materials to meet analytical challenges such as improvements in sensitivity, selectivity, and detection limit. Metal-organic frameworks (MOFs) are an emerging class of microporous materials, and their unusual properties such as high surface area, good thermal stability, uniform structured nanoscale cavities, and the availability of in-pore functionality and outer-surface modification are attractive for diverse analytical applications. This Account summarizes our research on the analytical applications of MOFs ranging from sampling to chromatographic separation. MOFs have been either directly used or engineered to meet the demands of various analytical applications. Bulk MOFs with microsized crystals are convenient sorbents for direct application to in-field sampling and solid-phase extraction. Quartz tubes packed with MOF-5 have shown excellent stability, adsorption efficiency, and reproducibility for in-field sampling and trapping of atmospheric formaldehyde. The 2D copper(II) isonicotinate packed microcolumn has demonstrated large enhancement factors and good shape- and size-selectivity when applied to on-line solid-phase extraction of polycyclic aromatic hydrocarbons in water samples. We have explored the molecular sieving effect of MOFs for the efficient enrichment of peptides with simultaneous exclusion of proteins from biological fluids. These results show promise for the future of MOFs in peptidomics research. Moreover, nanosized MOFs and engineered thin films of MOFs are promising materials as novel coatings for solid-phase microextraction. We have developed an in situ hydrothermal growth approach to fabricate thin films of MOF-199 on etched stainless steel wire for solid-phase microextraction of volatile benzene homologues with large enhancement factors and wide linearity. Their high thermal stability and easy-to-engineer nanocrystals make MOFs attractive as new stationary phases to fabricate MOF-coated capillaries for high-resolution gas chromatography (GC). We have explored a dynamic coating approach to fabricate a MOF-coated capillary for the GC separation of important raw chemicals and persistent organic pollutants with high resolution and excellent selectivity. We have combined a MOF-coated fiber for solid-phase microextraction with a MOF-coated capillary for GC separation, which provides an effective MOF-based tandem molecular sieve platform for selective microextraction and high-resolution GC separation of target analytes in complex samples. Microsized MOFs with good solvent stability are attractive stationary phases for high-performance liquid chromatography (HPLC). These materials have shown high resolution and good selectivity and reproducibility in both the normal-phase HPLC separation of fullerenes and substituted aromatics on MIL-101 packed columns and position isomers on a MIL-53(Al) packed column and the reversed-phase HPLC separation of a wide range of analytes from nonpolar to polar and acidic to basic solutes. Despite the above achievements, further exploration of MOFs in analytical chemistry is needed. Especially, analytical application-oriented engineering of MOFs is imperative for specific applications.

Synthesis of MIL-100(Fe)@MIL-53(Fe) as a novel hybrid photocatalyst and evaluation photocatalytic and photoelectrochemical performance under visible light irradiation

NASA Astrophysics Data System (ADS)

Abdpour, Soheil; Kowsari, Elaheh; Moghaddam, Mohammad Reza Alavi

2018-06-01

The MIL-100(Fe)@MIL-53(Fe) was synthesized by the ultrasound method, while the initial solution for the preparation of the photocatalysts was included nanoparticles of MIL-100(Fe) and a precursor solution for the synthesizing of MIL-53(Fe). After an appropriate time of reaction, nanoparticles of MIL-100(Fe) were decorated on the surface of MIL-53(Fe). Phtoelectrochemical/electrochemical and photocatalytic degradation of methyl orange over MIL-100(Fe)@MIL-53(Fe) were explored. The phtoelectrochemical/electrochemical and photocatalytic performance of the prepared photocatalysts revealed that the introduction of nanoparticles of the MIL-100(Fe) on the surface of MIL-53(Fe) enhanced the photocatalytic performance of the resulted photocatalyst compared to pure MIL-53(Fe) and MIL-100(Fe). The enhanced photocatalytic efficiency is ascribed to increase the visible light region absorption and to decrease the electron-hole recombination rate in the hybrid photocatalyst. The present work demonstrated that the photocatalytic properties of metal organic frameworks (MOFs) can be improved by the fabrication of hybrid photocatalysts based on the different types of MOFs.

The Tuning of Optical Properties of Nanoscale MOFs-Based Thin Film through Post-Modification.

PubMed

Yin, Wenchang; Tao, Cheng-An; Zou, Xiaorong; Wang, Fang; Qu, Tianlian; Wang, Jianfang

2017-08-29

Optical properties, which determine the application of optical devices in different fields, are the most significant properties of optical thin films. In recent years, Metal-organic framework (MOF)-based optical thin films have attracted increasing attention because of their novel optical properties and important potential applications in optical and photoelectric devices, especially optical thin films with tunable optical properties. This study reports the first example of tuning the optical properties of a MOF-based optical thin film via post-modification. The MOF-based optical thin film was composed of NH₂-MIL-53(Al) nanorods (NRs) (MIL: Materials from Institute Lavoisier), and was constructed via a spin-coating method. Three aldehydes with different lengths of carbon chains were chosen to modify the MOF optical thin film to tune their optical properties. After post-modification, the structural color of the NH₂-MIL-53(Al) thin film showed an obvious change from purple to bluish violet and cyan. The reflection spectrum and the reflectivity also altered in different degrees. The effective refractive index ( n eff ) of MOFs thin film can also be tuned from 1.292 to 1.424 at a wavelength of 750 nm. The success of tuning of the optical properties of MOFs thin films through post-modification will make MOFs optical thin films meet different needs of optical properties in various optical and optoelectronic devices.

The Tuning of Optical Properties of Nanoscale MOFs-Based Thin Film through Post-Modification

PubMed Central

Zou, Xiaorong; Wang, Fang; Qu, Tianlian; Wang, Jianfang

2017-01-01

Optical properties, which determine the application of optical devices in different fields, are the most significant properties of optical thin films. In recent years, Metal-organic framework (MOF)-based optical thin films have attracted increasing attention because of their novel optical properties and important potential applications in optical and photoelectric devices, especially optical thin films with tunable optical properties. This study reports the first example of tuning the optical properties of a MOF-based optical thin film via post-modification. The MOF-based optical thin film was composed of NH2-MIL-53(Al) nanorods (NRs) (MIL: Materials from Institute Lavoisier), and was constructed via a spin-coating method. Three aldehydes with different lengths of carbon chains were chosen to modify the MOF optical thin film to tune their optical properties. After post-modification, the structural color of the NH2-MIL-53(Al) thin film showed an obvious change from purple to bluish violet and cyan. The reflection spectrum and the reflectivity also altered in different degrees. The effective refractive index (neff) of MOFs thin film can also be tuned from 1.292 to 1.424 at a wavelength of 750 nm. The success of tuning of the optical properties of MOFs thin films through post-modification will make MOFs optical thin films meet different needs of optical properties in various optical and optoelectronic devices. PMID:28850057

The structure-directed effect of Al-based metal–organic frameworks on fabrication of alumina by thermal treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Dandan, E-mail: liudandan_upc@126.com; Dai, Fangna, E-mail: fndai@upc.edu.cn; Collage of Science, China University of Petroleum

2015-05-15

Highlights: • We use Al-MOFs as precursor in the fabrication process of mesoporous alumina by thermal treatment. • The obtained mesoporous alumina has dual pore system and five-fold aluminum. • The aluminum building units in the precursor show structure-directed effect on the formation of alumina. - Abstract: In this work, the block-shaped Al-based metal–organic frameworks (Al-MOFs) MIL-53 have been synthesized by hydrothermal method. To detect the correlation between the structure of Al-MOFs and the formation of alumina, the ligands are eliminated by thermal treatment. MIL-53 and the calcination products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR),more » scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption and solid-state {sup 27}Al nuclear magnetic resonance ({sup 27}Al NMR). It was found that after calcination, the block-shaped Al-MOFs precursor turns into high-crystallinity mesoporous alumina nanosheets, and the thermal treatment product γ-alumina possesses a dual pore system and a large surface area (146 m{sup 2}/g), with five-fold aluminum. During the thermal treatment process, the structure of MIL-53 and its secondary building units have structure-directed effect in the formation of alumina.« less

Toward Understanding Drug Incorporation and Delivery from Biocompatible Metal-Organic Frameworks in View of Cutaneous Administration.

PubMed

Rojas, Sara; Colinet, Isabel; Cunha, Denise; Hidalgo, Tania; Salles, Fabrice; Serre, Christian; Guillou, Nathalie; Horcajada, Patricia

2018-03-31

Although metal-organic frameworks (MOFs) have widely demonstrated their convenient performances as drug-delivery systems, there is still work to do to fully understand the drug incorporation/delivery processes from these materials. In this work, a combined experimental and computational investigation of the main structural and physicochemical parameters driving drug adsorption/desorption kinetics was carried out. Two model drugs (aspirin and ibuprofen) and three water-stable, biocompatible MOFs (MIL-100(Fe), UiO-66(Zr), and MIL-127(Fe)) have been selected to obtain a variety of drug-matrix couples with different structural and physicochemical characteristics. This study evidenced that the drug-loading and drug-delivery processes are mainly governed by structural parameters (accessibility of the framework and drug volume) as well as the MOF/drug hydrophobic/hydrophilic balance. As a result, the delivery of the drug under simulated cutaneous conditions (aqueous media at 37 °C) demonstrated that these systems fulfill the requirements to be used as topical drug-delivery systems, such as released payload between 1 and 7 days. These results highlight the importance of the rational selection of MOFs, evidencing the effect of geometrical and chemical parameters of both the MOF and the drug on the drug adsorption and release.

Toward Understanding Drug Incorporation and Delivery from Biocompatible Metal–Organic Frameworks in View of Cutaneous Administration

PubMed Central

2018-01-01

Although metal–organic frameworks (MOFs) have widely demonstrated their convenient performances as drug-delivery systems, there is still work to do to fully understand the drug incorporation/delivery processes from these materials. In this work, a combined experimental and computational investigation of the main structural and physicochemical parameters driving drug adsorption/desorption kinetics was carried out. Two model drugs (aspirin and ibuprofen) and three water-stable, biocompatible MOFs (MIL-100(Fe), UiO-66(Zr), and MIL-127(Fe)) have been selected to obtain a variety of drug–matrix couples with different structural and physicochemical characteristics. This study evidenced that the drug-loading and drug-delivery processes are mainly governed by structural parameters (accessibility of the framework and drug volume) as well as the MOF/drug hydrophobic/hydrophilic balance. As a result, the delivery of the drug under simulated cutaneous conditions (aqueous media at 37 °C) demonstrated that these systems fulfill the requirements to be used as topical drug-delivery systems, such as released payload between 1 and 7 days. These results highlight the importance of the rational selection of MOFs, evidencing the effect of geometrical and chemical parameters of both the MOF and the drug on the drug adsorption and release. PMID:29623304

Elucidating the breathing of the metal-organic framework MIL-53(Sc) with ab initio molecular dynamics simulations and in situ X-ray powder diffraction experiments.

PubMed

Chen, Linjiang; Mowat, John P S; Fairen-Jimenez, David; Morrison, Carole A; Thompson, Stephen P; Wright, Paul A; Düren, Tina

2013-10-23

Ab initio molecular dynamics (AIMD) simulations have been used to predict structural transitions of the breathing metal-organic framework (MOF) MIL-53(Sc) in response to changes in temperature over the range 100-623 K and adsorption of CO2 at 0-0.9 bar at 196 K. The method has for the first time been shown to predict successfully both temperature-dependent structural changes and the structural response to variable sorbate uptake of a flexible MOF. AIMD employing dispersion-corrected density functional theory accurately simulated the experimentally observed closure of MIL-53(Sc) upon solvent removal and the transition of the empty MOF from the closed-pore phase to the very-narrow-pore phase (symmetry change from P2(1)/c to C2/c) with increasing temperature, indicating that it can directly take into account entropic as well as enthalpic effects. We also used AIMD simulations to mimic the CO2 adsorption of MIL-53(Sc) in silico by allowing the MIL-53(Sc) framework to evolve freely in response to CO2 loadings corresponding to the two steps in the experimental adsorption isotherm. The resulting structures enabled the structure determination of the two CO2-containing intermediate and large-pore phases observed by experimental synchrotron X-ray diffraction studies with increasing CO2 pressure; this would not have been possible for the intermediate structure via conventional methods because of diffraction peak broadening. Furthermore, the strong and anisotropic peak broadening observed for the intermediate structure could be explained in terms of fluctuations of the framework predicted by the AIMD simulations. Fundamental insights from the molecular-level interactions further revealed the origin of the breathing of MIL-53(Sc) upon temperature variation and CO2 adsorption. These simulations illustrate the power of the AIMD method for the prediction and understanding of the behavior of flexible microporous solids.

Selective Hydrogen Isotope Separation via Breathing Transition in MIL-53(Al).

PubMed

Kim, Jin Yeong; Zhang, Linda; Balderas-Xicohténcatl, Rafael; Park, Jaewoo; Hirscher, Michael; Moon, Hoi Ri; Oh, Hyunchul

2017-12-13

Breathing of MIL-53(Al), a flexible metal-organic framework (MOF), leads to dynamic changes as narrow pore (np) transitions to large pore (lp). During the flexible and reversible transition, the pore apertures are continuously adjusted, thus providing the tremendous opportunity to separate mixtures of similar-sized and similar-shaped molecules that require precise pore tuning. Herein, for the first time, we report a strategy for effectively separating hydrogen isotopes through the dynamic pore change during the breathing of MIL-53(Al), a representative of flexible MOFs. The experiment shows that the selectivity for D 2 over H 2 is strongly related to the state of the pore structure of MIL-53(Al). The highest selectivity (S D 2 /H 2 = 13.6 at 40 K) was obtained by optimizing the exposure temperature, pressure, and time to systematically tune the pore state of MIL-53(Al).

A Plasmonic Colloidal Photocatalyst Composed of a Metal-Organic Framework Core and a Gold/Anatase Shell for Visible-Light-Driven Wastewater Purification from Antibiotics and Hydrogen Evolution.

PubMed

Tilgner, Dominic; Kempe, Rhett

2017-03-02

Porous coordination polymers (PCP) or metal- organic frameworks (MOF) are promising materials for the generation of photocatalytically active composite materials. Here, a novel synthesis concept is reported, which permits the formation of PCP/MOF-core-Au/anatase-shell materials. These materials are photocatalysts for wastewater purification and hydrogen generation from water under visible-light illumination. MIL-101 (Cr) is utilized as the core material, which directs the size of the core-shell compound and ensures the overall stability. In addition, its excellent reversible large molecule sorption behavior allows the materials synthesis. The crystalline anatase shell is generated stepwise under mild conditions using titanium(IV) isopropoxide as a precursor. The high degree of control of the vapor phase deposition process permits the precise anatase shell formation. The generation of plasmonic active gold particles on the TiO 2 shell leads to an efficient material for visible-light-driven photocatalysis with a higher activity than gold-decorated P25 (Degussa). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aldehyde-alcohol reactions catalyzed under mild conditions by chromium(III) terephthalate metal organic framework (MIL-101) and phosphotungstic acid composites.

PubMed

Bromberg, Lev; Hatton, T Alan

2011-12-01

Porous materials based on chromium(III) terephthalate metal organic frameworks (MIL-101) and their composites with phosphotungstic acid (PTA) were studied as heterogeneous acid catalysts in aldehyde-alcohol reactions exemplified by acetaldehyde-phenol (A-P) condensation and dimethylacetal formation from benzaldehyde and methanol (B-M reaction). The MIL-101 was synthesized solvothermically in water, and the MIL101/PTA composite materials were obtained by either impregnation of the already prepared MIL-101 porous matrix with phosphotungstic acid solution or by solvothermic treatment of aqueous mixtures of Cr(NO(3))(3), and terephthalic and phosphotungstic acids. The MIL101/PTA materials appeared to be effective catalysts for both A-P and B-M reactions occurring at room temperature, with half-lives ranging from 0.5 h (A-P) to 1.5-2 h (B-M) and turnover numbers over 600 for A-P and over 2900 for the B-M reaction, respectively. A synergistic effect of the strong acidic moieties (PTA) addition to mildly acidic Brønsted and Lewis acid cites of the MIL-101 was observed with the MIL101/PTA composites. The ability of the PTA and MIL101/PTA materials to strongly absorb and condense acetaldehyde vapors was discovered, with the MIL101/PTA absorbing over 10-fold its dry weight of acetaldehyde condensate at room temperature. The acetaldehyde was converted rapidly to crotonaldehyde and higher-molecular-weight compounds while in contact with MIL-101 and MIL101/PTA materials. The stability of the MIL-101 and MIL101/PTA catalysts was assessed within four cycles of the 1-day alcohol-aldehyde reactions in terms of the overall catalyst recovery, PTA or Cr content, and reaction rate constants in each cycle. The loss of the catalyst over 4 cycles was approximately 10 wt % for all tested catalysts due to the incomplete recovery and minute dissolution of the components. The reaction rates in all cycles remained unchanged and the catalyst losses stopped after the third cycle. The developed MIL101/PTA composites appear to be feasible for industrial catalytic applications. © 2011 American Chemical Society

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez, Carlos A.; Nune, Satish K.; Annapureddy, Harsha V.

Metal-organic frameworks (MOFs) have proved to be very attractive for applications including gas storage, separation, sensing and catalysis. In particular, CO2 separation from flue gas in post-combustion processes is one of the main focuses of research among the scientific community. One of the major issues that are preventing the successful commercialization of these novel materials (e.g., MgDOBDC and NiDOBDC) is their high affinity towards water that not only compromises gas sorption capacity but also the chemical stability. In this paper, we demonstrate a novel post-synthesis modification approach to modify MOFs towards increasing hydrophobic behavior and chemical stability against moisture withoutmore » compromising CO2 sorption capacity. Our approach consists of incorporating hydrophobic moieties on the external surface of the MOFs via physical adsorption. The rationale behind this concept is to increase the surface hydrophobicity in the porous materials without the need of introducing bulky functionalities inside the pore which compromises the sorption capacity toward other gases. This allows MOF interaction/sorption of CO2 molecules comparable to unmodified MOFs. We herein report preliminary results on three routinely studied MOF materials [MIL-101(Cr), MgDOBDC and NiDOBDC] demonstrating that the polymer-modified MOFs retain CO2 sorption capacity while reducing the water adsorption up to three times, respect to the un-modified materials, via an equilibrium effect. Furthermore, the water stability of the polymer-functionalized MOFs is significantly higher than the water stability of the bare material. Molecular dynamic simulations demonstrated that this equilibrium effect implies a fundamental and permanent change in the water sorption capacity of MOFs. This approach can also be employed to render moisture stability and selectivity to MOFs that find applications in gas separations, catalysis and sensing where water plays a critical role in compromising MOF performance and recyclability.« less

Dubinin-Astakhov model for acetylene adsorption on metal-organic frameworks

NASA Astrophysics Data System (ADS)

Cheng, Peifu; Hu, Yun Hang

2016-07-01

Acetylene (C2H2) is explosive at a pressure above 29 psi, causing a safety issue for its storage and applications. C2H2 adsorption on metal-organic frameworks (MOFs) has been explored to solve the issue. However, a suitable isotherm equation for C2H2 adsorption on various MOFs has not been found. In this paper, it was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C2H2 adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. In contrast, commonly used Langmuir and BET models exhibited their inapplicability for C2H2 adsorption on those MOFs.

Magnetic solid phase extraction of typical polycyclic aromatic hydrocarbons from environmental water samples with metal organic framework MIL-101 (Cr) modified zero valent iron nano-particles.

PubMed

Zhou, Qingxiang; Lei, Man; Wu, Yalin; Yuan, Yongyong

2017-03-03

Metal-organic framework material has been paid more attention because of its good physical and chemical properties. Nanoscale zero valent iron is also in the center of concern recently. Combination of their merits will give impressive results. Present study firstly synthesized a new magnetic nanomaterial nano-scale zero valent iron-functionalized metal-organic framworks MIL-101 (Fe@MIL-101) by co-precipitation method. The morphology and structure of the as-prepared Fe@MIL-101 were characterized by transmission electron microscopy and X-ray diffraction, etc. The experimental results showed that Fe@MIL-101 earned good adsorption ability to polycyclic aromatic hydrocarbons. The limits of detection of developed magnetic solid phase extraction were all below 0.064μgL -1 and precision can be expressed as relative standard deviation (RSD, %) and which was better than 4.4% (n=6). The real water analysis indicated that the spiked recoveries were satisfied, and Fe@MIL-101 earned excellent reusability. All these demonstrated that Fe@MIL-101 exhibited excellent adsorption capability to polycyclic aromatic hydrocarbons and would be a good adsorbent for development of new monitoring methods for environmental pollutants. Copyright © 2017 Elsevier B.V. All rights reserved.

Insights in the analytical performance of neat metal-organic frameworks in the determination of pollutants of different nature from waters using dispersive miniaturized solid-phase extraction and liquid chromatography.

PubMed

Rocío-Bautista, Priscilla; Pino, Verónica; Pasán, Jorge; López-Hernández, Irene; Ayala, Juan H; Ruiz-Pérez, Catalina; Afonso, Ana M

2018-03-01

Five metal-organic frameworks (MOFs), specifically HKUST-1, MOF-5(Zn), MIL-53(Al), UiO-64 and MOF-74(Zn) are synthesized, characterized, and utilized in a miniaturized solid-phase extraction method under dispersive mode (D-µSPE) for the determination of six pollutants of different nature, including one polycyclic aromatic hydrocarbon, two hormones, two drugs, and one disinfectant, from environmental waters (tap water and wastewater). A discussion of possible interactions justifying the partitioning of target analytes to the MOFs is included, considering not only the analytes' physicochemical characteristics but also those of MOFs: metal nature, structural environment of MOF pores, pore size and pore aperture widths, among others. MIL-53(Al) is selected for its versatility and high extraction efficiency for the target compounds. The D-µSPE method using MIL-53(Al) is optimized and used in combination with high-performance liquid chromatography (HPLC) with diode array detector (DAD) or liquid-chromatography with time-of-flight mass spectrometric detector (LC-TOF). Under optimum conditions, only 5mg of MIL-53(Al) are required for 10mL of water, with the aid of 5min of vortex and 5min of centrifugation. Elution is accomplished with 200µL of acetonitrile (3 times), and evaporation down to 100µL before LC injection. Detection limits down to 0.040μgL -1 for triclosan and 0.013μgL -1 for atrazine are obtained for the entire method using HPLC-DAD and LC-TOF, respectively. The method, operating at low spiked levels (2µgL -1 for HPLC-DAD and 0.7µgL -1 for LC-TOF), is also characterized for average relative recoveries of 109% and 105%; relative standard deviation values lower than 8.7% and 7.5%; and average extraction efficiencies of 41.2% and 49.1%; using HPLC-DAD and LC-TOF, respectively; while demonstrating adequate analytical performance with complex samples such as wastewaters. Copyright © 2017 Elsevier B.V. All rights reserved.

Pyrolytic in situ magnetization of metal-organic framework MIL-100 for magnetic solid-phase extraction.

PubMed

Huo, Shu-Hui; An, Hai-Yan; Yu, Jing; Mao, Xue-Feng; Zhang, Zhe; Bai, Lei; Huang, Yan-Feng; Zhou, Peng-Xin

2017-09-29

In this study, we report a facile, environmental friendly fabrication of a type of magnetic metal-organic framework (MOF) MIL-100 that can be used for magnetic solid-phase extraction (MSPE). The magnetic MOF composites were fabricated using in situ calcination method. The as-synthesized materials exhibited both high porosity and magnetic characteristics. They used for the MSPE of polycyclic aromatic hydrocarbons (PAHs) from water samples. Such MOF-based magnetic solid-phase extraction in combination with gas chromatography equipped with a flame ionization detector (GC-FID), exhibited wide linearity (0.02-250μgL -1 ), low detection limits (4.6-8.9ngL -1 ), and high enrichment factors (452-907) for PAHs. The relative standard deviations (RSDs) for intra- and inter-day extractions of PAHs were ranging from 1.7% to 9.8% and 3.8% to 9.2%, respectively. The recoveries for spiked PAHs (1μgL -1 ) in water samples were in the range of 88.5% to 106.6%. The results showed that the special anion-π orbital (electron donor-acceptor) interaction and π-π stacking between magnetic MIL-100 and PAHs play an important role in the adsorption of PAHs. Copyright © 2017. Published by Elsevier B.V.

Preparation of Pickering emulsions stabilized by metal organic frameworks using oscillatory woven metal micro-screen.

PubMed

Sabouni, R; Gomaa, H G

2015-06-14

Uniform Pickering emulsions stabilized by metal organic frameworks (MOFs) MIL-101 and ZIF-8 nanoparticles (NPs) were successfully prepared using an oscillatory woven metal microscreen (WMMS) emulsification system in the presence and the absence of surfactants. The effects of operating and system parameters including the frequency and amplitude of oscillation, the type of nano-particle and/or surfactant on the droplet size and coefficient of variance of the prepared emulsions are investigated. The results showed that both the hydrodynamics of the system and the hydrophobic/hydrophilic nature of the NP influenced the interfacial properties of the oil-water interface during droplet formation and after detachment, which in turn affected the final droplet size and distribution. Comparison between the measured and predicted droplet size using a simple torque balance (TB) model is discussed.

Connecting defects and amorphization in UiO-66 and MIL-140 metal–organic frameworks: a combined experimental and computational study.

PubMed

Bennett, Thomas D; Todorova, Tanya K; Baxter, Emma F; Reid, David G; Gervais, Christel; Bueken, Bart; Van de Voorde, B; De Vos, Dirk; Keen, David A; Mellot-Draznieks, Caroline

2016-01-21

The mechanism and products of the structural collapse of the metal–organic frameworks (MOFs) UiO-66, MIL-140B and MIL-140C upon ball-milling are investigated through solid state 13C NMR and pair distribution function (PDF) studies, finding amorphization to proceed by the breaking of a fraction of metal–ligand bonding in each case. The amorphous products contain inorganic–organic bonding motifs reminiscent of the crystalline phases. Whilst the inorganic Zr6O4(OH)4 clusters of UiO-66 remain intact upon structural collapse, the ZrO backbone of the MIL-140 frameworks undergoes substantial distortion. Density functional theory calculations have been performed to investigate defective models of MIL-140B and show, through comparison of calculated and experimental 13C NMR spectra, that amorphization and defects in the materials are linked.

The Current Status of Hydrogen Storage in Metal-Organic Frameworks

DTIC Science & Technology

2008-06-24

they228 | Energy Environ. Sci., 2008, 1 , 222–235tested, HKUST - 1 , a MOF composed of copper ions and 1,3,5- benzenetricarboxylate,109 reaches an effective...uptake capacity at high pressure.116 In the case of HKUST - 1 , both neutron powder diffraction and inelastic neutron scattering (INS) data support that...117,118 This conclusion is confirmed indirectly by desorption studies of hydrogen in various MOFs ( HKUST - 1 , MIL-53, MOF-5, and IRMOF-8), where the

Microfluidic paper-based device for colorimetric determination of glucose based on a metal-organic framework acting as peroxidase mimetic.

PubMed

Ortiz-Gómez, Inmaculada; Salinas-Castillo, Alfonso; García, Amalia García; Álvarez-Bermejo, José Antonio; de Orbe-Payá, Ignacio; Rodríguez-Diéguez, Antonio; Capitán-Vallvey, Luis Fermín

2017-12-13

This work presents a microfluidic paper-based analytical device (μPAD) for glucose determination using a supported metal-organic framework (MOF) acting as a peroxidase mimic. The catalytic action of glucose oxidase (GOx) on glucose causes the formation of H 2 O 2 , and the MOF causes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H 2 O 2 to form a blue-green product with an absorption peak at 650 nm in the detection zone. A digital camera and the iOS feature of a smartphone are used for the quantitation of glucose with the S coordinate of the HSV color space as the analytical parameter. Different factors such as the concentration of TMB, GOx and MOF, pH and buffer, sample volume, reaction time and reagent position in the μPAD were optimized. Under optimal conditions, the value for the S coordinate increases linearly up to 150 μmol·L -1 glucose concentrations, with a 2.5 μmol·L -1 detection limit. The μPAD remains stable for 21 days under conventional storage conditions. Such an enzyme mimetic-based assay to glucose determination using Fe-MIL-101 MOF implemented in a microfluidic paper-based device possesses advantages over enzyme-based assays in terms of costs, durability and stability compared to other existing glucose determination methods. The procedure was applied to the determination of glucose in (spiked) serum and urine. Graphical abstract Schematic representation of microfluidic paper-based analytical device using metal-organic framework as a peroxidase mimic for colorimetric glucose detection with digital camera or smartphone and iOS app readout.

Ag{sup II} doped MIL-101 and its adsorption of iodine with high speed in solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, Ping; Qi, Bingbing; Liu, Ying

In order to improve the adsorption speed of iodine from water, MIL-101 with extra-large specific surface area (3054 m{sup 2}/g) was chosen as a base material, and then, Ag was doped into MIL-101 to enhance its adsorption capacity through an incipient-wetness impregnation method. With the characterization of SEM-EDS, TEM, XRD, XPS, TGA, IR, and BET techniques, the resulting Ag was identified to be stay in the framework of MIL-101 stably in the form of Ag{sup II} (generally, Ag{sup II} cation is not stable). However, after the adsorption of I{sup −} anions, Ag{sup II} stay in the cages of MIL-101 inmore » the form of AgI/AgI{sub 3}. It is important to note that, all adsorbents show high adsorption speed of iodine in solution. The equilibrium adsorption time of the adsorbents were acquired by only a few minutes, which can be attributed to its large BET surface area. An interesting note is that, when the doping amount of Ag is less than 9%, the iodine anions adsorption capacity of Ag@MIL-101 is greater than its theoretical adsorption capacity. It shows that both physical adsorption and chemical adsorption are existed in the adsorption process. This study hopefully leads to a new and highly efficient Ag-based adsorbent for iodide adsorb from solutions. - Graphical abstract: Ag{sup II} stay in the framework of MIL-101 stably because of F{sup -}, after the adsorption of I{sup -} anions, Ag{sup I}I /Ag{sup I}I{sub 3} stay in the cages of MIL-101. The equilibrium adsorption time of Ag@MIL-101 were acquired by only a few minutes. - Highlights: • Ag{sup II} was doped into MIL-101 by an incipient-wetness impregnation method. • Both physical adsorption and chemical adsorption are verified in the adsorption process. • Ag@MIL-101 exhibits high adsorption speed and adsorption capacity. • Ag@MIL-101 can be effectively applied to the removal of radioactive iodide anions from water in acidic and neutral medium.« less

An amino-functionalized magnetic framework composite of type Fe3O4-NH2@MIL-101(Cr) for extraction of pyrethroids coupled with GC-ECD.

PubMed

He, Xi; Yang, Wei; Li, Sijia; Liu, Yu; Hu, Baichun; Wang, Ting; Hou, Xiaohong

2018-01-24

An amino-functionalized magnetic framework composite of type Fe 3 O 4 -NH 2 @MIL-101(Cr) was synthesized using a solvothermal method. The material was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption, and magnetometry. The composite combines the advantages of amino-modified Fe 3 O 4 and MIL-101(Cr). The presence of amino groups facilitates the fairly specific adsorption of pyrethroids. The composite was employed as a sorbent for magnetic solid phase extraction of five pyrethroids from environmental water samples. Following desorption with acidified acetone, the pyrethroids were quantified by gas chromatography with electron capture detection. The detection limits for bifenthrin, fenpropathrin, λ-cyhalothrin, permethrin, and deltamethrin range from 5 to 9 pg·mL -1 . The method is rapid, accurate, and highly sensitive. The molecular interactions and free binding energies between MIL-101(Cr) and the five pyrethroids were calculated by means of molecular docking. Graphical abstract A novel functionalized magnetic framework composite of type Fe 3 O 4 -NH 2 @MIL-101(Cr) was synthesized. It was applied as a sorbent for magnetic solid phase extraction of pyrethroids prior to their quantitation by gas chromatography with electron capture detection. The molecular interactions of analytes and MIL-101(Cr) were studied.

Microwave assisted synthesis of metal-organic framework MIL-101 nanocrystals as sorbent and pseudostationary phase in capillary electrophoresis for the separation of anthraquinones in environmental water samples.

PubMed

Liu, Yue; Hu, Jia; Li, Yan; Shang, Yun-Tao; Wang, Jia-Qi; Zhang, Ye; Wang, Zhong-Liang

2017-10-01

In this work, a CE method was developed to separate five anthraquinones: aloe-emodin, rhein, emodin, chrysophanol, and physcion. The CE method used a nano-sized metal organic framework MIL-101 (nMIL-101) as pseudostationary phase (PSP) and sorbent for dispersed particle extraction (DPE). The nMIL-101 was synthesized by microwave technique and was characterized by UV-vis, TEM, Zeta potential, X-ray diffraction spectrometry and micropore physisorption. In this method, anthraquinones were adsorbed by nMIL-101 of a fast kinetics within 10 min and then separated by CE. The CE conditions were optimized considering time, pH, buffer ionic strength, and nanoparticles concentration. The optimal CE condition is using 20 mM sodium borate buffer (pH 9.1) containing 15% methanol (v/v) and 400 mg/L nMIL-101 as additives within 8 min. The LODs varied from 24 to 57 μg/L, which were lower than those previously reported. Our method has been successfully applied to determine trace anthraquinones in environmental water samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dye-sensitized MIL-101 metal organic frameworks loaded with Ni/NiOx nanoparticles for efficient visible-light-driven hydrogen generation

NASA Astrophysics Data System (ADS)

Liu, Xin-Ling; Wang, Rong; Zhang, Ming-Yi; Yuan, Yu-Peng; Xue, Can

2015-10-01

The Ni/NiOx particles were in situ photodeposited on MIL-101 metal organic frameworks as catalysts for boosting H2 generation from Erythrosin B dye sensitization under visible-light irradiation. The highest H2 production rate of 125 μmol h-1 was achieved from the system containing 5 wt. % Ni-loaded MIL-101 (20 mg) and 30 mg Erythrosin B dye. Moreover, the Ni/NiOx catalysts show excellent stability for long-term photocatalytic reaction. The enhancement on H2 generation is attributed to the efficient charge transfer from photoexcited dye to the Ni catalyst via MIL-101. Our results demonstrate that the economical Ni/NiOx particles are durable and active catalysts for photocatalytic H2 generation.

Metal-Organic Frameworks as Highly Active Electrocatalysts for High-Energy Density, Aqueous Zinc-Polyiodide Redox Flow Batteries.

PubMed

Li, Bin; Liu, Jian; Nie, Zimin; Wang, Wei; Reed, David; Liu, Jun; McGrail, Pete; Sprenkle, Vincent

2016-07-13

The new aqueous zinc-polyiodide redox flow battery (RFB) system with highly soluble active materials as well as ambipolar and bifunctional designs demonstrated significantly enhanced energy density, which shows great potential to reduce RFB cost. However, the poor kinetic reversibility and electrochemical activity of the redox reaction of I3(-)/I(-) couples on graphite felts (GFs) electrode can result in low energy efficiency. Two nanoporous metal-organic frameworks (MOFs), MIL-125-NH2 and UiO-66-CH3, that have high surface areas when introduced to GF surfaces accelerated the I3(-)/I(-) redox reaction. The flow cell with MOF-modified GFs serving as a positive electrode showed higher energy efficiency than the pristine GFs; increases of about 6.4% and 2.7% occurred at the current density of 30 mA/cm(2) for MIL-125-NH2 and UiO-66-CH3, respectively. Moreover, UiO-66-CH3 is more promising due to its excellent chemical stability in the weakly acidic electrolyte. This letter highlights a way for MOFs to be used in the field of RFBs.

Dehydrogenative coupling of silanes with alcohols catalyzed by Cu3(BTC)2.

PubMed

Dhakshinamoorthy, Amarajothi; Concepcion, Patricia; Garcia, Hermenegildo

2016-02-14

Cu3(BTC)2 is an efficient and reusable heterogeneous catalyst for the dehydrogenative coupling of silanes with alcohols. Activity data and CO adsorption suggest that Cu(II) and in situ generated Cu(I) are the active species. Other MOFs such as Fe(BTC), MIL-101(Cr) and UiO-66(Zr) are unable to promote this cross-coupling.

Transformation of metal-organic frameworks for molecular sieving membranes

PubMed Central

Li, Wanbin; Zhang, Yufan; Zhang, Congyang; Meng, Qin; Xu, Zehai; Su, Pengcheng; Li, Qingbiao; Shen, Chong; Fan, Zheng; Qin, Lei; Zhang, Guoliang

2016-01-01

The development of simple, versatile strategies for the synthesis of metal-organic framework (MOF)-derived membranes are of increasing scientific interest, but challenges exist in understanding suitable fabrication mechanisms. Here we report a route for the complete transformation of a series of MOF membranes and particles, based on multivalent cation substitution. Through our approach, the effective pore size can be reduced through the immobilization of metal salt residues in the cavities, and appropriate MOF crystal facets can be exposed, to achieve competitive molecular sieving capabilities. The method can also be used more generally for the synthesis of a variety of MOF membranes and particles. Importantly, we design and synthesize promising MOF membranes candidates that are hard to achieve through conventional methods. For example, our CuBTC/MIL-100 membrane exhibits 89, 171, 241 and 336 times higher H2 permeance than that of CO2, O2, N2 and CH4, respectively. PMID:27090597

Correlation of Gas Permeability in a Metal-Organic Framework MIL-101(Cr)–Polysulfone Mixed-Matrix Membrane with Free Volume Measurements by Positron Annihilation Lifetime Spectroscopy (PALS)

PubMed Central

Jeazet, Harold B. Tanh; Koschine, Tönjes; Staudt, Claudia; Raetzke, Klaus; Janiak, Christoph

2013-01-01

Hydrothermally stable particles of the metal-organic framework MIL-101(Cr) were incorporated into a polysulfone (PSF) matrix to produce mixed-matrix or composite membranes with excellent dispersion of MIL-101 particles and good adhesion within the polymer matrix. Pure gas (O2, N2, CO2 and CH4) permeation tests showed a significant increase of gas permeabilities of the mixed-matrix membranes without any loss in selectivity. Positron annihilation lifetime spectroscopy (PALS) indicated that the increased gas permeability is due to the free volume in the PSF polymer and the added large free volume inside the MIL-101 particles. The trend of the gas transport properties of the composite membranes could be reproduced by a Maxwell model. PMID:24957061

Screening metal-organic frameworks for selective noble gas adsorption in air: effect of pore size and framework topology.

PubMed

Parkes, Marie V; Staiger, Chad L; Perry, John J; Allendorf, Mark D; Greathouse, Jeffery A

2013-06-21

The adsorption of noble gases and nitrogen by sixteen metal-organic frameworks (MOFs) was investigated using grand canonical Monte Carlo simulation. The MOFs were chosen to represent a variety of net topologies, pore dimensions, and metal centers. Three commercially available MOFs (HKUST-1, AlMIL-53, and ZIF-8) and PCN-14 were also included for comparison. Experimental adsorption isotherms, obtained from volumetric and gravimetric methods, were used to compare krypton, argon, and nitrogen uptake with the simulation results. Simulated trends in gas adsorption and predicted selectivities among the commercially available MOFs are in good agreement with experiment. In the low pressure regime, the expected trend of increasing adsorption with increasing noble gas polarizabilty is seen. For each noble gas, low pressure adsorption correlates with several MOF properties, including free volume, topology, and metal center. Additionally, a strong correlation exists between the Henry's constant and the isosteric heat of adsorption for all gases and MOFs considered. Finally, we note that the simulated and experimental gas selectivities demonstrated by this small set of MOFs show improved performance compared to similar values reported for zeolites.

TiO2-Containing Carbon Derived from a Metal-Organic Framework Composite: A Highly Active Catalyst for Oxidative Desulfurization.

PubMed

Bhadra, Biswa Nath; Song, Ji Yoon; Khan, Nazmul Abedin; Jhung, Sung Hwa

2017-09-13

A new metal-organic framework (MOF) composite consisting of Ti- and Zn-based MOFs (ZIF-8(x)@H 2 N-MIL-125; in brief, ZIF(x)@MOF) was designed and synthesized. The pristine MOF [H 2 N-MIL-125 (MOF)]- and an MOF-composite [ZIF(30)@MOF]-derived mesoporous carbons consisting of TiO 2 nanoparticles were prepared by pyrolysis (named MDC-P and MDC-C, respectively). MDC-C showed a higher surface area, larger pore sizes, and larger mesopore volumes than MDC-P. In addition, the TiO 2 nanoparticles on MDC-C have more uniform shapes and sizes and are smaller than those of MDC-P. The obtained MDC-C and MDC-P [together with MOF, ZIF(30)@MOF, pure/nanocrystalline TiO 2 , and activated carbon] were applied in the oxidative desulfurization reaction of dibenzothiophene in a model fuel. The MDC-C, even with a lower TiO 2 content than that of MDC-P, showed an outstanding catalytic performance, especially with a very low catalyst dose (i.e., a very high quantity of dibenzothiophene was converted per unit weight of the catalyst), fast kinetics (∼3 times faster than that for MDC-P), and a low activation energy (lower than that for any reported catalyst) for the oxidation of dibenzothiophene. The large mesopores of MDC-C and the well-dispersed/small TiO 2 might be the dominant factors for the superior catalytic conversions. The oxidative desulfurization of other sulfur-containing organic compounds with various electron densities was also studied with MDC-C to understand the mechanism of catalysis. Moreover, the MDC-C catalyst can be reused many times in the oxidative desulfurization reaction after a simple washing with acetone. Finally, composing MOFs and subsequent pyrolysis is suggested as an effective way to prepare a catalyst with well-dispersed active sites, large pores, and high mesoporosity.

Magnetic Control of MOF Crystal Orientation and Alignment.

PubMed

Cheng, Fei; Marshall, Ellis S; Young, Adam J; Robinson, Peter J; Bouillard, Jean-Sebastien G; Adawi, Ali M; Vermeulen, Nicolaas A; Farha, Omar K; Reithofer, Michael R; Chin, Jia Min

2017-11-07

Most metal-organic frameworks (MOFs) possess anisotropic properties, the full exploitation of which necessitates a general strategy for the controllable orientation of such MOF crystals. Current methods largely rely upon layer-by-layer MOF epitaxy or tuning of MOF crystal growth on appropriate substrates, yielding MOFs with fixed crystal orientations. Here, the dynamic magnetic alignment of different MOF crystals (NH 2 -MIL-53(Al) and NU-1000) is shown. The MOFs were magnetized by electrostatic adsorption of iron oxide nanoparticles, dispersed in curable polymer resins (Formlabs 1+ clear resin/ Sylgard 184), magnetically oriented, and fixed by resin curing. The importance of crystal orientation on MOF functionality was demonstrated whereby magnetically aligned NU-1000/Sylgard 184 composite was excited with linearly polarized 405 nm light, affording an anisotropic fluorescence response dependent on the polarization angle of the excitation beam relative to NU-1000 crystal orientation. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dye-sensitized MIL-101 metal organic frameworks loaded with Ni/NiO{sub x} nanoparticles for efficient visible-light-driven hydrogen generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xin-Ling; Wang, Rong; Yuan, Yu-Peng, E-mail: yupengyuan@ahu.edu.cn, E-mail: cxue@ntu.edu.sg

2015-10-01

The Ni/NiO{sub x} particles were in situ photodeposited on MIL-101 metal organic frameworks as catalysts for boosting H{sub 2} generation from Erythrosin B dye sensitization under visible-light irradiation. The highest H{sub 2} production rate of 125 μmol h{sup −1} was achieved from the system containing 5 wt. % Ni-loaded MIL-101 (20 mg) and 30 mg Erythrosin B dye. Moreover, the Ni/NiO{sub x} catalysts show excellent stability for long-term photocatalytic reaction. The enhancement on H{sub 2} generation is attributed to the efficient charge transfer from photoexcited dye to the Ni catalyst via MIL-101. Our results demonstrate that the economical Ni/NiO{sub x}more » particles are durable and active catalysts for photocatalytic H{sub 2} generation.« less

Magnetic iron(III)-based framework composites for the magnetic solid-phase extraction of fungicides from environmental water samples.

PubMed

Huang, Yan-Feng; Liu, Qiao-Huan; Li, Kang; Li, Ying; Chang, Na

2018-03-01

We adopted a facile hydrofluoric acid-free hydro-/solvothermal method for the preparation of four magnetic iron(III)-based framework composites (MIL-101@Fe 3 O 4 -COOH, MIL-101-NH 2 @Fe 3 O 4 -COOH, MIL-53@Fe 3 O 4 -COOH, and MIL-53-NH 2 @Fe 3 O 4 -COOH). The obtained four magnetic iron(III)-based framework composites were applied to magnetic separation and enrichment of the fungicides (prochloraz, myclobutanil, tebuconazole, and iprodione) from environmental samples before high-performance liquid chromatographic analysis. MIL-101-NH 2 @Fe 3 O 4 -COOH showed more remarkable pre-concentration ability for the fungicides as compared to the other three magnetic iron(III)-based framework composites. The extraction parameters affecting enrichment efficiency including extraction time, sample pH, elution time, and the desorption solvent were investigated and optimized. Under the optimized conditions, the standard curve of correlation coefficients were all above 0.991, the limits of detection were 0.04-0.4 μg/L, and the relative standard deviations were below 10.2%. The recoveries of two real water samples ranged from 71.1-99.1% at the low spiking level (30 μg/L). Therefore, the MIL-101-NH 2 @Fe 3 O 4 -COOH composites are attractive for the rapid and efficient extraction of fungicides from environmental water samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, Structural Characterization and Up-Conversion Luminescence Properties of NaYF4:Er3+,Yb3+@MOFs Nanocomposites

NASA Astrophysics Data System (ADS)

Giang, Lam Thi Kieu; Marciniak, Lukasz; Huy, Tran Quang; Vu, Nguyen; Le, Ngo Thi Hong; Binh, Nguyen Thanh; Lam, Tran Dai; Minh, Le Quoc

2017-10-01

This paper describes a facile synthesis of NaYF4:Er3+,Yb3+ nanoparticles embraced in metal-organic frameworks (MOFs), known as NaYF4:Er3+, Yb3+@MOFs core/shell nanostructures, by using iron(III) carboxylate (MIL-100) and zeolitic imidazolate frameworks (ZIF-8). Morphological, structural and optical characterization of these nanostructures were investigated by field emission-scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, and up-conversion luminescence measurements. Results showed that spherical-shaped NaYF4:Er3+,Yb3+@MIL-100 nanocomposites with diameters of 150-250 nm, and rod-shaped NaYF4:Er3+,Yb3+@ZIF-8 nanocomposites with lengths of 300-550 nm, were successfully synthesized. Under a 980-nm laser excitation at room temperature, the NaYF4:Er3+,Yb3+@MOFs nanocomposites exhibited strong up-conversion luminescence with two emission bands in the green part of spectrum at 520 nm and 540 nm corresponding to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ ions, respectively, and a red emission band at 655 nm corresponding to the 4F9/2 → 4I15/2 transition of Er3+ ions. The above properties of NaYF4:Er3+,Yb3+@MOFs make them promising candidates for applications in biotechnology.

Metal-organic frameworks as selectivity regulators for hydrogenation reactions

NASA Astrophysics Data System (ADS)

Zhao, Meiting; Yuan, Kuo; Wang, Yun; Li, Guodong; Guo, Jun; Gu, Lin; Hu, Wenping; Zhao, Huijun; Tang, Zhiyong

2016-11-01

Owing to the limited availability of natural sources, the widespread demand of the flavouring, perfume and pharmaceutical industries for unsaturated alcohols is met by producing them from α,β-unsaturated aldehydes, through the selective hydrogenation of the carbon-oxygen group (in preference to the carbon-carbon group). However, developing effective catalysts for this transformation is challenging, because hydrogenation of the carbon-carbon group is thermodynamically favoured. This difficulty is particularly relevant for one major category of heterogeneous catalyst: metal nanoparticles supported on metal oxides. These systems are generally incapable of significantly enhancing the selectivity towards thermodynamically unfavoured reactions, because only the edges of nanoparticles that are in direct contact with the metal-oxide support possess selective catalytic properties; most of the exposed nanoparticle surfaces do not. This has inspired the use of metal-organic frameworks (MOFs) to encapsulate metal nanoparticles within their layers or inside their channels, to influence the activity of the entire nanoparticle surface while maintaining efficient reactant and product transport owing to the porous nature of the material. Here we show that MOFs can also serve as effective selectivity regulators for the hydrogenation of α,β-unsaturated aldehydes. Sandwiching platinum nanoparticles between an inner core and an outer shell composed of an MOF with metal nodes of Fe3+, Cr3+ or both (known as MIL-101; refs 19, 20, 21) results in stable catalysts that convert a range of α,β-unsaturated aldehydes with high efficiency and with significantly enhanced selectivity towards unsaturated alcohols. Calculations reveal that preferential interaction of MOF metal sites with the carbon-oxygen rather than the carbon-carbon group renders hydrogenation of the former by the embedded platinum nanoparticles a thermodynamically favoured reaction. We anticipate that our basic design strategy will allow the development of other selective heterogeneous catalysts for important yet challenging transformations.

Metal-organic frameworks as selectivity regulators for hydrogenation reactions.

PubMed

Zhao, Meiting; Yuan, Kuo; Wang, Yun; Li, Guodong; Guo, Jun; Gu, Lin; Hu, Wenping; Zhao, Huijun; Tang, Zhiyong

2016-11-03

Owing to the limited availability of natural sources, the widespread demand of the flavouring, perfume and pharmaceutical industries for unsaturated alcohols is met by producing them from α,β-unsaturated aldehydes, through the selective hydrogenation of the carbon-oxygen group (in preference to the carbon-carbon group). However, developing effective catalysts for this transformation is challenging, because hydrogenation of the carbon-carbon group is thermodynamically favoured. This difficulty is particularly relevant for one major category of heterogeneous catalyst: metal nanoparticles supported on metal oxides. These systems are generally incapable of significantly enhancing the selectivity towards thermodynamically unfavoured reactions, because only the edges of nanoparticles that are in direct contact with the metal-oxide support possess selective catalytic properties; most of the exposed nanoparticle surfaces do not. This has inspired the use of metal-organic frameworks (MOFs) to encapsulate metal nanoparticles within their layers or inside their channels, to influence the activity of the entire nanoparticle surface while maintaining efficient reactant and product transport owing to the porous nature of the material. Here we show that MOFs can also serve as effective selectivity regulators for the hydrogenation of α,β-unsaturated aldehydes. Sandwiching platinum nanoparticles between an inner core and an outer shell composed of an MOF with metal nodes of Fe 3+ , Cr 3+ or both (known as MIL-101; refs 19, 20, 21) results in stable catalysts that convert a range of α,β-unsaturated aldehydes with high efficiency and with significantly enhanced selectivity towards unsaturated alcohols. Calculations reveal that preferential interaction of MOF metal sites with the carbon-oxygen rather than the carbon-carbon group renders hydrogenation of the former by the embedded platinum nanoparticles a thermodynamically favoured reaction. We anticipate that our basic design strategy will allow the development of other selective heterogeneous catalysts for important yet challenging transformations.

Ship-in-a-bottle CMPO in MIL-101(Cr) for selective uranium recovery from aqueous streams through adsorption.

PubMed

De Decker, Jeroen; Folens, Karel; De Clercq, Jeriffa; Meledina, Maria; Van Tendeloo, Gustaaf; Du Laing, Gijs; Van Der Voort, Pascal

2017-08-05

Mesoporous MIL-101(Cr) is used as host for a ship-in-a-bottle type adsorbent for selective U(VI) recovery from aqueous environments. The acid-resistant cage-type MOF is built in-situ around N,N-Diisobutyl-2-(octylphenylphosphoryl)acetamide (CMPO), a sterically demanding ligand with high U(VI) affinity. This one-step procedure yields an adsorbent which is an ideal compromise between homogeneous and heterogeneous systems, where the ligand can act freely within the pores of MIL-101, without leaching, while the adsorbent is easy separable and reusable. The adsorbent was characterized by XRD, FTIR spectroscopy, nitrogen adsorption, XRF, ADF-STEM and EDX, to confirm and quantify the successful encapsulation of the CMPO in MIL-101, and the preservation of the host. Adsorption experiments with a central focus on U(VI) recovery were performed. Very high selectivity for U(VI) was observed, while competitive metal adsorption (rare earths, transition metals...) was almost negligible. The adsorption capacity was calculated at 5.32mg U/g (pH 3) and 27.99mg U/g (pH 4), by fitting equilibrium data to the Langmuir model. Adsorption kinetics correlated to the pseudo-second-order model, where more than 95% of maximum uptake is achieved within 375min. The adsorbed U(VI) is easily recovered by desorption in 0.1M HNO 3 . Three adsorption/desorption cycles were performed. Copyright © 2017 Elsevier B.V. All rights reserved.

Novel Metal-Organic Framework (MOF) Based Composite Material for the Sequestration of U(VI) and Th(IV) Metal Ions from Aqueous Environment.

PubMed

Alqadami, Ayoub Abdullah; Naushad, Mu; Alothman, Zeid Abdullah; Ghfar, Ayman A

2017-10-18

The combination of magnetic nanoparticles and metal-organic frameworks (MOFs) has demonstrated their prospective for pollutant sequestration. In this work, a magnetic metal-organic framework nanocomposite (Fe 3 O 4 @AMCA-MIL53(Al) was prepared and used for the removal of U(VI) and Th(IV) metal ions from aqueous environment. Fe 3 O 4 @AMCA-MIL53(Al) nanocomposite was characterized by TGA, FTIR, SEM-EDX, XRD, HRTEM, BET, VSM (vibrating sample magnetometry), and XPS analyses. A batch technique was applied for the removal of the aforesaid metal ions using Fe 3 O 4 @AMCA-MIL53(Al) at different operating parameters. The isotherm and kinetic data were accurately described by the Langmuir and pseudo-second-order models. The adsorption capacity was calculated to be 227.3 and 285.7 mg/g for U(VI) and Th(IV), respectively, by fitting the equilibrium data to the Langmuir model. The kinetic studies demonstrated that the equilibrium time was 90 min for each metal ion. Various thermodynamic parameters were evaluated which indicated the endothermic and spontaneous nature of adsorption. The collected outcomes showed that Fe 3 O 4 @AMCA-MIL53(Al) was a good material for the exclusion of these metal ions from aqueous medium. The adsorbed metals were easily recovered by desorption in 0.01 M HCl. The excellent adsorption capacity and the response to the magnetic field made this novel material an auspicious candidate for environmental remediation technologies.

Phosphotungstic acid encapsulated in the mesocages of amine-functionalized metal-organic frameworks for catalytic oxidative desulfurization.

PubMed

Wang, Xu-Sheng; Huang, Yuan-Biao; Lin, Zu-Jin; Cao, Rong

2014-08-21

Highly dispersed Keggin-type phosphotungstic acid (H3PW12O40, PTA) encapsulated in the mesocages of amine-functionalized metal-organic frameworks MIL-101(Cr)-NH2 has been prepared by an anion-exchange method. PTA anions (PW12O40(3-)) are stabilized in the mesocages via the electrostatic interaction with amino groups of the MIL-101(Cr)-NH2. The obtained catalyst (denoted PTA@MIL-101(Cr)-NH2) exhibits high catalytic activity in the extractive and catalytic oxidative desulfurization (ECODS) system under mild conditions. Moreover, it can be easily recovered and recycled several times without leaching and loss of activity.

Helically structured metal–organic frameworks fabricated by using supramolecular assemblies as templates† †Electronic supplementary information (ESI) available: Detailed TEM images and other extensive figures. See DOI: 10.1039/c4sc03278k Click here for additional data file.

PubMed Central

Wang, Hui; Zhu, Wei; Li, Jian; Tian, Tian; Lan, Yue; Gao, Ning; Wang, Chen; Zhang, Meng; Faul, Charl F. J.

2015-01-01

The controlled formation of MOF-based superstructures with well-defined nanoscale sizes and exquisite morphologies represents a big challenge, but can trigger a new set of properties distinct from their bulk counterparts. Here we report on the use of a self-assembled organic object to template the first example of a nanoscale metal–organic framework (MOF) with a helical morphology. Two prototypical MOFs (HKUST-1 and MIL-100) were used to exemplify the growth of such materials on supramolecular assemblies. Interestingly, it was found that, dependent on the nature of the precursors, not only could well-defined helical MOF nanotubes be facilely fabricated, but novel helical bundle nanostructures could also be formed. These resultant MOF superstructures show additional optical properties and could be used as precursors for the preparation of chiral nanocarbons. PMID:28757993

Selective O 2 sorption at ambient temperatures via node distortions in Sc-MIL-100

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sava Gallis, Dorina F.; Chapman, Karena W.; Rodriguez, Mark A.

2016-04-14

In this study, oxygen selectivity in metal-organic frameworks (MOFs) at exceptionally high temperatures originally predicted by Density Functional Theory (DFT) and Grand Canonical Monte Carlo (GCMC) modeling is now confirmed by synthesis, sorption metal center access, in particular Sc and Fe. Based on DFT M-O 2 binding energies, we chose the large pored MIL-100 framework for metal center access, in particular Sc and Fe. Both resulted in preferential O 2 and N 2 gas uptake at temperatures ranging from 77 K to ambient temperatures (258 K, 298 K and 313 K).

A novel metal-organic framework composite MIL-101(Cr)@GO as an efficient sorbent in dispersive micro-solid phase extraction coupling with UHPLC-MS/MS for the determination of sulfonamides in milk samples.

PubMed

Jia, Xiuna; Zhao, Pan; Ye, Xiu; Zhang, Lianjun; Wang, Ting; Chen, Qinyu; Hou, Xiaohong

2017-07-01

As a novel material, metal-organic framework/graphite oxide (MIL-101(Cr)@GO) has great potential for the pretreatment of trace analytes. In the present study, MIL-101(Cr)@GO was synthesized using a solvothermal synthesis method at the nanoscale and was applied as sorbent in the dispersive micro-solid phase extraction (DMSPE) for the enrichment of the trace sulfonamides (SAs) from milk samples for the first time. Several experimental parameters including kinds of sorbents, the effect of pH, the amount of MIL-101(Cr)@GO, ionic strength, adsorption time, desorption solvent and desorption time were investigated. Under the optimal conditions, the linear ranges were from 0.1 to 10μg/L, 0.2-20μg/L or 0.5-50μg/L for the analytes with regression coefficients (r) from 0.9942 to 0.9999. The limits of detection were between 0.012 and 0.145μg/L. The recoveries ranged from 79.83% to 103.8% with relative standard deviations (RSDs)<10% (n=3). MIL-101(Cr)@GO exhibited remarkable advantages compared to MIL-101(Cr), MIL-100(Fe), activated carbon and other sorbent materials used in pretreatment methods. A simple, rapid, sensitive, inexpensive and less solvent consuming method of DMSPE-ultra-high performance liquid chromatography-tandem mass spectrometry (DMSPE-UHPLC-MS/MS) was successfully applied to the pre-concentration and determination of twelve SAs in milk samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Size- and morphology-controllable synthesis of MIL-96 (Al) by hydrolysis and coordination modulation of dual aluminium source and ligand systems.

PubMed

Liu, Dandan; Liu, Yunqi; Dai, Fangna; Zhao, Jinchong; Yang, Kang; Liu, Chenguang

2015-10-07

In this paper, an efficient method to fabricate Al-based metal organic framework (Al-MOF) MIL-96 crystals with controllable size and morphology, by mixing other forms of reactants to replace the coordination modulators or capping agents, is presented. The size and morphology of the MIL-96 crystals can be selectively varied by simply altering the ratio of dual reactants via their hydrolysis reaction. All the samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and nitrogen sorption. Then based on the BFDH theory, a mechanism for the impact of hydrolysis of reactants on the crystal size and morphology is presented and discussed. We also evaluated the performance of these MOFs as sorbents for capturing CO2, and they all show enhanced adsorption properties compared with the bulk material, displaying high adsorption capacities on CO2 at atmospheric pressure and ambient temperature.

Sorptive extraction using polydimethylsiloxane/metal-organic framework coated stir bars coupled with high performance liquid chromatography-fluorescence detection for the determination of polycyclic aromatic hydrocarbons in environmental water samples.

PubMed

Hu, Cong; He, Man; Chen, Beibei; Zhong, Cheng; Hu, Bin

2014-08-22

In this work, metal-organic frameworks (MOFs, Al-MIL-53-NH₂) were synthesized via the hydrothermal method, and novel polydimethylsiloxane/metal-organic framework (PDMS/MOFs, PDMS/Al-MIL-53-NH₂)-coated stir bars were prepared by the sol-gel technique. The preparation reproducibility of the PDMS/MOFs-coated stir bar was good, with relative standard deviations (RSDs) ranging from 4.8% to 14.9% (n=7) within one batch and from 6.2% to 16.9% (n=6) among different batches. Based on this fact, a new method of PDMS/MOFs-coated stir bar sorptive extraction (SBSE) and ultrasonic-assisted liquid desorption (UALD) coupled with high performance liquid chromatography-fluorescence detection (HPLC-FLD) was developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. To obtain the best extraction performance for PAHs, several parameters affecting SBSE, such as extraction time, stirring rate, and extraction temperature, were investigated. Under optimal experimental conditions, wide linear ranges and good RSDs (n=7) were obtained. With enrichment factors (EFs) of 16.1- to 88.9-fold (theoretical EF, 142-fold), the limits of detection (LODs, S/N=3) of the developed method for the target PAHs were found to be in the range of 0.05-2.94 ng/L. The developed method was successfully applied to the analysis of PAHs in Yangtze River and East Lake water samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Isosteric heat of hydrogen adsorption on MOFs: comparison between adsorption calorimetry, sorption isosteric method, and analytical models

NASA Astrophysics Data System (ADS)

Kloutse, A. F.; Zacharia, R.; Cossement, D.; Chahine, R.; Balderas-Xicohténcatl, R.; Oh, H.; Streppel, B.; Schlichtenmayer, M.; Hirscher, M.

2015-12-01

Isosteric heat of adsorption is an important parameter required to describe the thermal performance of adsorptive storage systems. It is most frequently calculated from adsorption isotherms measured over wide ranges of pressure and temperature, using the so-called adsorption isosteric method. Direct quantitative estimation of isosteric heats on the other hand is possible using the coupled calorimetric-volumetric method, which involves simultaneous measurement of heat and adsorption. In this work, we compare the isosteric heats of hydrogen adsorption on microporous materials measured by both methods. Furthermore, the experimental data are compared with the isosteric heats obtained using the modified Dubinin-Astakhov, Tóth, and Unilan adsorption analytical models to establish the reliability and limitations of simpler methods and assumptions. To this end, we measure the hydrogen isosteric heats on five prototypical metal-organic frameworks: MOF-5, Cu-BTC, Fe-BTC, MIL-53, and MOF-177 using both experimental methods. For all MOFs, we find a very good agreement between the isosteric heats measured using the calorimetric and isosteric methods throughout the range of loading studied. Models' prediction on the other hand deviates from both experiments depending on the MOF studied and the range of loading. Under low-loadings of less than 5 mol kg-1, the isosteric heat of hydrogen adsorption decreases in the order Cu-BTC > MIL-53 > MOF-5 > Fe-BTC > MOF-177. The order of isosteric heats is coherent with the strength of hydrogen interaction revealed from previous thermal desorption spectroscopy measurements.

Pore Breathing of Metal-Organic Frameworks by Environmental Transmission Electron Microscopy.

PubMed

Parent, Lucas R; Pham, C Huy; Patterson, Joseph P; Denny, Michael S; Cohen, Seth M; Gianneschi, Nathan C; Paesani, Francesco

2017-10-11

Metal-organic frameworks (MOFs) have emerged as a versatile platform for the rational design of multifunctional materials, combining large specific surface areas with flexible, periodic frameworks that can undergo reversible structural transitions, or "breathing", upon temperature and pressure changes, and through gas adsorption/desorption processes. Although MOF breathing can be inferred from the analysis of adsorption isotherms, direct observation of the structural transitions has been lacking, and the underlying processes of framework reorganization in individual MOF nanocrystals is largely unknown. In this study, we describe the characterization and elucidation of these processes through the combination of in situ environmental transmission electron microscopy (ETEM) and computer simulations. This combined approach enables the direct monitoring of the breathing behavior of individual MIL-53(Cr) nanocrystals upon reversible water adsorption and temperature changes. The ability to characterize structural changes in single nanocrystals and extract lattice level information through in silico correlation provides fundamental insights into the relationship between pore size/shape and host-guest interactions.

Thin Film Nanocomposite Membrane Filled with Metal-Organic Frameworks UiO-66 and MIL-125 Nanoparticles for Water Desalination

PubMed Central

Kadhom, Mohammed; Hu, Weiming; Deng, Baolin

2017-01-01

Knowing that the world is facing a shortage of fresh water, desalination, in its different forms including reverse osmosis, represents a practical approach to produce potable water from a saline source. In this report, two kinds of Metal-Organic Frameworks (MOFs) nanoparticles (NPs), UiO-66 (~100 nm) and MIL-125 (~100 nm), were embedded separately into thin-film composite membranes in different weight ratios, 0%, 0.05%, 0.1%, 0.15%, 0.2%, and 0.3%. The membranes were synthesized by the interfacial polymerization (IP) of m-phenylenediamine (MPD) in aqueous solution and trimesoyl chloride (TMC) in an organic phase. The as-prepared membranes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), contact angle measurement, attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy, and salt rejection and water flux assessments. Results showed that both UiO-66 and MIL-125 could improve the membranes’ performance and the impacts depended on the NPs loading. At the optimum NPs loadings, 0.15% for UiO-66 and 0.3% for MIL-125, the water flux increased from 62.5 L/m2 h to 74.9 and 85.0 L/m2 h, respectively. NaCl rejection was not significantly affected (UiO-66) or slightly improved (MIL-125) by embedding these NPs, always at >98.5% as tested at 2000 ppm salt concentration and 300 psi transmembrane pressure. The results from this study demonstrate that it is promising to apply MOFs NPs to enhance the TFC membrane performance for desalination. PMID:28613247

Fe3O4 and metal-organic framework MIL-101(Fe) composites catalyze luminol chemiluminescence for sensitively sensing hydrogen peroxide and glucose.

PubMed

Qian Tang, Xue; Dan Zhang, Yi; Wei Jiang, Zhong; Mei Wang, Dong; Zhi Huang, Cheng; Fang Li, Yuan

2018-03-01

In this work, Fe 3 O 4 and metal-organic framework MIL-101(Fe) composites (Fe 3 O 4 /MIL-101(Fe)) was demonstrated to possess excellent catalytic property to directly catalyze luminol chemiluminescence without extra oxidants. We utilized Fe 3 O 4 /MIL-101(Fe) to develop a ultra-sensitive quantitative analytical method for H 2 O 2 and glucose. The possible mechanism of the chemiluminescence reaction had been investigated. Under optimal conditions, the relative chemiluminescence intensity was linearly proportional to the logarithm of H 2 O 2 concentration in the range of 5-150nM with a limit of detection of 3.7nM (signal-to-noise ratio = 3), and glucose could be linearly detected in the range from 5 to 100nM and the detection limit was 4.9nM (signal-to-noise ratio = 3). Furthermore, the present approach was successfully applied to quantitative determination of H 2 O 2 in medical disinfectant and glucose in human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

A multifunctional hemin@metal-organic framework and its application to construct an electrochemical aptasensor for thrombin detection

NASA Astrophysics Data System (ADS)

Xie, Shunbi; Ye, Jiawei; Yuan, Yali; Chai, Yaqin; Yuan, Ruo

2015-10-01

A new type of multifunctional metal-organic framework (MOF) has been synthesized by encapsulating hemin into the nano-sized Fe-MIL-88 MOFs (hemin@MOFs) and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of an enzyme for signal amplification. The gold nanoparticle functionalized hemin@MOFs (Au/hemin@MOFs) have not only simultaneously served as redox mediators and solid electrocatalysts, but have also been utilized as an ideal loading platform to immobilize a large number of biomolecules. In this aptasensor, Au/hemin@MOFs conjugated with glucose oxidase (GOD) and thrombin binding aptamer (TBA II) were used as the secondary aptamer bioconjugates (Au/hemin@MOF-TBA II-GOD bioconjugates), and TB was sandwiched between Au/hemin@MOF-TBA II-GOD bioconjugates and the amino-terminated TBA I which was self-assembled on the gold nanoparticle (AuNP) modified electrode. The GOD could oxidize glucose into gluconic acid accompanied by the generation of H2O2. The generated H2O2 on the electrode surface was further electrocatalyzed by hemin@MOFs to amplify the electrochemical signal of hemin contained in hemin@MOFs. Therefore, the synthesized hemin@MOFs represented a new paradigm for multifunctional materials since it combined three different functions including serving as catalysts, redox mediators and loading platforms within a single material. With such an ingenious design, a wide linear range of 0.0001 nM to 30 nM was acquired with a relatively low detection limit of 0.068 pM for TB detection.A new type of multifunctional metal-organic framework (MOF) has been synthesized by encapsulating hemin into the nano-sized Fe-MIL-88 MOFs (hemin@MOFs) and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of an enzyme for signal amplification. The gold nanoparticle functionalized hemin@MOFs (Au/hemin@MOFs) have not only simultaneously served as redox mediators and solid electrocatalysts, but have also been utilized as an ideal loading platform to immobilize a large number of biomolecules. In this aptasensor, Au/hemin@MOFs conjugated with glucose oxidase (GOD) and thrombin binding aptamer (TBA II) were used as the secondary aptamer bioconjugates (Au/hemin@MOF-TBA II-GOD bioconjugates), and TB was sandwiched between Au/hemin@MOF-TBA II-GOD bioconjugates and the amino-terminated TBA I which was self-assembled on the gold nanoparticle (AuNP) modified electrode. The GOD could oxidize glucose into gluconic acid accompanied by the generation of H2O2. The generated H2O2 on the electrode surface was further electrocatalyzed by hemin@MOFs to amplify the electrochemical signal of hemin contained in hemin@MOFs. Therefore, the synthesized hemin@MOFs represented a new paradigm for multifunctional materials since it combined three different functions including serving as catalysts, redox mediators and loading platforms within a single material. With such an ingenious design, a wide linear range of 0.0001 nM to 30 nM was acquired with a relatively low detection limit of 0.068 pM for TB detection. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04532k

MIL-100 derived nitrogen-embodied carbon shells embedded with iron nanoparticles

NASA Astrophysics Data System (ADS)

Mao, Chengyu; Kong, Aiguo; Wang, Yuan; Bu, Xianhui; Feng, Pingyun

2015-06-01

The use of metal-organic frameworks (MOFs) as templates and precursors to synthesize new carbon materials with controllable morphology and pre-selected heteroatom doping holds promise for applications as efficient non-precious metal catalysts. Here, we report a facile pyrolysis pathway to convert MIL-100 into nitrogen-doped carbon shells encapsulating Fe nanoparticles in a comparative study involving multiple selected nitrogen sources. The hierarchical porous architecture, embedded Fe nanoparticles, and nitrogen decoration endow this composite with a superior oxygen reduction activity. Furthermore, the excellent durability and high methanol tolerance even outperform the commercial Pt-C catalyst.The use of metal-organic frameworks (MOFs) as templates and precursors to synthesize new carbon materials with controllable morphology and pre-selected heteroatom doping holds promise for applications as efficient non-precious metal catalysts. Here, we report a facile pyrolysis pathway to convert MIL-100 into nitrogen-doped carbon shells encapsulating Fe nanoparticles in a comparative study involving multiple selected nitrogen sources. The hierarchical porous architecture, embedded Fe nanoparticles, and nitrogen decoration endow this composite with a superior oxygen reduction activity. Furthermore, the excellent durability and high methanol tolerance even outperform the commercial Pt-C catalyst. Electronic supplementary information (ESI) available: Material synthesis and elemental analysis, electrochemistry measurements, and additional figures. See DOI: 10.1039/c5nr02346g

MOF-Bacteriophage Biosensor for Highly Sensitive and Specific Detection of Staphylococcus aureus.

PubMed

Bhardwaj, Neha; Bhardwaj, Sanjeev K; Mehta, Jyotsana; Kim, Ki-Hyun; Deep, Akash

2017-10-04

To produce a sensitive and specific biosensor for Staphylococcus aureus, bacteriophages have been interfaced with a water-dispersible and environmentally stable metal-organic framework (MOF), NH 2 -MIL-53(Fe). The conjugation of the MOF with bacteriophages has been achieved through the use of glutaraldehyde as cross-linker. Highly sensitive detection of S. aureus in both synthetic and real samples was realized by the proposed MOF-bacteriophage biosensor based on the photoluminescence quenching phenomena: limit of detection (31 CFU/mL) and range of detection (40 to 4 × 10 8 CFU/mL). This is the first report exploiting the use of an MOF-bacteriophage complex for the biosensing of S. aureus. The results of our study highlight that the proposed biosensor is more sensitive than most of the previous methods while exhibiting some advanced features like specificity, regenerability, extended range of linear detection, and stability for long-term storage (even at room temperature).

Preparation of alumina-hercynite nano-spinel via one-step thermal conversion of Fe-doped metal-organic framework MIL-53(Al)

NASA Astrophysics Data System (ADS)

Chen, Shuyi; Lu, Huigong; Wu, Yi-nan; Gu, Yifan; Li, Fengting; Morlay, Catherine

2016-09-01

Alumina-hercynite nano-spinel powders were prepared via one-step pyrolysis of iron-acetylacetone-doped Al-based metal-organic framework (MOF), i.e., MIL-53(Al). Organic ferric source, iron acetylacetone, was incorporated in situ into the framework of MIL-53(Al) during the solvothermal synthesis process. Under high-temperature pyrolysis, alumina derived from the MIL-53(Al) matrix and ferric oxides originated from the decomposition of organic ferric precursor in the framework were thermally converted into hercynite (FeAl2O4). The prepared samples were characterized using transmission electron microscopy, X-ray diffraction, N2 sorption, thermogravimetry, Raman spectroscopy and X-ray photoelectron spectroscopy. The final products were identified to be composed of alumina, hercynite and trace amounts of carbon depending on pyrolysis temperature. The experimental results showed that hercynite phase can be obtained and stabilized at low temperatures between 900 and 1100 °C under inert atmosphere. The final products were composed of nano-sized particles with an average size below 100 nm of individual crystal and specific surface areas of 18-49 m2 g-1.

Photocatalyzed Hydrogen Evolution from Water by a Composite Catalyst of NH2 -MIL-125(Ti) and Surface Nickel(II) Species.

PubMed

Meyer, Kim; Bashir, Shahid; Llorca, Jordi; Idriss, Hicham; Ranocchiari, Marco; van Bokhoven, Jeroen A

2016-09-19

A composite of the metal-organic framework (MOF) NH 2 -MIL-125(Ti) and molecular and ionic nickel(II) species, catalyzed hydrogen evolution from water under UV light. In 95 v/v % aqueous conditions the composite produced hydrogen in quantities two orders of magnitude higher than that of the virgin framework and an order of magnitude greater than that of the molecular catalyst. In a 2 v/v % water and acetonitrile mixture, the composite demonstrated a TOF of 28 mol H 2  g(Ni) -1  h -1 and remained active for up to 50 h, sustaining catalysis for three times longer and yielding 20-fold the amount of hydrogen. Appraisal of physical mixtures of the MOF and each of the nickel species under identical photocatalytic conditions suggest that similar surface localized light sensitization and proton reduction processes operate in the composite catalyst. Both nickel species contribute to catalytic conversion, although different activation behaviors are observed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoelectrical, photophysical and photocatalytic properties of Al based MOFs: MIL-53(Al) and MIL-53-NH{sub 2}(Al)

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, Yang; Li, Huiliang; Liu, Yuanyuan, E-mail: yyliu@sdu.edu.cn

Two Al based MOFs (MIL-53(Al) and MIL-53-NH{sub 2} (Al)) were synthesized, and their photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water were investigated. Different from the ligand to metal charge transfer process previously reported, we proposes a new photocatalytic mechanism based on electron tunneling according to the results of theoretical calculation, steady state and time resolved fluorescence spectra. The organic linkers absorb photons, giving rise to electrons and holes. Then, the photogenerated electrons tunnel through the AlO{sub 6}-octahedra, which not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activitymore » of Al based MOFs. - Graphical abstract: The photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water of two Al based MOFs were investigated. A new photocatalytic mechanism was proposed based on electron tunneling according to the results of both theoretical calculation and steady state, time resolved fluorescence spectra. The electron tunneling process not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs.« less

Covalent immobilization of metal–organic frameworks onto the surface of nylon—a new approach to the functionalization and coloration of textiles

PubMed Central

Yu, Ming; Li, Wanxin; Wang, Ziqiang; Zhang, Bowu; Ma, Hongjuan; Li, Linfan; Li, Jingye

2016-01-01

The prevention of refractory organic pollution caused by conventional dyeing and the development of new fabrics with various functions are two issues to be solved urgently in the field of textile fabrication. Here, we report a new environmentally friendly route for the simultaneous coloration and functionalization of textiles by the covalent immobilization of a metal–organic framework, Cr-based MIL-101(Cr), onto the surfaces of nylon fabrics by co-graft polymerization with 2-hydroxyethyl acrylate initiated by γ-ray irradiation. The Cr(III) clusters color the nylon fabric, and the color intensity varies with the MIL-101 content, providing a “green” textile coloration method that is different from conventional dyeing processes. An X-ray diffraction (XRD) analysis shows that the nanoporous structure of the original MIL-101 particles is retained during radiation-induced graft polymerization. Numerous nanopores are introduced onto the surface of the nylon fabric, which demonstrated better sustained-release-of-aroma performance versus pristine nylon fabric in tests. The modified fabrics exhibit laundering durability, with MIL-101 nanoparticles intact on the nylon surface after 30 h of dry cleaning. PMID:26948405

Solid-phase extraction with the metal-organic framework MIL-101(Cr) combined with direct analysis in real time mass spectrometry for the fast analysis of triazine herbicides.

PubMed

Li, Xianjiang; Xing, Jiawei; Chang, Cuilan; Wang, Xin; Bai, Yu; Yan, Xiuping; Liu, Huwei

2014-06-01

MIL-101(Cr) is an excellent metal-organic framework with high surface area and nanoscale cavities, making it promising in solid-phase extraction. Herein, we used MIL-101(Cr) as a solid-phase extraction packing material combined with fast detection of direct analysis in real time mass spectrometry (DART-MS) for the analysis of triazine herbicides. After systematic optimization of the operation parameters, including the gas temperature of DART, the moving speed of the 1D platform, solvent for desorption, amount of MIL-101(Cr) extraction time, eluent volume and salt concentration, this method can realize the simultaneous detection of five kinds of triazine herbicides. The limits of detection were 0.1∼0.2 ng/mL and the linear ranges covered more than two orders of magnitude with the quantitation limits of 0.5∼1 ng/mL. Moreover, the developed method has been applied for the analysis of lake water samples and the recoveries for spiked analytes were in the range of 85∼110%. These results showed that solid-phase extraction with metal-organic frameworks is an efficient sample preparation approach for DART-MS analysis and could find more applications in environmental analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of ultrathin MIL-96(Al) films and study of CO2 adsorption/desorption processes using quartz crystal microbalance.

PubMed

Andrés, Miguel A; Benzaqui, M; Serre, C; Steunou, N; Gascón, I

2018-06-01

This contribution reports the fabrication and characterization of ultrathin films of nanoparticles of the water stable microporous Al tricarboxylate metal organic framework MIL-96(Al). The preparation of MOF dispersions in chloroform has been optimized to obtain dense monolayer films of good quality, without nanoparticle agglomeration, at the air-water interface that can be deposited onto solid substrates of different nature without any previous substrate functionalization. The MOF studied shows great interest for CO 2 capture because it presents Al 3+ Lewis centers and hydroxyl groups that strongly interact with CO 2 molecules. A comparative CO 2 adsorption study on drop-cast, Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) films using a Quartz Crystal Microbalance-based setup (QCM) has revealed that the CO 2 uptake depends strongly on the film fabrication procedure and the storage conditions. Noteworthy the CO 2 adsorption capacity of LB films is increased by 30% using a simple and green treatment (immersion of the film into water during 12 h just after film preparation). Finally, the stability of LB MOF monolayers upon several CO 2 adsorption/desorption cycles has been demonstrated, showing that CO 2 can be easily desorbed from the films at 303 K by flowing an inert gas (He). These results show that MOF LB monolayers can be of great interest for the development of MOF-based devices that require the use of very small MOF quantities, especially gas sensors. Copyright © 2018 Elsevier Inc. All rights reserved.

A multifunctional hemin@metal-organic framework and its application to construct an electrochemical aptasensor for thrombin detection.

PubMed

Xie, Shunbi; Ye, Jiawei; Yuan, Yali; Chai, Yaqin; Yuan, Ruo

2015-11-21

A new type of multifunctional metal-organic framework (MOF) has been synthesized by encapsulating hemin into the nano-sized Fe-MIL-88 MOFs (hemin@MOFs) and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of an enzyme for signal amplification. The gold nanoparticle functionalized hemin@MOFs (Au/hemin@MOFs) have not only simultaneously served as redox mediators and solid electrocatalysts, but have also been utilized as an ideal loading platform to immobilize a large number of biomolecules. In this aptasensor, Au/hemin@MOFs conjugated with glucose oxidase (GOD) and thrombin binding aptamer (TBA II) were used as the secondary aptamer bioconjugates (Au/hemin@MOF-TBA II-GOD bioconjugates), and TB was sandwiched between Au/hemin@MOF-TBA II-GOD bioconjugates and the amino-terminated TBA I which was self-assembled on the gold nanoparticle (AuNP) modified electrode. The GOD could oxidize glucose into gluconic acid accompanied by the generation of H2O2. The generated H2O2 on the electrode surface was further electrocatalyzed by hemin@MOFs to amplify the electrochemical signal of hemin contained in hemin@MOFs. Therefore, the synthesized hemin@MOFs represented a new paradigm for multifunctional materials since it combined three different functions including serving as catalysts, redox mediators and loading platforms within a single material. With such an ingenious design, a wide linear range of 0.0001 nM to 30 nM was acquired with a relatively low detection limit of 0.068 pM for TB detection.

Constructing Free Standing Metal Organic Framework MIL-53 Membrane Based on Anodized Aluminum Oxide Precursor

PubMed Central

Zhang, Yunlu; Gao, Qiuming; Lin, Zhi; Zhang, Tao; Xu, Jiandong; Tan, Yanli; Tian, Weiqian; Jiang, Lei

2014-01-01

Metal organic framework (MOF) materials have attracted great attention due to their well-ordered and controllable pores possessing of prominent potentials for gas molecule sorption and separation performances. Organizing the MOF crystals to a continuous membrane with a certain scale will better exhibit their prominent potentials. Reports in recent years concentrate on well grown MOF membranes on specific substrates. Free standing MOF membranes could have more important applications since they are independent from the substrates. However, the method to prepare such a membrane has been a great challenge because good mechanical properties and stabilities are highly required. Here, we demonstrate a novel and facile technique for preparing the free standing membrane with a size as large as centimeter scale. The substrate we use proved itself not only a good skeleton but also an excellent precursor to fulfill the reaction. This kind of membrane owns a strong mechanical strength, based on the fact that it is much thinner than the composite membranes grown on substrates and it could exhibit good property of gas separation. PMID:24821299

Selective O 2 Sorption at Ambient Temperatures via Node Distortions in Sc-MIL-100

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sava Gallis, Dorina F.; Chapman, Karena W.; Rodriguez, Mark A.

2016-05-24

An open pored metal–organic framework (MOF) with oxygen selectivity at exceptionally high temperatures is confirmed by synthesis, sorption, and synchrotron structural analyses. The large-pore MIL-100 framework with access to the metal center (e.g., Sc and Fe) resulted in preferential O2 over N2 gas uptake at temperatures ranging from 77 K to ambient temperatures (258, 298, and 313 K). Most notably, Sc-MIL-100 shows exceptional O2 sorption; pair distribution function analyses indicate that this is due to distortions in the framework owing to the size of Sc atoms, in particular in the trimer metal cluster. Experimental studies also correlate very well withmore » GCMC simulations, confirming more favorable O2-framework interactions at pressures up to 1 bar, due to the close proximity of O2 to the high density of metal centers in the small tetrahedral cages. Both materials maintain their crystallinity upon gas adsorption cycling, are regenerable, and show exceptional promise for use in energy efficient oxygen purification processes, such as Pressure Swing Adsorption.« less

CuNi NPs supported on MIL-101 as highly active catalysts for the hydrolysis of ammonia borane

NASA Astrophysics Data System (ADS)

Gao, Doudou; Zhang, Yuhong; Zhou, Liqun; Yang, Kunzhou

2018-01-01

The catalysts containing Cu, Ni bi-metallic nanoparticles were successfully synthesized by in-situ reduction of Cu2+ and Ni2+ salts into the highly porous and hydrothermally stable metal-organic framework MIL-101 via a simple liquid impregnation method. When the total amount of loading metal is 3 × 10-4 mol, Cu2Ni1@MIL-101 catalyst shows higher catalytic activity comparing to CuxNiy@MIL-101 with different molar ratio of Cu and Ni (x, y = 0, 0.5, 1.5, 2, 2.5, 3). Cu2Ni1@MIL-101 catalyst has the highest catalytic activity comparing to mono-metallic Cu and Ni counterparts and pure bi-metallic CuNi nanoparticles in hydrolytic dehydrogeneration of ammonia borane (AB) at room temperature. Additionally, in the hydrolysis reaction, the Cu2Ni1@MIL- 101 catalyst possesses excellent catalytic performances, which exhibit highly catalytic activity with turn over frequency (TOF) value of 20.9 mol H2 min-1 Cu mol-1 and a very low activation energy value of 32.2 kJ mol-1. The excellent catalytic activity has been successfully achieved thanks to the strong bi-metallic synergistic effects, uniform distribution of nanoparticles and the bi-functional effects between CuNi nanoparticles and the host of MIL-101. Moreover, the catalyst also displays satisfied durable stability after five cycles for the hydrolytically releasing H2 from AB. The non-noble metal catalysts have broad prospects for commercial applications in the field of hydrogen-stored materials due to the low prices and excellent catalytic activity.

Enhanced proton conductivity of Nafion hybrid membrane under different humidities by incorporating metal-organic frameworks with high phytic acid loading.

PubMed

Li, Zhen; He, Guangwei; Zhang, Bei; Cao, Ying; Wu, Hong; Jiang, Zhongyi; Tiantian, Zhou

2014-06-25

In this study, phytic acid (myo-inositol hexaphosphonic acid) was first immobilized by MIL101 via vacuum-assisted impregnation method. The obtained phytic@MIL101 was then utilized as a novel filler to incorporate into Nafion to fabricate hybrid proton exchange membrane for application in PEMFC under different relative humidities (RHs), especially under low RHs. High loading and uniform dispersion of phytic acid in MIL 101(Cr) were achieved as demonstrated by ICP, FT-IR, XPS, and EDS-mapping. The phytic@MIL101 was dispersed homogeneously in the Nafion matrix when the filler content was less than 12%. Hybrid membranes were evaluated by proton conductivity, mechanical property, thermal stability, and so forth. Remarkably, the Nafion/phytic@MIL hybrid membranes showed high proton conductivity at different RHs, especially under low RHs, which was up to 0.0608 S cm(-1) and 7.63 × 10(-4) S cm(-1) at 57.4% RH and 10.5% RH (2.8 and 11.0 times higher than that of pristine membrane), respectively. Moreover, the mechanical property of Nafion/phtic@MIL hybrid membranes was substantially enhanced and the thermal stability of membranes was well preserved.

Gas Phase Sensing of Alcohols by Metal Organic Framework–Polymer Composite Materials

PubMed Central

2017-01-01

Affinity layers play a crucial role in chemical sensors for the selective and sensitive detection of analytes. Here, we report the use of composite affinity layers containing Metal Organic Frameworks (MOFs) in a polymeric matrix for sensing purposes. Nanoparticles of NH2-MIL-53(Al) were dispersed in a Matrimid polymer matrix with different weight ratios (0–100 wt %) and drop-casted on planar capacitive transducer devices. These coated devices were electrically analyzed using impedance spectroscopy and investigated for their sensing properties toward the detection of a series of alcohols and water in the gas phase. The measurements indicated a reversible and reproducible response in all devices. Sensor devices containing 40 wt % NH2-MIL-53(Al) in Matrimid showed a maximum response for methanol and water. The sensor response time slowed down with increasing MOF concentration until 40 wt %. The half time of saturation response (τ0.5) increased by ∼1.75 times for the 40 wt % composition compared to devices coated with Matrimid only. This is attributed to polymer rigidification near the MOF/polymer interface. Higher MOF loadings (≥50 wt %) resulted in brittle coatings with a response similar to the 100 wt % MOF coating. Cross-sensitivity studies showed the ability to kinetically distinguish between the different alcohols with a faster response for methanol and water compared to ethanol and 2-propanol. The observed higher affinity of the pure Matrimid polymer toward methanol compared to water allows also for a higher uptake of methanol in the composite matrices. Also, as indicated by the sensing studies with a mixture of water and methanol, the methanol uptake is independent of the presence of water up to 6000 ppm of water. The NH2-MIL-53(Al) MOFs dispersed in the Matrimid matrix show a sensitive and reversible capacitive response, even in the presence of water. By tuning the precise compositions, the affinity kinetics and overall affinity can be tuned, showing the promise of this type of chemical sensors. PMID:28440621

Discovering the enzyme mimetic activity of metal-organic framework (MOF) for label-free and colorimetric sensing of biomolecules.

PubMed

Wang, Ying; Zhu, Yingjing; Binyam, Atsebeha; Liu, Misha; Wu, Yinan; Li, Fengting

2016-12-15

A label-free sensing strategy based on the enzyme-mimicking activity of MOF was demonstrated for colorimetric detection of biomolecules. Firstly obvious blue color was observed due to the high efficiency of peroxidase-like catalytic activity of Fe-MIL-88A (an ion-based MOF material) toward 3,3',5,5'-tetramethylbenzidine (TMB). Then in the presence of target biomolecule and corresponding aptamer, the mimetic activity of Fe-MIL-88A can be strongly inhibited and used directly to realize the colorimetric detection. On the basis of the interesting findings, we designed a straightforward, label-free and sensitive colorimetric method for biomolecule detection by using the enzyme mimetic property of MOF coupling with molecular recognition element. Compared with the existed publications, our work breaks the routine way by setting up an inorganic-organic MOF-aptamer hybrid platform for colorimetric determination of biomolecules, expanding the targets scope from H2O2 or glucose to biomolecules. As a proof of concept, thrombin and thrombin aptamer was used as a model analyte. The limit of detection of 10nM can be achieved with naked eyes and ultrahigh selectivity of thrombin toward numerous interfering substances with 10-fold concentration was demonstrated significantly. Of note, the method was further applied for the detection of thrombin in human serum samples, showing the results in agreement with those values obtained in an immobilization buffer by the colorimetric method. This inorganic-organic MOF-aptamer sensing strategy may in principle be universally applicable for the detection of a range of environmental or biomedical molecules of interests. Copyright © 2016 Elsevier B.V. All rights reserved.

Statistical mechanics of binary mixture adsorption in metal-organic frameworks in the osmotic ensemble.

PubMed

Dunne, Lawrence J; Manos, George

2018-03-13

Although crucial for designing separation processes little is known experimentally about multi-component adsorption isotherms in comparison with pure single components. Very few binary mixture adsorption isotherms are to be found in the literature and information about isotherms over a wide range of gas-phase composition and mechanical pressures and temperature is lacking. Here, we present a quasi-one-dimensional statistical mechanical model of binary mixture adsorption in metal-organic frameworks (MOFs) treated exactly by a transfer matrix method in the osmotic ensemble. The experimental parameter space may be very complex and investigations into multi-component mixture adsorption may be guided by theoretical insights. The approach successfully models breathing structural transitions induced by adsorption giving a good account of the shape of adsorption isotherms of CO 2 and CH 4 adsorption in MIL-53(Al). Binary mixture isotherms and co-adsorption-phase diagrams are also calculated and found to give a good description of the experimental trends in these properties and because of the wide model parameter range which reproduces this behaviour suggests that this is generic to MOFs. Finally, a study is made of the influence of mechanical pressure on the shape of CO 2 and CH 4 adsorption isotherms in MIL-53(Al). Quite modest mechanical pressures can induce significant changes to isotherm shapes in MOFs with implications for binary mixture separation processes.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

Statistical mechanics of binary mixture adsorption in metal-organic frameworks in the osmotic ensemble

NASA Astrophysics Data System (ADS)

Dunne, Lawrence J.; Manos, George

2018-03-01

Although crucial for designing separation processes little is known experimentally about multi-component adsorption isotherms in comparison with pure single components. Very few binary mixture adsorption isotherms are to be found in the literature and information about isotherms over a wide range of gas-phase composition and mechanical pressures and temperature is lacking. Here, we present a quasi-one-dimensional statistical mechanical model of binary mixture adsorption in metal-organic frameworks (MOFs) treated exactly by a transfer matrix method in the osmotic ensemble. The experimental parameter space may be very complex and investigations into multi-component mixture adsorption may be guided by theoretical insights. The approach successfully models breathing structural transitions induced by adsorption giving a good account of the shape of adsorption isotherms of CO2 and CH4 adsorption in MIL-53(Al). Binary mixture isotherms and co-adsorption-phase diagrams are also calculated and found to give a good description of the experimental trends in these properties and because of the wide model parameter range which reproduces this behaviour suggests that this is generic to MOFs. Finally, a study is made of the influence of mechanical pressure on the shape of CO2 and CH4 adsorption isotherms in MIL-53(Al). Quite modest mechanical pressures can induce significant changes to isotherm shapes in MOFs with implications for binary mixture separation processes. This article is part of the theme issue `Modern theoretical chemistry'.

Metal-organic framework MIL-101 as sorbent based on double-pumps controlled on-line solid-phase extraction coupled with high-performance liquid chromatography for the determination of flavonoids in environmental water samples.

PubMed

Liu, Yue; Hu, Jia; Li, Yan; Li, Xiao-Shuang; Wang, Zhong-Liang

2016-10-01

A novel method with high sensitivity for the rapid determination of chrysin, apigenin and luteolin in environment water samples was developed by double-pumps controlled on-line solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC). In the developed technique, metal organic framework MIL-101 was synthesized and applied as a sorbent for SPE. The as-synthesized MIL-101 was characterized by scanning electron microscope, X-ray diffraction spectrometry, thermal gravimetric analysis and micropore physisorption analysis. The MIL-101 behaved as a fast kinetics in the adsorption of chrysin, apigenin and luteolin. On-line SPE of chrysin, apigenin and luteolin was processed by loading a sample solution at a flow rate of 1.0 mL/min for 10 min. The extracted analytes were subsequently eluted into a ZORBAX Bonus-RP analytical column (25 cm long × 4.6 mm i.d.) for HPLC separation under isocratic condition with a mobile phase (MeOH: ACN: 0.02 M H 3 PO 4 = 35:35:30) at a flow rate of 1.0 mL/min. Experimental conditions, including ionic strength, sample pH, sample loading rates, sample loading time and desorption analytes time, were further optimized to obtain efficient preconcentration and high-precision determination of the analytes mentioned above. The method achieved the merits of simplicity, rapidity, sensitivity, wide linear range and high sample throughput. The possible mechanism for the adsorption of flavonoids on MIL-101 was proposed. The developed method has been applied to determine trace chrysin, apigenin and luteolin in a variety of environmental water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Long-Lived Photoinduced Charge Separation in a Trinuclear Iron-μ 3 -oxo-based Metal–Organic Framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanna, Lauren; Kucheryavy, Pavel; Liu, Cunming

2017-06-14

The presence of long-lived charge-separated excited states in metal-organic frameworks (MOFs) can enhance their photocatalytic activity by decreasing the probability that photogenerated electrons and holes recombine before accessing adsorbed reactants. Detecting these charge separated states via optical transient absorption, however, can be challenging when they lack definitive optical signatures. Here, we investigate the long-lived excited state of a MOF with such vague optical properties, MIL-100(Fe), comprised of Fe3-μ3-oxo clusters and trimesic acid linkers using Fe K-edge X-ray transient absorption (XTA) spectroscopy, to unambiguously determine its ligand-to-metal charge transfer character. Spectra measured at time delays up to 3.6 μs confirm themore » long lived nature of the charge separated excited state. Several trinuclear iron μ3- oxo carboxylate complexes, which model the trinuclear cores of the MOF structure, are measured for comparison using both steady state XAS and XTA to further support this assignment and corresponding decay time. The MOF is prepared as a colloidal nanoparticle suspension for these measurements so both its fabrication and particle size analysis are presented, as well.« less

Aptamer-Mediated Up-conversion Core/MOF Shell Nanocomposites for Targeted Drug Delivery and Cell Imaging

PubMed Central

Deng, Kerong; Hou, Zhiyao; Li, Xuejiao; Li, Chunxia; Zhang, Yuanxin; Deng, Xiaoran; Cheng, Ziyong; Lin, Jun

2015-01-01

Multifunctional nanocarriers for targeted bioimaging and drug delivery have attracted much attention in early diagnosis and therapy of cancer. In this work, we develop a novel aptamer-guided nanocarrier based on the mesoporous metal-organic framework (MOF) shell and up-conversion luminescent NaYF4:Yb3+/Er3+ nanoparticles (UCNPs) core for the first time to achieve these goals. These UCNPs, chosen as optical labels in biological assays and medical imaging, could emit strong green emission under 980 nm laser. The MOF structure based on iron (III) carboxylate materials [MIL-100 (Fe)] possesses high porosity and non-toxicity, which is of great value as nanocarriers for drug storage/delivery. As a unique nanoplatform, the hybrid inorganic-organic drug delivery vehicles show great promising for simultaneous targeted labeling and therapy of cancer cells. PMID:25597762

In-situ synthesis of SiO2@MOF composites for high-efficiency removal of aniline from aqueous solution

NASA Astrophysics Data System (ADS)

Han, Tongtong; Li, Caifeng; Guo, Xiangyu; Huang, Hongliang; Liu, Dahuan; Zhong, Chongli

2016-12-01

A series of SiO2@aluminum-MOF(MIL-68) composites with different SiO2 loadings have been synthesized by a simple and mild compositing strategy for high-efficiency removal of aniline. As evidenced from SEM and TEM images as well as the particle size distribution, the incorporation of SiO2 can improve the dispersity of MIL-68(Al) in composites, and result in the smaller particle size than that of pristine MIL-68(Al). Besides, the adsorption of aniline over SiO2, MIL-68(Al), the physical mixture of these two materials, and SiO2@MIL-68(Al) composites was investigated comparatively, demonstrating a relatively high adsorption capacity (531.9 mg g-1) of 7% SiO2@MIL-68(Al) towards aniline. Combining the ultrafast adsorption dynamics (reaching equilibrium within 40 s) and great reusability, 7% SiO2@MIL-68(Al) shows excellent adsorption performance. This indicates that the SiO2@MIL-68(Al) composites possess great potential applications as a kind of fascinating adsorbent in water pollution protection.

Reliably Modeling the Mechanical Stability of Rigid and Flexible Metal–Organic Frameworks

PubMed Central

2017-01-01

Conspectus Over the past two decades, metal–organic frameworks (MOFs) have matured from interesting academic peculiarities toward a continuously expanding class of hybrid, nanoporous materials tuned for targeted technological applications such as gas storage and heterogeneous catalysis. These oft-times crystalline materials, composed of inorganic moieties interconnected by organic ligands, can be endowed with desired structural and chemical features by judiciously functionalizing or substituting these building blocks. As a result of this reticular synthesis, MOF research is situated at the intriguing intersection between chemistry and physics, and the building block approach could pave the way toward the construction of an almost infinite number of possible crystalline structures, provided that they exhibit stability under the desired operational conditions. However, this enormous potential is largely untapped to date, as MOFs have not yet found a major breakthrough in technological applications. One of the remaining challenges for this scale-up is the densification of MOF powders, which is generally achieved by subjecting the material to a pressurization step. However, application of an external pressure may substantially alter the chemical and physical properties of the material. A reliable theoretical guidance that can presynthetically identify the most stable materials could help overcome this technological challenge. In this Account, we describe the recent research the progress on computational characterization of the mechanical stability of MOFs. So far, three complementary approaches have been proposed, focusing on different aspects of mechanical stability: (i) the Born stability criteria, (ii) the anisotropy in mechanical moduli such as the Young and shear moduli, and (iii) the pressure-versus-volume equations of state. As these three methods are grounded in distinct computational approaches, it is expected that their accuracy and efficiency will vary. To date, however, it is unclear which set of properties are suited and reliable for a given application, as a comprehensive comparison for a broad variety of MOFs is absent, impeding the widespread use of these theoretical frameworks. Herein, we fill this gap by critically assessing the performance of the three computational models on a broad set of MOFs that are representative for current applications. These materials encompass the mechanically rigid UiO-66(Zr) and MOF-5(Zn) as well as the flexible MIL-47(V) and MIL-53(Al), which undergo pressure-induced phase transitions. It is observed that the Born stability criteria and pressure-versus-volume equations of state give complementary insight into the macroscopic and microscopic origins of instability, respectively. However, interpretation of the Born stability criteria becomes increasingly difficult when less symmetric materials are considered. Moreover, pressure fluctuations during the simulations hamper their accuracy for flexible materials. In contrast, the pressure-versus-volume equations of state are determined in a thermodynamic ensemble specifically targeted to mitigate the effects of these instantaneous fluctuations, yielding more accurate results. The critical Account presented here paves the way toward a solid computational framework for an extensive presynthetic screening of MOFs to select those that are mechanically stable and can be postsynthetically densified before their use in targeted applications. PMID:29155552

Reliably Modeling the Mechanical Stability of Rigid and Flexible Metal-Organic Frameworks.

PubMed

Rogge, Sven M J; Waroquier, Michel; Van Speybroeck, Veronique

2018-01-16

Over the past two decades, metal-organic frameworks (MOFs) have matured from interesting academic peculiarities toward a continuously expanding class of hybrid, nanoporous materials tuned for targeted technological applications such as gas storage and heterogeneous catalysis. These oft-times crystalline materials, composed of inorganic moieties interconnected by organic ligands, can be endowed with desired structural and chemical features by judiciously functionalizing or substituting these building blocks. As a result of this reticular synthesis, MOF research is situated at the intriguing intersection between chemistry and physics, and the building block approach could pave the way toward the construction of an almost infinite number of possible crystalline structures, provided that they exhibit stability under the desired operational conditions. However, this enormous potential is largely untapped to date, as MOFs have not yet found a major breakthrough in technological applications. One of the remaining challenges for this scale-up is the densification of MOF powders, which is generally achieved by subjecting the material to a pressurization step. However, application of an external pressure may substantially alter the chemical and physical properties of the material. A reliable theoretical guidance that can presynthetically identify the most stable materials could help overcome this technological challenge. In this Account, we describe the recent research the progress on computational characterization of the mechanical stability of MOFs. So far, three complementary approaches have been proposed, focusing on different aspects of mechanical stability: (i) the Born stability criteria, (ii) the anisotropy in mechanical moduli such as the Young and shear moduli, and (iii) the pressure-versus-volume equations of state. As these three methods are grounded in distinct computational approaches, it is expected that their accuracy and efficiency will vary. To date, however, it is unclear which set of properties are suited and reliable for a given application, as a comprehensive comparison for a broad variety of MOFs is absent, impeding the widespread use of these theoretical frameworks. Herein, we fill this gap by critically assessing the performance of the three computational models on a broad set of MOFs that are representative for current applications. These materials encompass the mechanically rigid UiO-66(Zr) and MOF-5(Zn) as well as the flexible MIL-47(V) and MIL-53(Al), which undergo pressure-induced phase transitions. It is observed that the Born stability criteria and pressure-versus-volume equations of state give complementary insight into the macroscopic and microscopic origins of instability, respectively. However, interpretation of the Born stability criteria becomes increasingly difficult when less symmetric materials are considered. Moreover, pressure fluctuations during the simulations hamper their accuracy for flexible materials. In contrast, the pressure-versus-volume equations of state are determined in a thermodynamic ensemble specifically targeted to mitigate the effects of these instantaneous fluctuations, yielding more accurate results. The critical Account presented here paves the way toward a solid computational framework for an extensive presynthetic screening of MOFs to select those that are mechanically stable and can be postsynthetically densified before their use in targeted applications.

Cathode composites for Li-S batteries via the use of oxygenated porous architectures.

PubMed

Demir-Cakan, Rezan; Morcrette, Mathieu; Nouar, Farid; Davoisne, Carine; Devic, Thomas; Gonbeau, Danielle; Dominko, Robert; Serre, Christian; Férey, Gérard; Tarascon, Jean-Marie

2011-10-12

Li-S rechargeable batteries are attractive for electric transportation because of their low cost, environmentally friendliness, and superior energy density. However, the Li-S system has yet to conquer the marketplace, owing to its drawbacks, namely, soluble polysulfide formation. To tackle this issue, we present here a strategy based on the use of a mesoporous chromium trimesate metal-organic framework (MOF) named MIL-100(Cr) as host material for sulfur impregnation. Electrodes containing sulfur impregnated within the pores of the MOF were found to show a marked increase in the capacity retention of Li-S cathodes. Complementary transmission electron microscopy and X-ray photoelectron spectroscopy measurements demonstrated the reversible capture and release of the polysulfides by the pores of MOF during cycling and evidenced a weak binding between the polysulphides and the oxygenated framework. Such an approach was generalized to other mesoporous oxide structures, such as mesoporous silica, for instance SBA-15, having the same positive effect as the MOF on the capacity retention of Li-S cells. Besides pore sizes, the surface activity of the mesoporous additives, as observed for the MOF, appears to also have a pronounced effect on enhancing the cycle performance. Increased knowledge about the interface between polysulfide species and oxide surfaces could lead to novel approaches in the design and fabrication of long cycle life S electrodes.

Metal-Organic Frameworks for Cultural Heritage Preservation: The Case of Acetic Acid Removal.

PubMed

Dedecker, Kevin; Pillai, Renjith S; Nouar, Farid; Pires, João; Steunou, Nathalie; Dumas, Eddy; Maurin, Guillaume; Serre, Christian; Pinto, Moisés L

2018-04-25

The removal of low concentrations of acetic acid from indoor air at museums poses serious preservation problems that the current adsorbents cannot easily address owing to their poor affinity for acetic acid and/or their low adsorption selectivity versus water. In this context, a series of topical water-stable metal-organic frameworks (MOFs) with different pore sizes, topologies, hydrophobic characters, and functional groups was explored through a joint experimental-computational exploration. We demonstrate how a subtle combination of sufficient hydrophobicity and optimized host-guest interactions allows one to overcome the challenge of capturing traces of this very polar volatile organic compound in the presence of humidity. The optimal capture of acetic acid was accomplished with MOFs that do not show polar groups in the inorganic node or have lipophilic but polar (e.g., perfluoro) groups functionalized to the organic linkers, that is, the best candidates from the list of explored MOFs are MIL-140B and UiO-66-2CF 3 . These two MOFs present the appropriate pore size to favor a high degree of confinement, together with organic spacers that allow an enhancement of the van der Waals interactions with the acetic acid. We establish in this work that MOFs can be a viable solution to this highly challenging problem in cultural heritage protection, which is a new field of application for this type of hybrid materials.

High efficiency removal of triclosan by structure-directing agent modified mesoporous MIL-53(Al).

PubMed

Dou, Rongni; Zhang, Junya; Chen, Yuancai; Feng, Siyuan

2017-03-01

In order to expand the potential applications of metal-organic frameworks (MOFs), structure directing agents modified mesoporous MIL-53(Al) (MIL-53(Al)-1) was investigated to adsorb triclosan (TCS) with two different initial concentrations. MIL-53(Al)-1 with high mesoporosity and total pore volume exhibited higher adsorption capacity and 4.4 times faster adsorption of TCS at low concentration (1 mg L -1 ) than that of microporous MIL-53(Al). Also, mesoporous as well as microporous MIL-53(Al) showed significant higher adsorption capacity and two orders of magnitude greater fast uptake of TCS than two kinds of mesoporous-activated carbon. The adsorption of TCS onto MIL-53(Al)-1 released more energy and had higher disorderliness than TCS on MIL-53(Al). The superior adsorption characteristics of MIL-53(Al)-1 were preserved over a wide pH range (4-9), at high concentration of ionic strengths, and in the presence of coexisting compounds (anions, cations, phenol, aniline, and humic acid). The selectivity adsorption and Fourier transform infrared (FT-IR) spectra revealed that TCS adsorption on MIL-53(Al)s was mainly driven by hydrophobicity interaction assisted with hydrogen bonding on MIL-53(Al)s. MIL-53(Al)s can be effectively regenerated several times by washing with 90% methanol-water (pH 11). All of the above results demonstrated MIL-53(Al)s are promising adsorbents for water purification. Graphical abstract.

Bivalent metal-based MIL-53 analogues: Synthesis, properties and application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yongxin; University of the Chinese Academy of Science, Beijing 100049; Liu, Dan, E-mail: liudan2007@ciac.ac.cn

Trivalent metal-based MIL-53 (Al{sup 3+}, Cr{sup 3+}, Fe{sup 3+}, In{sup 3+}) compounds are interesting metal–organic frameworks (MOFs) with breathing effect and are promising gas sorption materials. Replacing bridging μ{sub 2}-OH group by neutral ligands such as pyridine N-oxide and its derivatives (PNOs), the trivalent metal-based MIL-53 analogous structures could be extended to bivalent metal systems. The introduction of PNOs and bivalent metal elements endows the frameworks with new structural features and physical and chemical properties. This minireview summarizes the recent development of bivalent metal-based MIL-53 analogues (Mn{sup 2+}, Co{sup 2+}, Ni{sup 2+}), typically, focusing on the synthetic strategies and potentialmore » applications based on our own works and literatures. We present the synthetic strategy to achieve structures evolution from single-ligand-walled to double-ligand-walled channel. Properties and application of these new materials in a wide range of potential areas are discussed including thermal stability, gas adsorption, magnetism and liquid-phase separation. Promising directions of this research field are also highlighted. - Graphical abstract: The recent development of bivalent metal-based MIL-53 analogues (Mn{sup 2+}, Co{sup 2+}, Ni{sup 2+}) on their synthetic strategies, properties and potential applications was reviewed. - Highlights: • Structure features of bivalent metal-based MIL-53 analogues are illustrated. • Important properties and application are presented. • Host–guest interactions are main impetus for liquid-phase separation. • Promising directions of bivalent metal-based MIL-53 analogues are highlighted.« less

The MIL-88A-Derived Fe3O4-Carbon Hierarchical Nanocomposites for Electrochemical Sensing

PubMed Central

Wang, Li; Zhang, Yayun; Li, Xia; Xie, Yingzhen; He, Juan; Yu, Jie; Song, Yonghai

2015-01-01

Metal or metal oxides/carbon nanocomposites with hierarchical superstructures have become one of the most promising functional materials in sensor, catalysis, energy conversion, etc. In this work, novel hierarchical Fe3O4/carbon superstructures have been fabricated based on metal-organic frameworks (MOFs)-derived method. Three kinds of Fe-MOFs (MIL-88A) with different morphologies were prepared beforehand as templates, and then pyrolyzed to fabricate the corresponding novel hierarchical Fe3O4/carbon superstructures. The systematic studies on the thermal decomposition process of the three kinds of MIL-88A and the effect of template morphology on the products were carried out in detail. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and thermal analysis were employed to investigate the hierarchical Fe3O4/carbon superstructures. Based on these resulted hierarchical Fe3O4/carbon superstructures, a novel and sensitive nonenzymatic N-acetyl cysteine sensor was developed. The porous and hierarchical superstructures and large surface area of the as-formed Fe3O4/carbon superstructures eventually contributed to the good electrocatalytic activity of the prepared sensor towards the oxidation of N-acetyl cysteine. The proposed preparation method of the hierarchical Fe3O4/carbon superstructures is simple, efficient, cheap and easy to mass production. It might open up a new way for hierarchical superstructures preparation. PMID:26387535

Metal Nanoparticles Covered with a Metal-Organic Framework: From One-Pot Synthetic Methods to Synergistic Energy Storage and Conversion Functions.

PubMed

Kobayashi, Hirokazu; Mitsuka, Yuko; Kitagawa, Hiroshi

2016-08-01

Hybrid materials composed of metal nanoparticles and metal-organic frameworks (MOFs) have attracted much attention in many applications, such as enhanced gas storage and catalytic, magnetic, and optical properties, because of the synergetic effects between the metal nanoparticles and MOFs. In this Forum Article, we describe our recent progress on novel synthetic methods to produce metal nanoparticles covered with a MOF (metal@MOF). We first present Pd@copper(II) 1,3,5-benzenetricarboxylate (HKUST-1) as a novel hydrogen-storage material. The HKUST-1 coating on Pd nanocrystals results in a remarkably enhanced hydrogen-storage capacity and speed in the Pd nanocrystals, originating from charge transfer from Pd nanocrystals to HKUST-1. Another material, Pd-Au@Zn(MeIM)2 (ZIF-8, where HMeIM = 2-methylimidazole), exhibits much different catalytic activity for alcohol oxidation compared with Pd-Au nanoparticles, indicating a design guideline for the development of composite catalysts with high selectivity. A composite material composed of Cu nanoparticles and Cr3F(H2O)2O{C6H3(CO2)3}2 (MIL-100-Cr) demonstrates higher catalytic activity for CO2 reduction into methanol than Cu/γ-Al2O3. We also present novel one-pot synthetic methods to produce composite materials including Pd/ZIF-8 and Ni@Ni2(dhtp) (MOF-74, where H4dhtp = 2,5-dihydroxyterephthalic acid).

The direct heat measurement of mechanical energy storage metal-organic frameworks.

PubMed

Rodriguez, Julien; Beurroies, Isabelle; Loiseau, Thierry; Denoyel, Renaud; Llewellyn, Philip L

2015-04-07

In any process, the heat exchanged is an essential property required in its development. Whilst the work related to structural transitions of some flexible metal-organic frameworks (MOFs) has been quantified and linked with potential applications such as molecular springs or shock absorbers, the heat related to such transitions has never been directly measured. This has now been carried out with MIL-53(Al) using specifically devised calorimetry experiments. We project the importance of these heats in devices such as molecular springs or dampers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High performance liquid chromatography of substituted aromatics with the metal-organic framework MIL-100(Fe): Mechanism analysis and model-based prediction.

PubMed

Qin, Weiwei; Silvestre, Martin Eduardo; Li, Yongli; Franzreb, Matthias

2016-02-05

Metal-organic framework (MOF) MIL-100(Fe) with well-defined thickness was homogenously coated onto the outer surface of magnetic microparticles via a liquid-phase epitaxy method. The as-synthesized MIL-100(Fe) was used as stationary phase for high-performance liquid chromatography (HPLC) and separations of two groups of mixed aromatic hydrocarbons (toluene, styrene and p-xylene; acetanilide, 2-nirtoaniline and 1-naphthylamine) using methanol/water as mobile phase were performed to evaluate its performance. Increasing water content of the mobile phase composition can greatly improve the separations on the expense of a longer elution time. Stepwise elution significantly shortens the elution time of acetanilide, 2-nirtoaniline and 1-naphthylamine mixtures, while still achieving a baseline separation. Combining the experimental results and in-depth modeling using a recently developed chromatographic software (ChromX), adsorption equilibrium parameters, including the affinities and maximum capacities, for each analyte toward the MIL-100(Fe) are obtained. In addition, the pore diffusivity of aromatic hydrocarbons within MIL-100(Fe) was determined to be 5×10(-12)m(2)s(-1). While the affinities of MIL-100(Fe) toward the analyte molecules differs much, the maximum capacities of the analytes are in a narrow range with q*MOFmax,toluene=3.55molL(-1), q*MOFmax,styrene or p-xylene=3.53molL(-1), and q*MOFmax,anilines=3.12molL(-1) corresponding to approximately 842 toluene and 838 styrene or p-xylene, and 740 aniline molecules per MIL-100(Fe) unit cell, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

ZIF-Derived Nitrogen-Doped Porous Carbons for Xe Adsorption and Separation

NASA Astrophysics Data System (ADS)

Zhong, Shan; Wang, Qian; Cao, Dapeng

2016-02-01

Currently, finding high capacity adsorbents with large selectivity to capture Xe is still a great challenge. In this work, nitrogen-doped porous carbons were prepared by programmable temperature carbonization of zeolitic imidazolate framework-8 (ZIF-8) and ZIF-8/xylitol composite precursors and the resultant samples are marked as Carbon-Z and Carbon-ZX, respectively. Further adsorption measurements indicate that ZIF-derived nitrogen-doped Carbon-ZX exhibits extremely high Xe capacity of 4.42 mmol g-1 at 298 K and 1 bar, which is higher than almost all other pristine MOFs such as CuBTC, Ni/DOBDC, MOF-5 and Al-MIL-53, and even more than three times of the matrix ZIF-8 at similar conditions. Moreover, Carbon-ZX also shows the highest Xe/N2 selectivity about ~120, which is much larger than all other reported MOFs. These remarkable features illustrate that ZIF-derived nitrogen-doped porous carbon is an excellent adsorbent for Xe adsorption and separation at room temperature.

Chitosan-coated mesoporous MIL-100(Fe) nanoparticles as improved bio-compatible oral nanocarriers

PubMed Central

Hidalgo, T.; Giménez-Marqués, M.; Bellido, E.; Avila, J.; Asensio, M. C.; Salles, F.; Lozano, M. V.; Guillevic, M.; Simón-Vázquez, R.; González-Fernández, A.; Serre, C.; Alonso, M. J.; Horcajada, P.

2017-01-01

Nanometric biocompatible Metal-Organic Frameworks (nanoMOFs) are promising candidates for drug delivery. Up to now, most studies have targeted the intravenous route, related to pain and severe complications; whereas nanoMOFs for oral administration, a commonly used non-invasive and simpler route, remains however unexplored. We propose here the biofriendly preparation of a suitable oral nanocarrier based on the benchmarked biocompatible mesoporous iron(III) trimesate nanoparticles coated with the bioadhesive polysaccharide chitosan (CS). This method does not hamper the textural/structural properties and the sorption/release abilities of the nanoMOFs upon surface engineering. The interaction between the CS and the nanoparticles has been characterized through a combination of high resolution soft X-ray absorption and computing simulation, while the positive impact of the coating on the colloidal and chemical stability under oral simulated conditions is here demonstrated. Finally, the intestinal barrier bypass capability and biocompatibility of CS-coated nanoMOF have been assessed in vitro, leading to an increased intestinal permeability with respect to the non-coated material, maintaining an optimal biocompatibility. In conclusion, the preservation of the interesting physicochemical features of the CS-coated nanoMOF and their adapted colloidal stability and progressive biodegradation, together with their improved intestinal barrier bypass, make these nanoparticles a promising oral nanocarrier. PMID:28256600

Chitosan-coated mesoporous MIL-100(Fe) nanoparticles as improved bio-compatible oral nanocarriers

NASA Astrophysics Data System (ADS)

Hidalgo, T.; Giménez-Marqués, M.; Bellido, E.; Avila, J.; Asensio, M. C.; Salles, F.; Lozano, M. V.; Guillevic, M.; Simón-Vázquez, R.; González-Fernández, A.; Serre, C.; Alonso, M. J.; Horcajada, P.

2017-03-01

Nanometric biocompatible Metal-Organic Frameworks (nanoMOFs) are promising candidates for drug delivery. Up to now, most studies have targeted the intravenous route, related to pain and severe complications; whereas nanoMOFs for oral administration, a commonly used non-invasive and simpler route, remains however unexplored. We propose here the biofriendly preparation of a suitable oral nanocarrier based on the benchmarked biocompatible mesoporous iron(III) trimesate nanoparticles coated with the bioadhesive polysaccharide chitosan (CS). This method does not hamper the textural/structural properties and the sorption/release abilities of the nanoMOFs upon surface engineering. The interaction between the CS and the nanoparticles has been characterized through a combination of high resolution soft X-ray absorption and computing simulation, while the positive impact of the coating on the colloidal and chemical stability under oral simulated conditions is here demonstrated. Finally, the intestinal barrier bypass capability and biocompatibility of CS-coated nanoMOF have been assessed in vitro, leading to an increased intestinal permeability with respect to the non-coated material, maintaining an optimal biocompatibility. In conclusion, the preservation of the interesting physicochemical features of the CS-coated nanoMOF and their adapted colloidal stability and progressive biodegradation, together with their improved intestinal barrier bypass, make these nanoparticles a promising oral nanocarrier.

An efficient ratiometric fluorescence sensor based on metal-organic frameworks and quantum dots for highly selective detection of 6-mercaptopurine.

PubMed

Jin, Meng; Mou, Zhao-Li; Zhang, Rui-Ling; Liang, Si-Si; Zhang, Zhi-Qi

2017-05-15

The development of a simple and accurate quantitative method for the determination of 6-mercaptopurine (6-MP) is of great importance because of its serious side effects. Ratiometric fluorescence (RF) sensors are not subject to interference from environmental factors, and exhibit enhanced precision and accuracy. Therefore, a novel RF sensor for the selective detection of 6-MP was developed based on a dual-emission nanosensor. The nanosensor was fabricated by combining a blue-emission metal-organic framework (MOF) NH 2 -MIL-53(Al) (λ em =425nm) with green-emission 3-mercaptopropionic acid-capped CdTe quantum dots (MPA-CdTe QDs) (λ em =528nm) under a single excitation wavelength (335nm). Upon addition of 6-MP, the fluorescence of NH 2 -MIL-53(Al) in the nanohybrid was selectively quenched due to strong inner filter effects, while the fluorescence of the MPA-CdTe QDs was enhanced. The novel RF sensor exhibited higher selectivity towards 6-MP than CdTe QDs alone, and higher sensitivity than MOFs alone. 6-MP could be detected in the range of 0-50μM with a detection limit of 0.15μM (S/N=3). The developed sensor was applied for the determination of 6-MP in human urine samples and satisfactory results were obtained. Overall, a novel and efficient fluorescence-based method was developed for the detection of 6-MP in biosamples. Copyright © 2016 Elsevier B.V. All rights reserved.

Magnetic porous carbon nanocomposites derived from metal-organic frameworks as a sensing platform for DNA fluorescent detection.

PubMed

Tan, Hongliang; Tang, Gonge; Wang, Zhixiong; Li, Qian; Gao, Jie; Wu, Shimeng

2016-10-12

Metal-organic frameworks (MOFs) have emerged as very fascinating functional materials due to their tunable nature and diverse applications. In this work, we prepared a magnetic porous carbon (MPC) nanocomposite by employing iron-containing MOFs (MIL-88A) as precursors through a one-pot thermolysis method. It was found that the MPC can absorb selectively single-stranded DNA (ssDNA) probe to form MPC/ssDNA complex and subsequently quench the labelled fluorescent dye of the ssDNA probe, which is resulted from the synergetic effect of magnetic nanoparticles and carbon matrix. Upon the addition of complementary target DNA, however, the absorbed ssDNA probe could be released from MPC surface by forming double-stranded DNA with target DNA, and accompanied by the recovery of the fluorescence of ssDNA probe. Based on these findings, a sensing platform with low background signal for DNA fluorescent detection was developed. The proposed sensing platform exhibits high sensitivity with detection limit of 1 nM and excellent selectivity to specific target DNA, even single-base mismatched nucleotide can be distinguished. We envision that the presented study would provide a new perspective on the potential applications of MOF-derived nanocomposites in biomedical fields. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and characterization of mangenese(III) porphyrin supported on imidazole modified chloromethylated MIL-101(Cr): A heterogeneous and reusable catalyst for oxidation of hydrocarbons with sodium periodate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zadehahmadi, Farnaz; Tangestaninejad, Shahram, E-mail: stanges@sci.ui.ac.ir; Moghadam, Majid, E-mail: moghadamm@sci.ui.ac.ir

2014-10-15

In the present work, chloromethylated MIL-101(Cr) modified with imidazole, Im-MIL-101, was applied as a support for immobilizing of tetraphenylporphyrinatomangenese(III) chloride. The imidazole-bound MIL-101, Im-MIL-101, not only used as support for immobilization of manganese porphyrin but also applied as a heterogeneous axial base. The Mn(TPP)Cl@Im-MIL-101 catalyst was characterized by UV–vis, FT-IR, X-ray diffraction (XRD), N{sub 2} adsorption, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), elemental analysis and inductively coupled plasma (ICP) methods. The catalytic activity of this new catalytic system was investigated in the alkene epoxidation and alkane hydroxylation using NaIO{sub 4} as an oxidant in CH{sub 3}CN/H{submore » 2}O at room temperature. This heterogeneous catalyst is highly efficient, stable and reusable in the oxidation of hydrocarbons. - Highlights: • MIL-101 was modified by covalent post synthetic modification. • Mn(TPP)Cl was anchored to imidazole modified MIL-101 by covalent attachment. • A heterogeneous catalyst was prepared. • The catalyst was used for epoxidation of alkenes and hydroxylation of alkanes. • The catalyst was reusable.« less

Metal organic framework g-C3N4/MIL-53(Fe) heterojunctions with enhanced photocatalytic activity for Cr(VI) reduction under visible light

NASA Astrophysics Data System (ADS)

Huang, Wenyuan; Liu, Ning; Zhang, Xiaodong; Wu, Minghong; Tang, Liang

2017-12-01

In this study, hybrid nanocomposites based on Fe-based MOF and graphitic carbon nitride (g-C3N4) were developed by a facile solvothermal method. The as-prepared materials were characterized by XRD, FESEM, TEM, XPS and PL analysis. It was showed that the introduction of a certain amount of g-C3N4 on the surface of MIL-53(Fe) would improve the separation and migration rate of photo-induced charges, consequently resulting in the boost of photocatalytic efficiency. Compared with g-C3N4 and MIL-53(Fe), the CMFe composites displayed more excellent visible light-resposive photocatalytic activity for the reduction of Cr(VI). The optimal doping content of g-C3N4 in g-C3N4/MIL-53(Fe) composite was determined to be 3.0 wt%, and it showed about 2.1 and 2.0 times as high photocatalytic efficiency for the reduction of Cr(VI) as that of pure g-C3N4 and MIL-53(Fe), respectively. Meanwhile, the composite exhibited good reusability and stability in the process of cyclic experiments. A possible photocatalytic reaction mechanism was also investigated in detail by the related electrochemical analysis.

Na intercalation in Fe-MIL-100 for aqueous Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chavez, James S.; Harrison, Katharine L.; Sava Gallis, Dorina F.

Here we report for the first time the feasibility of using metal–organic frameworks (MOFs) as electrodes for aqueous Na-ion batteries. We show that Fe-MIL-100, a known redox-active MOF, is electrochemically active in a Na aqueous electrolyte, under various compositions. Emphasis was placed on investigating the electrode–electrolyte interface, with a focus on identifying the relationship between additives in the composition of the working electrode, particle size and overall performance. We found that the energy storage capacity is primarily dependent on the binder additive in the composite; the best activity for this MOF is obtained with Nafion as a binder, owing tomore » its hydrophilic and ion conducting nature. Kynar-bound electrodes are clearly less effective, due to their hydrophobic character, which impedes wetting of the electrode. The binder-free systems show the poorest electrochemical activity. There is little difference in the overall performance as function of particle size (micro vs. nano), implying the storage capacities in this study are not limited by ionic and/or electronic conductivity. Excellent reversibility and high coulombic efficiency are achieved at higher potential ranges, observed after cycle 20. That is despite progressive capacity decay observed in the initial cycles. Importantly, structural analyses of cycled working electrodes confirm that the long range crystallinity remains mainly unaltered with cycling. These findings suggest that limited reversibility of the intercalated Na ions in the lower potential range, together with the gradual lack of available active sites in subsequent cycles is responsible for the rapid decay in capacity retention.« less

Na intercalation in Fe-MIL-100 for aqueous Na-ion batteries

DOE PAGES

Chavez, James S.; Harrison, Katharine L.; Sava Gallis, Dorina F.

2017-05-04

Here we report for the first time the feasibility of using metal–organic frameworks (MOFs) as electrodes for aqueous Na-ion batteries. We show that Fe-MIL-100, a known redox-active MOF, is electrochemically active in a Na aqueous electrolyte, under various compositions. Emphasis was placed on investigating the electrode–electrolyte interface, with a focus on identifying the relationship between additives in the composition of the working electrode, particle size and overall performance. We found that the energy storage capacity is primarily dependent on the binder additive in the composite; the best activity for this MOF is obtained with Nafion as a binder, owing tomore » its hydrophilic and ion conducting nature. Kynar-bound electrodes are clearly less effective, due to their hydrophobic character, which impedes wetting of the electrode. The binder-free systems show the poorest electrochemical activity. There is little difference in the overall performance as function of particle size (micro vs. nano), implying the storage capacities in this study are not limited by ionic and/or electronic conductivity. Excellent reversibility and high coulombic efficiency are achieved at higher potential ranges, observed after cycle 20. That is despite progressive capacity decay observed in the initial cycles. Importantly, structural analyses of cycled working electrodes confirm that the long range crystallinity remains mainly unaltered with cycling. These findings suggest that limited reversibility of the intercalated Na ions in the lower potential range, together with the gradual lack of available active sites in subsequent cycles is responsible for the rapid decay in capacity retention.« less

Electrochemical activity of Fe-MIL-100 as a positive electrode for Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sava Gallis, Dorina F.; Pratt III, Harry D.; Anderson, Travis M.

2016-01-01

Here we investigate the electrochemical activity of metal-organic frameworks (MOFs) as positive electrodes for Na-ion batteries in coin cell configurations. The performance of Fe-MIL-100 material is highly dependent on the choice of sodium salt source, and electrolyte system. The overall capacity fades over many cycles, however the high Coulombic efficiency is maintained. This can be correlated with inaccessibility of active sites for Na intercalation, due to the increase of extra carbonaceous material inside the pores. High resolution synchrotron powder X-ray and pair distribution function analyses of the as-made and cycled electrodes reveal the structure maintains the long-range order with progressivemore » cycling. This finding suggests that careful consideration of all variables in battery components, and especially electrolyte selection can lead to greatly improved performances.« less

Programming MOFs for water sorption: amino-functionalized MIL-125 and UiO-66 for heat transformation and heat storage applications.

PubMed

Jeremias, Felix; Lozan, Vasile; Henninger, Stefan K; Janiak, Christoph

2013-12-07

Sorption-based heat transformation and storage appliances are very promising for utilizing solar heat and waste heat in cooling or heating applications. The economic and ecological efficiency of sorption-based heat transformation depends on the availability of suitable hydrophilic and hydrothermally stable sorption materials. We investigated the feasibility of using the metal-organic frameworks UiO-66(Zr), UiO-67(Zr), H2N-UiO-66(Zr) and H2N-MIL-125(Ti) as sorption materials in heat transformations by means of volumetric water adsorption measurements, determination of the heat of adsorption and a 40-cycle ad/desorption stress test. The amino-modified compounds H2N-UiO-66 and H2N-MIL-125 feature high heat of adsorption (89.5 and 56.0 kJ mol(-1), respectively) and a very promising H2O adsorption isotherm due to their enhanced hydrophilicity. For H2N-MIL-125 the very steep rise of the H2O adsorption isotherm in the 0.1 < p/p0 < 0.2 region is especially beneficial for the intended heat pump application.

Magnetic metal-organic frameworks for fast and efficient solid-phase extraction of six Sudan dyes in tomato sauce.

PubMed

Shi, Xin-Ran; Chen, Xue-Lei; Hao, Yu-Lan; Li, Li; Xu, Hou-Jun; Wang, Man-Man

2018-06-01

Magnetic solid-phase extraction is an effective and useful technique to preconcentrate trace analytes from food samples. In this study, a magnetic trimeric chromium octahedral metal-organic framework (Fe 3 O 4 -NH 2 @MIL-101) was fabricated and characterized. Fe 3 O 4 -NH 2 @MIL-101 was applied as an adsorbent of magnetic solid-phase extraction combined with high performance liquid chromatography to effectively isolate and simultaneously determine six Sudan dyes (Para Red, Sudan I-IV, and Sudan Red 7B) from tomato sauce. Potential factors affecting the MSPE were investigated in detail, and adsorption efficiency of Fe 3 O 4 -NH 2 @MIL-101 was compared with those of conventional adsorbents, such as neutral alumina, HLB, and C 18 . The developed method facilitated the extraction with using only 3 mg of adsorbent in 2 min. In addition, enhancement factors of 50, linear range of 0.01-25 μg/mL, and detection limit (S/N = 3) of 0.5-2.5 μg/kg were obtained. The intra-day and inter-day recoveries for spiked Sudan dyes were in the range of 72.6%-92.9% and 69.6%-91.6%, respectively, with relative standard deviations of ≤9.2%. Copyright © 2018 Elsevier B.V. All rights reserved.

Synthesis and characterization of mangenese(III) porphyrin supported on imidazole modified chloromethylated MIL-101(Cr): A heterogeneous and reusable catalyst for oxidation of hydrocarbons with sodium periodate

NASA Astrophysics Data System (ADS)

Zadehahmadi, Farnaz; Tangestaninejad, Shahram; Moghadam, Majid; Mirkhani, Valiollah; Mohammadpoor-Baltork, Iraj; Khosropour, Ahmad R.; Kardanpour, Reihaneh

2014-10-01

In the present work, chloromethylated MIL-101(Cr) modified with imidazole, Im-MIL-101, was applied as a support for immobilizing of tetraphenylporphyrinatomangenese(III) chloride. The imidazole-bound MIL-101, Im-MIL-101, not only used as support for immobilization of manganese porphyrin but also applied as a heterogeneous axial base. The Mn(TPP)Cl@Im-MIL-101 catalyst was characterized by UV-vis, FT-IR, X-ray diffraction (XRD), N2 adsorption, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), elemental analysis and inductively coupled plasma (ICP) methods. The catalytic activity of this new catalytic system was investigated in the alkene epoxidation and alkane hydroxylation using NaIO4 as an oxidant in CH3CN/H2O at room temperature. This heterogeneous catalyst is highly efficient, stable and reusable in the oxidation of hydrocarbons.

Surface mediated assembly of small, metastable gold nanoclusters

NASA Astrophysics Data System (ADS)

Pettibone, John M.; Osborn, William A.; Rykaczewski, Konrad; Talin, A. Alec; Bonevich, John E.; Hudgens, Jeffrey W.; Allendorf, Mark D.

2013-06-01

The unique properties of metallic nanoclusters are attractive for numerous commercial and industrial applications but are generally less stable than nanocrystals. Thus, developing methodologies for stabilizing nanoclusters and retaining their enhanced functionality is of great interest. We report the assembly of PPh3-protected Au9 clusters from a heterogeneous mixture into films consisting of sub 3 nm nanocluster assemblies. The depositing nanoclusters are metastable in solution, but the resulting nanocluster assemblies are stabilized indefinitely in air or fresh solvent. The films exhibit distinct structure from Au nanoparticles observed by X-ray diffraction, and film dissolution data support the preservation of small nanoclusters. UV-Vis spectroscopy, electrospray ionization mass spectrometry, X-ray photoelectron spectroscopy and electron microscopy are used to elucidate information regarding the nanocluster formation and assembly mechanism. Preferential deposition of nanocluster assemblies can be achieved on multiple substrates, including polymer, Cr, Si, SiO2, SiNx, and metal-organic frameworks (MOFs). Unlike other vapor phase coating processes, nanocluster assembly on the MIL-68(In) MOF crystal is capable of preferentially coating the external surface and stabilizing the crystal structure in hydrothermal conditions, which should enhance their storage, separation and delivery capabilities.The unique properties of metallic nanoclusters are attractive for numerous commercial and industrial applications but are generally less stable than nanocrystals. Thus, developing methodologies for stabilizing nanoclusters and retaining their enhanced functionality is of great interest. We report the assembly of PPh3-protected Au9 clusters from a heterogeneous mixture into films consisting of sub 3 nm nanocluster assemblies. The depositing nanoclusters are metastable in solution, but the resulting nanocluster assemblies are stabilized indefinitely in air or fresh solvent. The films exhibit distinct structure from Au nanoparticles observed by X-ray diffraction, and film dissolution data support the preservation of small nanoclusters. UV-Vis spectroscopy, electrospray ionization mass spectrometry, X-ray photoelectron spectroscopy and electron microscopy are used to elucidate information regarding the nanocluster formation and assembly mechanism. Preferential deposition of nanocluster assemblies can be achieved on multiple substrates, including polymer, Cr, Si, SiO2, SiNx, and metal-organic frameworks (MOFs). Unlike other vapor phase coating processes, nanocluster assembly on the MIL-68(In) MOF crystal is capable of preferentially coating the external surface and stabilizing the crystal structure in hydrothermal conditions, which should enhance their storage, separation and delivery capabilities. Electronic supplementary information (ESI) available: Further details on stored plating solution preparation, film characterization, solution processing, MOF crystal FIB reconstruction and stability are available. See DOI: 10.1039/c3nr01708g

Competitive removal of hazardous dyes from aqueous solution by MIL-68(Al): Derivative spectrophotometric method and response surface methodology approach

NASA Astrophysics Data System (ADS)

Tehrani, Mahnaz Saghanejhad; Zare-Dorabei, Rouholah

2016-05-01

MIL-68(Al) as a metal-organic framework (MOF) was synthesized and characterized by different techniques such as SEM, BET, FTIR, and XRD analysis. This material was then applied for simulations removal of malachite green (MG) and methylene blue (MB) dyes from aqueous solutions using second order derivative spectrophotometric method (SODS) which was applied to resolve the overlap between the spectra of these dyes. The dependency of dyes removal efficiency in binary solutions was examined and optimized toward various parameters including initial dye concentration, pH of the solution, adsorbent dosage and ultrasonic contact time using central composite design (CCD) under response surface methodology (RSM) approach. The optimized experimental conditions were set as pH 7.78, contact time 5 min, initial MB concentration 22 mg L- 1, initial MG concentration 12 mg L- 1 and adsorbent dosage 0.0055 g. The equilibrium data was fitted to isotherm models such as Langmuir, Freundlich and Tempkin and the results revealed the suitability of the Langmuir model. The maximum adsorption capacity of 666.67 and 153.85 mg g- 1 was obtained for MB and MG removal respectively. Kinetics data fitting to pseudo-first order, pseudo-second order and Elovich models confirmed the applicability of pseudo-second order kinetic model for description of the mechanism and adsorption rate. Dye-loaded MIL-68(Al) can be easily regenerated using methanol and applied for three frequent sorption/desorption cycles with high performance. The impact of ionic strength on removal percentage of both dyes in binary mixture was studied by using NaCl and KCl soluble salts at different concentrations. According to our findings, only small dosage of the proposed MOF is considerably capable to remove large amounts of dyes at room temperature and in very short time that is a big advantage of MIL-68(Al) as a promising adsorbent for adsorptive removal processes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wen; Banerjee, Debasis; Liu, Jian

A redox-active metal-organic composite material shows improved and selective O-2 adsorption over N-2 with respect to individual components (MIL-101 and ferrocene). The O-2 sensitivity of the composite material arises due to the formation of maghemite nanoparticles with the pore of the metal-organic framework material.

Polyethyleneimine Incorporated Metal-Organic Frameworks Adsorbent for Highly Selective CO2 Capture

PubMed Central

Lin, Yichao; Yan, Qiuju; Kong, Chunlong; Chen, Liang

2013-01-01

A series of polyethyleneimine (PEI) incorporated MIL-101 adsorbents with different PEI loadings were reported for the first time in the present work. Although the surface area and pore volume of MIL-101 decreased significantly after loading PEI, all the resulting composites exhibited dramatically enhanced CO2 adsorption capacity at low pressures. At 100 wt% PEI loading, the CO2 adsorption capacity at 0.15 bar reached a very competitive value of 4.2 mmol g−1 at 25°C, and 3.4 mmol g−1 at 50°C. More importantly, the resulting adsorbents displayed rapid adsorption kinetics and ultrahigh selectivity for CO2 over N2 in the designed flue gas with 0.15 bar CO2 and 0.75 bar N2. The CO2 over N2 selectivity was up to 770 at 25°C, and 1200 at 50°C. We believe that the PEI based metal-organic frameworks is an attractive adsorbent for CO2 capture. PMID:23681218

Ultrasound-assisted biodiesel production by a novel composite of Fe(III)-based MOF and phosphotangestic acid as efficient and reusable catalyst.

PubMed

Nikseresht, Ahmad; Daniyali, Asra; Ali-Mohammadi, Mahdi; Afzalinia, Ahmad; Mirzaie, Abbas

2017-07-01

In this work, esterification of oleic acid by various alcohols is achieved with high yields under ultrasonic irradiation. This reaction performed with a novel heterogeneous catalyst that fabricated by heteropoly acid and Fe(III)-based MOF, namely MIL-53 (Fe). Syntheses of MIL-53 and encapsulation process carry out by ultrasound irradiation at ambient temperature and atmospheric pressure. The prepared composite was characterized by various techniques such as XRD, FT-IR, SEM, BET and ICP that demonstrate excellent catalytic activities, while being highly convenient to synthesize. The obtained results revealed that ultrasound irradiation could be used for the appropriate and rapid biodiesel production. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of ligand functionalization on the photocatalytic properties of titanium-based MOF: A density functional theory study

NASA Astrophysics Data System (ADS)

Li, Yi; Fu, Yuqing; Ni, Bilian; Ding, Kaining; Chen, Wenkai; Wu, Kechen; Huang, Xin; Zhang, Yongfan

2018-03-01

The first principle calculations have been performed to investigate the geometries, band structures and optical absorptions of a series of MIL-125 MOFs, in which the 1,4-benzenedicarboxylate (BDC) linkers are modified by different types and amounts of chemical groups, including NH2, OH, and NO2. Our results indicate that new energy bands will appear in the band gap of pristine MIL-125 after introducing new group into BDC linker, but the components of these band gap states and the valence band edge position are sensitive to the type of functional group as well as the corresponding amount. Especially, only the incorporation of amino group can obviously decrease the band gap of MIL-125, and the further reduction of the band gap can be observed if the amount of NH2 is increased. Although MIL-125 functionalized by NH2 group exhibits relatively weak or no activity for the photocatalytic O2 evolution by splitting water, such ligand modification can effectively improve the efficiency in H2 production because now the optical absorption in the visible light region is significantly enhanced. Furthermore, the adsorption of water molecule becomes more favorable after introducing of amino group, which is also beneficial for the water-splitting reaction. The present study can provide theoretical insights to design new photocatalysts based on MIL-125.

Materials for energy, drug, and information storage

NASA Astrophysics Data System (ADS)

Cheng, Peifu

It is generally recognized that H2O adsorption on a porous material would inhibit H2 adsorption. However, Chapter 3 reports that stable H2O-functionalized ZIF-8(a representative MOF), which was obtained by the simple water treatment of ZIF-8 at ambient temperature, can increase its H2 adsorption heat from 5.2 to 10.1 kJ/mol. As a result, the reversible H2 capacity at ambient temperature increased by 77%. A suitable isotherm equation for C2H2 adsorption on various MOFs has not been found. Chapter 4 demonstrates that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C2H 2 adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. Furthermore, it was found that the adsorption of C2H2 on the defected MIL-53 is stronger than that on MIL-53 without defection, reflected by adsorption-heat increase from 19.3 to 25.1 kJ/mol. Chapter 5 finds that the adsorption of CO2 on the defected ZIF-8 is stronger than that on ZIF-8 without defection, reflected by initial adsorption-heat increase from 16.0 to 22.8 kJ/mol. As a result, the specific reversible CO2 capacity per surface area increased with increasing defects. A novel strategy was developed to enhance the hydrophilicity on the external surface of ZIF-8 without reducing or blocking the internal pores in Chapter 6. A simple ball-milling approach combined with water treatment results in a significantly higher cell viability without compromising its hydroxyurea loading and release capacity. It's a challenge to build a memristor with odd-symmetric I--V features. In Chapter 7, a novel strategy, in which two same asymmetric switch components can be combined as a symmetric device, is reported to create an odd-symmetric memristor. Furthermore, with this strategy, the surface-sulphurization was performed on both sides of a Ag foil, leading to a Ag2S/Ag/Ag2S odd-symmetric memristor consisting of two asymmetric Ag2S/Ag memristive switches. Chapter 8 demonstrate that 2H phase of bulk MoS2 possessed an ohmic feature, whereas 1T phase of exfoliated MoS2 nanosheets exhibited a unique memristive behaviour due to voltage-dependent resistance change. Furthermore, an ideal odd-symmetric memristor with odd-symmetric I--V characteristics was successfully fabricated by the 1T phase MoS2 nanosheets via combining two asymmetric switches anti-serially.

Molecular simulation of gas adsorption and diffusion in a breathing MOF using a rigid force field.

PubMed

García-Pérez, E; Serra-Crespo, P; Hamad, S; Kapteijn, F; Gascon, J

2014-08-14

Simulation of gas adsorption in flexible porous materials is still limited by the slow progress in the development of flexible force fields. Moreover, the high computational cost of such flexible force fields may be a drawback even when they are fully developed. In this work, molecular simulations of gas adsorption and diffusion of carbon dioxide and methane in NH2-MIL-53(Al) are carried out using a linear combination of two crystallographic structures with rigid force fields. Once the interactions of carbon dioxide molecules and the bridging hydroxyls groups of the framework are optimized, an excellent match is found for simulations and experimental data for the adsorption of methane and carbon dioxide, including the stepwise uptake due to the breathing effect. In addition, diffusivities of pure components are calculated. The pore expansion by the breathing effect influences the self-diffusion mechanism and much higher diffusivities are observed at relatively high adsorbate loadings. This work demonstrates that using a rigid force field combined with a minimum number of experiments, reproduces adsorption and simulates diffusion of carbon dioxide and methane in the flexible metal-organic framework NH2-MIL-53(Al).

3D metal-organic framework as highly efficient biosensing platform for ultrasensitive and rapid detection of bisphenol A.

PubMed

Wang, Xue; Lu, Xianbo; Wu, Lidong; Chen, Jiping

2015-03-15

As is well known, bisphenol A (BPA), usually exists in daily plastic products, is one of the most important endocrine disrupting chemicals. In this work, copper-centered metal-organic framework (Cu-MOF) was synthesized, which was characterized by SEM, TEM, XRD, FTIR and electrochemical method. The resultant Cu-MOF was explored as a robust electrochemical biosensing platform by choosing tyrosinase (Tyr) as a model enzyme for ultrasensitive and rapid detection of BPA. The Cu-MOF provided a 3D structure with a large specific surface area, which was beneficial for enzyme and BPA absorption, and thus improved the sensitivity of the biosensor. Furthermore, Cu-MOF as a novel sorbent could increase the available BPA concentration to react with tyrosinase through π-π stacking interactions between BPA and Cu-MOF. The Tyr biosensor exhibited a high sensitivity of 0.2242A M(-1) for BPA, a wide linear range from 5.0×10(-8) to 3.0×10-6moll(-1), and a low detection limit of 13nmoll(-1). The response time for detection of BPA is less than 11s. The proposed method was successfully applied to rapid and selective detection of BPA in plastic products with satisfactory results. The recoveries are in the range of 94.0-101.6% for practical applications. With those remarkable advantages, MOFs-based 3D structures show great prospect as robust biosensing platform for ultrasensitive and rapid detection of BPA. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Hydrogen storage behaviors of Ni-doped graphene Oxide/MIL-101 hybrid composites.

PubMed

Lee, Seul-Yi; Park, Soo-Jin

2013-01-01

In this work, Ni-doped graphene oxide/MIL-101 hybrid composites (Ni--GO/MIL) were prepared to investigate their hydrogen storage behaviors. Ni--GO/MIL was synthesized by adding Ni--GO in situ during the synthesis of MIL-101 using a hydrothermal process, which was conducted by conventional convection heating with Cr(III) ion as a metal center and telephthalic acid as organic ligands. The crystalline structures and morphologies were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The specific surface area and micropore volume were investigated by N2/77 K adsorption isotherms using the Brunauer-Emmett-Teller (BET) method and Dubinin-Radushkevic (D-R) equation, respectively. The hydrogen storage capacity was investigated by BEL-HP at 77 K and 1 bar. The obtained results show that Ni--GO/MIL presents new directions for achieving novel hybrid materials with higher hydrogen storage capacity.

Study of the scale-up, formulation, ageing and ammonia adsorption capacity of MIL-100(Fe), Cu-BTC and CPO-27(Ni) for use in respiratory protection filters.

PubMed

Hindocha, S; Poulston, S

2017-09-01

The metal-organic frameworks (MOFs) MIL-100(Fe), Cu-BTC and CPO-27(Ni) were synthesised in 1 kg batches. The materials were then formed in two different industrially relevant ways. Firstly, dry granulation was used to produce pellets which were sieved to give material with a 300-1000 μm size, and the fines were subsequently recycled to mimic a large scale industrial process. Secondly, wet granulation with a polymer was used to produce granules which were again sieved to 300-1000 μm. XRD data shows that the structures of MIL-100(Fe) and CPO-27(Ni) remain intact during both forming processes, whilst Cu-BTC is shown to degrade during processing. This is in line with the ammonia adsorption data obtained for the formed materials which evaluated the ammonia adsorption capacity of the materials using breakthrough measurements. MIL-100(Fe) and CPO-27(Ni) are shown to have capacities of 47 mg g -1 and 62 mg g -1 respectively whilst Cu-BTC has a decreased capacity of 37 mg g -1 from 97 mg g -1 upon forming. The formed materials were also aged at 25 °C and 80% humidity for a week and the ammonia adsorption capacity re-evaluated. As expected, Cu-BTC decomposed under these conditions, whilst MIL-100(Fe) and CPO-27(Ni) show slightly decreased ammonia adsorption capacities of 36 mg g -1 and 60 mg g -1 respectively.

A flexible metal-organic framework with a high density of sulfonic acid sites for proton conduction

NASA Astrophysics Data System (ADS)

Yang, Fan; Xu, Gang; Dou, Yibo; Wang, Bin; Zhang, Heng; Wu, Hui; Zhou, Wei; Li, Jian-Rong; Chen, Banglin

2017-11-01

The design of stable electrolyte materials with high proton conductivity for use in proton exchange membrane fuel cells remains a challenge. Most of the materials explored have good conductivity at high relative humidity (RH), but significantly decreased conductivity at reduced RH. Here we report a chemically stable and structurally flexible metal-organic framework (MOF), BUT-8(Cr)A, possessing a three-dimensional framework structure with one-dimensional channels, in which high-density sulfonic acid (-SO3H) sites arrange on channel surfaces for proton conduction. We propose that its flexible nature, together with its -SO3H sites, could allow BUT-8(Cr)A to self-adapt its framework under different humid environments to ensure smooth proton conduction pathways mediated by water molecules. Relative to other MOFs, BUT-8(Cr)A not only has a high proton conductivity of 1.27 × 10-1 S cm-1 at 100% RH and 80 °C but also maintains moderately high proton conductivity at a wide range of RH and temperature.

Solvent-free mechanochemical synthesis and magnetic properties of rare-earth based metal-organic frameworks

DOE PAGES

Singh, N. K.; Gupta, S.; Pecharsky, V. K.; ...

2016-11-17

Mechanical milling of benzene 1,3,5-tricarboxylic acid [C 6H 3(COOH) 3], both with the single and mixed rare earth carbonates [R 2(CO 3) 3·xH 2O; R = Gd, Tb and Dy], leads to the formation of metal-organic frameworks [R{C 6H 3(COO) 3}] that adopt MIL-78 type structure. M(T) data of the investigated MOFs do not show any apparent onset of long range magnetic ordering down to 2 K. The M(H) data for Gd{C 6H 3(COO) 3}collected at 2 K show deviations from the magnetization behavior expected for non-interacting Gd 3+ ions. For the Gd based MOF the temperature dependence of themore » isothermal magnetic entropy change (i.e. magnetocaloric effect, ΔS M) exhibits a monotonous increase with decreasing temperature and at T = 3.5 K it reaches 34.1 J kg $-$1K $-$1 for a field change (ΔH) of 50 kOe. Finally, for the same ΔH the maximum values of ΔS M for R = Tb and Dy are 5.5 J kg $-$1K $-$1 and 8.5 J kg $-$1K $-$1 at 9.5 K and 4.5 K, respectively.« less

System and method for the capture and storage of waste

DOEpatents

Nenoff, Tina M.; Sava Gallis, Dorina Florentina; Chapman, Karena; Chupas, Peter

2015-10-20

The present disclosure is directed to systems and methods that absorb waste into a metal-organic framework (MOF), and applying pressure to the MOF material's framework to crystallize or make amorphous the MOF material thereby changing the MOF's pore structure and sorption characteristics without collapsing the MOF framework.

Pore Space Partition in Metal-Organic Frameworks.

PubMed

Zhai, Quan-Guo; Bu, Xianhui; Zhao, Xiang; Li, Dong-Sheng; Feng, Pingyun

2017-02-21

Metal-organic framework (MOF) materials have emerged as one of the favorite crystalline porous materials (CPM) because of their compositional and geometric tunability and many possible applications. In efforts to develop better MOFs for gas storage and separation, a number of strategies including creation of open metal sites and implantation of Lewis base sites have been used to tune host-guest interactions. In addition to these chemical factors, the geometric features such as pore size and shape, surface area, and pore volume also play important roles in sorption energetics and uptake capacity. For efficient capture of small gas molecules such as carbon dioxide under ambient conditions, large surface area or high pore volume are often not needed. Instead, maximizing host-guest interactions or the density of binding sites by encaging gas molecules in snug pockets of pore space can be a fruitful approach. To put this concept into practice, the pore space partition (PSP) concept has been proposed and has achieved a great experimental success. In this account, we will highlight many efforts to implement PSP in MOFs and impact of PSP on gas uptake performance. In the synthetic design of PSP, it is helpful to distinguish between factors that contribute to the framework formation and factors that serve the purpose of PSP. Because of the need for complementary structural roles, the synthesis of MOFs with PSP often involves multicomponent systems including mixed ligands, mixed inorganic nodes, or both. It is possible to accomplish both framework formation and PSP with a single type of polyfunctional ligands that use some functional groups (called framework-forming group) for framework formation and the remaining functional groups (called pore-partition group) for PSP. Alternatively, framework formation and PSP can be shouldered by different chemical species. For example, in a mixed-ligand system, one ligand (called framework-forming agent) can play the role of the framework formation while the other type of ligand (called pore-partition agent) can assume the role of PSP. PSP is sensitive to the types of inorganic secondary building units (SBUs). The coexistence of SBUs complementary in charge, connectivity, and so on can promote PSP. The use of heterometallic systems can promote the diversity of SBUs coexistent under a given condition. Heterometallic system with metal ions of different oxidation states also provides the charge tunability of SBUs and the overall framework, providing an additional level of control in self-assembly and ultimately in the materials' properties. Of particular interest is the PSP in MIL-88 type (acs-type topology) structure, which has led to a huge family of CPMs (called pacs CPMs, pacs = partitioned acs) exhibiting low isosteric heat of adsorption and yet superior CO 2 uptake capacity.

Effect of titanium ester on synthesizing NH2-MIL-125(Ti): Morphology changes from circular plate to octahedron and rhombic dodecahedron

NASA Astrophysics Data System (ADS)

Hu, Shen; Liu, Min; Guo, Xinwen; Kuang, Zhichong; Li, Keyan; Song, Chunshan; Zhang, Guoliang

2018-06-01

Titanium based MOF materials NH2-MIL-125 was synthesized through solvothermal method. By increasing the concentration of the reactants, the morphology of NH2-MIL-125 can be controlled from circular plate to special polyhedron. Meanwhile, the polyhedron can be modulated from octahedron to rhombic dodecahedron through changing the titanium ester of the reactants from tetraethyl titanate to tetrabutyl titanate. This is the first time to obtain NH2-MIL-125 with rhombic dodecahedron morphology. The test of acetic acid as additive on morphology changes shows that the adsorption of additives on special facets shows a more significant impact on the morphology formation. The morphology control of NH2-MIL-125 based on the modulation of the type of titanium ester, reactants concentration, and the added acetic acid concentration were detailed exhibited and explained.

H5PV2Mo10O40 encapsulated in MIL-101(Cr): facile synthesis and characterization of rationally designed composite materials for efficient decontamination of sulfur mustard.

PubMed

Li, Yanqin; Gao, Qi; Zhang, Lijuan; Zhou, Yunshan; Zhong, Yuxu; Ying, Ying; Zhang, Mingcai; Huang, Chunqian; Wang, Yong'an

2018-05-08

Currently extensive effort is compulsively expended to decontaminate efficiently banned chemical war agents. In this work, H5PV2Mo10O40 molecules have been encapsulated in mesoporous MIL-101(Cr), which features two types of mesoporous cages (internal diameters of 29 Å and 34 Å) and microporous windows (diameters of 12 Å and 16 Å), leading to the formation of a new composite H5PV2Mo10O40@MIL-101(Cr) through a simple impregnation method. The composite was characterized thoroughly by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, TG/DTA, and textural analysis thereby confirming the encapsulation of the H5PV2Mo10O40 into MIL-101(Cr). The decontamination efficiency of sulfur mustard (4 μL HD in 40 μL of petroleum ether) by 20 mg of the composite is found to be 97.39% in 120 min under ambient conditions. GC-MS analysis on the decontaminated products using 2-chloroethyl ethyl sulfide (CEES), which has been widely used as a simulant of sulfur mustard, showed that MIL-101(Cr) just decontaminates CEES by adsorption, while CEES can be decontaminated under ambient conditions by a synergetic combination of adsorption of MIL-101(Cr) and subsequent chemical oxidation degradation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO) due to the presence of highly dispersed H5PV2Mo10O40 within the composites.

Metal Organic Framework-Metal Oxide Composites for Toxic Gas Adsorption and Sensing

DTIC Science & Technology

2014-05-01

zeolitic imidazolate framework Zn(NO3)2 zinc nitrate ZrCl4 zirconium chloride 21 SUMMARY Metal organic frameworks (MOFs) and metal oxide-MOF...performed better for the other gases and conditions. Compared to the standard adsorbents BPL carbon and zeolite 13X, the cobalt and magnesium MOF...g)24 and zeolite 5A (1.25 mmol/g),25 compared to 3.5 mmol/g for Ni-MOF-74, 4 mmol/g for Mg-MOF-74, and 6 mmol/g for Co-MOF-74. Mg-MOF-74 shows the

Method for the capture and storage of waste

DOEpatents

None

2017-01-24

Systems and methods for capturing waste are disclosed. The systems and methods provide for a high level of confinement and long term stability. The systems and methods include adsorbing waste into a metal-organic framework (MOF), and applying pressure to the MOF material's framework to crystallize or make amorphous the MOF material thereby changing the MOF's pore structure and sorption characteristics without collapsing the MOF framework.

Dynamic microwave assisted extraction coupled with dispersive micro-solid-phase extraction of herbicides in soybeans.

PubMed

Li, Na; Wu, Lijie; Nian, Li; Song, Ying; Lei, Lei; Yang, Xiao; Wang, Kun; Wang, Zhibing; Zhang, Liyuan; Zhang, Hanqi; Yu, Aimin; Zhang, Ziwei

2015-09-01

Non-polar solvent dynamic microwave assisted extraction was firstly applied to the treatment of high-fat soybean samples. In the dispersive micro-solid-phase extraction (D-µ-SPE), the herbicides in the high-fat extract were directly adsorbed on metal-organic frameworks MIL-101(Cr). The effects of several experimental parameters, including extraction solvent, microwave absorption medium, microwave power, volume and flow rate of extraction solvent, amount of MIL-101(Cr), and D-µ-SPE time, were investigated. At the optimal conditions, the limits of detection for the herbicides ranged from 1.56 to 2.00 μg kg(-1). The relative recoveries of the herbicides were in the range of 91.1-106.7%, and relative standard deviations were equal to or lower than 6.7%. The present method was simple, rapid and effective. A large amount of fat was also removed. This method was demonstrated to be suitable for treatment of high-fat samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Metallated metal-organic frameworks

DOEpatents

Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

2017-02-07

Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

Metallated metal-organic frameworks

DOEpatents

Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

2017-08-22

Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

Experimental screening of porous materials for high pressure gas adsorption and evaluation in gas separations: application to MOFs (MIL-100 and CAU-10).

PubMed

Wiersum, Andrew D; Giovannangeli, Christophe; Vincent, Dominique; Bloch, Emily; Reinsch, Helge; Stock, Norbert; Lee, Ji Sun; Chang, Jong-San; Llewellyn, Philip L

2013-02-11

A high-throughput gas adsorption apparatus is presented for the evaluation of adsorbents of interest in gas storage and separation applications. This instrument is capable of measuring complete adsorption isotherms up to 40 bar on six samples in parallel using as little as 60 mg of material. Multiple adsorption cycles can be carried out and four gases can be used sequentially, giving as many as 24 adsorption isotherms in 24 h. The apparatus has been used to investigate the effect of metal center (MIL-100) and functional groups (CAU-10) on the adsorption of N(2), CO(2), and light hydrocarbons on MOFs. This demonstrates how it can serve to evaluate sample quality and adsorption reversibility, to determine optimum activation conditions and to estimate separation properties. As such it is a useful tool for the screening of novel adsorbents for different applications in gas separation, providing significant time savings in identifying potentially interesting materials.

Metal-organic framework materials with ultrahigh surface areas

DOEpatents

Farha, Omar K.; Hupp, Joseph T.; Wilmer, Christopher E.; Eryazici, Ibrahim; Snurr, Randall Q.; Gomez-Gualdron, Diego A.; Borah, Bhaskarjyoti

2015-12-22

A metal organic framework (MOF) material including a Brunauer-Emmett-Teller (BET) surface area greater than 7,010 m.sup.2/g. Also a metal organic framework (MOF) material including hexa-carboxylated linkers including alkyne bond. Also a metal organic framework (MOF) material including three types of cuboctahedron cages fused to provide continuous channels. Also a method of making a metal organic framework (MOF) material including saponifying hexaester precursors having alkyne bonds to form a plurality of hexa-carboxylated linkers including alkyne bonds and performing a solvothermal reaction with the plurality of hexa-carboxylated linkers and one or more metal containing compounds to form the MOF material.

Molecular Retrofitting Adapts a Metal–Organic Framework to Extreme Pressure

DOE PAGES

Kapustin, Eugene A.; Lee, Seungkyu; Alshammari, Ahmad S.; ...

2017-06-07

Despite numerous studies on chemical and thermal stability of metal-organic frameworks (MOFs), mechanical stability remains largely undeveloped. No strategy exists to control the mechanical deformation of MOFs under ultrahigh pressure, to date. We show that the mechanically unstable MOF-520 can be retrofitted by precise placement of a rigid 4,4'-biphenyldicarboxylate (BPDC) linker as a "girder" to afford a mechanically robust framework: MOF-520-BPDC. This retrofitting alters how the structure deforms under ultrahigh pressure and thus leads to a drastic enhancement of its mechanical robustness. While in the parent MOF-520 the pressure transmitting medium molecules diffuse into the pore and expand the structuremore » from the inside upon compression, the girder in the new retrofitted MOF-520-BPDC prevents the framework from expansion by linking two adjacent secondary building units together. As a result, the modified MOF is stable under hydrostatic compression in a diamond-anvil cell up to 5.5 gigapascal. The increased mechanical stability of MOF-520-BPDC prohibits the typical amorphization observed for MOFs in this pressure range. Direct correlation between the orientation of these girders within the framework and its linear strain was estimated, providing new insights for the design of MOFs with optimized mechanical properties.« less

Surface mediated assembly of small, metastable gold nanoclusters.

PubMed

Pettibone, John M; Osborn, William A; Rykaczewski, Konrad; Talin, A Alec; Bonevich, John E; Hudgens, Jeffrey W; Allendorf, Mark D

2013-07-21

The unique properties of metallic nanoclusters are attractive for numerous commercial and industrial applications but are generally less stable than nanocrystals. Thus, developing methodologies for stabilizing nanoclusters and retaining their enhanced functionality is of great interest. We report the assembly of PPh3-protected Au9 clusters from a heterogeneous mixture into films consisting of sub 3 nm nanocluster assemblies. The depositing nanoclusters are metastable in solution, but the resulting nanocluster assemblies are stabilized indefinitely in air or fresh solvent. The films exhibit distinct structure from Au nanoparticles observed by X-ray diffraction, and film dissolution data support the preservation of small nanoclusters. UV-Vis spectroscopy, electrospray ionization mass spectrometry, X-ray photoelectron spectroscopy and electron microscopy are used to elucidate information regarding the nanocluster formation and assembly mechanism. Preferential deposition of nanocluster assemblies can be achieved on multiple substrates, including polymer, Cr, Si, SiO2, SiNx, and metal-organic frameworks (MOFs). Unlike other vapor phase coating processes, nanocluster assembly on the MIL-68(In) MOF crystal is capable of preferentially coating the external surface and stabilizing the crystal structure in hydrothermal conditions, which should enhance their storage, separation and delivery capabilities.

Peptide assembly-driven metal-organic framework (MOF) motors for micro electric generators

DOE PAGES

Ikezoe, Yasuhiro; Fang, Justin; Wasik, Tomasz L.; ...

2014-11-22

Peptide–metal–organic framework (Pep-MOF) motors, whose motions are driven by anisotropic surface tension gradients created via peptide self-assembly around frameworks, can rotate microscopic rotors and magnets fast enough to generate an electric power of 0.1 μW. Finally, a new rigid Pep-MOF motor can be recycled by refilling the peptide fuel into the nanopores of the MOF.

The metal-organic framework HKUST-1 as efficient sorbent in a vortex-assisted dispersive micro solid-phase extraction of parabens from environmental waters, cosmetic creams, and human urine.

PubMed

Rocío-Bautista, Priscilla; Martínez-Benito, Carla; Pino, Verónica; Pasán, Jorge; Ayala, Juan H; Ruiz-Pérez, Catalina; Afonso, Ana M

2015-07-01

Three metal-organic frameworks (MOFs), specifically HKUST-1, MOF-5, and MIL-53(Al), have been synthetized, characterized, studied and compared in a vortex-assisted dispersive micro-solid-phase extraction (VA-D-µ-SPE) procedure in combination with high-performance liquid chromatography (HPLC) with diode-array detection (DAD) for determining seven parabens in environmental waters (tap water, swimming pool water, and water coming from a spa pool), human urine (from two volunteers), and cosmetic creams (two commercial brands). Experimental parameters, such as nature and amount of MOF, sample volume, nature of elution solvent and its amount, vortex and centrifugation time, among others, were properly optimized. HKUST-1 was the most adequate MOF to work with. Detection limits for the overall method down to 0.1 μgL(-1) for butylparaben (BPB) and benzylparaben (BzPB) were obtained, with determination coefficients (R(2)) higher than 0.9966 for a range of 0.5-147 μgL(-1) (depending on the paraben), average relative recoveries (RR, in %) of 80.3% at the low spiked level (7 μgL(-1)), and relative standard deviation (RSD) values below 10% also at the low spiked level. The strength of the affinity between HKUST-1 and parabens was evaluated, and it ranged from 33.5% for isopropylparaben (iPPB) to 77.0% for isobutylparaben (iBPB). When analyzing complex environmental waters, RR values of 78%, inter-day precision values (as RSD) lower than 15%, and intra-day precision values lower than 7.8% were obtained, despite the observed matrix effect. When analyzing cosmetic creams, parabens were detected, with contents ranging from 0.14 ± 0.01 μgg(-1) for EPB in the healing cream analyzed to 1.12 ± 0.07 mgg(-1) for MPB in the mask cream analyzed, with precision values (RSD) lower than 12% and RR values from 63.7% for propylparaben (PPB) to 121% for iPPB. When analyzing human urine, no parabens were detected but the method could be performed with RSD values lower than 19%. These results show the adequateness of MOFs as sorbents in VA-D-µ-SPE procedures despite sample complexity. Copyright © 2015 Elsevier B.V. All rights reserved.

Non-platinum metal-organic framework based electro-catalyst for promoting oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Das, Dipanwita; Raut, Vrushali; Kireeti, Kota V. M. K.; Jha, Neetu

2018-04-01

We developed two non-precious Metal Organic Framework (MOF) based electrocatalysts, MOF-5 and MOF-i using solvothermal and refluxing methods. The MOFs prepared has been characterized by powder X-ray diffractometer (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) for structural and morphological insights. SEM images reveal cubic shape for solvothermally synthesized MOF-5, whereas refluxing method leads to platelet morphology of MOF-i. The synthesized MOFs has been investigated for Oxygen Reduction Reaction (ORR) studies using Cyclic Voltammetry (CV) and Linear Sweep Voltammetry (LSV), with MOF modified Glassy Carbon (GC) as working electrode. The electrochemical data suggests higher activity of MOF-5 towards ORR compared to MOF-i.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kapustin, Eugene A.; Lee, Seungkyu; Alshammari, Ahmad S.

Despite numerous studies on chemical and thermal stability of metal-organic frameworks (MOFs), mechanical stability remains largely undeveloped. No strategy exists to control the mechanical deformation of MOFs under ultrahigh pressure, to date. We show that the mechanically unstable MOF-520 can be retrofitted by precise placement of a rigid 4,4'-biphenyldicarboxylate (BPDC) linker as a "girder" to afford a mechanically robust framework: MOF-520-BPDC. This retrofitting alters how the structure deforms under ultrahigh pressure and thus leads to a drastic enhancement of its mechanical robustness. While in the parent MOF-520 the pressure transmitting medium molecules diffuse into the pore and expand the structuremore » from the inside upon compression, the girder in the new retrofitted MOF-520-BPDC prevents the framework from expansion by linking two adjacent secondary building units together. As a result, the modified MOF is stable under hydrostatic compression in a diamond-anvil cell up to 5.5 gigapascal. The increased mechanical stability of MOF-520-BPDC prohibits the typical amorphization observed for MOFs in this pressure range. Direct correlation between the orientation of these girders within the framework and its linear strain was estimated, providing new insights for the design of MOFs with optimized mechanical properties.« less

Intercalation of Coordinatively Unsaturated Fe(III) Ion within Interpenetrated Metal-Organic Framework MOF-5.

PubMed

Holmberg, Rebecca J; Burns, Thomas; Greer, Samuel M; Kobera, Libor; Stoian, Sebastian A; Korobkov, Ilia; Hill, Stephen; Bryce, David L; Woo, Tom K; Murugesu, Muralee

2016-06-01

Coordinatively unsaturated Fe(III) metal sites were successfully incorporated into the iconic MOF-5 framework. This new structure, Fe(III) -iMOF-5, is the first example of an interpenetrated MOF linked through intercalated metal ions. Structural characterization was performed with single-crystal and powder XRD, followed by extensive analysis by spectroscopic methods and solid-state NMR, which reveals the paramagnetic ion through its interaction with the framework. EPR and Mössbauer spectroscopy confirmed that the intercalated ions were indeed Fe(III) , whereas DFT calculations were employed to ascertain the unique pentacoordinate architecture around the Fe(III) ion. Interestingly, this is also the first crystallographic evidence of pentacoordinate Zn(II) within the MOF-5 SBU. This new MOF structure displays the potential for metal-site addition as a framework connector, thus creating further opportunity for the innovative development of new MOF materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reconfigurable electronics using conducting metal-organic frameworks

DOEpatents

Allendorf, Mark D.; Talin, Albert Alec; Leonard, Francois; Stavila, Vitalie

2017-07-18

A device including a porous metal organic framework (MOF) disposed between two terminals, the device including a first state wherein the MOF is infiltrated by a guest species to form an electrical path between the terminals and a second state wherein the electrical conductivity of the MOF is less than the electrical conductivity in the first state. A method including switching a porous metal organic framework (MOF) between two terminals from a first state wherein a metal site in the MOF is infiltrated by a guest species that is capable of charge transfer to a second state wherein the MOF is less electrically conductive than in the first state.

MOF-Sensitized Solar Cells Enabled by a Pillared Porphyrin Framework

DOE PAGES

Spoerke, Erik D.; Small, Leo J.; Foster, Michael E.; ...

2017-03-01

Metal–organic frameworks (MOFs) are highly ordered, functionally tunable supramolecular materials with the potential to improve dye-sensitized solar cells (DSSCs). Several recent reports have indicated that photocurrent can be generated in Grätzel-type DSSC devices when MOFs are used as the sensitizer. However, the specific role(s) of the incorporated MOFs and the potential influence of residual MOF precursor species on device performance are unclear. Herein, we describe the assembly and characterization of a simplified DSSC platform in which isolated MOF crystals are used as the sensitizer in a planar device architecture. We selected a pillared porphyrin framework (PPF) as the MOF sensitizer,more » taking particular care to avoid contamination from light-absorbing MOF precursors. Photovoltaic and electrochemical characterization under simulated 1-sun and wavelength-selective illumination revealed photocurrent generation that is clearly ascribable to the PPF MOF. In conclusion, continued refinement of highly versatile MOF structure and chemistry holds promise for dramatic improvements in emerging photovoltaic technologies.« less

Colorometric detection of water using MOF-polymer films and composites

DOEpatents

Allendorf, Mark D.; Talin, Albert Alec

2016-05-24

A method including exposing a mixture of a porous metal organic framework (MOF) and a polymer to a predetermined molecular species, wherein the MOF has an open metal site for the predetermined molecular species and the polymer has a porosity for the predetermined molecular species; and detecting a color change of the MOF in the presence of the predetermined molecular species. A method including combining a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species. An article of manufacture including a mixture of a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species.

Functionalization of cotton fiber by partial etherification and self-assembly of polyoxometalate encapsulated in Cu3(BTC)2 metal-organic framework.

PubMed

Lange, Laura E; Obendorf, S Kay

2015-02-25

A combination of a Keggin-type polyoxometalate (POM), [CuPW11O39](5-), with a Cu3(BTC)2 metal-organic framework (MOF-199/HKUST-1; where BTC is benzene-1,3,5-tricarboxylate), was successfully self-assembled on a cellulose substrate (cotton) with a room-temperature process. Cotton fibers were functionalized by partial etherification. Cu3(BTC)2 metal-organic framework and polyoxometalate encapsulated in Cu3(BTC)2 metal-organic framework were self-assembled on the carboxymethylate ion sites initiated with copper nitrate using ethanol and water as solvents. Octahedral crystals were observed on both MOF-cotton and POM-MOF-cotton; both contained copper while the POM-MOF-cotton also contained tungsten. Occupancy of POM in MOF cages was calculated to be about 13%. Moisture content remained at 3 to 4 wt % similar to that of untreated cotton. Reactivity to both hydrogen sulfide and methyl parathion was higher for POM-MOF-cotton due to the Keggin polyoxometalate and the extra-framework cations Cu(2+) ions compensating the charges of the encapsulated Keggins. The POM-MOF material was found to effectively remove 0.089 mg of methyl parathion per mg of MOF from a hexane solution while MOF-cotton removed only 0.054 mg of methyl parathion per mg of MOF.

A Review on Breathing Behaviors of Metal-Organic-Frameworks (MOFs) for Gas Adsorption

PubMed Central

Alhamami, Mays; Doan, Huu; Cheng, Chil-Hung

2014-01-01

Metal-organic frameworks (MOFs) are a new class of microporous materials that possess framework flexibility, large surface areas, “tailor-made” framework functionalities, and tunable pore sizes. These features empower MOFs superior performances and broader application spectra than those of zeolites and phosphine-based molecular sieves. In parallel with designing new structures and new chemistry of MOFs, the observation of unique breathing behaviors upon adsorption of gases or solvents stimulates their potential applications as host materials in gas storage for renewable energy. This has attracted intense research energy to understand the causes at the atomic level, using in situ X-ray diffraction, calorimetry, Fourier transform infrared spectroscopy, and molecular dynamics simulations. This article is developed in the following order: first to introduce the definition of MOFs and the observation of their framework flexibility. Second, synthesis routes of MOFs are summarized with the emphasis on the hydrothermal synthesis, owing to the environmental-benign and economically availability of water. Third, MOFs exhibiting breathing behaviors are summarized, followed by rationales from thermodynamic viewpoint. Subsequently, effects of various functionalities on breathing behaviors are appraised, including using post-synthetic modification routes. Finally, possible framework spatial requirements of MOFs for yielding breathing behaviors are highlighted as the design strategies for new syntheses. PMID:28788614

Peptide Assembly-Driven Metal-Organic Framework (MOF) Motors for Micro Electric Generator

PubMed Central

Ikezoe, Yasuhiro; Fang, Justin; Wasik, Tomasz L.; Uemura, Takashi; Zheng, Yongtai; Kitagawa, Susumu

2014-01-01

Peptide-MOF motors, whose motions are driven by anisotropic surface gradients created via peptide self-assembly around nanopores of MOFs, can rotate microscopic rotors and magnet fast enough to generate electric power of 0.1 µW. To make the peptide-MOF generator recyclable, a new MOF is applied as a host motor engine, which has a more rigid framework with higher H2O affinity so that peptide release occurs more efficiently via guest exchange without the destruction of MOF. PMID:25418936

Fabrication of heterostructured BiOBr/Bi24O31Br10/TiO2 photocatalyst by pyrolysis of MOF composite for dye degradation

NASA Astrophysics Data System (ADS)

Zhu, Shuai-Ru; Wu, Meng-Ke; Zhao, Wen-Na; Yi, Fei-Yan; Tao, Kai; Han, Lei

2017-11-01

The pyrolysis of metal-organic frameworks has emerged as a promising route to synthesize metal oxides with diverse phase compositions, morphologies, sizes and surface areas. The BiOBr/Bi24O31Br10/TiO2 (BBT) heterostructures have been achieved for the first time by calcining BiOBr/MIL-125(Ti) composite at 500 °C in air. The BBT-2 composite exhibited the highest photocatalytic performance for degradation of RhB under visible light irradiation. The enhanced photocatalytic activity is attributed to narrower band-gaps and synergistic effect originating from the well-aligned straddling band-structures between BiOBr, Bi24O31Br10 and TiO2, also result in an faster interfacial charge transfer during the photocatalytic reaction. This work could be conductive to the design of heterostructured photocatalysts contained metal oxide by pyrolytic conversion of metal-organic frameworks for significantly improved photocatalytic performance.

Creating Hierarchical Pores by Controlled Linker Thermolysis in Multivariate Metal-Organic Frameworks.

PubMed

Feng, Liang; Yuan, Shuai; Zhang, Liang-Liang; Tan, Kui; Li, Jia-Luo; Kirchon, Angelo; Liu, Ling-Mei; Zhang, Peng; Han, Yu; Chabal, Yves J; Zhou, Hong-Cai

2018-02-14

Sufficient pore size, appropriate stability, and hierarchical porosity are three prerequisites for open frameworks designed for drug delivery, enzyme immobilization, and catalysis involving large molecules. Herein, we report a powerful and general strategy, linker thermolysis, to construct ultrastable hierarchically porous metal-organic frameworks (HP-MOFs) with tunable pore size distribution. Linker instability, usually an undesirable trait of MOFs, was exploited to create mesopores by generating crystal defects throughout a microporous MOF crystal via thermolysis. The crystallinity and stability of HP-MOFs remain after thermolabile linkers are selectively removed from multivariate metal-organic frameworks (MTV-MOFs) through a decarboxylation process. A domain-based linker spatial distribution was found to be critical for creating hierarchical pores inside MTV-MOFs. Furthermore, linker thermolysis promotes the formation of ultrasmall metal oxide nanoparticles immobilized in an open framework that exhibits high catalytic activity for Lewis acid-catalyzed reactions. Most importantly, this work provides fresh insights into the connection between linker apportionment and vacancy distribution, which may shed light on probing the disordered linker apportionment in multivariate systems, a long-standing challenge in the study of MTV-MOFs.

Electronic properties of bimetallic metal–organic frameworks (MOFs): Tailoring the density of electronic states through MOF modularity

DOE PAGES

Dolgopolova, Ekaterina A.; Brandt, Amy J.; Ejegbavwo, Otega A.; ...

2017-03-18

The development of porous well-defined hybrid materials (e.g., metal-organic frameworks or MOFs) will add a new dimension to a wide number of applications ranging from supercapacitors and electrodes to 'smart' membranes and thermoelectrics. From this perspective, the understanding and tailoring of the electronic properties of MOFs are key fundamental challenges that could unlock the full potential of these materials. In this work, we focused on the fundamental insights responsible for the electronic properties of three distinct classes of bimetallic systems, M x-yM' y-MOFs, M xM' y- MOFs, and M x(ligand-M' y)-MOFs, in which the second metal (M') incorporation occurs throughmore » (i) metal (M) replacement in the framework nodes (type I), (ii) metal node extension (type II), and (iii) metal coordination to the organic ligand (type III), respectively. We employed microwave conductivity, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, powder X-ray diffraction, inductively coupled plasma atomic emission spectroscopy, pressed-pellet conductivity, and theoretical modeling to shed light on the key factors responsible for the tunability of MOF electronic structures. Experimental prescreening of MOFs was performed based on changes in the density of electronic states near the Fermi edge, which was used as a starting point for further selection of suitable MOFs. As a result, we demonstrated that the tailoring of MOF electronic properties could be performed as a function of metal node engineering, framework topology, and/or the presence of unsaturated metal sites while preserving framework porosity and structural integrity. Finally, these studies unveil the possible pathways for transforming the electronic properties of MOFs from insulating to semiconducting, as well as provide a blueprint for the development of hybrid porous materials with desirable electronic structures.« less

Metal-organic frameworks with high capacity and selectivity for harmful gases

PubMed Central

Britt, David; Tranchemontagne, David; Yaghi, Omar M.

2008-01-01

Benchmarks have been established for the performance of six metal-organic frameworks (MOFs) and isoreticular MOFs (IRMOFs, which have the same underlying topology as MOF-5), MOF-5, IRMOF-3, MOF-74, MOF-177, MOF-199, and IRMOF-62, as selective adsorbents for eight harmful gases: sulfur dioxide, ammonia, chlorine, tetrahydrothiophene, benzene, dichloromethane, ethylene oxide, and carbon monoxide. Kinetic breakthrough measurements are used to determine the calculated dynamic adsorption capacity of each “benchmark” MOF for each gas. The capacity of each MOF is compared to that of a sample of Calgon BPL activated carbon. We find that pore functionality plays a dominant role in determining the dynamic adsorption performance of MOFs. MOFs featuring reactive functionality outperform BPL carbon in all but one case and exhibit high dynamic adsorption capacities up to 35% by weight. PMID:18711128

Structure-directing effects of ionic liquids in the ionothermal synthesis of metal-organic frameworks.

PubMed

Vaid, Thomas P; Kelley, Steven P; Rogers, Robin D

2017-07-01

Traditional synthesis of metal-organic frameworks (MOFs) involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a 'solvothermal' reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs), rather than an organic solvent, in 'ionothermal' reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given.

Discovery and introduction of a (3,18)-connected net as an ideal blueprint for the design of metal-organic frameworks.

PubMed

Guillerm, Vincent; Weseliński, Łukasz J; Belmabkhout, Youssef; Cairns, Amy J; D'Elia, Valerio; Wojtas, Łukasz; Adil, Karim; Eddaoudi, Mohamed

2014-08-01

Metal-organic frameworks (MOFs) are a promising class of porous materials because it is possible to mutually control their porous structure, composition and functionality. However, it is still a challenge to predict the network topology of such framework materials prior to their synthesis. Here we use a new rare earth (RE) nonanuclear carboxylate-based cluster as an 18-connected molecular building block to form a gea-MOF (gea-MOF-1) based on a (3,18)-connected net. We then utilized this gea net as a blueprint to design and assemble another MOF (gea-MOF-2). In gea-MOF-2, the 18-connected RE clusters are replaced by metal-organic polyhedra, peripherally functionalized so as to have the same connectivity as the RE clusters. These metal-organic polyhedra act as supermolecular building blocks when they form gea-MOF-2. The discovery of a (3,18)-connected MOF followed by deliberate transposition of its topology to a predesigned second MOF with a different chemical system validates the prospective rational design of MOFs.

Polymer–Metal–Organic Frameworks (polyMOFs) as Water Tolerant Materials for Selective Carbon Dioxide Separations

DOE PAGES

Zhang, Zhenjie; Nguyen, Ha Thi Hoang; Miller, Stephen A.; ...

2015-12-28

Recently, polymer–metal–organic frameworks (polyMOFs) were reported as a new class of hybrid porous materials that combine advantages of both organic polymers and crystalline MOFs. Herein, we report a bridging coligand strategy to prepare new types of polyMOFs, demonstrating that polyMOFs are compatible with additional MOF architectures besides that of the earlier reported IRMOF-1 type polyMOF. Gas sorption studies revealed that these polyMOF materials exhibited relatively high CO 2 sorption but very low N 2 sorption, making them promising materials for CO 2/N 2 separations. Furthermore, these polyMOFs demonstrated exceptional water stability attributed to the hydrophobicity of polymer ligands as wellmore » as the cross-linking of the polymer chains within the MOF.« less

Peptide assembly-driven metal-organic framework (MOF) motors for micro electric generators.

PubMed

Ikezoe, Yasuhiro; Fang, Justin; Wasik, Tomasz L; Uemura, Takashi; Zheng, Yongtai; Kitagawa, Susumu; Matsui, Hiroshi

2015-01-14

Peptide-metal-organic framework (Pep-MOF) motors, whose motions are driven by anisotropic surface tension gradients created via peptide self-assembly around frameworks, can rotate microscopic rotors and magnets fast enough to generate an electric power of 0.1 μW. A new rigid Pep-MOF motor can be recycled by refilling the peptide fuel into the nanopores of the MOF. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal organic frameworks for the catalytic detoxification of chemical warfare nerve agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hupp, Joseph T.; Farha, Omar K.; Katz, Michael J.

A method of using a metal organic framework (MOF) comprising a metal ion and an at least bidendate organic ligand to catalytically detoxify chemical warfare nerve agents including exposing the metal-organic-framework (MOF) to the chemical warfare nerve agent and catalytically decomposing the nerve agent with the MOF.

Tunable Impedance Spectroscopy Sensors via Selective Nanoporous Materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nenoff, Tina M.; Small, Leo J

Impedance spectroscopy was leveraged to directly detect the sorption of I 2 by selective adsorption into nanoporous metal organic frameworks (MOF). Films of three different types of MOF frameworks, respectively, were drop cast onto platinum interdigitated electrodes, dried, and exposed to gaseous I 2 at 25, 40, or 70 C. The MOF frameworks varied in topology from small pores (equivalent to I 2 diameter) to large pore frameworks. The combination of the chemistry of the framework and pore size dictated quantity and kinetics of I 2 adsorption. Air, argon, methanol, and water were found to produce minimal changes in ZIF-8more » impedance. Independent of MOF framework characteristics, all resultant sensors showed high response to I 2 in air. As an example of sensor output, I 2 was readily detected at 25 C in air within 720 s of exposure, using an un-optimized sensor geometry with a small pored MOF. Further optimization of sensor geometry, decreasing MOF film thicknesses and maximizing sensor capacitance, will enable faster detection of trace I 2 .« less

Silver-induced reconstruction of an adeninate-based metal-organic framework for encapsulation of luminescent adenine-stabilized silver clusters.

PubMed

Jonckheere, Dries; Coutino-Gonzalez, Eduardo; Baekelant, Wouter; Bueken, Bart; Reinsch, Helge; Stassen, Ivo; Fenwick, Oliver; Richard, Fanny; Samorì, Paolo; Ameloot, Rob; Hofkens, Johan; Roeffaers, Maarten B J; De Vos, Dirk E

2016-05-21

Bright luminescent silver-adenine species were successfully stabilized in the pores of the MOF-69A (zinc biphenyldicarboxylate) metal-organic framework, starting from the intrinsically blue luminescent bio-MOF-1 (zinc adeninate 4,4'-biphenyldicarboxylate). Bio-MOF-1 is transformed to the MOF-69A framework by selectively leaching structural adenine linkers from the original framework using silver nitrate solutions in aqueous ethanol. Simultaneously, bright blue-green luminescent silver-adenine clusters are formed inside the pores of the recrystallized MOF-69A matrix in high local concentrations. The structural transition and concurrent changes in optical properties were characterized using a range of structural, physicochemical and spectroscopic techniques (steady-state and time-resolved luminescence, quantum yield determination, fluorescence microscopy). The presented results open new avenues for exploring the use of MOFs containing luminescent silver clusters for solid-state lighting and sensor applications.

Substrate-Independent Epitaxial Growth of the Metal-Organic Framework MOF-508a.

PubMed

Wilson, M; Barrientos-Palomo, S N; Stevens, P C; Mitchell, N L; Oswald, G; Nagaraja, C M; Badyal, J P S

2018-01-31

Plasmachemical deposition is a substrate-independent method for the conformal surface functionalization of solid substrates. Structurally well-defined pulsed plasma deposited poly(1-allylimidazole) layers provide surface imidazole linker groups for the directed liquid-phase epitaxial (layer-by-layer) growth of metal-organic frameworks (MOFs) at room temperature. For the case of microporous [Zn (benzene-1,4-dicarboxylate)-(4,4'-bipyridine) 0.5 ] (MOF-508), the MOF-508a polymorph containing two interpenetrating crystal lattice frameworks undergoes orientated Volmer-Weber growth and displays CO 2 gas capture behavior at atmospheric concentrations in proportion to the number of epitaxially grown MOF-508 layers.

Stable metal-organic frameworks as a host platform for catalysis and biomimetics.

PubMed

Qin, Jun-Sheng; Yuan, Shuai; Lollar, Christina; Pang, Jiandong; Alsalme, Ali; Zhou, Hong-Cai

2018-04-24

Recent years have witnessed the exploration and synthesis of an increasing number of metal-organic frameworks (MOFs). The utilization of stable MOFs as a platform for catalysis and biomimetics is discussed. This Feature Article will provide insights into the rational design and synthesis of three types of stable MOF catalysts on the basis of structural features of MOFs, that is, (i) MOF catalysts with catalytic sites on metal nodes, (ii) MOF catalysts with catalytic sites immobilized in organic struts, and (iii) MOF catalysts with catalytic centres encapsulated in the pores. Then, MOFs used in biomimetics including biomimetic mineralization, biosensors and biomimetic replication are introduced. Finally, a discussion on the challenges that must be addressed for successful implementation of MOFs in catalysis and biomimetics is presented.

Metal-organic framework catalysts for selective cleavage of aryl-ether bonds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allendorf, Mark D.; Stavila, Vitalie

The present invention relates to methods of employing a metal-organic framework (MOF) as a catalyst for cleaving chemical bonds. In particular instances, the MOF results in selective bond cleavage that results in hydrogenolyzis. Furthermore, the MOF catalyst can be reused in multiple cycles. Such MOF-based catalysts can be useful, e.g., to convert biomass components.

Guest-induced emergent properties in Metal–Organic Frameworks

DOE PAGES

Allendorf, Mark D.; Foster, Michael E.; Léonard, François; ...

2015-03-19

Metal–Organic frameworks (MOFs) are crystalline nanoporous materials comprised of organic electron donors linked to metal ions by strong coordination bonds. Applications such as gas storage and separations are currently receiving considerable attention, but if the unique properties of MOFs could be extended to electronics, magnetics, and photonics, the impact on material science would greatly increase. Recently, we obtained “emergent properties,” such as electronic conductivity and energy transfer, by infiltrating MOF pores with “guest” molecules that interact with the framework electronic structure. In this Perspective, we define a path to emergent properties based on the Guest@MOF concept, using zinc-carboxylate and copper-paddlewheelmore » MOFs for illustration. Energy transfer and light harvesting are discussed for zinc carboxylate frameworks infiltrated with triplet-scavenging organometallic compounds and thiophene- and fullerene-infiltrated MOF-177. In addition, we discuss the mechanism of charge transport in TCNQ-infiltrated HKUST-1, the first MOF with electrical conductivity approaching conducting organic polymers. Lastly, these examples show that guest molecules in MOF pores should be considered not merely as impurities or analytes to be sensed but also as an important aspect of rational design.« less

Target-catalyzed hairpin assembly and metal-organic frameworks mediated nonenzymatic co-reaction for multiple signal amplification detection of miR-122 in human serum.

PubMed

Li, Yuliang; Yu, Chao; Yang, Bo; Liu, Zhirui; Xia, Peiyuan; Wang, Qian

2018-04-15

Herein, a new type of multifunctional iron based metal-organic frameworks (PdNPs@Fe-MOFs) has been synthesized by assembly palladium nanoparticles on the surface of Fe-MIL-88NH 2 MOFs microcrystals, and first applied in electrochemical biosensor for ultrasensitive detection of microRNA-122 (miR-122, a biomarker of drug-induced liver injury). The nanohybrids have not only been utilized as ideal nanocarriers for immobilization of signal probes, but also used as redox probes and electrocatalysts. In this biosensor, two hairpin probes were designed as capture probes and signal probes, respectively. The nanohybrids conjugated with streptavidin and biotinylated signal probes were used as the tracer labels, target miR-122 was sandwiched between the tracer labels and thiol-terminated capture probes inserted in MCH monolayer on the gold nanoparticles-functionalized nitrogen-doped graphene sheets (AuNPs@N-G) modified electrode. Based on target-catalyzed hairpin assembly, target miR-122 could trigger the hybridization of capture probes and signal probes to further be released to initiate the next reaction process resulted in numerous tracer indicators anchored onto the sensing interfaces. Thus, the detection signal could be dramatically enhanced towards the electrocatalytic oxidation of 3,3',5,5'-tetramethylbenzidine in the presence of H 2 O 2 owing to the intrinsic and intriguing peroxidase-like activity of the nanohybrids. With the assist of target-catalyzed hairpin assembly and PdNPs@Fe-MOFs mimetic co-reaction for signal amplification, a wide detection range from 0.01fM to 10pM was achieved with a low detection limit of 0.003fM (S/N =3). Furthermore, the proposed biosensor exhibited excellent specificity and recovery in spiked serum samples, and was successfully used for detecting miR-122 in real biological samples, which provided a rapid and efficient method for detecting drug-induced liver injury at an early stage. Copyright © 2017. Published by Elsevier B.V.

QuickFF: A program for a quick and easy derivation of force fields for metal-organic frameworks from ab initio input.

PubMed

Vanduyfhuys, Louis; Vandenbrande, Steven; Verstraelen, Toon; Schmid, Rochus; Waroquier, Michel; Van Speybroeck, Veronique

2015-05-15

QuickFF is a software package to derive accurate force fields for isolated and complex molecular systems in a quick and easy manner. Apart from its general applicability, the program has been designed to generate force fields for metal-organic frameworks in an automated fashion. The force field parameters for the covalent interaction are derived from ab initio data. The mathematical expression of the covalent energy is kept simple to ensure robustness and to avoid fitting deficiencies as much as possible. The user needs to produce an equilibrium structure and a Hessian matrix for one or more building units. Afterward, a force field is generated for the system using a three-step method implemented in QuickFF. The first two steps of the methodology are designed to minimize correlations among the force field parameters. In the last step, the parameters are refined by imposing the force field parameters to reproduce the ab initio Hessian matrix in Cartesian coordinate space as accurate as possible. The method is applied on a set of 1000 organic molecules to show the easiness of the software protocol. To illustrate its application to metal-organic frameworks (MOFs), QuickFF is used to determine force fields for MIL-53(Al) and MOF-5. For both materials, accurate force fields were already generated in literature but they requested a lot of manual interventions. QuickFF is a tool that can easily be used by anyone with a basic knowledge of performing ab initio calculations. As a result, accurate force fields are generated with minimal effort. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Metal-organic-framework-derived carbons: Applications as solid-base catalyst and support for Pd nanoparticles in tandem catalysis

DOE PAGES

Li, Xinle; Zhang, Biying; Fang, Yuhui; ...

2017-02-11

Here, the facile pyrolysis of a bipyridyl metal-organic framework, MOF-253, produces N-doped porous carbons (Cz-MOF-253), which exhibit excellent catalytic activity in the Knoevenagel condensation reaction and outperform other nitrogen-containing MOF-derived carbons. More importantly, by virtue of their high Lewis basicity and porous nature, Cz-MOF-253-supported Pd nanoparticles (Pd/Cz-MOF-253-800) show excellent performance in a one-pot sequential Knoevenagel condensation-hydrogenation reaction.

Three-Dimensional Networked Metal-Organic Frameworks with Conductive Polypyrrole Tubes for Flexible Supercapacitors.

PubMed

Xu, Xingtao; Tang, Jing; Qian, Huayu; Hou, Shujin; Bando, Yoshio; Hossain, Md Shahriar A; Pan, Likun; Yamauchi, Yusuke

2017-11-08

Metal-organic frameworks (MOFs) with high porosity and a regular porous structure have emerged as a promising electrode material for supercapacitors, but their poor electrical conductivity limits their utilization efficiency and capacitive performance. To increase the overall electrical conductivity as well as the efficiency of MOF particles, three-dimensional networked MOFs are developed via using preprepared conductive polypyrrole (PPy) tubes as the support for in situ growth of MOF particles. As a result, the highly conductive PPy tubes that run through the MOF particles not only increase the electron transfer between MOF particles and maintain the high effective porosity of the MOFs but also endow the MOFs with flexibility. Promoted by such elaborately designed MOF-PPy networks, the specific capacitance of MOF particles has been increased from 99.2 F g -1 for pristine zeolitic imidazolate framework (ZIF)-67 to 597.6 F g -1 for ZIF-PPy networks, indicating the importance of the design of the ZIF-PPy continuous microstructure. Furthermore, a flexible supercapacitor device based on ZIF-PPy networks shows an outstanding areal capacitance of 225.8 mF cm -2 , which is far above other MOFs-based supercapacitors reported up to date, confirming the significance of in situ synthetic chemistry as well as the importance of hybrid materials on the nanoscale.

Mechanized azobenzene-functionalized zirconium metal-organic framework for on-command cargo release.

PubMed

Meng, Xiangshi; Gui, Bo; Yuan, Daqiang; Zeller, Matthias; Wang, Cheng

2016-08-01

Stimuli-responsive metal-organic frameworks (MOFs) have gained increasing attention recently for their potential applications in many areas. We report the design and synthesis of a water-stable zirconium MOF (Zr-MOF) that bears photoresponsive azobenzene groups. This particular MOF can be used as a reservoir for storage of cargo in water, and the cargo-loaded MOF can be further capped to construct a mechanized MOF through the binding of β-cyclodextrin with the azobenzene stalks on the MOF surface. The resulting mechanized MOF has shown on-command cargo release triggered by ultraviolet irradiation or addition of competitive agents without premature release. This study represents a simple approach to the construction of stimuli-responsive mechanized MOFs, and considering mechanized UiO-68-azo made from biocompatible components, this smart system may provide a unique MOF platform for on-command drug delivery in the future.

Mechanized azobenzene-functionalized zirconium metal-organic framework for on-command cargo release

PubMed Central

Meng, Xiangshi; Gui, Bo; Yuan, Daqiang; Zeller, Matthias; Wang, Cheng

2016-01-01

Stimuli-responsive metal-organic frameworks (MOFs) have gained increasing attention recently for their potential applications in many areas. We report the design and synthesis of a water-stable zirconium MOF (Zr-MOF) that bears photoresponsive azobenzene groups. This particular MOF can be used as a reservoir for storage of cargo in water, and the cargo-loaded MOF can be further capped to construct a mechanized MOF through the binding of β-cyclodextrin with the azobenzene stalks on the MOF surface. The resulting mechanized MOF has shown on-command cargo release triggered by ultraviolet irradiation or addition of competitive agents without premature release. This study represents a simple approach to the construction of stimuli-responsive mechanized MOFs, and considering mechanized UiO-68-azo made from biocompatible components, this smart system may provide a unique MOF platform for on-command drug delivery in the future. PMID:27493996

Regulating the spatial distribution of metal nanoparticles within metal-organic frameworks to enhance catalytic efficiency

DOE PAGES

Yang, Qiu; Liu, Wenxian; Wang, Bingqing; ...

2017-02-14

Composites incorporating metal nanoparticles (MNPs) within metal-organic frameworks (MOFs) have broad applications in many fields. However, the controlled spatial distribution of the MNPs within MOFs remains a challenge for addressing key issues in catalysis, for example, the efficiency of catalysts due to the limitation of molecular diffusion within MOF channels. We report a facile strategy that enables MNPs to be encapsulated into MOFs with controllable spatial localization by using metal oxide both as support to load MNPs and as a sacrificial template to grow MOFs. This strategy is versatile to a variety of MNPs and MOF crystals. By localizing themore » encapsulated MNPs closer to the surface of MOFs, the resultant MNPs@MOF composites not only exhibit effective selectivity derived from MOF cavities, but also enhanced catalytic activity due to the spatial regulation of MNPs as close as possible to the MOF surface.« less

Hydrothermal fabrication of few-layer MoS2 nanosheets within nanopores on TiO2 derived from MIL-125(Ti) for efficient photocatalytic H2 evolution

NASA Astrophysics Data System (ADS)

Ye, Fei; Li, Houfen; Yu, Hongtao; Chen, Shuo; Quan, Xie

2017-12-01

Protons tend to bond strongly with unsaturated-coordinate S element located at the edge of nano-MoS2 and are consequently reduced to H2. Therefore, increasing the active S atoms quantity will be a feasible approach to enhance hydrogen evolution. Herein we developed a porous TiO2 derived from metal organic frameworks (MOFs) as scaffold to restrict the growth and inhibit the aggregation of MoS2 nanosheets. As a result, the thickness of the prepared MoS2 nanosheets was less than 3 nm (1-4 layers), with more edges and active S atoms being exposed. This few-layer MoS2-porous TiO2 exhibits a H2 evolution rate of 897.5 μmol h-1 g-1, which is nearly twice as much as free-stand MoS2 nanosheets and twenty times more than physical mixture of MoS2 with porous TiO2. The high performance is attributed to that more active edge sites in few-layer MoS2-porous TiO2 are exposed than pure MoS2. This work provides a new method to construct MOFs derived porous structures for controlling MoS2 to expose active sites for HER.

Construction of flexible metal-organic framework (MOF) papers through MOF growth on filter paper and their selective dye capture.

PubMed

Park, Jeehyun; Oh, Moonhyun

2017-09-14

The conjugation of metal-organic frameworks (MOFs) with other materials is an excellent strategy for the production of advanced materials having desired properties and so appropriate applicability. In particular, the integration of MOFs with a flexible paper is expected to form valuable materials in separation technology. Here we report a simple method for the generation of MOF papers through the compact and uniform growth of MOF nanoparticles on the cellulose surface of a carboxymethylated filter paper. The resulting MOF papers show a selective capture ability for negatively charged organic dyes and they can be used for dye separation through simple filtration of a dye solution on the MOF papers. In addition, MOF papers can be reused after a simple washing process without losing their effective dye capture ability.

Mixed-Metal Strategy on Metal-Organic Frameworks (MOFs) for Functionalities Expansion: Co Substitution Induces Aerobic Oxidation of Cyclohexene over Inactive Ni-MOF-74.

PubMed

Sun, Dengrong; Sun, Fangxiang; Deng, Xiaoyu; Li, Zhaohui

2015-09-08

Different amounts of Co-substituted Ni-MOF-74 have been prepared via a post-synthetic metal exchange. Inductively coupled plasma mass spectrometry, powder X-ray diffraction (XRD), N2 adsorption/desorption, and extended X-ray absorption fine structure (EXAFS) analyses indicated the successful metathesis between Co and Ni in Ni-MOF-74 to form the solid-solution-like mixed-metal Co/Ni-MOF-74. It was found that introduction of active Co into the Ni-MOF-74 framework enabled the inert Ni-MOF-74 to show activity for cyclohexene oxidation. Since Co was favorably substituted at positions more accessible to the substrate, the mixed-metal Co/Ni-MOF-74 showed superior catalytic performance, compared with pure Co-MOF-74 containing a similar amount of Co. This study provides a facile method to develop solid-solution-like MOFs for heterogeneous catalysis and highlights the great potential of this mixed-metal strategy in the development of MOFs with specific endowed functionalities.

Metal-organic frameworks in chromatography.

PubMed

Yusuf, Kareem; Aqel, Ahmad; ALOthman, Zeid

2014-06-27

Metal-organic frameworks (MOFs) emerged approximately two decades ago and are the youngest class of porous materials. Despite their short existence, MOFs are finding applications in a variety of fields because of their outstanding chemical and physical properties. This review article focuses on the applications of MOFs in chromatography, including high-performance liquid chromatography (HPLC), gas chromatography (GC), and other chromatographic techniques. The use of MOFs in chromatography has already had a significant impact; however, the utilisation of MOFs in chromatography is still less common than other applications, and the number of MOF materials explored in chromatography applications is limited. Copyright © 2014 Elsevier B.V. All rights reserved.

New Autonomous Motors of Metal-Organic Framework (MOF) Powered by Reorganization of Self-Assembled Peptides at interfaces

PubMed Central

Ikezoe, Yasuhiro; Washino, Gosuke; Uemura, Takashi; Kitagawa, Susumu; Matsui, Hiroshi

2012-01-01

There have developed a variety of microsystems that harness energy and convert it to mechanical motion. Here we developed new autonomous biochemical motors by integrating metal-organic framework (MOF) and self-assembling peptides. MOF is applied as an energy-storing cell that assembles peptides inside nanoscale pores of the coordination framework. The robust assembling nature of peptides enables reconfiguring their assemblies at the water-MOF interface, which is converted to fuel energy. Re-organization of hydrophobic peptides could create the large surface tension gradient around the MOF and it efficiently powers the translation motion of MOF. As a comparison, the velocity of normalized by volume for the DPA-MOF particle is faster and the kinetic energy per the unit mass of fuel is more than twice as large as the one for previous gel motor systems. This demonstration opens the new application of MOF and reconfigurable molecular self-assembly and it may evolve into the smart autonomous motor that mimic bacteria to swim and harvest target chemicals by integrating recognition units. PMID:23104155

Topological Transformation of a Metal–Organic Framework Triggered by Ligand Exchange

DOE PAGES

Miera, Greco Gonzalez; Gomez, Antonio Bermejo; Chupas, Peter J.; ...

2017-04-06

Metal-organic frameworks (MOFs) have shown to be unsuspectedly dynamic. Here we describe the topological interconversion of a new framework in the bio-MOF-100 family (dia-c) into the known isomer (lcs) by doubling the pore volume, which occurs during post-synthesis modifications. During this transformation, re-assembling of the MOF building blocks into a completely different framework occurs, involving breaking/forming of metal-ligand bonds. MOF crystallinity and local structure are retained, as determined by powder X-ray diffraction (PXRD) and pair distribution function (PDF) analyses, respectively. We have exploited the inherent dynamism of bio-MOF-100 by coupling chemical decorations of the framework using solvent-assisted ligand exchange (SALE)more » to the topological change. Following this method and starting from the pristine dense dia-c phase, open lcs-bio-MOF-100 was prepared and functionalized in-situ with an iridium complex (IrL). Alternatively, the dia-c MOF could be modified with wide-ranging amounts of IrL up to ca. 50 mol%, as determined by solution 1H Nuclear Magnetic Resonance (NMR) spectroscopy, by tuning the concentration of the solutions used and with no evidence for isomer interconversion. The single-site nature of the iridium complexes within the MOFs was assessed by X-ray absorption spectroscopy (XAS) and PDF analyses. As a result, ligand exchanges occurred quantitatively at room temperature, with no need of excess of the iridium metallolinker.« less

Topological Transformation of a Metal–Organic Framework Triggered by Ligand Exchange

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miera, Greco Gonzalez; Gomez, Antonio Bermejo; Chupas, Peter J.

Metal-organic frameworks (MOFs) have shown to be unsuspectedly dynamic. Here we describe the topological interconversion of a new framework in the bio-MOF-100 family (dia-c) into the known isomer (lcs) by doubling the pore volume, which occurs during post-synthesis modifications. During this transformation, re-assembling of the MOF building blocks into a completely different framework occurs, involving breaking/forming of metal-ligand bonds. MOF crystallinity and local structure are retained, as determined by powder X-ray diffraction (PXRD) and pair distribution function (PDF) analyses, respectively. We have exploited the inherent dynamism of bio-MOF-100 by coupling chemical decorations of the framework using solvent-assisted ligand exchange (SALE)more » to the topological change. Following this method and starting from the pristine dense dia-c phase, open lcs-bio-MOF-100 was prepared and functionalized in-situ with an iridium complex (IrL). Alternatively, the dia-c MOF could be modified with wide-ranging amounts of IrL up to ca. 50 mol%, as determined by solution 1H Nuclear Magnetic Resonance (NMR) spectroscopy, by tuning the concentration of the solutions used and with no evidence for isomer interconversion. The single-site nature of the iridium complexes within the MOFs was assessed by X-ray absorption spectroscopy (XAS) and PDF analyses. As a result, ligand exchanges occurred quantitatively at room temperature, with no need of excess of the iridium metallolinker.« less

A mixed molecular building block strategy for the design of nested polyhedron metal-organic frameworks.

PubMed

Tian, Dan; Chen, Qiang; Li, Yue; Zhang, Ying-Hui; Chang, Ze; Bu, Xian-He

2014-01-13

A mixed molecular building block (MBB) strategy for the synthesis of double-walled cage-based porous metal-organic frameworks (MOFs) is presented. By means of this method, two isostructural porous MOFs built from unprecedented double-walled metal-organic octahedron were obtained by introducing two size-matching C3 -symmetric molecular building blocks with different rigidities. With their unique framework structures, these MOFs provide, to the best of our knowledge, the first examples of double-walled octahedron-based MOFs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal-Organic Framework (MOF) Compounds: Photocatalysts for Redox Reactions and Solar Fuel Production.

PubMed

Dhakshinamoorthy, Amarajothi; Asiri, Abdullah M; García, Hermenegildo

2016-04-25

Metal-organic frameworks (MOFs) are crystalline porous materials formed from bi- or multipodal organic linkers and transition-metal nodes. Some MOFs have high structural stability, combined with large flexibility in design and post-synthetic modification. MOFs can be photoresponsive through light absorption by the organic linker or the metal oxide nodes. Photoexcitation of the light absorbing units in MOFs often generates a ligand-to-metal charge-separation state that can result in photocatalytic activity. In this Review we discuss the advantages and uniqueness that MOFs offer in photocatalysis. We present the best practices to determine photocatalytic activity in MOFs and for the deposition of co-catalysts. In particular we give examples showing the photocatalytic activity of MOFs in H2 evolution, CO2 reduction, photooxygenation, and photoreduction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enzyme-MOF (metal-organic framework) composites.

PubMed

Lian, Xizhen; Fang, Yu; Joseph, Elizabeth; Wang, Qi; Li, Jialuo; Banerjee, Sayan; Lollar, Christina; Wang, Xuan; Zhou, Hong-Cai

2017-06-06

The ex vivo application of enzymes in various processes, especially via enzyme immobilization techniques, has been extensively studied in recent years in order to enhance the recyclability of enzymes, to minimize enzyme contamination in the product, and to explore novel horizons for enzymes in biomedical applications. Possessing remarkable amenability in structural design of the frameworks as well as almost unparalelled surface tunability, Metal-Organic Frameworks (MOFs) have been gaining popularity as candidates for enzyme immobilization platforms. Many MOF-enzyme composites have achieved unprecedented results, far outperforming free enzymes in many aspects. This review summarizes recent developments of MOF-enzyme composites with special emphasis on preparative techniques and the synergistic effects of enzymes and MOFs. The applications of MOF-enzyme composites, primarily in transferation, catalysis and sensing, are presented as well. The enhancement of enzymatic activity of the composites over free enzymes in biologically incompatible conditions is emphasized in many cases.

Tuning metal–carboxylate coordination in crystalline metal–organic frameworks through surfactant media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Junkuo; Ye, Kaiqi; State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012

Although it has been widely demonstrated that surfactants can efficiently control the size, shape and surface properties of micro/nanocrystals of metal–organic frameworks (MOFs) due to the strong interactions between surfactants and crystal facets of MOFs, the use of surfactants as reaction media to grow MOF single crystals is unprecedented. In addition, compared with ionic liquids, surfactants are much cheaper and can have multifunctional properties such as acidic, basic, neutral, cationic, anionic, or even block. These factors strongly motivate us to develop a new synthetic strategy: growing crystalline MOFs in surfactants. In this report, eight new two-dimensional (2D) or three-dimensional (3D)more » MOFs have been successfully synthesized in an industrially-abundant and environmentally-friendly surfactant: polyethylene glycol-200 (PEG-200). Eight different coordination modes of carboxylates, ranging from monodentate η{sup 1} mode to tetra-donor coordination µ{sub 3}-η{sup 1}:η{sup 2}:η{sup 1} mode, have been founded in our research. The magnetic properties of Co-based MOFs were investigated and MOF NTU-Z6b showed a phase transition with a Curie temperature (T{sub c}) at 5 K. Our strategy of growing crystalline MOFs in surfactant could offer exciting opportunities for preparing novel MOFs with diverse structures and interesting properties. - Graphical abstract: Surfactants have been used as reaction media to grow MOF single crystals for the first time. Eight new two-dimensional or three-dimensional MOFs were successfully synthesized in surfactant polyethylene glycol-200 (PEG-200). Coordination modes of carboxylates up to eight were founded. Our strategy of growing crystalline MOFs in surfactant could offer exciting opportunities for preparing novel MOFs with diverse structures and interesting properties. Display Omitted - Highlights: • Surfactant-thermal synthesis of crystalline metal–organic frameworks. • Eight new 2-D or 3-D metal–organic frameworks. • Eight different metal–carboxylate coordination modes.« less

Modeling adsorption properties of structurally deformed metal–organic frameworks using structure–property map

PubMed Central

Lim, Dae-Woon; Kim, Sungjune; Harale, Aadesh; Yoon, Minyoung; Suh, Myunghyun Paik; Kim, Jihan

2017-01-01

Structural deformation and collapse in metal-organic frameworks (MOFs) can lead to loss of long-range order, making it a challenge to model these amorphous materials using conventional computational methods. In this work, we show that a structure–property map consisting of simulated data for crystalline MOFs can be used to indirectly obtain adsorption properties of structurally deformed MOFs. The structure–property map (with dimensions such as Henry coefficient, heat of adsorption, and pore volume) was constructed using a large data set of over 12000 crystalline MOFs from molecular simulations. By mapping the experimental data points of deformed SNU-200, MOF-5, and Ni-MOF-74 onto this structure–property map, we show that the experimentally deformed MOFs share similar adsorption properties with their nearest neighbor crystalline structures. Once the nearest neighbor crystalline MOFs for a deformed MOF are selected from a structure–property map at a specific condition, then the adsorption properties of these MOFs can be successfully transformed onto the degraded MOFs, leading to a new way to obtain properties of materials whose structural information is lost. PMID:28696307

Research Update: Mechanical properties of metal-organic frameworks - Influence of structure and chemical bonding

NASA Astrophysics Data System (ADS)

Li, Wei; Henke, Sebastian; Cheetham, Anthony K.

2014-12-01

Metal-organic frameworks (MOFs), a young family of functional materials, have been attracting considerable attention from the chemistry, materials science, and physics communities. In the light of their potential applications in industry and technology, the fundamental mechanical properties of MOFs, which are of critical importance for manufacturing, processing, and performance, need to be addressed and understood. It has been widely accepted that the framework topology, which describes the overall connectivity pattern of the MOF building units, is of vital importance for the mechanical properties. However, recent advances in the area of MOF mechanics reveal that chemistry plays a major role as well. From the viewpoint of materials science, a deep understanding of the influence of chemical effects on MOF mechanics is not only highly desirable for the development of novel functional materials with targeted mechanical response, but also for a better understanding of important properties such as structural flexibility and framework breathing. The present work discusses the intrinsic connection between chemical effects and the mechanical behavior of MOFs through a number of prototypical examples.

Silver-induced reconstruction of an adeninate-based metal–organic framework for encapsulation of luminescent adenine-stabilized silver clusters† †Electronic supplementary information (ESI) available: Experimental details and additional structural, physicochemical and optical characterisation. See DOI: 10.1039/c6tc00260a Click here for additional data file.

PubMed Central

Jonckheere, Dries; Coutino-Gonzalez, Eduardo; Baekelant, Wouter; Bueken, Bart; Reinsch, Helge; Stassen, Ivo; Fenwick, Oliver; Richard, Fanny; Samorì, Paolo; Ameloot, Rob; Hofkens, Johan

2016-01-01

Bright luminescent silver-adenine species were successfully stabilized in the pores of the MOF-69A (zinc biphenyldicarboxylate) metal–organic framework, starting from the intrinsically blue luminescent bio-MOF-1 (zinc adeninate 4,4′-biphenyldicarboxylate). Bio-MOF-1 is transformed to the MOF-69A framework by selectively leaching structural adenine linkers from the original framework using silver nitrate solutions in aqueous ethanol. Simultaneously, bright blue-green luminescent silver-adenine clusters are formed inside the pores of the recrystallized MOF-69A matrix in high local concentrations. The structural transition and concurrent changes in optical properties were characterized using a range of structural, physicochemical and spectroscopic techniques (steady-state and time-resolved luminescence, quantum yield determination, fluorescence microscopy). The presented results open new avenues for exploring the use of MOFs containing luminescent silver clusters for solid-state lighting and sensor applications. PMID:28496980

32 CFR 806b.53 - Training tools.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Justice Privacy web pages. Go to http://www.foia.af.mil. Click on “Resources.” (b) “The Privacy Act of... Privacy Act 101 and is available on-line at http://www.foia.af.mil. (d) Training slides for use by the... http://www.foia.af.mil, under “Resources.” Note: Formal school training groups that develop or modify...

32 CFR 806b.53 - Training tools.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Justice Privacy web pages. Go to http://www.foia.af.mil. Click on “Resources.” (b) “The Privacy Act of... Privacy Act 101 and is available on-line at http://www.foia.af.mil. (d) Training slides for use by the... http://www.foia.af.mil, under “Resources.” Note: Formal school training groups that develop or modify...

32 CFR 806b.53 - Training tools.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Justice Privacy web pages. Go to http://www.foia.af.mil. Click on “Resources.” (b) “The Privacy Act of... Privacy Act 101 and is available on-line at http://www.foia.af.mil. (d) Training slides for use by the... http://www.foia.af.mil, under “Resources.” Note: Formal school training groups that develop or modify...

32 CFR 806b.53 - Training tools.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Justice Privacy web pages. Go to http://www.foia.af.mil. Click on “Resources.” (b) “The Privacy Act of... Privacy Act 101 and is available on-line at http://www.foia.af.mil. (d) Training slides for use by the... http://www.foia.af.mil, under “Resources.” Note: Formal school training groups that develop or modify...

Force-Field Prediction of Materials Properties in Metal-Organic Frameworks

PubMed Central

2016-01-01

In this work, MOF bulk properties are evaluated and compared using several force fields on several well-studied MOFs, including IRMOF-1 (MOF-5), IRMOF-10, HKUST-1, and UiO-66. It is found that, surprisingly, UFF and DREIDING provide good values for the bulk modulus and linear thermal expansion coefficients for these materials, excluding those that they are not parametrized for. Force fields developed specifically for MOFs including UFF4MOF, BTW-FF, and the DWES force field are also found to provide accurate values for these materials’ properties. While we find that each force field offers a moderately good picture of these properties, noticeable deviations can be observed when looking at properties sensitive to framework vibrational modes. This observation is more pronounced upon the introduction of framework charges. PMID:28008758

Stable Metal–Organic Frameworks with Group 4 Metals: Current Status and Trends

PubMed Central

2018-01-01

Group 4 metal-based metal–organic frameworks (MIV-MOFs), including Ti-, Zr-, and Hf-based MOFs, are one of the most attractive classes of MOF materials owing to their superior chemical stability and structural tunability. Despite being a relatively new field, MIV-MOFs have attracted significant research attention in the past few years, leading to exciting advances in syntheses and applications. In this outlook, we start with a brief overview of the history and current status of MIV-MOFs, emphasizing the challenges encountered in their syntheses. The unique properties of MIV-MOFs are discussed, including their high chemical stability and strong tolerance toward defects. Particular emphasis is placed on defect engineering in Zr-MOFs which offers additional routes to tailor their functions. Photocatalysis of MIV-MOF is introduced as a representative example of their emerging applications. Finally, we conclude with the perspective of new opportunities in synthesis and defect engineering. PMID:29721526

Predictive framework for shape-selective separations in three-dimensional zeolites and metal-organic frameworks.

PubMed

First, Eric L; Gounaris, Chrysanthos E; Floudas, Christodoulos A

2013-05-07

With the growing number of zeolites and metal-organic frameworks (MOFs) available, computational methods are needed to screen databases of structures to identify those most suitable for applications of interest. We have developed novel methods based on mathematical optimization to predict the shape selectivity of zeolites and MOFs in three dimensions by considering the energy costs of transport through possible pathways. Our approach is applied to databases of over 1800 microporous materials including zeolites, MOFs, zeolitic imidazolate frameworks, and hypothetical MOFs. New materials are identified for applications in gas separations (CO2/N2, CO2/CH4, and CO2/H2), air separation (O2/N2), and chemicals (propane/propylene, ethane/ethylene, styrene/ethylbenzene, and xylenes).

Novel Applications for Oxalate-Phosphate-Amine Metal-Organic-Frameworks (OPA-MOFs): Can an Iron-Based OPA-MOF Be Used as Slow-Release Fertilizer?

PubMed Central

Anstoetz, Manuela; Rose, Terry J.; Clark, Malcolm W.; Yee, Lachlan H.; Raymond, Carolyn A.; Vancov, Tony

2015-01-01

A porous iron-based oxalate-phosphate-amine metal-organic framework material (OPA-MOF) was investigated as a microbially-induced slow-release nitrogen (N) and phosphorus (P) fertilizer. Seedling growth, grain yields, nutrient uptake of wheat plants, and soil dynamics in incubated soil, were investigated using OPA-MOF vs standard P (triple-superphosphate) and N (urea) fertilizers in an acidic Ferralsol at two application rates (equivalent 120 and 40 kg N ha-1). While urea hydrolysis in the OPA-MOF treatment was rapid, conversion of ammonium to nitrate was significantly inhibited compared to urea treatment. Reduced wheat growth in OPA-MOF treatments was not caused by N-deficiency, but by limited P-bioavailability. Two likely reasons were slow P-mobilisation from the OPA-MOF or rapid P-binding in the acid soil. P-uptake and yield in OPA-MOF treatments were significantly higher than in nil-P controls, but significantly lower than in conventionally-fertilised plants. OPA-MOF showed potential as enhanced efficiency N fertilizer. However, as P-bioavailability was insufficient to meet plant demands, further work should determine if P-availability may be enhanced in alkaline soils, or whether central ions other than Fe, forming the inorganic metal-P framework in the MOF, may act as a more effective P-source in acid soils. PMID:26633174

Novel Applications for Oxalate-Phosphate-Amine Metal-Organic-Frameworks (OPA-MOFs): Can an Iron-Based OPA-MOF Be Used as Slow-Release Fertilizer?

PubMed

Anstoetz, Manuela; Rose, Terry J; Clark, Malcolm W; Yee, Lachlan H; Raymond, Carolyn A; Vancov, Tony

2015-01-01

A porous iron-based oxalate-phosphate-amine metal-organic framework material (OPA-MOF) was investigated as a microbially-induced slow-release nitrogen (N) and phosphorus (P) fertilizer. Seedling growth, grain yields, nutrient uptake of wheat plants, and soil dynamics in incubated soil, were investigated using OPA-MOF vs standard P (triple-superphosphate) and N (urea) fertilizers in an acidic Ferralsol at two application rates (equivalent 120 and 40 kg N ha(-1)). While urea hydrolysis in the OPA-MOF treatment was rapid, conversion of ammonium to nitrate was significantly inhibited compared to urea treatment. Reduced wheat growth in OPA-MOF treatments was not caused by N-deficiency, but by limited P-bioavailability. Two likely reasons were slow P-mobilisation from the OPA-MOF or rapid P-binding in the acid soil. P-uptake and yield in OPA-MOF treatments were significantly higher than in nil-P controls, but significantly lower than in conventionally-fertilised plants. OPA-MOF showed potential as enhanced efficiency N fertilizer. However, as P-bioavailability was insufficient to meet plant demands, further work should determine if P-availability may be enhanced in alkaline soils, or whether central ions other than Fe, forming the inorganic metal-P framework in the MOF, may act as a more effective P-source in acid soils.

Unveiling the Effects of Linker Substitution in Suzuki Coupling with Palladium Nanoparticles in Metal–Organic Frameworks [Unveiling the Effects of Linker Substitution in Suzuki Coupling Reaction with Palladium Nanoparticles in Metal–Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xinle; Zhang, Biying; Van Zeeland, Ryan

The establishment of structure–property relationships in heterogeneous catalysis is of prime importance but remains a formidable challenge. Metal–organic frameworks (MOFs) featuring excellent chemical tunability are emerging as an auspicious platform for the atomic-level control of heterogeneous catalysis. Herein, we encapsulate palladium nanoparticles (Pd NPs) in a series of isoreticular mixed-linker MOFs, and the obtained MOF-Pd NPs catalysts were used to unveil the electronic and steric effects of linker substitution on the activity of these catalysts in the Suzuki–Miyaura cross-coupling reactions. Significantly, m-6,6'-Me2bpy-MOF-Pd exhibits a remarkable enhancement in the activity compared to non-functionalized m-bpy-MOF-Pd and m-4,4'-Me 2bpy-MOF-Pd. This study unambiguously demonstratesmore » that the stereoelectronic properties of linker units are crucial to the catalytic activity of nanoparticles encapsulated in MOFs. More interestingly, the trend of activity change is consistent with our previous work on catalytic sites generated in situ from Pd(II) coordinated in MOFs bearing the same functional groups, which suggests that both MOF-Pd NPs and MOF-Pd(II) catalysts generate similar active centers during Suzuki–Miyaura coupling reactions. Lastly, this work paves a new avenue to the fabrication of advanced and tunable MOF-based catalysts through rational linker engineering.« less

Unveiling the Effects of Linker Substitution in Suzuki Coupling with Palladium Nanoparticles in Metal–Organic Frameworks [Unveiling the Effects of Linker Substitution in Suzuki Coupling Reaction with Palladium Nanoparticles in Metal–Organic Frameworks

DOE PAGES

Li, Xinle; Zhang, Biying; Van Zeeland, Ryan; ...

2018-01-18

The establishment of structure–property relationships in heterogeneous catalysis is of prime importance but remains a formidable challenge. Metal–organic frameworks (MOFs) featuring excellent chemical tunability are emerging as an auspicious platform for the atomic-level control of heterogeneous catalysis. Herein, we encapsulate palladium nanoparticles (Pd NPs) in a series of isoreticular mixed-linker MOFs, and the obtained MOF-Pd NPs catalysts were used to unveil the electronic and steric effects of linker substitution on the activity of these catalysts in the Suzuki–Miyaura cross-coupling reactions. Significantly, m-6,6'-Me2bpy-MOF-Pd exhibits a remarkable enhancement in the activity compared to non-functionalized m-bpy-MOF-Pd and m-4,4'-Me 2bpy-MOF-Pd. This study unambiguously demonstratesmore » that the stereoelectronic properties of linker units are crucial to the catalytic activity of nanoparticles encapsulated in MOFs. More interestingly, the trend of activity change is consistent with our previous work on catalytic sites generated in situ from Pd(II) coordinated in MOFs bearing the same functional groups, which suggests that both MOF-Pd NPs and MOF-Pd(II) catalysts generate similar active centers during Suzuki–Miyaura coupling reactions. Lastly, this work paves a new avenue to the fabrication of advanced and tunable MOF-based catalysts through rational linker engineering.« less

Minerals with metal-organic framework structures

PubMed Central

Huskić, Igor; Pekov, Igor V.; Krivovichev, Sergey V.; Friščić, Tomislav

2016-01-01

Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals. PMID:27532051

Nanoscale Fluorescent Metal-Organic Framework@Microporous Organic Polymer Composites for Enhanced Intracellular Uptake and Bioimaging.

PubMed

Wang, Lei; Wang, Weiqi; Zheng, Xiaohua; Li, Zhensheng; Xie, Zhigang

2017-01-26

Polymer-modified metal-organic frameworks combine the advantages of both soft polymers and crystalline metal-organic frameworks (MOFs). It is a big challenge to develop simple methods for surface modification of MOFs. In this work, MOF@microporous organic polymer (MOP) hybrid nanoparticles (UNP) have been synthesized by epitaxial growth of luminescent boron-dipyrromethene (BODIPYs)-imine MOPs on the surface of UiO-MOF seeds, which exhibit low cytotoxicity, smaller size distribution, well-retained pore integrity, and available functional sites. After folic acid grafting, the enhanced intracellular uptake and bioimaging was validated. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Minerals with metal-organic framework structures.

PubMed

Huskić, Igor; Pekov, Igor V; Krivovichev, Sergey V; Friščić, Tomislav

2016-08-01

Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals.

An in situ self-assembly template strategy for the preparation of hierarchical-pore metal-organic frameworks

PubMed Central

Huang, Hongliang; Li, Jian-Rong; Wang, Keke; Han, Tongtong; Tong, Minman; Li, Liangsha; Xie, Yabo; Yang, Qingyuan; Liu, Dahuan; Zhong, Chongli

2015-01-01

Metal-organic frameworks (MOFs) have recently emerged as a new type of nanoporous materials with tailorable structures and functions. Usually, MOFs have uniform pores smaller than 2 nm in size, limiting their practical applications in some cases. Although a few approaches have been adopted to prepare MOFs with larger pores, it is still challenging to synthesize hierarchical-pore MOFs (H-MOFs) with high structural controllability and good stability. Here we demonstrate a facile and versatile method, an in situ self-assembly template strategy for fabricating stable H-MOFs, in which multi-scale soluble and/or acid-sensitive metal-organic assembly (MOA) fragments form during the reactions between metal ions and organic ligands (to construct MOFs), and act as removable dynamic chemical templates. This general strategy was successfully used to prepare various H-MOFs that show rich porous properties and potential applications, such as in large molecule adsorption. Notably, the mesopore sizes of the H-MOFs can be tuned by varying the amount of templates. PMID:26548441

Double-Sided Electrochromic Device Based on Metal-Organic Frameworks.

PubMed

Mjejri, Issam; Doherty, Cara M; Rubio-Martinez, Marta; Drisko, Glenna L; Rougier, Aline

2017-11-22

Devices displaying controllably tunable optical properties through an applied voltage are attractive for smart glass, mirrors, and displays. Electrochromic material development aims to decrease power consumption while increasing the variety of attainable colors, their brilliance, and their longevity. We report the first electrochromic device constructed from metal organic frameworks (MOFs). Two MOF films, HKUST-1 and ZnMOF-74, are assembled so that the oxidation of one corresponds to the reduction of the other, allowing the two sides of the device to simultaneously change color. These MOF films exhibit cycling stability unrivaled by other MOFs and a significant optical contrast in a lithium-based electrolyte. HKUST-1 reversibly changed from bright blue to light blue and ZnMOF-74 from yellow to brown. The electrochromic device associates the two MOF films via a PMMA-lithium based electrolyte membrane. The color-switching of these MOFs does not arise from an organic-linker redox reaction, signaling unexplored possibilities for electrochromic MOF-based materials.

Gaseous species as reaction tracers in the solvothermal synthesis of the zinc oxide terephthalate MOF-5.

PubMed

Hausdorf, Steffen; Baitalow, Felix; Seidel, Jürgen; Mertens, Florian O R L

2007-05-24

Gaseous species emitted during the zinc oxide/zinc hydroxide 1,4-benzenedicarboxylate metal organic framework synthesis (MOF-5, MOF-69c) have been used to investigate the reaction scheme that leads to the framework creation. Changes of the gas-phase composition over time indicate that the decomposition of the solvent diethylformamide occurs at least via two competing reaction pathways that can be linked to the reaction's overall water and pH management. From isotope exchange experiments, we deduce that one of the decomposition pathways leads to the removal of water from the reaction mixture, which sets the conditions when the synthesis of an oxide-based (MOF-5) instead of an hydroxide-based MOF (MOF-69c) occurs. A quantitative account of most reactants and byproducts before and after the MOF-5/MOF-69c synthesis is presented. From the investigation of the reaction intermediates and byproducts, we derive a proposal of a basic reaction scheme for the standard synthesis zinc oxide carboxylate MOFs.

The Cooperativity of Fe3O4 and Metal-Organic Framework as Multifunctional Nanocomposites for Laser Desorption Ionization Process.

PubMed

Fu, Chung-Wei; Lirio, Stephen; Shih, Yung-Han; Liu, Wan-Ling; Lin, Chia-Her; Huang, Hsi-Ya

2018-05-10

We report a novel and facile strategy for developing a water stable magnetic metal organic framework nanocomposite (Fe3O4@MOF), in which a Keggin polyoxometalate, phosphotungstic acid (HPW), was encapsulated within the MOF framework via one-pot synthesis method. The combination of HPW-embedded MOF and Fe3O4 endowed the composite with high surface area, strong UV absorption, good hydrophilicity, and enhanced water stability. With these unique properties, the Fe3O4@MOF embedded HPW were served as adsorbent as well as matrix for (surface-assisted laser desorption ionization mass spectrometry) SALDI-MS analysis of polar and non-polar compounds. The synergistic effect of Fe3O4 and MOF showed an interference-free background at low mass region than the pristine MOF or Fe3O4 counterpart. This simple approach can be used as new platform in developing magnetic MOF composites without the time consuming and labor-intensive preparation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selectively catalytic activity of metal–organic frameworks depending on the N-position within the pyridine ring of their building blocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Haitao, E-mail: xuhaitao@ecust.edu.cn; Gou, Yongxia; Ye, Jing

2016-05-15

Iron metal–organic frameworks (MOFs) [Fe(L){sub 2}(SCN){sub 2}]{sub ∝} (L1: 4-bpdh=2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene for 1Fe; and L2: 3-bpdh=2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene for 2Fe) were assembled in a MeOH–H{sub 2}O solvent system. 1Fe exhibits a two-dimensional extended-grid network, whereas 2Fe exhibits a stair-like double-chain; the N-position within the pyridine ring of the complexes was observed to regulate the MOF structure as layers or chains. Furthermore, selectively catalytic activity was observed for the layered MOF but not the chain-structured MOF; micro/nanoparticles of the layered MOF were therefore investigated for new potential applications of micro/nano MOFs. - Graphical abstract: Iron metal–organic frameworks (MOFs) [Fe(L){sub 2}(SCN){sub 2}]{sub ∝} (L1: 4-bpdh=2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadienemore » for 1Fe; and L2: 3-bpdh=2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene for 2Fe) were assembled in a MeOH–H{sub 2}O solvent system. The N-position within the pyridine ring of the complexes was observed to regulate the MOF structure as layers or chains. Selectively catalytic activity was observed for the layered MOF but not the chain-structured MOF. - Highlights: • Synthesis and structure of metal–organic framework [Fe(L){sub 2}(SCN){sub 2}]{sub ∝}. • Selectively catalytic activity depending on the N-position within the pyridine ring. • The degradation and conversion of methyl orange.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgopolova, Ekaterina A.; Brandt, Amy J.; Ejegbavwo, Otega A.

The development of porous well-defined hybrid materials (e.g., metal-organic frameworks or MOFs) will add a new dimension to a wide number of applications ranging from supercapacitors and electrodes to 'smart' membranes and thermoelectrics. From this perspective, the understanding and tailoring of the electronic properties of MOFs are key fundamental challenges that could unlock the full potential of these materials. In this work, we focused on the fundamental insights responsible for the electronic properties of three distinct classes of bimetallic systems, M x-yM' y-MOFs, M xM' y- MOFs, and M x(ligand-M' y)-MOFs, in which the second metal (M') incorporation occurs throughmore » (i) metal (M) replacement in the framework nodes (type I), (ii) metal node extension (type II), and (iii) metal coordination to the organic ligand (type III), respectively. We employed microwave conductivity, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, powder X-ray diffraction, inductively coupled plasma atomic emission spectroscopy, pressed-pellet conductivity, and theoretical modeling to shed light on the key factors responsible for the tunability of MOF electronic structures. Experimental prescreening of MOFs was performed based on changes in the density of electronic states near the Fermi edge, which was used as a starting point for further selection of suitable MOFs. As a result, we demonstrated that the tailoring of MOF electronic properties could be performed as a function of metal node engineering, framework topology, and/or the presence of unsaturated metal sites while preserving framework porosity and structural integrity. Finally, these studies unveil the possible pathways for transforming the electronic properties of MOFs from insulating to semiconducting, as well as provide a blueprint for the development of hybrid porous materials with desirable electronic structures.« less

An efficient synthesis strategy for metal-organic frameworks: Dry-gel synthesis of MOF-74 framework with high yield and improved performance

DOE PAGES

Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; ...

2016-06-16

Here, vapor-assisted dry-gel synthesis of MOF-74 structure, specifically NiMOF-74 from its synthetic precursors, was conducted with high yield and improved performance showing promise for gas (CO 2) and water adsorption applications. Unlike conventional synthesis, which takes 72 h, this kinetic study showed that NiMOF-74 forms within 12 h under dry-gel conditions with similar performance characteristics and exhibits the best performance characteristics after 48 h of heating.

Adsorptive performance of MOF nanocomposite for methylene blue and malachite green dyes: Kinetics, isotherm and mechanism.

PubMed

Alqadami, Ayoub Abdullah; Naushad, Mu; Alothman, Z A; Ahamad, Tansir

2018-06-06

In the present study, Fe 3 O 4 @AMCA-MIL-53(Al) nanocomposite was utilized for the adsorptive removal of highly toxic MB and MG dyes from aqueous environment. The batch adsorption tests were performed at different contact time, pH, Fe 3 O 4 @AMCA-MIL-53(Al) dose, initial concentration of dyes and temperature. The maximum adsorption capacity of MB and MG dyes onto of Fe 3 O 4 @AMCA-MIL-53(Al) using Langmuir equation was 1.02 and 0.90 m mol/g, respectively. The isotherm and kinetic studies revealed that adsorption data were well fitted to Langmuir isotherm and pseudo-first-order kinetics models. Various thermodynamic parameters were also calculated and interpreted. The positive and negative values of ΔH° and ΔG° indicated that the adsorption was endothermic and spontaneous, respectively. The adsorptive binding of MB and MG on Fe 3 O 4 @AMCA-MIL53(Al) nanocomposite was directed by carboxylate and amide groups through electrostatic interaction, π-π interaction and hydrogen bonding. The desorption of both dyes from Fe 3 O 4 @AMCA-MIL-53(Al) was also performed using mixed solution of 0.01 M HCl/ethanol. Thus, we conclude that the Fe 3 O 4 @AMCA-MIL-53(Al) was an outstanding material for the removal of dyes from aqueous environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Titanium–Organic Framework as an Exemplar of Combining the Chemistry of Metal– and Covalent–Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Ha L.; Gándara, Felipe; Furukawa, Hiroyasu

A crystalline material with a two-dimensional structure, termed metal–organic framework-901 (MOF-901), was prepared using a strategy that combines the chemistry of MOFs and covalent–organic frameworks (COFs). This strategy involves in situ generation of an amine-functionalized titanium oxo cluster, Ti6O6(OCH3)6(AB)6 (AB = 4-aminobenzoate), which was linked with benzene-1,4-dialdehyde using imine condensation reactions, typical of COFs. The crystal structure of MOF-901 is composed of hexagonal porous layers that are likely stacked in staggered conformation (hxl topology). This MOF represents the first example of combining metal cluster chemistry with dynamic organic covalent bond formation to give a new crystalline, extended framework of titaniummore » metal, which is rarely used in MOFs. The incorporation of Ti(IV) units made MOF-901 useful in the photocatalyzed polymerization of methyl methacrylate (MMA). The resulting polyMMA product was obtained with a high-number-average molar mass (26 850 g mol–1) and low polydispersity index (1.6), which in many respects are better than those achieved by the commercially available photocatalyst (P-25 TiO2). Additionally, the catalyst can be isolated, reused, and recycled with no loss in performance.« less

Force-field prediction of materials properties in metal-organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, Peter G.; Moosavi, Seyed Mohamad; Witman, Matthew

In this work, MOF bulk properties are evaluated and compared using several force fields on several well-studied MOFs, including IRMOF-1 (MOF-5), IRMOF-10, HKUST-1, and UiO-66. It is found that, surprisingly, UFF and DREIDING provide good values for the bulk modulus and linear thermal expansion coefficients for these materials, excluding those that they are not parametrized for. Force fields developed specifically for MOFs including UFF4MOF, BTW-FF, and the DWES force field are also found to provide accurate values for these materials’ properties. While we find that each force field offers a moderately good picture of these properties, noticeable deviations can bemore » observed when looking at properties sensitive to framework vibrational modes. As a result, this observation is more pronounced upon the introduction of framework charges.« less

Complete Transmetalation in a Metal-Organic Framework by Metal Ion Metathesis in a Single Crystal for Selective Sensing of Phosphate Ions in Aqueous Media.

PubMed

Asha, K S; Bhattacharjee, Rameswar; Mandal, Sukhendu

2016-09-12

A complete transmetalation has been achieved on a barium metal-organic framework (MOF), leading to the isolation of a new Tb-MOF in a single-crystal (SC) to single-crystal (SC) fashion. It leads to the transformation of an anionic framework with cations in the pore to one that is neutral. The mechanistic studies proposed a core-shell metal exchange through dissociation of metal-ligand bonds. This Tb-MOF exhibits enhanced photoluminescence and acts as a selective sensor for phosphate anion in aqueous medium. Thus, this work not only provides a method to functionalize a MOF that can have potential application in sensing but also elucidates the formation mechanism of the resulting MOF. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Force-field prediction of materials properties in metal-organic frameworks

DOE PAGES

Boyd, Peter G.; Moosavi, Seyed Mohamad; Witman, Matthew; ...

2016-12-23

In this work, MOF bulk properties are evaluated and compared using several force fields on several well-studied MOFs, including IRMOF-1 (MOF-5), IRMOF-10, HKUST-1, and UiO-66. It is found that, surprisingly, UFF and DREIDING provide good values for the bulk modulus and linear thermal expansion coefficients for these materials, excluding those that they are not parametrized for. Force fields developed specifically for MOFs including UFF4MOF, BTW-FF, and the DWES force field are also found to provide accurate values for these materials’ properties. While we find that each force field offers a moderately good picture of these properties, noticeable deviations can bemore » observed when looking at properties sensitive to framework vibrational modes. As a result, this observation is more pronounced upon the introduction of framework charges.« less

Surfactant-thermal method to prepare two new cobalt metal-organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Xianglin; Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430074; Toh, Yong Siang

2015-12-15

Employing surfactants as reaction media, two new metal-organic frameworks (MOFs):(HTEA){sub 3}[Co{sub 3}(BTC){sub 3}] (NTU-Z33) and (HTEA)[Co{sub 3}(HBTC){sub 2}(BTC)] (NTU-Z34) (H{sub 3}BTC=1,3,5-benzenetricarboxylic acid, TEA=trimethylamine, and NTU=Nanyang Technological University), have been successfully synthesized and fully characterized. Note that NTU-Z33 has an unusual trimeric [Co{sub 3}(COO){sub 9}] secondary building unit (SBU). Magnetic characterization suggests that both compounds have weak antiferromagnetic behaviors. Our success in preparing new crystalline Co-BTC based MOFs under different surfactant media could provide a new road to prepare new diverse MOFs through various combinations of surfactants. - Graphical abstract: Employing surfactants as reaction media, two new metal-organic frame-works (MOFs) havemore » been successfully synthesized and magnetic study suggests that both compounds have weak antiferromagnetic behaviors. - Highlights: • Two novel metal-organic frame-works (MOFs). • Synthesis through surfactant-thermal condition. • weak antiferromagnetic behaviors for both compounds.« less

Hierarchical 3D ordered meso-/macroporous metal-organic framework produced through a facile template-free self-assembly

NASA Astrophysics Data System (ADS)

Yang, Xiaoli; Wu, Suilan; Wang, Panhao; Yang, Lin

2018-02-01

The synthesis of well-ordered hierarchical metal-organic frameworks (MOFs) in an efficient manner is a great challenge. Here, a 3D regular ordered meso-/macroporous MOF of Cu-TATAB (referred to as MM-MOF) was synthesized through a facile template-free self-assembly process with pore sizes of 31 nm and 119 nm.

Bimetallic Metal-Organic Frameworks: Probing the Lewis Acid Site for CO2 Conversion.

PubMed

Zou, Ruyi; Li, Pei-Zhou; Zeng, Yong-Fei; Liu, Jia; Zhao, Ruo; Duan, Hui; Luo, Zhong; Wang, Jin-Gui; Zou, Ruqiang; Zhao, Yanli

2016-05-01

A highly porous metal-organic framework (MOF) incorporating two kinds of second building units (SBUs), i.e., dimeric paddlewheel (Zn2 (COO)4 ) and tetrameric (Zn4 (O)(CO2 )6 ), is successfully assembled by the reaction of a tricarboxylate ligand with Zn(II) ion. Subsequently, single-crystal-to-single-crystal metal cation exchange using the constructed MOF is investigated, and the results show that Cu(II) and Co(II) ions can selectively be introduced into the MOF without compromising the crystallinity of the pristine framework. This metal cation-exchangeable MOF provides a useful platform for studying the metal effect on both gas adsorption and catalytic activity of the resulted MOFs. While the gas adsorption experiments reveal that Cu(II) and Co(II) exchanged samples exhibit comparable CO2 adsorption capability to the pristine Zn(II) -based MOF under the same conditions, catalytic investigations for the cycloaddition reaction of CO2 with epoxides into related carbonates demonstrate that Zn(II) -based MOF affords the highest catalytic activity as compared with Cu(II) and Co(II) exchanged ones. Molecular dynamic simulations are carried out to further confirm the catalytic performance of these constructed MOFs on chemical fixation of CO2 to carbonates. This research sheds light on how metal exchange can influence intrinsic properties of MOFs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Green Synthesis of Cyclodextrin-Based Metal-Organic Frameworks through the Seed-Mediated Method for the Encapsulation of Hydrophobic Molecules.

PubMed

Qiu, Chao; Wang, Jinpeng; Qin, Yang; Fan, Haoran; Xu, Xueming; Jin, Zhengyu

2018-04-25

Metal-organic frameworks (MOFs) are attracting considerable attention as a result of their unique structural properties, such as a high surface area, highly porous topology, and tunable size and shape, which enable them to have potential applications as a new class of carriers for functional agent or drug delivery. However, most of the MOFs and the polymers used are not pharmaceutically acceptable. For the first time, this study successfully conducted the rapid synthesis of cyclodextrin metal-organic frameworks (CD-MOFs) through a facile and green seed-mediated method. The size control, crystal structure, and thermal properties of CD-MOFs with and without seeds were investigated. When 1 mg/mL seed was added, the size of γ-CD-MOF crystals decreased from 6.2 ± 0.8 to 1.8 ± 0.4 μm. The CD-MOFs synthesized though the seed-mediated method had higher crystallinity and thermal stability than those that were not. Furthermore, the CD-MOFs could encapsulate hydrophobic molecules, such as Nile red (NR), which was chosen as a model, and the interaction mechanism between γ-CD-MOFs and NR was investigated. Results showed the formation of a 1:1 complex between NR and CD-MOFs, demonstrating the potential of these polymers as carriers for hydrophobic drug delivery applications.

A Triazole-Containing Metal-Organic Framework as a Highly Effective and Substrate Size-Dependent Catalyst for CO2 Conversion.

PubMed

Li, Pei-Zhou; Wang, Xiao-Jun; Liu, Jia; Lim, Jie Sheng; Zou, Ruqiang; Zhao, Yanli

2016-02-24

A highly porous metal-organic framework (MOF) incorporating both exposed metal sites and nitrogen-rich triazole groups was successfully constructed via solvothermal assembly of a clicked octcarboxylate ligand and Cu(II) ions, which presents a high affinity toward CO2 molecules clearly verified by gas adsorption and Raman spectral detection. The constructed MOF featuring CO2-adsorbing property and exposed Lewis-acid metal sites could serve as an excellent catalyst for CO2-based chemical fixation. Catalytic activity of the MOF was confirmed by remarkably high efficiency on CO2 cycloaddition with small epoxides. When extending the substrates to larger ones, its activity showed a sharp decrease. These observations reveal that MOF-catalyzed CO2 cycloaddition of small substrates was carried out within the framework, while large ones cannot easily enter into the porous framework for catalytic reactions. Thus, the synthesized MOF exhibits high catalytic selectivity to different substrates on account of the confinement of the pore diameter. The high efficiency and size-dependent selectivity toward small epoxides on catalytic CO2 cycloaddition make this MOF a promising heterogeneous catalyst for carbon fixation.

Tunable photoluminescent metal-organic-frameworks and method of making the same

DOEpatents

Nenoff, Tina M.; Sava Gallis, Dorina Florentina; Rohwer, Lauren E.S.

2017-08-22

The present disclosure is directed to new photoluminescent metal-organic frameworks (MOFs). The newly developed MOFs include either non rare earth element (REE) transition metal atoms or limited concentrations of REE atoms, including: Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Ru, Ag, Cd, Sn, Sb, Ir, Pb, Bi, that are located in the MOF framework in site isolated locations, and have emission colors ranging from white to red, depending on the metal concentration levels and/or choice of ligand.

Construction of hierarchically porous metal–organic frameworks through linker labilization

DOE PAGES

Yuan, Shuai; Zou, Lanfang; Qin, Jun-Sheng; ...

2017-05-25

One major goal of metal–organic framework (MOF) research is the expansion of pore size and volume. Although many approaches have been attempted to increase the pore size of MOF materials, it is still a challenge to construct MOFs with precisely customized pore apertures for specific applications. W present a new method, namely linker labilization, to increase the MOF porosity and pore size, giving rise to hierarchical-pore architectures. Microporous MOFs with robust metal nodes and pro-labile linkers were initially synthesized. The mesopores were subsequently created as crystal defects through the splitting of a pro-labile-linker and the removal of the linker fragmentsmore » by acid treatment. We also demonstrate that linker labilization method can create controllable hierarchical porous structures in stable MOFs, which facilitates the diffusion and adsorption process of guest molecules to improve the performances of MOFs in adsorption and catalysis.« less

Pristine Metal-Organic Frameworks and their Composites for Energy Storage and Conversion.

PubMed

Liang, Zibin; Qu, Chong; Guo, Wenhan; Zou, Ruqiang; Xu, Qiang

2017-11-22

Metal-organic frameworks (MOFs), a new class of crystalline porous organic-inorganic hybrid materials, have recently attracted increasing interest in the field of energy storage and conversion. Herein, recent progress of MOFs and MOF composites for energy storage and conversion applications, including photochemical and electrochemical fuel production (hydrogen production and CO 2 reduction), water oxidation, supercapacitors, and Li-based batteries (Li-ion, Li-S, and Li-O 2 batteries), is summarized. Typical development strategies (e.g., incorporation of active components, design of smart morphologies, and judicious selection of organic linkers and metal nodes) of MOFs and MOF composites for particular energy storage and conversion applications are highlighted. A broad overview of recent progress is provided, which will hopefully promote the future development of MOFs and MOF composites for advanced energy storage and conversion applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chiral Recognition and Separation by Chirality-Enriched Metal-Organic Frameworks.

PubMed

Das, Saikat; Xu, Shixian; Ben, Teng; Qiu, Shilun

2018-05-16

Endowed with chiral channels and pores, chiral metal-organic frameworks (MOFs) are highly useful; however, their synthesis remains a challenge given that most chiral building blocks are expensive. Although MOFs with induced chirality have been reported to avoid this shortcoming, no study providing evidence for the ee value of such MOFs has yet been reported. We herein describe the first study on the efficiency of chiral induction in MOFs using inexpensive achiral building blocks and fully recoverable chiral dopants to control the handedness of racemic MOFs. This method yielded chirality-enriched MOFs with accessible pores. The ability of the materials to form host-guest complexes was probed with enantiomers of varying size and coordination and in solvents with varying polarity. Furthermore, mixed-matrix membranes (MMMs) composed of chirality-enriched MOF particles dispersed in a polymer matrix demonstrated a new route for chiral separation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Construction of hierarchically porous metal-organic frameworks through linker labilization

NASA Astrophysics Data System (ADS)

Yuan, Shuai; Zou, Lanfang; Qin, Jun-Sheng; Li, Jialuo; Huang, Lan; Feng, Liang; Wang, Xuan; Bosch, Mathieu; Alsalme, Ali; Cagin, Tahir; Zhou, Hong-Cai

2017-05-01

A major goal of metal-organic framework (MOF) research is the expansion of pore size and volume. Although many approaches have been attempted to increase the pore size of MOF materials, it is still a challenge to construct MOFs with precisely customized pore apertures for specific applications. Herein, we present a new method, namely linker labilization, to increase the MOF porosity and pore size, giving rise to hierarchical-pore architectures. Microporous MOFs with robust metal nodes and pro-labile linkers were initially synthesized. The mesopores were subsequently created as crystal defects through the splitting of a pro-labile-linker and the removal of the linker fragments by acid treatment. We demonstrate that linker labilization method can create controllable hierarchical porous structures in stable MOFs, which facilitates the diffusion and adsorption process of guest molecules to improve the performances of MOFs in adsorption and catalysis.

Fabrication of COF-MOF Composite Membranes and Their Highly Selective Separation of H2/CO2.

PubMed

Fu, Jingru; Das, Saikat; Xing, Guolong; Ben, Teng; Valtchev, Valentin; Qiu, Shilun

2016-06-22

The search for new types of membrane materials has been of continuous interest in both academia and industry, given their importance in a plethora of applications, particularly for energy-efficient separation technology. In this contribution, we demonstrate for the first time that a metal-organic framework (MOF) can be grown on the covalent-organic framework (COF) membrane to fabricate COF-MOF composite membranes. The resultant COF-MOF composite membranes demonstrate higher separation selectivity of H2/CO2 gas mixtures than the individual COF and MOF membranes. A sound proof for the synergy between two porous materials is the fact that the COF-MOF composite membranes surpass the Robeson upper bound of polymer membranes for mixture separation of a H2/CO2 gas pair and are among the best gas separation MOF membranes reported thus far.

Construction of hierarchically porous metal–organic frameworks through linker labilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Shuai; Zou, Lanfang; Qin, Jun-Sheng

One major goal of metal–organic framework (MOF) research is the expansion of pore size and volume. Although many approaches have been attempted to increase the pore size of MOF materials, it is still a challenge to construct MOFs with precisely customized pore apertures for specific applications. W present a new method, namely linker labilization, to increase the MOF porosity and pore size, giving rise to hierarchical-pore architectures. Microporous MOFs with robust metal nodes and pro-labile linkers were initially synthesized. The mesopores were subsequently created as crystal defects through the splitting of a pro-labile-linker and the removal of the linker fragmentsmore » by acid treatment. We also demonstrate that linker labilization method can create controllable hierarchical porous structures in stable MOFs, which facilitates the diffusion and adsorption process of guest molecules to improve the performances of MOFs in adsorption and catalysis.« less

Impact of linker engineering on the catalytic activity of metal–organic frameworks containing Pd(II)–bipyridine complexes

DOE PAGES

Li, Xinle; Van Zeeland, Ryan; Maligal-Ganesh, Raghu V.; ...

2016-08-09

A series of mixed-linker bipyridyl metal–organic framework (MOF)-supported palladium(II) catalysts were used to elucidate the electronic and steric effects of linker substitution on the activity of these catalysts in the context of Suzuki–Miyaura cross-coupling reactions. m-6,6'-Me 2bpy-MOF-PdCl 2 exhibited 110- and 496-fold enhancements in activity compared to nonfunctionalized m-bpy-MOF-PdCl 2 and m-4,4'-Me 2bpy-MOF-PdCl 2, respectively. Furthermore, this result clearly demonstrates that the stereoelectronic properties of metal-binding linker units are critical to the activity of single-site organometallic catalysts in MOFs and highlights the importance of linker engineering in the design and development of efficient MOF catalysts.

Liquid phase blending of metal-organic frameworks.

PubMed

Longley, Louis; Collins, Sean M; Zhou, Chao; Smales, Glen J; Norman, Sarah E; Brownbill, Nick J; Ashling, Christopher W; Chater, Philip A; Tovey, Robert; Schönlieb, Carola-Bibiane; Headen, Thomas F; Terrill, Nicholas J; Yue, Yuanzheng; Smith, Andrew J; Blanc, Frédéric; Keen, David A; Midgley, Paul A; Bennett, Thomas D

2018-06-15

The liquid and glass states of metal-organic frameworks (MOFs) have recently become of interest due to the potential for liquid-phase separations and ion transport, alongside the fundamental nature of the latter as a new, fourth category of melt-quenched glass. Here we show that the MOF liquid state can be blended with another MOF component, resulting in a domain structured MOF glass with a single, tailorable glass transition. Intra-domain connectivity and short range order is confirmed by nuclear magnetic resonance spectroscopy and pair distribution function measurements. The interfacial binding between MOF domains in the glass state is evidenced by electron tomography, and the relationship between domain size and T g investigated. Nanoindentation experiments are also performed to place this new class of MOF materials into context with organic blends and inorganic alloys.

Determination of heavy metal ions in vegetable samples using a magnetic metal-organic framework nanocomposite sorbent.

PubMed

Hassanpour, Akbar; Hosseinzadeh-Khanmiri, Rahim; Babazadeh, Mirzaagha; Abolhasani, Jafar; Ghorbani-Kalhor, Ebrahim

2015-01-01

This paper describes the synthesis and application of a novel magnetic metal-organic framework (MOF) [(Fe₃O₄-benzoyl isothiocyanate)/Cu₃(benzene-1,3,5-tricarboxylate)₂] to pre-concentrate trace amounts of Cd(II), Pb(II), Zn(II) and Cr(III) ions and their determination by flame atomic absorption spectrometry. A Box-Behnken design was used to find the parameters affecting the pre-concentration procedure through response surface methodology. Three factors including uptake time, amount of the magnetic sorbent and pH of the sample were selected as affecting factors in the sorption step, and four factors including type, volume and concentration of the eluent as well as the elution time were selected in the elution step for the optimisation study. The opted values were 30 mg, 10.1 min, 5.9, EDTA, 4.0 ml, 0.57 mol l(-1) EDTA solution and 13.0 min for the amount of the magnetic sorbent, uptake time, pH of the sample, type, volume, concentration of the eluent, and elution time, respectively. The limits of detection (LODs) were 0.12, 0.7, 0.16, and 0.4 ng ml(-1) for Cd(II), Pb(II), Zn(II) and Cr(III) ions, respectively. The relative standard deviations (RSDs) of the method were less than 7.2% for five separate batch experiments for the determination of 30 μg l(-1) of Cd(II), Pb(II), Zn(II) and Cr(III) ions. The sorption capacity of the [(Fe₃O₄-benzoyl isothiocyanate)/MOF] was 175 mg g(-1) for Cd(II), 168 mg g(-1) for Pb(II), 210 mg g(-1) for Zn(II) and 196 mg g(-1) for Cr(III). It was found that the magnetic MOF nanocomposite demonstrated a higher capacity compared with Fe₃O₄-benzoyl isothiocyanate. Finally, the magnetic MOF nanocomposite was successfully applied to the rapid extraction of trace amounts of the heavy metal ions from vegetable samples.

ACT-R/E: An Embodied Cognitive Architecture for Human-Robot Interaction

DTIC Science & Technology

2013-01-01

Threaded Cognition: An Integrated Theory of Concurrent Multitasking . Psychological Review, 115(1), 101–130, http://dx.doi.org/10.1037/0033-295X...Trafton, Naval Research Laboratory, Washington, DC, USA Email : greg.trafton@nrl.navy.mil Laura Hiatt, Naval Research Laboratory, Washington, DC, USA Email ...laura.hiatt@nrl.navy.mil Anthony Harrison, Naval Research Laboratory, Washington, DC, USA Email : anthony.harrison@nrl.navy.mil Frank Tamborello, Naval

Synthesis and Electric Properties of a Two-Dimensional Metal-Organic Framework Based on Phthalocyanine.

PubMed

Nagatomi, Hisanori; Yanai, Nobuhiro; Yamada, Teppei; Shiraishi, Kanji; Kimizuka, Nobuo

2018-02-06

Complexation of copper(II) 2,3,9,10,16,17,23,24-octahydroxy-29H,31H-phthalocyanine (CuPcOH) with copper(II) ions gives a two-dimensional (2D) metal-organic framework (MOF). This is the first report of a phthalocyanine-based MOF. This 2D MOF was obtained as a black powder and showed an electrical conductivity of 1.6×10 -6  S cm -1 at 80 °C. When this MOF is used as a cathode of lithium ion battery (LIB), large charge/discharge capacities of 151/128 mAh g -1 were obtained. In addition, it showed a good stability during 200 charge/discharge cycles. The obtained LIB performance mainly originates from the electrically conductive and redox-active framework of the phthalocyanine-based 2D MOF and its hierarchical microporous/mesoporous structure. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transformation of metal-organic framework to polymer gel by cross-linking the organic ligands preorganized in metal-organic framework.

PubMed

Ishiwata, Takumi; Furukawa, Yuki; Sugikawa, Kouta; Kokado, Kenta; Sada, Kazuki

2013-04-10

Until now, seamless fusion of metal-organic frameworks (MOFs) and covalently cross-linked polymer gels (PG) at molecular level has been extremely rare, since these two matters have been regarded as opposite, that is, hard versus soft. In this report, we demonstrate transformation of cubic MOF crystals to PG via inner cross-linking of the organic linkers in the void space of MOF, followed by decomposition of the metal coordination. The obtained PG behaved as a polyelectrolyte gel, indicating the high content of ionic groups inside. Metal ions were well adsorbed in the PG due to its densely packed carboxylate groups. A chimera-type hybrid material consisting of MOF and PG was obtained by partial hydrolysis of resulting cross-linked MOF. The shape of resulting PG network well reflected the crystal structure of MOF employed as a template. Our results will connect the two different network materials that have been ever studied in the two different fields to provide new soft and hard hybrid materials, and the unique copolymerization in the large void space of the MOF will open a new horizon toward "ideal network polymers" never prepared before now.

Metal-Organic Framework Thin Film Coated Optical Fiber Sensors: A Novel Waveguide-Based Chemical Sensing Platform.

PubMed

Kim, Ki-Joong; Lu, Ping; Culp, Jeffrey T; Ohodnicki, Paul R

2018-02-23

Integration of optical fiber with sensitive thin films offers great potential for the realization of novel chemical sensing platforms. In this study, we present a simple design strategy and high performance of nanoporous metal-organic framework (MOF) based optical gas sensors, which enables detection of a wide range of concentrations of small molecules based upon extremely small differences in refractive indices as a function of analyte adsorption within the MOF framework. Thin and compact MOF films can be uniformly formed and tightly bound on the surface of etched optical fiber through a simple solution method which is critical for manufacturability of MOF-based sensor devices. The resulting sensors show high sensitivity/selectivity to CO 2 gas relative to other small gases (H 2 , N 2 , O 2 , and CO) with rapid (

Microfluidic approach toward continuous and ultrafast synthesis of metal-organic framework crystals and hetero structures in confined microdroplets.

PubMed

Faustini, Marco; Kim, Jun; Jeong, Guan-Young; Kim, Jin Yeong; Moon, Hoi Ri; Ahn, Wha-Seung; Kim, Dong-Pyo

2013-10-02

Herein, we report a novel nanoliter droplet-based microfluidic strategy for continuous and ultrafast synthesis of metal-organic framework (MOF) crystals and MOF heterostructures. Representative MOF structures, such as HKUST-1, MOF-5, IRMOF-3, and UiO-66, were synthesized within a few minutes via solvothermal reactions with substantially faster kinetics in comparison to the conventional batch processes. The approach was successfully extended to the preparation of a demanding Ru3BTC2 structure that requires high-pressure hydrothermal synthesis conditions. Finally, three different types of core-shell MOF composites, i.e., Co3BTC2@Ni3BTC2, MOF-5@diCH3-MOF-5, and Fe3O4@ZIF-8, were synthesized by exploiting a unique two-step integrated microfluidic synthesis scheme in a continuous-flow mode. The synthesized MOF crystals were characterized by X-ray diffraction, scanning electron microscopy, and BET surface area measurements. In comparison with bare MOF-5, MOF-5@diCH3-MOF-5 showed enhanced structural stability in the presence of moisture, and the catalytic performance of Fe3O4@ZIF-8 was examined using Knoevenagel condensation as a probe reaction. The microfluidic strategy allowed continuous fabrication of high-quality MOF crystals and composites exhibiting distinct morphological characteristics in a time-efficient manner and represents a viable alternative to the time-consuming and multistep MOF synthesis processes.

Antifungal activity of water-stable copper-containing metal-organic frameworks

NASA Astrophysics Data System (ADS)

Bouson, Supaporn; Krittayavathananon, Atiweena; Phattharasupakun, Nutthaphon; Siwayaprahm, Patcharaporn; Sawangphruk, Montree

2017-10-01

Although metal-organic frameworks (MOFs) or porous coordination polymers have been widely studied, their antimicrobial activities have not yet been fully investigated. In this work, antifungal activity of copper-based benzene-tricarboxylate MOF (Cu-BTC MOF), which is water stable and industrially interesting, is investigated against Candida albicans, Aspergillus niger, Aspergillus oryzae and Fusarium oxysporum. The Cu-BTC MOF can effectively inhibit the growth rate of C. albicans and remarkably inhibit the spore growth of A. niger, A. oryzae and F. oxysporum. This finding shows the potential of using Cu-BTC MOF as a strong biocidal material against representative yeasts and moulds that are commonly found in the food and agricultural industries.

Antifungal activity of water-stable copper-containing metal-organic frameworks

PubMed Central

Bouson, Supaporn; Krittayavathananon, Atiweena; Phattharasupakun, Nutthaphon; Siwayaprahm, Patcharaporn

2017-01-01

Although metal-organic frameworks (MOFs) or porous coordination polymers have been widely studied, their antimicrobial activities have not yet been fully investigated. In this work, antifungal activity of copper-based benzene-tricarboxylate MOF (Cu-BTC MOF), which is water stable and industrially interesting, is investigated against Candida albicans, Aspergillus niger, Aspergillus oryzae and Fusarium oxysporum. The Cu-BTC MOF can effectively inhibit the growth rate of C. albicans and remarkably inhibit the spore growth of A. niger, A. oryzae and F. oxysporum. This finding shows the potential of using Cu-BTC MOF as a strong biocidal material against representative yeasts and moulds that are commonly found in the food and agricultural industries. PMID:29134075

Surface functionalization of metal organic frameworks for mixed matrix membranes

DOEpatents

Albenze, Erik; Lartey, Michael; Li, Tao; Luebke, David R.; Nulwala, Hunaid B.; Rosi, Nathaniel L.; Venna, Surendar R.

2017-03-21

Mixed Matrix Membrane (MMM) are composite membranes for gas separation and comprising a quantity of inorganic filler particles, in particular metal organic framework (MOF), dispersed throughout a polymer matrix comprising one or more polymers. This disclosure is directed to MOF functionalized through addition of a pendant functional group to the MOF, in order to improve interaction with a surrounding polymer matrix in a MMM. The improved interaction aids in avoiding defects in the MMM due to incompatible interfaces between the polymer matrix and the MOF particle, in turn increasing the mechanical and gas separation properties of the MMM. The disclosure is also directed to a MMM incorporating the surface functionalized MOF.

Transient Mass and Thermal Transport during Methane Adsorption into the Metal-Organic Framework HKUST-1.

PubMed

Babaei, Hasan; McGaughey, Alan J H; Wilmer, Christopher E

2018-01-24

Methane adsorption into the metal-organic framework (MOF) HKUST-1 and the resulting heat generation and dissipation are investigated using molecular dynamics simulations. Transient simulations reveal that thermal transport in the MOF occurs two orders of magnitude faster than gas diffusion. A large thermal resistance at the MOF-gas interface (equivalent to 127 nm of bulk HKUST-1), however, prevents fast release of the generated heat. The mass transport resistance at the MOF-gas interface is equivalent to 1 nm of bulk HKUST-1 and does not present a bottleneck in the adsorption process. These results provide important insights into the application of MOFs for gas storage applications.

Breaking Down Chemical Weapons by Metal-Organic Frameworks.

PubMed

Mondal, Suvendu Sekhar; Holdt, Hans-Jürgen

2016-01-04

Seek and destroy: Filtration schemes and self-detoxifying protective fabrics based on the Zr(IV)-containing metal-organic frameworks (MOFs) MOF-808 and UiO-66 doped with LiOtBu have been developed that capture and hydrolytically detoxify simulants of nerve agents and mustard gas. Both MOFs function as highly catalytic elements in these applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Purification of metal-organic framework materials

DOEpatents

Farha, Omar K.; Hupp, Joseph T.

2012-12-04

A method of purification of a solid mixture of a metal-organic framework (MOF) material and an unwanted second material by disposing the solid mixture in a liquid separation medium having a density that lies between those of the wanted MOF material and the unwanted material, whereby the solid mixture separates by density differences into a fraction of wanted MOF material and another fraction of unwanted material.

Purification of metal-organic framework materials

DOEpatents

Farha, Omar K.; Hupp, Joseph T.

2015-06-30

A method of purification of a solid mixture of a metal-organic framework (MOF) material and an unwanted second material by disposing the solid mixture in a liquid separation medium having a density that lies between those of the wanted MOF material and the unwanted material, whereby the solid mixture separates by density differences into a fraction of wanted MOF material and another fraction of unwanted material.

Metal–Organic Frameworks as Active Materials in Electronic Sensor Devices

PubMed Central

Campbell, Michael G.; Dincă, Mircea

2017-01-01

In the past decade, advances in electrically conductive metal–organic frameworks (MOFs) and MOF-based electronic devices have created new opportunities for the development of next-generation sensors. Here we review this rapidly-growing field, with a focus on the different types of device configurations that have allowed for the use of MOFs as active components of electronic sensor devices. PMID:28498308

Synthesis and Characterization of Metal-Organic Frameworks (MOFs) That Are Difficult to Access De Novo

NASA Astrophysics Data System (ADS)

Karagiaridi, Olga

Metal-organic frameworks (MOFs) are a class of intriguing hybrid materials, comprised of metal-based nodes joined by organic linkers into a crystalline, porous, three-dimensional lattice. Their signature properties (well-defined surfaces, tailorability and ultra-high porosity) render them promising candidates for many applications, including, but not limited to, gas storage, gas separation, catalysis and sensing. One of the greatest challenges associated with MOF synthesis lies in the fact that obtaining a desired MOF structure that is tailored to perform a specific application is often not trivial. Traditional synthetic pathways termed "de novo synthesis" (typically one-pot reactions between the MOF structural building blocks under solvothermal conditions) often give rise to side products that do not possess the desired structure. To circumvent this problem, we have studied in depth two powerful MOF synthetic techniques -- solvent-assisted linker exchange (SALE) and transmetalation. These are heterogeneous reactions of parent MOF crystals with concentrated solutions of organic linkers and inorganic metal salts, respectively, that lead to the replacement of the linkers or metal nodes within the parent MOFs by the desired components, while the overall framework topology is preserved. The projects described in this dissertation have aimed to apply these techniques to transform simple (unfunctionalized) and easy to synthesize representative materials from various MOF systems to structurally and functionally interesting daughter products. Examples include synthesis of MOFs that are energetically "unfavorable", extension of MOF cages by longer linker incorporation, functionalization of MOF pores and endowment of MOFs with permanent and persistent porosity. Through these projects, we have been able to formulate a set of rules that can be applied to predict the successful outcome of SALE. Since the allure of MOFs lies in their applications, expanding the range of accessible MOF structures translates into potentially solving more relevant problems - especially those related to alternative energy and sustainability, which urgently need to be addressed given our current energy demands. We hope that SALE and transmetalation can provide alternative routes towards the synthesis of many new and exciting MOFs that can provide creative solutions to many of the problems that we face.

[Ti8Zr2O12(COO)16] Cluster: An Ideal Inorganic Building Unit for Photoactive Metal–Organic Frameworks

PubMed Central

2017-01-01

Metal–organic frameworks (MOFs) based on Ti-oxo clusters (Ti-MOFs) represent a naturally self-assembled superlattice of TiO2 nanoparticles separated by designable organic linkers as antenna chromophores, epitomizing a promising platform for solar energy conversion. However, despite the vast, diverse, and well-developed Ti-cluster chemistry, only a scarce number of Ti-MOFs have been documented. The synthetic conditions of most Ti-based clusters are incompatible with those required for MOF crystallization, which has severely limited the development of Ti-MOFs. This challenge has been met herein by the discovery of the [Ti8Zr2O12(COO)16] cluster as a nearly ideal building unit for photoactive MOFs. A family of isoreticular photoactive MOFs were assembled, and their orbital alignments were fine-tuned by rational functionalization of organic linkers under computational guidance. These MOFs demonstrate high porosity, excellent chemical stability, tunable photoresponse, and good activity toward photocatalytic hydrogen evolution reactions. The discovery of the [Ti8Zr2O12(COO)16] cluster and the facile construction of photoactive MOFs from this cluster shall pave the way for the development of future Ti-MOF-based photocatalysts. PMID:29392182

Metal-organic frameworks and their derived materials for electrochemical energy storage and conversion: Promises and challenges.

PubMed

Wu, Hao Bin; Lou, Xiong Wen David

2017-12-01

In addition to their conventional uses, metal-organic frameworks (MOFs) have recently emerged as an interesting class of functional materials and precursors of inorganic materials for electrochemical energy storage and conversion technologies. This class of MOF-related materials can be broadly categorized into two groups: pristine MOF-based materials and MOF-derived functional materials. Although the diversity in composition and structure leads to diverse and tunable functionalities of MOF-based materials, it appears that much more effort in this emerging field is devoted to synthesizing MOF-derived materials for electrochemical applications. This is in view of two main drawbacks of MOF-based materials: the low conductivity nature and the stability issue. On the contrary, MOF-derived synthesis strategies have substantial advantages in controlling the composition and structure of MOF-derived materials. From this perspective, we review some emerging applications of both groups of MOF-related materials as electrode materials for rechargeable batteries and electrochemical capacitors, efficient electrocatalysts, and even electrolytes for electrochemical devices. By highlighting the advantages and challenges of each class of materials for different applications, we hope to shed some light on the future development of this highly exciting area.

Metal-organic frameworks and their derived materials for electrochemical energy storage and conversion: Promises and challenges

PubMed Central

Wu, Hao Bin; Lou, Xiong Wen (David)

2017-01-01

In addition to their conventional uses, metal-organic frameworks (MOFs) have recently emerged as an interesting class of functional materials and precursors of inorganic materials for electrochemical energy storage and conversion technologies. This class of MOF-related materials can be broadly categorized into two groups: pristine MOF-based materials and MOF-derived functional materials. Although the diversity in composition and structure leads to diverse and tunable functionalities of MOF-based materials, it appears that much more effort in this emerging field is devoted to synthesizing MOF-derived materials for electrochemical applications. This is in view of two main drawbacks of MOF-based materials: the low conductivity nature and the stability issue. On the contrary, MOF-derived synthesis strategies have substantial advantages in controlling the composition and structure of MOF-derived materials. From this perspective, we review some emerging applications of both groups of MOF-related materials as electrode materials for rechargeable batteries and electrochemical capacitors, efficient electrocatalysts, and even electrolytes for electrochemical devices. By highlighting the advantages and challenges of each class of materials for different applications, we hope to shed some light on the future development of this highly exciting area. PMID:29214220

Electrochemistry and electrochemiluminescence from a redox-active metal-organic framework.

PubMed

Xu, Yang; Yin, Xue-Bo; He, Xi-Wen; Zhang, Yu-Kui

2015-06-15

The marriage of metal-organic frameworks (MOFs) and electrochemiluminescence (ECL) can combine their merits together. Designing ECL-active MOF with a high electron transfer capacity and high stability is critical for ECL emission. Here we reported the ECL from a redox-active MOF prepared from {Ru[4,4'-(HO2C)2-bpy]2bpy}(2+) and Zn(2+); a property of MOFs has not been reported previously. The MOF structure is independent of its charge and is therefore stable electrochemically. The redox-activity and well-ordered porous structure of the MOF were confirmed by its electrochemical properties and ECL emission. The high ECL emission indicated the ease of electron transfer between the MOF and co-reactants. Furthermore, the MOF exhibited permselectivity, charge selectivity, and catalytic selectivity along with a stable and concentration-dependent ECL emission toward co-reactants. ECL mechanism was proposed based on the results. The detection and recovery of cocaine in the serum sample was used to validate the feasibility of MOF- based ECL system. The information obtained in this study provides a better understanding of the redox properties of MOFs and their potential electrochemical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Pickering emulsions stabilized by a metal-organic framework (MOF) and graphene oxide (GO) for producing MOF/GO composites.

PubMed

Zhang, Fanyu; Liu, Lifei; Tan, Xiuniang; Sang, Xinxin; Zhang, Jianling; Liu, Chengcheng; Zhang, Bingxing; Han, Buxing; Yang, Guanying

2017-10-18

Herein we demonstrate the formation of a novel kind of Pickering emulsion that is stabilized by a Zr-based metal-organic framework (Zr-MOF) and graphene oxide (GO). It was found that the Zr-BDC-NO 2 and GO solids assembling at the oil/water interface can effectively stabilize the oil droplets that are dispersed in the water phase. Such a Pickering emulsion offers a facile route for fabricating Zr-MOF/GO composite materials. After removing water and oil by freeze drying from Pickering emulsions, the Zr-MOF/GO composites were obtained and their morphologies, structures and interaction properties were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectrometry, respectively. The influences of the concentration of GO and Zr-MOF on the emulsion microstructures and the properties of the MOF/GO composites were studied. Based on experimental results, the mechanisms for the emulsion formation by Zr-MOF and GO and the as-synthesized superstructures of the Zr-MOF/GO composite were proposed. It is expected that this facile and tunable route can be applied to the synthesis of different kinds of MOF-based or GO-based composite materials.

Surfactant-thermal method to synthesize a new Zn(II)-trimesic MOF with confined Ru(bpy){sub 3}{sup 2+} complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Hui; Gao, Junkuo, E-mail: jkgao@zstu.edu.cn; Wang, Jiangpeng

2015-03-15

A surfactant-thermal method was used to prepare a new zinc-1,3,5-benzentricarboxylate-based metal-organic framework (ZJU-100) with confined Ru(bpy){sub 3}{sup 2+} (RuBpy) complex by using surfactant PEG 400 as reaction medium. The RuBpy molecules were encapsulated between the 2-D sheets in ZJU-100. ZJU-100 showed bathochromic shift in the steady-state emission spectrum and increased emission lifetimes relative to RuBpy molecules. The extended lifetime is attributed to the reduced nonradiative decay rate due to the stabilization of RuBpy within the rigid MOF framework. These results represent the first example of MOF with confined complex synthesized by surfactant, indicating that the surfactant-thermal method could offer excitingmore » opportunities for preparing new MOFs host/guest materials with novel structures and interesting luminescent properties. - Graphical abstract: A surfactant-thermal method was used to prepare a new zinc-1,3,5-benzentricarboxylate-based metal-organic framework (ZJU-100) with confined Ru(bpy){sub 3}{sup 2+} (RuBpy) complex by using surfactant PEG 400 as reaction medium. - Highlights: • Surfactant-thermal synthesis of crystalline metal-organic framework host/guest materials. • RuBpy molecules were encapsulated between the 2-D sheets of MOFs. • Extended lifetime is observed due to the stabilization of RuBpy within the rigid MOF framework.« less

Highly Efficient Catalytic Hydrogen Evolution from Ammonia Borane Using the Synergistic Effect of Crystallinity and Size of Noble-Metal-Free Nanoparticles Supported by Porous Metal-Organic Frameworks.

PubMed

Liu, Penglong; Gu, Xiaojun; Kang, Kai; Zhang, Hao; Cheng, Jia; Su, Haiquan

2017-03-29

A series of nonprecious metal nanoparticles (NPs) supported by metal-organic framework MIL-101 were synthesized using four methods and their catalytic performance on hydrogen evolution from ammonia borane (NH 3 BH 3 ) was studied. The results showed that the crystalline Co NPs with size of 4.5-8.5 and 14.5-24.5 nm had low activities featuring the total turnover frequency (TOF) values of 9.9 and 4.5 mol H2 mol cat -1 min -1 , respectively. In contrast, the amorphous Co NPs with size of 1.6-2.6 and 13.5-24.5 nm exhibited high activities featuring the total TOF values of 51.4 and 22.3 mol H2 mol cat -1 min -1 , respectively. The remarkably different activities could be ascribed to the different crystallinity and size of Co NPs in the catalysts. Moreover, the ultrasound-assisted in situ method was also successfully applied to bimetallic systems, and MIL-101-supported amorphous CuCo, FeCo and NiCo NPs had the catalytic activities with total TOF values of 51.7, 50.8, and 44.3 mol H2 mol cat -1 min -1 , respectively, which were the highest in the values of the reported non-noble metal Co-based catalysts. The present approach, namely, using the synergistic effect of crystallinity and size of metal NPs, may offer a new prospect for high-performance and low-cost nanocatalysts.

Fe3O4@MOF core-shell magnetic microspheres as excellent catalysts for the Claisen-Schmidt condensation reaction

NASA Astrophysics Data System (ADS)

Ke, Fei; Qiu, Ling-Guang; Zhu, Junfa

2014-01-01

Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this work, we present a facile fabrication and characterization of a novel type of MOF-based porous catalyst, namely, Fe3O4@MIL-100(Fe) core-shell magnetic microspheres. It has been shown that these catalysts not only exhibit high catalytic activities for the Claisen-Schmidt condensation reactions under environmentally friendly conditions, but remarkably, they can be easily separated and recycled without significant loss of catalytic efficiency after being used for many times. Therefore, compared to other reported catalysts used in the Claisen-Schmidt condensation reactions, these catalysts are green, cheap and more suitable for large scale industrial applications.Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this work, we present a facile fabrication and characterization of a novel type of MOF-based porous catalyst, namely, Fe3O4@MIL-100(Fe) core-shell magnetic microspheres. It has been shown that these catalysts not only exhibit high catalytic activities for the Claisen-Schmidt condensation reactions under environmentally friendly conditions, but remarkably, they can be easily separated and recycled without significant loss of catalytic efficiency after being used for many times. Therefore, compared to other reported catalysts used in the Claisen-Schmidt condensation reactions, these catalysts are green, cheap and more suitable for large scale industrial applications. Electronic supplementary information (ESI) available: SEM and TEM images, and GC-MS spectra for chalcones. See DOI: 10.1039/c3nr05051c

Water Adsorption in Porous Metal-Organic Frameworks and Related Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furukawa, H; Gandara, F; Zhang, YB

2014-03-19

Water adsorption in porous materials is important for many applications such as dehumidification, thermal batteries, and delivery of drinking water in remote areas. In this study, we have identified three criteria for achieving high performing porous materials for water adsorption. These criteria deal with condensation pressure of water in the pores, uptake capacity, and recyclability and water stability of the material. In search of an excellently performing porous material, we have studied and compared the water adsorption properties of 23 materials, 20 of which are metal organic frameworks (MOFs). Among the MOFs are 10 zirconium(IV) MOFs with a subset ofmore » these, MOF-801-SC (single crystal form), -802, -805, -806, -808, -812, and -841 reported for the first time. MOF-801-P (microcrystalline powder form) was reported earlier and studied here for its water adsorption properties. MOF-812 was only made and structurally characterized but not examined for water adsorption because it is a byproduct of MOF-841 synthesis. All the new zirconium MOFs are made from the Zr6O4(OH)(4)(-CO2)(n) secondary building units (n = 6, 8, 10, or 12) and variously shaped carboxyl organic linkers to make extended porous frameworks. The permanent porosity of all 23 materials was confirmed and their water adsorption measured to reveal that MOF-801-P and MOF-841 are the highest performers based on the three criteria stated above; they are water stable, do not lose capacity after five adsorption/desorption cycles, and are easily regenerated at room temperature. An X-ray single-crystal study and a powder neutron diffraction study reveal the position of the water adsorption sites in MOF-801 and highlight the importance of the intermolecular interaction between adsorbed water molecules within the pores.« less

Water adsorption in porous metal-organic frameworks and related materials.

PubMed

Furukawa, Hiroyasu; Gándara, Felipe; Zhang, Yue-Biao; Jiang, Juncong; Queen, Wendy L; Hudson, Matthew R; Yaghi, Omar M

2014-03-19

Water adsorption in porous materials is important for many applications such as dehumidification, thermal batteries, and delivery of drinking water in remote areas. In this study, we have identified three criteria for achieving high performing porous materials for water adsorption. These criteria deal with condensation pressure of water in the pores, uptake capacity, and recyclability and water stability of the material. In search of an excellently performing porous material, we have studied and compared the water adsorption properties of 23 materials, 20 of which are metal-organic frameworks (MOFs). Among the MOFs are 10 zirconium(IV) MOFs with a subset of these, MOF-801-SC (single crystal form), -802, -805, -806, -808, -812, and -841 reported for the first time. MOF-801-P (microcrystalline powder form) was reported earlier and studied here for its water adsorption properties. MOF-812 was only made and structurally characterized but not examined for water adsorption because it is a byproduct of MOF-841 synthesis. All the new zirconium MOFs are made from the Zr6O4(OH)4(-CO2)n secondary building units (n = 6, 8, 10, or 12) and variously shaped carboxyl organic linkers to make extended porous frameworks. The permanent porosity of all 23 materials was confirmed and their water adsorption measured to reveal that MOF-801-P and MOF-841 are the highest performers based on the three criteria stated above; they are water stable, do not lose capacity after five adsorption/desorption cycles, and are easily regenerated at room temperature. An X-ray single-crystal study and a powder neutron diffraction study reveal the position of the water adsorption sites in MOF-801 and highlight the importance of the intermolecular interaction between adsorbed water molecules within the pores.

Liquid- and Gas-Phase Diffusion of Ferrocene in Thin Films of Metal-Organic Frameworks

PubMed Central

Zhou, Wencai; Wöll, Christof; Heinke, Lars

2015-01-01

The mass transfer of the guest molecules in nanoporous host materials, in particular in metal-organic frameworks (MOFs), is among the crucial features of their applications. By using thin surface-mounted MOF films in combination with a quartz crystal microbalance (QCM), the diffusion of ferrocene vapor and of ethanolic and hexanic ferrocene solution in HKUST-1 was investigated. For the first time, liquid- and gas-phase diffusion in MOFs was compared directly in the identical sample. The diffusion coefficients are in the same order of magnitude (~10−16 m2·s−1), whereas the diffusion coefficient of ferrocene in the empty framework is roughly 3-times smaller than in the MOF which is filled with ethanol or n-hexane.

Stable metal–organic frameworks as a host platform for catalysis and biomimetics

DOE PAGES

Qin, Jun-Sheng; Yuan, Shuai; Lollar, Christina; ...

2018-01-01

Recent years have witnessed the exploration and synthesis of an increasing number of metal–organic frameworks (MOFs). The utilization of stable MOFs as a platform for catalysis and biomimetics is discussed.

Post Modification of Metal-Organic Framework and Their Application In Cancer Theranostics

NASA Astrophysics Data System (ADS)

Lakkakula, Hima bindu

The research proposal aims to demonstrate that Metal-Organic Frameworks (MOFs) are mainly used for cancer theranostics which is the combination of both diagnostic and therapeutic functions. The research will emphasis on synthesis of Fe- MOFs by solvothermal nucleation, crystallization, characterization by microscopy and spectroscopy and evaluation with different lattice parameters and its morphology. Nowadays MOFs are used for the novel drug delivery purposes. The current published Fe- MOFs research focus is on the cancer theranostics by Indian medicines which will be impregnated into the MOFs and which will evaluate bioavailability and the chemotherapeutic activity of the drug. Nanotechnology provides the target specificity without affecting the healthy tissues. Other research problems to be addressed are the relationship between metal connectivity and ligand-based luminescence, MOF stability in an aqueous environment and activating it at increased temperature serves as a crucial role. The merits of this research are to increase the surface area and pore size of the drug so that the therapeutic efficacy can be improved. Moreover, the stabilization of metal-organic frameworks can also be enhanced with high surface area.

Patterning techniques for metal organic frameworks.

PubMed

Falcaro, Paolo; Buso, Dario; Hill, Anita J; Doherty, Cara M

2012-06-26

The tuneable pore size and architecture, chemical properties and functionalization make metal organic frameworks (MOFs) attractive versatile stimuli-responsive materials. In this context, MOFs hold promise for industrial applications and a fervent research field is currently investigating MOF properties for device fabrication. Although the material properties have a crucial role, the ability to precisely locate the functional material is fundamental for device fabrication. In this progress report, advancements in the control of MOF positioning and precise localization of functional materials within MOF crystals are presented. Advantages and limitations of each reviewed technique are critically investigated, and several important gaps in the technological development for device fabrication are highlighted. Finally, promising patterning techniques are presented which are inspired by previous studies in organic and inorganic crystal patterning for the future of MOF lithography. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Positronium emission spectra from self-assembled metal-organic frameworks

NASA Astrophysics Data System (ADS)

Crivelli, P.; Cooke, D.; Barbiellini, B.; Brown, B. L.; Feldblyum, J. I.; Guo, P.; Gidley, D. W.; Gerchow, L.; Matzger, A. J.

2014-06-01

Results of positronium (Ps) emission into vacuum from self-assembled metal-organic frameworks (MOFs) are presented and discussed in detail. Four different MOF crystals are considered, namely, MOF-5, IRMOF-8, ZnO4(FMA)3, and IRMOF-20. The measurements reveal that a fraction of the Ps is emitted into vacuum with a distinctly smaller energy than what one would expect for Ps localized in the MOFs' cells. Only calculations considering the Ps delocalized in a Bloch state can reproduce the measured Ps emission energy providing a robust demonstration of wave function delocalization in quantum mechanics. We show how the Bloch state population can be controlled by tuning the initial positron beam energy. Therefore, Ps in MOFs can be used both to simulate the dynamics of delocalized excitations in materials and to probe the MOFs for their advanced characterization.

Tunable electrical conductivity in metal-organic framework thin film devices

DOEpatents

Talin, Albert Alec; Allendorf, Mark D.; Stavila, Vitalie; Leonard, Francois

2016-08-30

A composition including a porous metal organic framework (MOF) including an open metal site and a guest species capable of charge transfer that can coordinate with the open metal site, wherein the composition is electrically conductive. A method including infiltrating a porous metal organic framework (MOF) including an open metal site with a guest species that is capable of charge transfer; and coordinating the guest species to the open metal site to form a composition including an electrical conductivity greater than an electrical conductivity of the MOF.

Tunable electrical conductivity in metal-organic framework thin film devices

DOEpatents

Talin, Albert Alec; Allendorf, Mark D.; Stavila, Vitalie; Leonard, Francois

2016-05-24

A composition including a porous metal organic framework (MOF) including an open metal site and a guest species capable of charge transfer that can coordinate with the open metal site, wherein the composition is electrically conductive. A method including infiltrating a porous metal organic framework (MOF) including an open metal site with a guest species that is capable of charge transfer; and coordinating the guest species to the open metal site to form a composition including an electrical conductivity greater than an electrical conductivity of the MOF.

Inkjet Printing of Lanthanide-Organic Frameworks for Anti-Counterfeiting Applications.

PubMed

da Luz, Leonis L; Milani, Raquel; Felix, Jorlandio F; Ribeiro, Igor R B; Talhavini, Márcio; Neto, Brenno A D; Chojnacki, Jaroslaw; Rodrigues, Marcelo O; Júnior, Severino A

2015-12-16

Photoluminescent lanthanide-organic frameworks (Ln-MOFs) were printed onto plastic and paper foils with a conventional inkjet printer. Ln-MOF inks were used to reproduce color images that can only be observed under UV light irradiation. This approach opens a new window for exploring Ln-MOF materials in technological applications, such as optical devices (e.g., lab-on-a-chip), as proof of authenticity for official documents.

Copper Benzenetricarboxylate Metal-Organic Framework Nucleation Mechanisms on Metal Oxide Powders and Thin Films formed by Atomic Layer Deposition.

PubMed

Lemaire, Paul C; Zhao, Junjie; Williams, Philip S; Walls, Howard J; Shepherd, Sarah D; Losego, Mark D; Peterson, Gregory W; Parsons, Gregory N

2016-04-13

Chemically functional microporous metal-organic framework (MOF) crystals are attractive for filtration and gas storage applications, and recent results show that they can be immobilized on high surface area substrates, such as fiber mats. However, fundamental knowledge is still lacking regarding initial key reaction steps in thin film MOF nucleation and growth. We find that thin inorganic nucleation layers formed by atomic layer deposition (ALD) can promote solvothermal growth of copper benzenetricarboxylate MOF (Cu-BTC) on various substrate surfaces. The nature of the ALD material affects the MOF nucleation time, crystal size and morphology, and the resulting MOF surface area per unit mass. To understand MOF nucleation mechanisms, we investigate detailed Cu-BTC MOF nucleation behavior on metal oxide powders and Al2O3, ZnO, and TiO2 layers formed by ALD on polypropylene substrates. Studying both combined and sequential MOF reactant exposure conditions, we find that during solvothermal synthesis ALD metal oxides can react with the MOF metal precursor to form double hydroxy salts that can further convert to Cu-BTC MOF. The acidic organic linker can also etch or react with the surface to form MOF from an oxide metal source, which can also function as a nucleation agent for Cu-BTC in the mixed solvothermal solution. We discuss the implications of these results for better controlled thin film MOF nucleation and growth.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondo, Atsushi, E-mail: kondoa@cc.tuat.ac.jp; Maeda, Kazuyuki

A 3D flexible metal–organic framework (MOF) with 1D hydrophilic and hydrophobic pores shows anisotropic thermal expansion with relatively large thermal expansion coefficient (α{sub a}=−21×10{sup −6} K{sup −1} and α{sub c}=79×10{sup −6} K{sup −1}) between 133 K and 383 K. Temperature change gives deformation of both pores, which expand in diameter and elongate in length on cooling and vice versa. The thermally induced structural change should be derived from a unique framework topology like “lattice fence”. Silica accommodation changes not only the nature of the MOF but also thermal responsiveness of the MOF. Since the hydrophobic pores in the material aremore » selectively blocked by the silica, the MOF with the silica is considered as a hydrophilic microporous material. Furthermore, inclusion of silica resulted in a drastic pore contraction in diameter and anisotropically changed the thermal responsiveness of the MOF. - Graphical abstract: A 3D metal–organic framework with hydrophilic and hydrophobic pores shows anisotropic thermal expansion behavior. The influence of silica filler in the hydrophobic pore was investigated. - Highlights: • Thermally induced structural change of a 3D MOF with a lattice fence topology was investigated. • The structural change was analyzed by synchrotron X-ray diffraction patterns. • Temperature change induces anisotropic thermal expansion/contraction of the MOF. • Silica inclusion anisotropically changes the thermal responsiveness of the MOF.« less

Evaluating topologically diverse metal–organic frameworks for cryo-adsorbed hydrogen storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gómez-Gualdrón, Diego A.; Colón, Yamil J.; Zhang, Xu

Metal–organic frameworks (MOFs) are porous materials synthesized by combining inorganic and organic molecular building blocks into crystalline networks of distinct topologies. Due to the combinatorial possibilities, there are millions of possible MOF structures. Aiming to exploit their exceptional tunability, surface areas and pore volumes, researchers have investigated MOFs for storage of gaseous fuels such as hydrogen for over a decade, but a suitable MOF to store hydrogen at ambient conditions has not yet been found. Here, we sought to rapidly determine the viability of using MOFs for hydrogen storage at recently proposed, cryogenic operating conditions. We constructed a large andmore » structurally diverse set of 13 512 potential MOF structures based on 41 different topologies and used molecular simulation to determine MOF hydrogen deliverable capacities between 100 bar/77 K and 5 bar/160 K. The highest volumetric deliverable capacity was 57 g L-1 of MOF, which surpasses the 37 g L-1 of tank of the incumbent technology (compressing hydrogen to 700 bar at ambient temperature). To validate our in silico MOF construction method, we synthesized a new isoreticular family of MOFs (she-MOF-x series) based on the she topology, which is extremely rare among MOFs. To validate our hydrogen storage predictions, we activated and measured hydrogen adsorption on she-MOF-1 and NU-1103. The latter MOF showed outstanding stability and a good combination of volumetric and gravimetric performance, presenting 43.2 g L-1 of MOF and 12.6 wt% volumetric and gravimetric deliverable capacities, respectively.« less

Bipyridine- and phenanthroline-based metal-organic frameworks for highly efficient and tandem catalytic organic transformations via directed C-H activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manna, Kuntal; Zhang, Teng; Greene, Francis X.

2015-02-16

We report here the synthesis of a series of robust and porous bipyridyl- and phenanthryl-based metal–organic frameworks (MOFs) of UiO topology (BPV-MOF, mBPV-MOF, and mPT-MOF) and their postsynthetic metalation to afford highly active single-site solid catalysts. While BPV-MOF was constructed from only bipyridyl-functionalized dicarboxylate linker, both mBPV- and mPT-MOF were built with a mixture of bipyridyl- or phenanthryl-functionalized and unfunctionalized dicarboxylate linkers. The postsynthetic metalation of these MOFs with [Ir(COD)(OMe)] 2 provided Ir-functionalized MOFs (BPV-MOF-Ir, mBPV-MOF-Ir, and mPT-MOF-Ir), which are highly active catalysts for tandem hydrosilylation of aryl ketones and aldehydes followed by dehydrogenative ortho-silylation of benzylicsilyl ethers as wellmore » as C–H borylation of arenes using B₂pin₂. Both mBPV-MOF-Ir and mPT-MOF-Ir catalysts displayed superior activities compared to BPV-MOF-Ir due to the presence of larger open channels in the mixed-linker MOFs. Impressively, mBPV-MOF-Ir exhibited high TONs of up to 17000 for C–H borylation reactions and was recycled more than 15 times. The mPT-MOF-Ir system is also active in catalyzing tandem dehydrosilylation/dehydrogenative cyclization of N-methylbenzyl amines to azasilolanes in the absence of a hydrogen acceptor. Importantly, MOF-Ir catalysts are significantly more active (up to 95 times) and stable than their homogeneous counterparts for all three reactions, strongly supporting the beneficial effects of active site isolation within MOFs. This work illustrates the ability to increase MOF open channel sizes by using the mixed linker approach and shows the enormous potential of developing highly active and robust single-site solid catalysts based on MOFs containing nitrogen-donor ligands for important organic transformations.« less

Gas adsorption properties of highly porous metal-organic frameworks containing functionalized naphthalene dicarboxylate linkers.

PubMed

Sim, Jaeung; Yim, Haneul; Ko, Nakeun; Choi, Sang Beom; Oh, Youjin; Park, Hye Jeong; Park, SangYoun; Kim, Jaheon

2014-12-28

Three functionalized metal-organic frameworks (MOFs), MOF-205-NH2, MOF-205-NO2, and MOF-205-OBn, formulated as Zn4O(BTB)4/3(L), where BTB is benzene-1,3,5-tribenzoate and L is 1-aminonaphthalene-3,7-dicarboxylate (NDC-NH2), 1-nitronaphthalene-3,7-dicarboxylate (NDC-NO2) or 1,5-dibenzyloxy-2,6-naphthalenedicarboxylate (NDC-(OBn)2), were synthesized and their gas (H2, CO2, or CH4) adsorption properties were compared to those of the un-functionalized, parent MOF-205. Ordered structural models for MOF-205 and its derivatives were built based on the crystal structures and were subsequently used for predicting porosity properties. Although the Brunauer-Emmett-Teller (BET) surface areas of the three MOF-205 derivatives were reduced (MOF-205, 4460; MOF-205-NH2, 4330; MOF-205-NO2, 3980; MOF-205-OBn, 3470 m(2) g(-1)), all three derivatives were shown to have enhanced H2 adsorption capacities at 77 K and CO2 uptakes at 253, 273, and 298 K respectively at 1 bar in comparison with MOF-205. The results indicate the following trend in H2 adsorption: MOF-205 < MOF-205-NO2 < MOF-205-NH2 < MOF-205-OBn. MOF-205-OBn showed good ideal adsorbed solution theory (IAST) selectivity values of 6.5 for CO2/N2 (15/85 in v/v) and 2.7 for CO2/CH4 (50/50 in v/v) at 298 K. Despite the large reduction (-22%) in the surface area, MOF-205-OBn displayed comparable total volumetric CO2 (at 48 bar) and CH4 (at 35 bar) storage capacities with those of MOF-205 at 298 K: MOF-205-OBn, 305 (CO2) and 112 (CH4) cm(3) cm(-3), and for MOF-205, 307 (CO2) and 120 (CH4) cm(3) cm(-3), respectively.

Metal-organic framework templated synthesis of porous inorganic materials as novel sorbents

DOEpatents

Taylor-Pashow, Kathryn M. L.; Lin, Wenbin; Abney, Carter W.

2017-03-21

A novel metal-organic framework (MOF) templated process for the synthesis of highly porous inorganic sorbents for removing radionuclides, actinides, and heavy metals is disclosed. The highly porous nature of the MOFs leads to highly porous inorganic sorbents (such as oxides, phosphates, sulfides, etc) with accessible surface binding sites that are suitable for removing radionuclides from high level nuclear wastes, extracting uranium from acid mine drainage and seawater, and sequestering heavy metals from waste streams. In some cases, MOFs can be directly used for removing these metal ions as MOFs are converted to highly porous inorganic sorbents in situ.

System and method for generating and/or screening potential metal-organic frameworks

DOEpatents

Wilmer, Christopher E; Leaf, Michael; Snurr, Randall Q; Farha, Omar K; Hupp, Joseph T

2015-04-21

A system and method for systematically generating potential metal-organic framework (MOFs) structures given an input library of building blocks is provided herein. One or more material properties of the potential MOFs are evaluated using computational simulations. A range of material properties (surface area, pore volume, pore size distribution, powder x-ray diffraction pattern, methane adsorption capability, and the like) can be estimated, and in doing so, illuminate unidentified structure-property relationships that may only have been recognized by taking a global view of MOF structures. In addition to identifying structure-property relationships, this systematic approach to identify the MOFs of interest is used to identify one or more MOFs that may be useful for high pressure methane storage.

System and method for generating and/or screening potential metal-organic frameworks

DOEpatents

Wilmer, Christopher E; Leaf, Michael; Snurr, Randall Q; Farha, Omar K; Hupp, Joseph T

2014-12-02

A system and method for systematically generating potential metal-organic framework (MOFs) structures given an input library of building blocks is provided herein. One or more material properties of the potential MOFs are evaluated using computational simulations. A range of material properties (surface area, pore volume, pore size distribution, powder x-ray diffraction pattern, methane adsorption capability, and the like) can be estimated, and in doing so, illuminate unidentified structure-property relationships that may only have been recognized by taking a global view of MOF structures. In addition to identifying structure-property relationships, this systematic approach to identify the MOFs of interest is used to identify one or more MOFs that may be useful for high pressure methane storage.

Efficient photocatalytic degradation of rhodamine 6G with a quantum dot-metal organic framework nanocomposite.

PubMed

Kaur, Rajnish; Vellingiri, Kowsalya; Kim, Ki-Hyun; Paul, A K; Deep, Akash

2016-07-01

The hybrid structures of metal organic frameworks (MOFs) and nanoparticles may offer the realization of effective photocatalytic materials due to combined benefits of the porous and molecular sieving properties of MOF matrix and the functional characteristics of encapsulated nanoparticles. In this study, cadmium telluride (CdTe) quantum dots (QD) are conjugated with a europium-MOF for the synthesis of a novel nanocomposite material with photocatalytic properties. Successful synthesis of a QD/Eu-MOF nanocomposite was characterized with various spectroscopic and microscopic techniques. This QD/Eu-MOF is found to be an effective catalyst to complete the degradation of Rhodamine 6G dye within 50 min. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemiresistive Sensor Arrays from Conductive 2D Metal–Organic Frameworks

DOE PAGES

Campbell, Michael G.; Liu, Sophie F.; Swager, Timothy M.; ...

2015-10-11

Applications of porous metal–organic frameworks (MOFs) in electronic devices are rare, owing in large part to a lack of MOFs that display electrical conductivity. Here, we describe the use of conductive two-dimensional (2D) MOFs as a new class of materials for chemiresistive sensing of volatile organic compounds (VOCs). We demonstrate that a family of structurally analogous 2D MOFs can be used to construct a cross-reactive sensor array that allows for clear discrimination between different categories of VOCs. Lastly, experimental data show that multiple sensing mechanisms are operative with high degrees of orthogonality, establishing that the 2D MOFs used here aremore » mechanistically unique and offer advantages relative to other known chemiresistor materials.« less

A versatile synthetic route for the preparation of titanium metal-organic frameworks

DOE PAGES

Zou, Lanfang; Feng, Dawei; Liu, Tian-Fu; ...

2016-02-01

Exploitation of new titanium metal–organic frameworks (Ti-MOFs) with high crystallinity has been attracting great attention due to their vast application potential in photocatalysis. Herein a versatile synthetic strategy, namely, High Valence Metathesis and Oxidation (HVMO), is developed to synthesize a series of Ti-MOFs with predesigned topologies and structures. The crystallinity of these Ti-MOFs was well maintained throughout, as confirmed by powder X-ray diffraction and gas adsorption measurements. Significantly, there were only a few examples of Ti-MOFs, not to mention a general synthetic strategy for various kinds of Ti-MOFs in the literature. This contribution also illustrates the intriguing potential of Ti-MOFmore » platforms in photocatalysis.« less

Enhanced stability of vitamin A palmitate microencapsulated by γ-cyclodextrin metal-organic frameworks.

PubMed

Zhang, Guoqing; Meng, Fanyue; Guo, Zhen; Guo, Tao; Peng, Hui; Xiao, Jian; Liu, Botao; Singh, Vikaramjeet; Gui, Shuangying; York, Peter; Qian, Wei; Wu, Li; Zhang, Jiwen

2018-04-24

γ-Cyclodextrin metal-organic frameworks (γ-CD-MOFs) are highly porous and bio-friendly novel materials formed by γ-CD as an organic ligand and potassium ion as an inorganic metal centre. The aim of this study was to enhance the stability of vitamin A palmitate (VAP) using γ-CD-MOFs as the carrier. Herein, γ-CD-MOFs displayed VAP microencapsulating capacity of 9.77 ± 0.24% with molar ratio as n MOFs :n VAP  = 3.2:1.0. It was important to find that the improved stability of VAP microencapsulated by γ-CD-MOFs without addition of any antioxidant(s) was better than that of the best available reference product in the market, with 1.6-fold elongated half-life. The protecting mechanism of γ-CD-MOFs for VAP contributed that VAP molecules preferentially curled inside the cavities of dual γ-CD pairs in γ-CD-MOFs. It was proved that γ-CD-MOFs were an efficient new carrier to deliver and protect VAP for food and pharmaceutical applications.

Synthesis of metal-organic framework films by pore diffusion method

NASA Astrophysics Data System (ADS)

Murayama, Naohiro; Nishimura, Yuki; Kajiro, Hiroshi; Kishida, Satoru; Kinoshita, Kentaro; Tottori Univ Team; Nippon Steel; Sumitomo Metal Co. Collaboration; Tottori Integrated Frontier Resaerch Center (Tifrec) Collaboration; Tottori University Electronic Display Resaerch Center (Tedrec) Collaboration

Metal-organic frameworks (MOFs) presents high controllability in designing the nano-scale pore, and this enable molecular storages, catalysts, gas sensors, gas separation membranes, and electronic devices for next-generation. Therefore, a simple method for film synthesis of MOFs compared with conventional methods [1] is strongly required. In this paper, we provide pore diffusion method, in which a substrate containing constituent metals of MOF is inserted in solution that includes only linker molecules of MOF. As a result, 2D growth of MOF was effectively enhanced, and the formation of flat and dense MOF films was attained. The growth time, t, dependence of film thickness, d, can be expressed by the relation of d = Aln(t + 1) + B, where A and B are constants. It means that ionized coppers diffuse through the pores of MOFs and the synthesis reaction proceeds at the MOF/solvent interface. We demonstrated the fabrication of a HKUST-1/Cu-TPA hetero structure by synthesizing a Cu-TPA film continuously after the growth of a HKUST-1 film on the CuOx substrate.

Ionic Liquid/Metal-Organic Framework Composites: From Synthesis to Applications.

PubMed

Kinik, Fatma Pelin; Uzun, Alper; Keskin, Seda

2017-07-21

Metal-organic frameworks (MOFs) have been widely studied for different applications owing to their fascinating properties such as large surface areas, high porosities, tunable pore sizes, and acceptable thermal and chemical stabilities. Ionic liquids (ILs) have been recently incorporated into the pores of MOFs as cavity occupants to change the physicochemical properties and gas affinities of MOFs. Several recent studies have shown that IL/MOF composites show superior performances compared with pristine MOFs in various fields, such as gas storage, adsorption and membrane-based gas separation, catalysis, and ionic conductivity. In this review, we address the recent advances in syntheses of IL/MOF composites and provide a comprehensive overview of their applications. Opportunities and challenges of using IL/MOF composites in many applications are reviewed and the requirements for the utilization of these composite materials in real industrial processes are discussed to define the future directions in this field. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrocatalytic Metal-Organic Frameworks for Energy Applications.

PubMed

Downes, Courtney A; Marinescu, Smaranda C

2017-11-23

With the global energy demand expected to increase drastically over the next several decades, the development of a sustainable energy system to meet this increase is paramount. Renewable energy sources can be coupled with electrochemical conversion processes to store energy in chemical bonds. To promote these difficult transformations, electrocatalysts that operate at high conversion rates and efficiency are required. Metal-organic frameworks (MOFs) have emerged as a promising class of materials; however, the insulating nature of MOFs has limited their application as electrocatalysts. The recent development of conductive MOFs has led to several electrocatalytic MOFs that display activity comparable to that of the best-performing heterogeneous catalysts. Although many electrocatalytic MOFs exhibit low activity and stability, the few successful examples highlight the possibility of MOF electrocatalysts as replacements for noble-metal-based catalysts in commercial energy-converting devices. We review herein the use of pristine MOFs as electrocatalysts to facilitate important energy-related reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal–Organic Framework Thin Film Coated Optical Fiber Sensors: A Novel Waveguide-Based Chemical Sensing Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Ki-Joong; Lu, Ping; Culp, Jeffrey T.

Integration of optical fiber with sensitive thin films offers great potential for the realization of novel chemical sensing platforms. In this study, we present a simple design strategy and high performance of nanoporous metal–organic framework (MOF) based optical gas sensors, which enables detection of a wide range of concentrations of small molecules based upon extremely small differences in refractive indices as a function of analyte adsorption within the MOF framework. Thin and compact MOF films can be uniformly formed and tightly bound on the surface of etched optical fiber through a simple solution method which is critical for manufacturability ofmore » MOF-based sensor devices. The resulting sensors show high sensitivity/selectivity to CO 2 gas relative to other small gases (H 2, N 2, O 2, and CO) with rapid (< tens of seconds) response time and excellent reversibility, which can be well correlated to the physisorption of gases into a nanoporous MOF. We propose a refractive index based sensing mechanism for the MOF-integrated optical fiber platform which results in an amplification of inherent optical absorption present within the MOF-based sensing layer with increasing values of effective refractive index associated with adsorption of gases.« less

Metal–Organic Framework Thin Film Coated Optical Fiber Sensors: A Novel Waveguide-Based Chemical Sensing Platform

DOE PAGES

Kim, Ki-Joong; Lu, Ping; Culp, Jeffrey T.; ...

2018-01-18

Integration of optical fiber with sensitive thin films offers great potential for the realization of novel chemical sensing platforms. In this study, we present a simple design strategy and high performance of nanoporous metal–organic framework (MOF) based optical gas sensors, which enables detection of a wide range of concentrations of small molecules based upon extremely small differences in refractive indices as a function of analyte adsorption within the MOF framework. Thin and compact MOF films can be uniformly formed and tightly bound on the surface of etched optical fiber through a simple solution method which is critical for manufacturability ofmore » MOF-based sensor devices. The resulting sensors show high sensitivity/selectivity to CO 2 gas relative to other small gases (H 2, N 2, O 2, and CO) with rapid (< tens of seconds) response time and excellent reversibility, which can be well correlated to the physisorption of gases into a nanoporous MOF. We propose a refractive index based sensing mechanism for the MOF-integrated optical fiber platform which results in an amplification of inherent optical absorption present within the MOF-based sensing layer with increasing values of effective refractive index associated with adsorption of gases.« less

Metal-organic frameworks for adsorption and separation of noble gases

DOEpatents

Allendorf, Mark D.; Greathouse, Jeffery A.; Staiger, Chad

2017-05-30

A method including exposing a gas mixture comprising a noble gas to a metal organic framework (MOF), including an organic electron donor and an adsorbent bed operable to adsorb a noble gas from a mixture of gases, the adsorbent bed including a metal organic framework (MOF) including an organic electron donor.

Hollow carbon nanobubbles: monocrystalline MOF nanobubbles and their pyrolysis.

PubMed

Zhang, Wei; Jiang, Xiangfen; Zhao, Yanyi; Carné-Sánchez, Arnau; Malgras, Victor; Kim, Jeonghun; Kim, Jung Ho; Wang, Shaobin; Liu, Jian; Jiang, Ji-Sen; Yamauchi, Yusuke; Hu, Ming

2017-05-01

While bulk-sized metal-organic frameworks (MOFs) face limits to their utilization in various research fields such as energy storage applications, nanoarchitectonics is believed to be a possible solution. It is highly challenging to realize MOF nanobubbles with monocrystalline frameworks. By a spatially controlled etching approach, here, we can achieve the synthesis of zeolitic imidazolate framework (ZIF-8) nanobubbles with a uniform size of less than 100 nm. Interestingly, the ZIF-8 nanobubbles possess a monocrystalline nanoshell with a thickness of around 10 nm. Under optimal pyrolytic conditions, the ZIF-8 nanobubbles can be converted into hollow carbon nanobubbles while keeping their original shapes. The structure of the nanobubble enhances the fast Na + /K + ion intercalation performance. Such remarkable improvement cannot be realized by conventional MOFs or their derived carbons.

Metal-organic frameworks: versatile heterogeneous catalysts for efficient catalytic organic transformations.

PubMed

Chughtai, Adeel H; Ahmad, Nazir; Younus, Hussein A; Laypkov, A; Verpoort, Francis

2015-10-07

Novel catalytic materials are highly demanded to perform a variety of catalytic organic reactions. MOFs combine the benefits of heterogeneous catalysis like easy post reaction separation, catalyst reusability, high stability and homogeneous catalysis such as high efficiency, selectivity, controllability and mild reaction conditions. The possible organization of active centers like metallic nodes, organic linkers, and their chemical synthetic functionalization on the nanoscale shows potential to build up MOFs particularly modified for catalytic challenges. In this review, we have summarized the recent research progress in heterogeneous catalysis by MOFs and their catalytic behavior in various organic reactions, highlighting the key features of MOFs as catalysts based on the active sites in the framework. Examples of their post functionalization, inclusion of active guest species and metal nanoparticles have been discussed. Finally, the use of MOFs as catalysts for asymmetric heterogeneous catalysis and stability of MOFs has been presented as separate sections.

Structural dynamics inside a functionalized metal–organic framework probed by ultrafast 2D IR spectroscopy

DOE PAGES

Nishida, Jun; Tamimi, Amr; Fei, Honghan; ...

2014-12-15

One key property of metal-organic frameworks (MOFs) are their structural elasticity. IHere we show that 2D IR spectroscopy with pulse-shaping techniques can probe the ultrafast structural fluctuations of MOFs. 2D IR data, obtained from a vibrational probe attached to the linkers of UiO-66 MOF in low concentration, revealed that the structural fluctuations have time constants of 7 and 670 ps with no solvent. Filling the MOF pores with dimethylformamide (DMF) slows the structural fluctuations by reducing the ability of the MOF to undergo deformations, and the dynamics of the DMF molecules are also greatly restricted. Finally, methodology advances were requiredmore » to remove the severe light scattering caused by the macroscopic-sized MOF particles, eliminate interfering oscillatory components from the 2D IR data, and address Förster vibrational excitation transfer.« less

Synthesis, functionalization, and applications of metal-organic frameworks in biomedicine.

PubMed

Chen, Wei; Wu, Chunsheng

2018-02-13

Metal-organic frameworks (MOFs), also known as coordination polymers, have attracted extensive research interest in the past few decades due to their unique physical structures and potentially vast applications. In this review, we outline the recent progress in the synthesis, functionalization and applications of MOFs in biomedicine, mainly focusing on two promising, yet challenging areas, i.e., drug delivery and biosensing applications. A major challenge is the proper functionalization of MOFs with demanding properties suitable for biomedical applications. Extensive studies on MOFs in biomedicine have led to substantial progress in the control of key properties of MOFs such as toxicity, size and shape, and biological stability. Due to their flexible composition, pore size and easy functionalization properties, MOFs can be utilized as key components for the development of various functional systems, and their applications in drug delivery and biosensing are reviewed. Future trends and perspectives in these research areas are also outlined.

Emerging Multifunctional Metal-Organic Framework Materials.

PubMed

Li, Bin; Wen, Hui-Min; Cui, Yuanjing; Zhou, Wei; Qian, Guodong; Chen, Banglin

2016-10-01

Metal-organic frameworks (MOFs), also known as coordination polymers, represent an interesting type of solid crystalline materials that can be straightforwardly self-assembled through the coordination of metal ions/clusters with organic linkers. Owing to the modular nature and mild conditions of MOF synthesis, the porosities of MOF materials can be systematically tuned by judicious selection of molecular building blocks, and a variety of functional sites/groups can be introduced into metal ions/clusters, organic linkers, or pore spaces through pre-designing or post-synthetic approaches. These unique advantages enable MOFs to be used as a highly versatile and tunable platform for exploring multifunctional MOF materials. Here, the bright potential of MOF materials as emerging multifunctional materials is highlighted in some of the most important applications for gas storage and separation, optical, electric and magnetic materials, chemical sensing, catalysis, and biomedicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The first chiral diene-based metal-organic frameworks for highly enantioselective carbon-carbon bond formation reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawano, Takahiro; Ji, Pengfei; McIsaac, Alexandra R.

2016-02-01

We have designed the first chiral diene-based metal–organic framework (MOF), E₂-MOF, and postsynthetically metalated E₂-MOF with Rh(I) complexes to afford highly active and enantioselective single-site solid catalysts for C–C bond formation reactions. Treatment of E₂-MOF with [RhCl(C₂H₄)₂]₂ led to a highly enantioselective catalyst for 1,4-additions of arylboronic acids to α,β-unsaturated ketones, whereas treatment of E₂-MOF with Rh(acac)(C₂H₄)₂ afforded a highly efficient catalyst for the asymmetric 1,2-additions of arylboronic acids to aldimines. Interestingly, E₂-MOF·Rh(acac) showed higher activity and enantioselectivity than the homogeneous control catalyst, likely due to the formation of a true single-site catalyst in the MOF. E₂-MOF·Rh(acac) was also successfullymore » recycled and reused at least seven times without loss of yield and enantioselectivity.« less

Imparting biomolecules to a metal-organic framework material by controlled DNA tetrahedron encapsulation

PubMed Central

Jia, Yongmei; Wei, Benmei; Duan, Ruixue; Zhang, Ying; Wang, Boya; Hakeem, Abdul; Liu, Nannan; Ou, Xiaowen; Xu, Shaofang; Chen, Zhifei; Lou, Xiaoding; Xia, Fan

2014-01-01

Recently, the incorporation of biomolecules in Metal-organic frameworks (MOFs) attracts many attentions because of controlling the functions, properties and stability of trapped molecules. Although there are few reports on protein/MOFs composites and their applications, none of DNA/MOFs composite is reported, as far as we know. Here, we report a new composite material which is self-assembled from 3D DNA (guest) and pre-synthesized MOFs (host) by electrostatic interactions and hydrophilic interactions in a well-dispersed fashion. Its biophysical characterization is well analyzed by fluorescence spectroscopy, quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). This new composite material keeps 3D DNA nanostructure more stable than only 3D DNA nanostructure in DI water at room temperature, and stores amounts of genetic information. It will make DNA as a guest for MOFs and MOFs become a new platform for the development of DNA nanotechnology. PMID:25090047

Phenanthroline-based metal–organic frameworks for Fe-catalyzed C sp3 –H amination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thacker, Nathan C.; Ji, Pengfei; Lin, Zekai

2017-01-01

We report here the synthesis of a robust and highly porous Fe-phenanthroline-based metal–organic framework (MOF) and its application in catalyzing challenging inter- and intramolecular C–H amination reactions. For the intermolecular amination reactions, a FeBr 2-metalated MOF selectively functionalized secondary benzylic and allylic C–H bonds. The intramolecular amination reactions utilizing organic azides as the nitrene source required the reduction of the FeBr 2-metalated MOF with NaBHEt 3to generate the active catalyst. For both reactions, Fe or Zr leaching was less than 0.1%, and MOFs could be recycled and reused with no loss in catalytic activity. Furthermore, MOF catalysts were significantly moremore » active than the corresponding homogeneous analogs. This work demonstrates the great potential of MOFs in generating highly active, recyclable, and reusable earth abundant metal catalysts for challenging organic transformations.« less

An Ultrahydrophobic Fluorous Metal-Organic Framework Derived Recyclable Composite as a Promising Platform to Tackle Marine Oil Spills.

PubMed

Mukherjee, Soumya; Kansara, Ankit M; Saha, Debasis; Gonnade, Rajesh; Mullangi, Dinesh; Manna, Biplab; Desai, Aamod V; Thorat, Shridhar H; Singh, Puyam S; Mukherjee, Arnab; Ghosh, Sujit K

2016-07-25

Derived from a strategically chosen hexafluorinated dicarboxylate linker aimed at the designed synthesis of a superhydrophobic metal-organic framework (MOF), the fluorine-rich nanospace of a water-stable MOF (UHMOF-100) exhibits excellent water-repellent features. It registered the highest water contact angle (≈176°) in the MOF domain, marking the first example of an ultrahydrophobic MOF. Various experimental and theoretical studies reinforce its distinctive water-repellent characteristics, and the conjugation of superoleophilicity and unparalleled hydrophobicity of a MOF material has been coherently exploited to achieve real-time oil/water separation in recyclable membrane form, with significant absorption capacity performance. This is also the first report of an oil/water separating fluorinated ultrahydrophobic MOF-based membrane material, with potential promise for tackling marine oil spillages. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal-organic framework tethering PNIPAM for ON-OFF controlled release in solution.

PubMed

Nagata, Shunjiro; Kokado, Kenta; Sada, Kazuki

2015-05-21

A smart metal-organic framework (MOF) exhibiting controlled release was achieved by modification with a thermoresponsive polymer (PNIPAM) via a surface-selective post-synthetic modification technique. Simple temperature variation readily switches "open" (lower temperature) and "closed" (higher temperature) states of the polymer-modified MOF through conformational change of PNIPAM grafted onto the MOF, resulting in controlled release of the included guest molecules such as resorufin, caffeine, and procainamide.

A new type of polyhedron-based metal-organic frameworks with interpenetrating cationic and anionic nets demonstrating ion exchange, adsorption and luminescent properties.

PubMed

Zhang, Zheng-Jie; Shi, Wei; Niu, Zheng; Li, Huan-Huan; Zhao, Bin; Cheng, Peng; Liao, Dai-Zheng; Yan, Shi-Ping

2011-06-14

An interesting new MOF, built with interpenetrating cationic (MOF-A(+)) and anionic (MOF-B(-)) nets that do not require counter ions to balance charge, together with an architectural strategy focused on the use of MOPs as nodes and MOCs as spacers for the generation of 3D frameworks, is reported. This journal is © The Royal Society of Chemistry 2011

Crystal Engineering of Naphthalenediimide-Based Metal-Organic Frameworks: Structure-Dependent Lithium Storage.

PubMed

Tian, Bingbing; Ning, Guo-Hong; Gao, Qiang; Tan, Li-Min; Tang, Wei; Chen, Zhongxin; Su, Chenliang; Loh, Kian Ping

2016-11-16

Metal-organic frameworks (MOFs) possess great structural diversity because of the flexible design of linker groups and metal nodes. The structure-property correlation has been extensively investigated in areas like chiral catalysis, gas storage and absorption, water purification, energy storage, etc. However, the use of MOFs in lithium storage is hampered by stability issues, and how its porosity helps with battery performance is not well understood. Herein, through anion and thermodynamic control, we design a series of naphthalenediimide-based MOFs 1-4 that can be used for cathode materials in lithium-ion batteries (LIBs). Complexation of the N,N'-di(4-pyridyl)-1,4,5,8-naphthalenediimide (DPNDI) ligand and CdX 2 (X = NO 3 - or ClO 4 - ) produces complexes MOFs 1 and 2 with a one-dimensional (1D) nonporous network and a porous, noninterpenetrated two-dimensional (2D) square-grid structure, respectively. With the DPNDI ligand and Co(NCS) 2 , a porous 1D MOF 3 as a kinetic product is obtained, while a nonporous, noninterpenetrated 2D square-grid structure MOF 4 as a thermodynamic product is formed. The performance of LIBs is largely affected by the stability and porosity of these MOFs. For instance, the initial charge-discharge curves of MOFs 1 and 2 show a specific capacity of ∼47 mA h g -1 with a capacity retention ratio of >70% during 50 cycles at 100 mA g -1 , which is much better than that of MOFs 3 and 4. The better performances are assigned to the higher stability of Cd(II) MOFs compared to that of Co(II) MOFs during the electrochemical process, according to X-ray diffraction analysis. In addition, despite having the same Cd(II) node in the framework, MOF 2 exhibits a lithium-ion diffusion coefficient (D Li ) larger than that of MOF 1 because of its higher porosity. X-ray photoelectron spectroscopy and Fourier transform infrared analysis indicate that metal nodes in these MOFs remain intact and only the DPNDI ligand undergoes the revisible redox reaction during the lithiation-delithiation process.

Formation of bimetallic metal-organic framework nanosheets and their derived porous nickel-cobalt sulfides for supercapacitors.

PubMed

Chen, Chen; Wu, Meng-Ke; Tao, Kai; Zhou, Jiao-Jiao; Li, Yan-Li; Han, Xue; Han, Lei

2018-04-24

Metal-organic frameworks (MOFs) show great advantages as new kinds of active materials for energy storage. In this study, bimetallic metal-organic frameworks (Ni/Co-MOFs) with nanosheet-assembled flower-like structures were synthesized by etching Ni-MOF microspheres in a cobalt nitrate solution. It can be clearly observed that the amount of Co(NO3)2 and etching time play crucial roles in the formation of Ni/Co-MOF nanosheets. The Ni/Co-MOFs were used as electrode materials for supercapacitors and the optimized Ni/Co-MOF-5 exhibited the highest capacitances of 1220.2 F g-1 and 986.7 F g-1 at current densities of 1 A g-1 and 10 A g-1, respectively. Ni/Co-MOF-5 was further sulfurized, and the derived Ni-Co-S electrode showed a higher specific capacitance of 1377.5 F g-1 at a current density of 1 A g-1 and a retention of 89.4% when the current density was increased to 10 A g-1, indicating superior rate capability. Furthermore, Ni/Co-MOF-5 and Ni-Co-S showed excellent cycling stability, i.e. about 87.8% and 93.7% of initial capacitance can be still maintained after 3000 cycles of charge-discharge. More interestingly, the Ni/Co-MOF-5//AC ASC shows an energy density of 30.9 W h kg-1 at a power density of 1132.8 W kg-1, and the Ni-Co-S//AC ASC displays a high energy density of 36.9 W h kg-1 at a power density of 1066.42 W kg-1. These results demonstrate that the as-synthesized bimetallic Ni/Co-MOF nanosheets and their derived nickel-cobalt sulfides have promising applications in electrochemical supercapacitors.

Photocatalytic CO2 Reduction to Formate Using a Mn(I) Molecular Catalyst in a Robust Metal-Organic Framework.

PubMed

Fei, Honghan; Sampson, Matthew D; Lee, Yeob; Kubiak, Clifford P; Cohen, Seth M

2015-07-20

A manganese bipyridine complex, Mn(bpydc)(CO)3Br (bpydc = 5,5'-dicarboxylate-2,2'-bipyridine), has been incorporated into a highly robust Zr(IV)-based metal-organic framework (MOF) for use as a CO2 reduction photocatalyst. In conjunction with [Ru(dmb)3](2+) (dmb = 4,4'-dimethyl-2,2'-bipyridine) as a photosensitizer and 1-benzyl-1,4-dihydronicotinamide (BNAH) as a sacrificial reductant, Mn-incorporated MOFs efficiently catalyze CO2 reduction to formate in DMF/triethanolamine under visible-light irradiation. The photochemical performance of the Mn-incorporated MOF reached a turnover number of approximately 110 in 18 h, exceeding that of the homogeneous reference systems. The increased activity of the MOF-incorporated Mn catalyst is ascribed to the struts of the framework providing isolated active sites, which stabilize the catalyst and inhibit dimerization of the singly reduced Mn complex. The MOF catalyst largely retained its crystallinity throughout prolonged catalysis and was successfully reused over several catalytic runs.

A Multi-responsive Regenerable Europium-Organic Framework Luminescent Sensor for Fe3+ , CrVI Anions, and Picric Acid.

PubMed

Liu, Wei; Huang, Xin; Xu, Cong; Chen, Chunyang; Yang, Lizi; Dou, Wei; Chen, Wanmin; Yang, Huan; Liu, Weisheng

2016-12-23

A novel luminescent microporous lanthanide metal-organic framework (Ln-MOF) based on a urea-containing ligand has been successfully assembled. Structural analysis revealed that the framework features two types of 1D channels, with urea N-H bonds projecting into the pores. Luminescence studies have revealed that the Ln-MOF exhibits high sensitivity, good selectivity, and a fast luminescence quenching response towards Fe 3+ , Cr VI anions, and picric acid. In particular, in the detection of Cr 2 O 7 2- and picric acid, the Ln-MOF can be simply and quickly regenerated, thus exhibiting excellent recyclability. To the best of our knowledge, this is the first example of a multi-responsive luminescent Ln-MOF sensor for Fe 3+ , Cr VI anions, and picric acid based on a urea derivative. This Ln-MOF may potentially be used as a multi-responsive regenerable luminescent sensor for the quantitative detection of toxic and harmful substances. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zn-BTC MOFs with active metal sites synthesized via a structure-directing approach for highly efficient carbon conversion.

PubMed

Huang, Xianqiang; Chen, Yifa; Lin, Zhengguo; Ren, Xiaoqian; Song, Yuna; Xu, Zhenzhu; Dong, Xinmei; Li, Xingguo; Hu, Changwen; Wang, Bo

2014-03-11

Three zinc-trimesic acid (Zn-BTC) MOFs, BIT-101, BIT-102 and BIT-103, have been synthesized via a structure-directing strategy. Interestingly, BIT-102 and -103 exhibit extraordinary catalytic performance (up to Conv. 100% and Sele. 95.2%) in the cycloaddition of CO2 under solvent- and halogen-free conditions without any additives or co-catalysts.

Biodegradable Core-shell Dual-Metal-Organic-Frameworks Nanotheranostic Agent for Multiple Imaging Guided Combination Cancer Therapy

PubMed Central

Wang, Dongdong; Zhou, Jiajia; Shi, Ruohong; Wu, Huihui; Chen, Ruhui; Duan, Beichen; Xia, Guoliang; Xu, Pengping; Wang, Hui; Zhou, Shu; Wang, Chengming; Wang, Haibao; Guo, Zhen; Chen, Qianwang

2017-01-01

Metal-organic-frameworks (MOFs) possess high porosity, large surface area, and tunable functionality are promising candidates for synchronous diagnosis and therapy in cancer treatment. Although large number of MOFs has been discovered, conventional MOF-based nanoplatforms are mainly limited to the sole MOF source with sole functionality. In this study, surfactant modified Prussian blue (PB) core coated by compact ZIF-8 shell (core-shell dual-MOFs, CSD-MOFs) has been reported through a versatile stepwise approach. With Prussian blue as core, CSD-MOFs are able to serve as both magnetic resonance imaging (MRI) and fluorescence optical imaging (FOI) agents. We show that CSD-MOFs crystals loading the anticancer drug doxorubicin (DOX) are efficient pH and near-infrared (NIR) dual-stimuli responsive drug delivery vehicles. After the degradation of ZIF-8, simultaneous NIR irradiation to the inner PB MOFs continuously generate heat that kill cancer cells. Their efficacy on HeLa cancer cell lines is higher compared with the respective single treatment modality, achieving synergistic chemo-thermal therapy efficacy. In vivo results indicate that the anti-tumor efficacy of CSD-MOFs@DOX+NIR was 7.16 and 5.07 times enhanced compared to single chemo-therapy and single thermal-therapy respectively. Our strategy opens new possibilities to construct multifunctional theranostic systems through integration of two different MOFs. PMID:29158848

Metal organic frameworks as sorption media for volatile and semi-volatile organic compounds at ambient conditions

PubMed Central

Vellingiri, Kowsalya; Szulejko, Jan E.; Kumar, Pawan; Kwon, Eilhann E.; Kim, Ki-Hyun; Deep, Akash; Boukhvalov, Danil W.; Brown, Richard J. C.

2016-01-01

In this research, we investigated the sorptive behavior of a mixture of 14 volatile and semi-volatile organic compounds (four aromatic hydrocarbons (benzene, toluene, p-xylene, and styrene), six C2-C5 volatile fatty acids (VFAs), two phenols, and two indoles) against three metal-organic frameworks (MOFs), i.e., MOF-5, Eu-MOF, and MOF-199 at 5 to 10 mPa VOC partial pressures (25 °C). The selected MOFs exhibited the strongest affinity for semi-volatile (polar) VOC molecules (skatole), whereas the weakest affinity toward was volatile (non-polar) VOC molecules (i.e., benzene). Our experimental results were also supported through simulation analysis in which polar molecules were bound most strongly to MOF-199, reflecting the presence of strong interactions of Cu2+ with polar VOCs. In addition, the performance of selected MOFs was compared to three well-known commercial sorbents (Tenax TA, Carbopack X, and Carboxen 1000) under the same conditions. The estimated equilibrium adsorption capacity (mg.g−1) for the all target VOCs was in the order of; MOF-199 (71.7) >Carboxen-1000 (68.4) >Eu-MOF (27.9) >Carbopack X (24.3) >MOF-5 (12.7) >Tenax TA (10.6). Hopefully, outcome of this study are expected to open a new corridor to expand the practical application of MOFs for the treatment diverse VOC mixtures. PMID:27324522

Luminescent Lanthanide MOFs: A Unique Platform for Chemical Sensing

PubMed Central

Zhao, Shu-Na; Wang, Guangbo

2018-01-01

In recent years, lanthanide metal–organic frameworks (LnMOFs) have developed to be an interesting subclass of MOFs. The combination of the characteristic luminescent properties of Ln ions with the intriguing topological structures of MOFs opens up promising possibilities for the design of LnMOF-based chemical sensors. In this review, we present the most recent developments of LnMOFs as chemical sensors by briefly introducing the general luminescence features of LnMOFs, followed by a comprehensive investigation of the applications of LnMOF sensors for cations, anions, small molecules, nitroaromatic explosives, gases, vapors, pH, and temperature, as well as biomolecules. PMID:29642458

Improvement in Thermal Stability of Sucralose by γ-Cyclodextrin Metal-Organic Frameworks.

PubMed

Lv, Nana; Guo, Tao; Liu, Botao; Wang, Caifen; Singh, Vikaramjeet; Xu, Xiaonan; Li, Xue; Chen, Dawei; Gref, Ruxandra; Zhang, Jiwen

2017-02-01

To explain thermal stability enhancement of an organic compound, sucralose, with cyclodextrin based metal organic frameworks. Micron and nanometer sized basic CD-MOFs were successfully synthesized by a modified vapor diffusion method and further neutralized with glacial acetic acid. Sucralose was loaded into CD-MOFs by incubating CD-MOFs with sucralose ethanol solutions. Thermal stabilities of sucralose-loaded basic CD-MOFs and neutralized CD-MOFs were investigated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and high performance liquid chromatography with evaporative light-scattering detection (HPLC-ELSD). Scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) results showed that basic CD-MOFs were cubic crystals with smooth surface and uniform sizes. The basic CD-MOFs maintained their crystalline structure after neutralization. HPLC-ELSD analysis indicated that the CD-MOF crystal size had significant influence on sucralose loading (SL). The maximal SL of micron CD-MOFs (CD-MOF-Micro) was 17.5 ± 0.9% (w/w). In contrast, 27.9 ± 1.4% of sucralose could be loaded in nanometer-sized basic CD-MOFs (CD-MOF-Nano). Molecular docking modeling showed that sucralose molecules preferentially located inside the cavities of γ-CDs pairs in CD-MOFs. Raw sucralose decomposed fast at 90°C, with 86.2 ± 0.2% of the compound degraded within only 1 h. Remarkably, sucralose stability was dramatically improved after loading in neutralized CD-MOFs, with only 13.7 ± 0.7% degradation at 90°C within 24 h. CD-MOFs efficiently incorporated sucralose and maintained its integrity upon heating at elevated temperatures.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Hongcai J

In the past decades, there has been an escalation of interest in the study of MOFs due to their fascinating structures and intriguing application potentials. Their exceptionally high surface areas, uniform yet tunable pore sizes, and well-defined adsorbate-MOF interaction sites make them suitable for hydrogen storage. Various strategies to increase the hydrogen capacity of MOFs, such as constructing pore sizes comparable to hydrogen molecules, increasing surface area and pore volume, utilizing catenation, and introducing coordinatively unsaturated metal centers (UMCs) have been widely explored to increase the hydrogen uptake of the MOFs. MOFs with hydrogen uptake approaching the DOE gravimetric storagemore » goal under reasonable pressure but cryo- temperature (typically 77 K) were achieved. However, the weak interaction between hydrogen molecules and MOFs has been the major hurdle limiting the hydrogen uptake of MOFs at ambient temperature. Along the road, we have realized both high surface area and strong interaction between framework and hydrogen are equally essential for porous materials to be practically applicable in Hydrogen storage. Increasing the isosteric heats of adsorption for hydrogen through the introduction of active centers into the framework could have great potential on rendering the framework with strong interaction toward hydrogen. Approaches on increasing the surface areas and improving hydrogen affinity by optimizing size and structure of the pores and the alignment of active centers around the pores in frameworks have been pursued, for example: (a) the introduction of coordinatively UMC (represents a metal center missing multiple ligands) with potential capability of multiple dihydrogen-binding (Kubas type, non-dissociative) per UMC, (b) the design and synthesis of proton-rich MOFs in which a + H3 binds dihydrogen just like a metal ion does, and (c) the preparation of MOFs and PPNs with well aligned internal electric fields. We believe the accomplishments of this DOE supported research will greatly benefit the future pursuit of hydrogen storage materials. The ultimate goal to increase the gravimetric and volumetric hydrogen storage capacity to meet DOE targets for Light-Duty Vehicles is achievable.« less

A Tunable Bimetallic MOF-74 for Adsorption Chiller Applications: A Tunable Bimetallic MOF-74 for Adsorption Chiller Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jian; Zheng, Jian; Barpaga, Dushyant

A mixed metal strategy, in which two different metal nodes coexist in one MOF framework, was examined using MOF-74. The Ni salt precursor for the MOF-74(Ni) analogue was partially replaced during synthesis with relatively inexpensive Zn salt. These bimetallic MOFs were developed and examined for water sorption for potential use in adsorption cooling/chiller applications. Varying concentration ratios of Ni:Zn in MOF-74 achieved using this mixed metal strategy were shown to provide unique impacts on H2O uptake while significantly mitigating the costs of synthesis

Recent Advances in Metal-Organic Frameworks for Heterogeneous Catalyzed Organic Transformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabale, Sandip R.; Zheng, Jian; Vemuri, Venkata Rama Ses

2016-12-12

In this review, we have summarized the recent advances in MOF based heterogeneous catalytic chemistry. Catalytic performance of various configurations of MOFs such as active sites, post synthetic modification and MOF derived catalyst, has been summarized in the context of various organic transformation reactions. Post synthetic modification of MOFs via functionalization of organic linkers with active catalytic moieties was deliberated. Also, efficacy of carbonaceous catalysts derived from MOFs was discussed.

Boosting Chemical Stability, Catalytic Activity, and Enantioselectivity of Metal-Organic Frameworks for Batch and Flow Reactions.

PubMed

Chen, Xu; Jiang, Hong; Hou, Bang; Gong, Wei; Liu, Yan; Cui, Yong

2017-09-27

A key challenge in heterogeneous catalysis is the design and synthesis of heterogeneous catalysts featuring high catalytic activity, selectivity, and recyclability. Here we demonstrate that high-performance heterogeneous asymmetric catalysts can be engineered from a metal-organic framework (MOF) platform by using a ligand design strategy. Three porous chiral MOFs with the framework formula [Mn 2 L(H 2 O) 2 ] are prepared from enantiopure phosphono-carboxylate ligands of 1,1'-biphenol that are functionalized with 3,5-bis(trifluoromethyl)-, bismethyl-, and bisfluoro-phenyl substituents at the 3,3'-position. For the first time, we show that not only chemical stability but also catalytic activity and stereoselectivity of the MOFs can be tuned by modifying the ligand structures. Particularly, the MOF incorporated with -CF 3 groups on the pore walls exhibits enhanced tolerance to water, weak acid, and base compared with the MOFs with -F and -Me groups. Under both batch and flow reaction systems, the CF 3 -containing MOF demonstrated excellent reactivity, selectivity, and recyclability, affording high yields and enantioselectivities for alkylations of indoles and pyrrole with a range of ketoesters or nitroalkenes. In contrast, the corresponding homogeneous catalysts gave low enantioselectivity in catalyzing the tested reactions.

Thermodynamics of metal-organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Di; Navrotsky, Alexandra, E-mail: anavrotsky@ucdavis.edu

Although there have been extensive studies over the past decade in the synthesis and application of metal-organic frameworks (MOFs), investigation of their thermodynamic stability and of the energetics of guest–host interactions has been much more limited. This review summarizes recent progress in experimental (calorimetric) determination of the thermodynamics of MOF materials. The enthalpies of MOFs relative to dense phase assemblages suggest only modest metastability, with a general increase of enthalpy with increasing molar volume, which becomes less pronounced at higher porosity. The energy landscape of nanoporous materials (inorganic and hybrid) consists of a pair of parallel patterns within a fairlymore » narrow range of metastability of 5–30 kJ per mole of tetrahedra in zeolites and mesoporous silicas or per mole of metal in MOFs. Thus strong thermodynamic instability does not seem to limit framework formation. There are strong interactions within the chemisorption range for small molecule–MOF interactions with defined chemical binding at the metal centers or other specific locations. Coexistence of surface binding and confinement can lead to much stronger guest–host interactions. - Graphical abstract: Energy landscape of inorganic and hybrid porous materials. - Highlights: • Thermochemical data on various MOF structures were experimentally determined. • MOFs are moderately unstable relative to their dense phase assemblage. • Overall energetic landscape of porous materials was revealed. • Guest–host interactions in MOFs were evaluated directly using calorimetry. • Confinement effect and defined chemical binding lead to strong interactions.« less

Planar Heterojunction Perovskite Solar Cells Incorporating Metal-Organic Framework Nanocrystals.

PubMed

Chang, Ting-Hsiang; Kung, Chung-Wei; Chen, Hsin-Wei; Huang, Tzu-Yen; Kao, Sheng-Yuan; Lu, Hsin-Che; Lee, Min-Han; Boopathi, Karunakara Moorthy; Chu, Chih-Wei; Ho, Kuo-Chuan

2015-11-25

Zr-based porphyrin metal-organic framework (MOF-525) nanocrystals with a crystal size of about 140 nm are synthesized and incorporated into perovskite solar cells. The morphology and crystallinity of the perovskite thin film are enhanced since the micropores of MOF-525 allow the crystallization of perovskite to occur inside; this observation results in a higher cell efficiency of the obtained MOF/perovskite solar cell. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Large H2 storage capacity of a new polyhedron-based metal-organic framework with high thermal and hygroscopic stability.

PubMed

Hong, Seunghee; Oh, Minhak; Park, Mira; Yoon, Ji Woong; Chang, Jong-San; Lah, Myoung Soo

2009-09-28

Two metal-organic frameworks (MOFs) based on metal-organic cuboctahedra were prepared using a rigid C3 symmetric ligand, where Zn polyhedron-based MOF (PMOF-2(Zn)) did not show any significant gas sorption behavior, whereas the isostructural Cu polyhedron-based MOF (PMOF-2(Cu)) showed a large surface area of approximately 4180 m2 g(-1), high hydrothermal stability, and very promising H2 sorption properties.

Detection of an explosive simulant via electrical impedance spectroscopy utilizing the UiO-66-NH2 metal-organic framework.

PubMed

Peterson, G W; McEntee, M; Harris, C R; Klevitch, A D; Fountain, A W; Soliz, J R; Balboa, A; Hauser, A J

2016-11-01

Electrical impedance spectroscopy, in conjunction with the metal-organic framework (MOF) UiO-66-NH 2 , is used to detect trace levels of the explosive simulant 2,6-dinitrotoluene. The combination of porosity and functionality of the MOF provides an effective dielectric structure, resulting in changes of impedance magnitude and phase angle. The promising data indicate that MOFs may be used in low-cost, robust explosive detection devices.

A single crystalline porphyrinic titanium metal–organic framework

DOE PAGES

Yuan, Shuai; Liu, Tian -Fu; Feng, Dawei; ...

2015-04-28

We successfully assembled the photocatalytic titanium-oxo cluster and photosensitizing porphyrinic linker into a metal–organic framework (MOF), namely PCN-22. A preformed titanium-oxo carboxylate cluster is adopted as the starting material to judiciously control the MOF growth process to afford single crystals. This synthetic method is useful to obtain highly crystalline titanium MOFs, which has been a daunting challenge in this field. Moreover, PCN-22 demonstrated permanent porosity and photocatalytic activities toward alcohol oxidation.

Mixed-linker strategy for the construction of multifunctional metal–organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, Jun-Sheng; Yuan, Shuai; Wang, Qi

2017-01-01

Mixed-linker strategy is a promising way to construct multifunctional metal–organic frameworks (MOFs). In this review, we demonstrate the recent developments, discussions and challenges related to the preparation and applications of four types of mixed-linker MOF materials.

Tuning metal-carboxylate coordination in crystalline metal-organic frameworks through surfactant media

NASA Astrophysics Data System (ADS)

Gao, Junkuo; Ye, Kaiqi; He, Mi; Xiong, Wei-Wei; Cao, Wenfang; Lee, Zhi Yi; Wang, Yue; Wu, Tom; Huo, Fengwei; Liu, Xiaogang; Zhang, Qichun

2013-10-01

Although it has been widely demonstrated that surfactants can efficiently control the size, shape and surface properties of micro/nanocrystals of metal-organic frameworks (MOFs) due to the strong interactions between surfactants and crystal facets of MOFs, the use of surfactants as reaction media to grow MOF single crystals is unprecedented. In addition, compared with ionic liquids, surfactants are much cheaper and can have multifunctional properties such as acidic, basic, neutral, cationic, anionic, or even block. These factors strongly motivate us to develop a new synthetic strategy: growing crystalline MOFs in surfactants. In this report, eight new two-dimensional (2D) or three-dimensional (3D) MOFs have been successfully synthesized in an industrially-abundant and environmentally-friendly surfactant: polyethylene glycol-200 (PEG-200). Eight different coordination modes of carboxylates, ranging from monodentate η1 mode to tetra-donor coordination μ3-η1:η2:η1 mode, have been founded in our research. The magnetic properties of Co-based MOFs were investigated and MOF NTU-Z6b showed a phase transition with a Curie temperature (Tc) at 5 K. Our strategy of growing crystalline MOFs in surfactant could offer exciting opportunities for preparing novel MOFs with diverse structures and interesting properties.

Facile synthesis of hydroxy-modified MOF-5 for improving the adsorption capacity of hydrogen by lithium doping.

PubMed

Kubo, Masaru; Hagi, Hayato; Shimojima, Atsushi; Okubo, Tatsuya

2013-11-01

A facile synthesis of partially hydroxy-modified MOF-5 and its improved H2-adsorption capacity by lithium doping are reported. The reaction of Zn(NO3)2·6H2O with a mixture of terephthalic acid (H2BDC) and 2-hydroxyterephthalic acid (H2BDC-OH) in DMF gave hydroxy-modified MOF-5 (MOF-5-OH-x), in which the molar fraction (x) of BDC-OH(2-) was up to 0.54 of the whole ligand. The MOF-5-OH-x frameworks had high BET surface areas (about 3300 m(2) g(-1)), which were comparable to that of MOF-5. We suggest that the MOF-5-OH-x frameworks are formed by the secondary growth of BDC(2-)-rich MOF-5 seed crystals, which are nucleated during the early stage of the reaction. Subsequent Li doping into MOF-5-OH-x results in increased H2 uptake at 77 K and 0.1 MPa from 1.23 to 1.39 wt.% and an increased isosteric heat of H2 adsorption from 5.1-4.2 kJ mol(-1) to 5.5-4.4 kJ mol(-1). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parkes, Marie V.; Sava Gallis, Dorina F.; Greathouse, Jeffery A.

Computational screening of metal-organic framework (MOF) materials for selective oxygen adsorption from air could lead to new sorbents for the oxyfuel combustion process feedstock streams. A comprehensive study on the effect of MOF metal chemistry on gas binding energies in two common but structurally disparate metal-organic frameworks has been undertaken. Dispersion-corrected density functional theory methods were used to calculate the oxygen and nitrogen binding energies with each of fourteen metals, respectively, substituted into two MOF series, M 2(dobdc) and M 3(btc) 2. The accuracy of DFT methods was validated by comparing trends in binding energy with experimental gas sorption measurements.more » A periodic trend in oxygen binding energies was found, with greater oxygen binding energies for early transition-metal-substituted MOFs compared to late transition metal MOFs; this was independent of MOF structural type. The larger binding energies were associated with oxygen binding in a side-on configuration to the metal, with concomitant lengthening of the O-O bond. In contrast, nitrogen binding energies were similar across the transition metal series, regardless of both MOF structural type and metal identity. Altogether, these findings suggest that early transition metal MOFs are best suited to separating oxygen from nitrogen, and that the MOF structural type is less important than the metal identity.« less

Flying MOFs: polyamine-containing fluidized MOF/SiO 2 hybrid materials for CO 2 capture from post-combustion flue gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luz, Ignacio; Soukri, Mustapha; Lail, Marty

Solid-state synthesis ensures a high loading and well dispersed growth of a large collection of metal–organic framework (MOF) nanostructures within a series of commercially available mesoporous silica allowing to render MOFs into fluidized solid sorbents for CO 2 capture from post-combustion flue gas in a fluidized-bed reactor.

Flying MOFs: polyamine-containing fluidized MOF/SiO 2 hybrid materials for CO 2 capture from post-combustion flue gas

DOE PAGES

Luz, Ignacio; Soukri, Mustapha; Lail, Marty

2018-01-01

Solid-state synthesis ensures a high loading and well dispersed growth of a large collection of metal–organic framework (MOF) nanostructures within a series of commercially available mesoporous silica allowing to render MOFs into fluidized solid sorbents for CO 2 capture from post-combustion flue gas in a fluidized-bed reactor.

In Situ, Time-Resolved, and Mechanistic Studies of Metal–Organic Framework Nucleation and Growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Vleet, Mary J.; Weng, Tingting; Li, Xinyi

The vast chemical and structural diversity of metal–organic frameworks (MOFs) opens up the exciting possibility of “crystal engineering” MOFs tailored for particular catalytic or separation applications. Yet the process of reaction discovery, optimization, and scale-up of MOF synthesis remains extremely challenging, presenting significant obstacles to the synthetic realization of many otherwise promising MOF structures. Recently, significant new insights into the fundamental processes governing MOF nucleation and growth, as well as the relationship between reaction parameters and synthetic outcome, have been derived using powerful in situ, time-resolved and/or mechanistic studies of MOF crystallization. This Review provides a summary and associated criticalmore » analysis of the results of these and other related “direct” studies of MOF nucleation and growth, with a particular emphasis on the recent advances in instrument technologies that have enabled such studies and on the major hypotheses, theories, and models that have been used to explain MOF formation. We conclude with a summary of the major insights that have been gained from the work summarized in this Review, outlining our own perspective on potential fruitful new directions for investigation.« less

One-pot synthesis of binary metal organic frameworks (HKUST-1 and UiO-66) for enhanced adsorptive removal of water contaminants.

PubMed

Azhar, Muhammad Rizwan; Abid, Hussein Rasool; Sun, Hongqi; Periasamy, Vijay; Tadé, Moses O; Wang, Shaobin

2017-03-15

In this study, binary metal organic frameworks (MOFs) with HKUST-1 and UiO-66 have been synthesized in a one-pot process. The synthesized MOFs were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), N 2 adsorption, and thermogravimetric analysis (TGA). The meso-porosity and thermal stability of the binary MOFs were higher than those of single HKUST-1 or UiO-66. The synthesized MOF hybrids were then tested for adsorptive removal of methylene blue (MB) from wastewater in terms of kinetic and isothermal adsorption as compared to a commercially available activated carbon (AC). All the synthesized MOFs showed significant removal of MB under a wide range of pH. The adsorption capacities of HKUST-1 are higher than UiO-66 and commercial AC while the binary MOFs presented an even higher adsorption capacity than single MOFs. This is the first time that binary HKUST-1 and UiO-66 MOFs have been successfully synthesized and demonstrated enhanced adsorptive removal of contaminants. Copyright © 2016 Elsevier Inc. All rights reserved.

In Situ, Time-Resolved, and Mechanistic Studies of Metal–Organic Framework Nucleation and Growth

DOE PAGES

Van Vleet, Mary J.; Weng, Tingting; Li, Xinyi; ...

2018-03-07

The vast chemical and structural diversity of metal–organic frameworks (MOFs) opens up the exciting possibility of “crystal engineering” MOFs tailored for particular catalytic or separation applications. Yet the process of reaction discovery, optimization, and scale-up of MOF synthesis remains extremely challenging, presenting significant obstacles to the synthetic realization of many otherwise promising MOF structures. Recently, significant new insights into the fundamental processes governing MOF nucleation and growth, as well as the relationship between reaction parameters and synthetic outcome, have been derived using powerful in situ, time-resolved and/or mechanistic studies of MOF crystallization. This Review provides a summary and associated criticalmore » analysis of the results of these and other related “direct” studies of MOF nucleation and growth, with a particular emphasis on the recent advances in instrument technologies that have enabled such studies and on the major hypotheses, theories, and models that have been used to explain MOF formation. We conclude with a summary of the major insights that have been gained from the work summarized in this Review, outlining our own perspective on potential fruitful new directions for investigation.« less

A New Class of Metal-Cyclam-Based Zirconium Metal-Organic Frameworks for CO2 Adsorption and Chemical Fixation.

PubMed

Zhu, Jie; Usov, Pavel M; Xu, Wenqian; Celis-Salazar, Paula J; Lin, Shaoyang; Kessinger, Matthew C; Landaverde-Alvarado, Carlos; Cai, Meng; May, Ann M; Slebodnick, Carla; Zhu, Dunru; Senanayake, Sanjaya D; Morris, Amanda J

2018-01-24

Metal-organic frameworks (MOFs) have shown great promise in catalysis, mainly due to their high content of active centers, large internal surface areas, tunable pore size, and versatile chemical functionalities. However, it is a challenge to rationally design and construct MOFs that can serve as highly stable and reusable heterogeneous catalysts. Here two new robust 3D porous metal-cyclam-based zirconium MOFs, denoted VPI-100 (Cu) and VPI-100 (Ni), have been prepared by a modulated synthetic strategy. The frameworks are assembled by eight-connected Zr 6 clusters and metallocyclams as organic linkers. Importantly, the cyclam core has accessible axial coordination sites for guest interactions and maintains the electronic properties exhibited by the parent cyclam ring. The VPI-100 MOFs exhibit excellent chemical stability in various organic and aqueous solvents over a wide pH range and show high CO 2 uptake capacity (up to ∼9.83 wt% adsorption at 273 K under 1 atm). Moreover, VPI-100 MOFs demonstrate some of the highest reported catalytic activity values (turnover frequency and conversion efficiency) among Zr-based MOFs for the chemical fixation of CO 2 with epoxides, including sterically hindered epoxides. The MOFs, which bear dual catalytic sites (Zr and Cu/Ni), enable chemistry not possible with the cyclam ligand under the same conditions and can be used as recoverable stable heterogeneous catalysts without losing performance.

Versatile Surface Functionalization of Metal-Organic Frameworks through Direct Metal Coordination with a Phenolic Lipid Enables Diverse Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Wei; Xiang, Guolei; Shang, Jin

Here, a novel strategy for the versatile functionalization of the external surface of metal-organic frameworks (MOFs) has been developed based on the direct coordination of a phenolic-inspired lipid molecule DPGG (1,2-dipalmitoyl-sn-glycero-3-galloyl) with metal nodes/sites surrounding MOF surface. X-ray diffraction and Argon sorption analysis prove that the modified MOF particles retain their structural integrity and porosity after surface modification. Density functional theory calculations reveal that strong chelation strength between the metal sites and the galloyl head group of DPGG is the basic prerequisite for successful coating. Due to the pH-responsive nature of metal-phenol complexation, the modification process is reversible by simplemore » washing in weak acidic water, showing an excellent regeneration ability for water-stable MOFs. Moreover, the colloidal stability of the modified MOFs in the nonpolar solvent allows them to be further organized into 2 dimensional MOF or MOF/polymer monolayers by evaporation-induced interfacial assembly conducted on an air/water interface. Lastly, the easy fusion of a second functional layer onto DPGG-modified MOF cores, enabled a series of MOF-based functional nanoarchitectures, such as MOFs encapsulated within hybrid supported lipid bilayers (so-called protocells), polyhedral core-shell structures, hybrid lipid-modified-plasmonic vesicles and multicomponent supraparticles with target functionalities, to be generated. for a wide range of applications.« less

Cobalt- and Cadmium-Based Metal-Organic Frameworks as High-Performance Anodes for Sodium Ion Batteries and Lithium Ion Batteries.

PubMed

Dong, Caifu; Xu, Liqiang

2017-03-01

Two multifunctional metal-organic frameworks (MOFs) with the same coordination mode, [Co(L)(H 2 O)] n ·2nH 2 O [defined as "Co(L) MOF"] and [Cd(L)(H 2 O)] n ·2nH 2 O [defined as "Cd(L) MOF"] (L = 5-aminoisophthalic acid) have been fabricated via a simple and versatile scalable solvothermal approach at 85 °C for 24 h. The relationship between the structure of the electrode materials (especially the coordination water and different metal ions) and the electrochemical properties of MOFs have been investigated for the first time. And then the possible electrochemical mechanisms of the electrodes have been studied and proposed. In addition, MOFs/RGO hybrid materials were prepared via ball milling, which demonstrated better electrochemical performances than those of individual Co(L) MOF and Cd(L) MOF. For example, when Co(L) MOF/RGO was applied as anode for sodium ion batteries (SIBs), it retained 206 mA h g -1 after 330 cycles at 500 mA g -1 and 1185 mA h g -1 could be obtained after 50 cycles at 100 mA g -1 for lithium-ion batteries (LIBs). The high-discharge capacity, excellent cyclic stability combined with the facile synthesis procedure enable Co(L) MOF- and Cd(L) MOF-based materials to be prospective anode materials for SIBs and LIBs.

Synthesis and Electrospraying of Nanoscale MOF (Metal Organic Framework) for High-Performance CO2 Adsorption Membrane

NASA Astrophysics Data System (ADS)

Wahiduzzaman; Allmond, Kelsey; Stone, John; Harp, Spencer; Mujibur, Khan

2017-01-01

We report the sonochemical synthesis of MOF (metal organic framework) nanoparticles of 30-200 nm in size and electrospraying of those particles on electrospun nanofibers to process a MOF-attached nanofibrous membrane. This membrane displayed significant selectivity towards CO2 and capacity of adsorbing with 4000-5000 ppm difference from a mixed gas flow of 1% CO2 and 99% N2. Applying ultrasonic waves during the MOF synthesis offered rapid dispersion and formation of crystalline MOF nanoparticles in room temperature. The MOF nanoparticles of 100-200 nm in size displayed higher surface area and adsorption capacity comparing to that of 30-60 nm in size. Nanofibrous membrane was produced by electrospinning of MOF blended PAN solution followed by electrospraying of additional MOF nanoparticles. This yielded uniform MOF deposition on nanofibers, occurred due to electrostatic attraction between highly charged nanoparticles and conductive nanofibers. A test bench for real-time CO2 adsorption at room temperature was built with non-dispersive Infrared (NDIR) CO2 sensors. Comparative tests were performed on the membrane to investigate its enhanced adsorption capacity. Three layers of the as-produced membranes displayed CO2 adsorption for approximately 2 h. Thermogravimetric analysis (TGA) of the membrane showed the thermal stability of the MOF and PAN up to 290 and 425 °C, respectively.

Effect of metal in M 3(btc) 2 and M 2(dobdc) MOFs for O 2/N 2 separations: A combined density functional theory and experimental study

DOE PAGES

Parkes, Marie V.; Sava Gallis, Dorina F.; Greathouse, Jeffery A.; ...

2015-03-02

Computational screening of metal-organic framework (MOF) materials for selective oxygen adsorption from air could lead to new sorbents for the oxyfuel combustion process feedstock streams. A comprehensive study on the effect of MOF metal chemistry on gas binding energies in two common but structurally disparate metal-organic frameworks has been undertaken. Dispersion-corrected density functional theory methods were used to calculate the oxygen and nitrogen binding energies with each of fourteen metals, respectively, substituted into two MOF series, M 2(dobdc) and M 3(btc) 2. The accuracy of DFT methods was validated by comparing trends in binding energy with experimental gas sorption measurements.more » A periodic trend in oxygen binding energies was found, with greater oxygen binding energies for early transition-metal-substituted MOFs compared to late transition metal MOFs; this was independent of MOF structural type. The larger binding energies were associated with oxygen binding in a side-on configuration to the metal, with concomitant lengthening of the O-O bond. In contrast, nitrogen binding energies were similar across the transition metal series, regardless of both MOF structural type and metal identity. Altogether, these findings suggest that early transition metal MOFs are best suited to separating oxygen from nitrogen, and that the MOF structural type is less important than the metal identity.« less

Synthesis and Electrospraying of Nanoscale MOF (Metal Organic Framework) for High-Performance CO2 Adsorption Membrane.

PubMed

Wahiduzzaman; Allmond, Kelsey; Stone, John; Harp, Spencer; Mujibur, Khan

2017-12-01

We report the sonochemical synthesis of MOF (metal organic framework) nanoparticles of 30-200 nm in size and electrospraying of those particles on electrospun nanofibers to process a MOF-attached nanofibrous membrane. This membrane displayed significant selectivity towards CO 2 and capacity of adsorbing with 4000-5000 ppm difference from a mixed gas flow of 1% CO 2 and 99% N 2 . Applying ultrasonic waves during the MOF synthesis offered rapid dispersion and formation of crystalline MOF nanoparticles in room temperature. The MOF nanoparticles of 100-200 nm in size displayed higher surface area and adsorption capacity comparing to that of 30-60 nm in size. Nanofibrous membrane was produced by electrospinning of MOF blended PAN solution followed by electrospraying of additional MOF nanoparticles. This yielded uniform MOF deposition on nanofibers, occurred due to electrostatic attraction between highly charged nanoparticles and conductive nanofibers. A test bench for real-time CO 2 adsorption at room temperature was built with non-dispersive Infrared (NDIR) CO 2 sensors. Comparative tests were performed on the membrane to investigate its enhanced adsorption capacity. Three layers of the as-produced membranes displayed CO 2 adsorption for approximately 2 h. Thermogravimetric analysis (TGA) of the membrane showed the thermal stability of the MOF and PAN up to 290 and 425 °C, respectively.

Kinetic Stability of MOF-5 in Humid Environments: Impact of Powder Densification, Humidity Level, and Exposure Time.

PubMed

Ming, Yang; Purewal, Justin; Yang, Jun; Xu, Chunchuan; Soltis, Rick; Warner, James; Veenstra, Mike; Gaab, Manuela; Müller, Ulrich; Siegel, Donald J

2015-05-05

Metal-organic frameworks (MOFs) are an emerging class of microporous, crystalline materials with potential applications in the capture, storage, and separation of gases. Of the many known MOFs, MOF-5 has attracted considerable attention because of its ability to store gaseous fuels at low pressure with high densities. Nevertheless, MOF-5 and several other MOFs exhibit limited stability upon exposure to reactive species such as water. The present study quantifies the impact of humid air exposure on the properties of MOF-5 as a function of exposure time, humidity level, and morphology (i.e., powders vs pellets). Properties examined include hydrogen storage capacity, surface area, and crystallinity. Water adsorption/desorption isotherms are measured using a gravimetric technique; the first uptake exhibits a type V isotherm with a sudden increase in uptake at ∼50% relative humidity. For humidity levels below this threshold only minor degradation is observed for exposure times up to several hours, suggesting that MOF-5 is more stable than generally assumed under moderately humid conditions. In contrast, irreversible degradation occurs in a matter of minutes for exposures above the 50% threshold. Fourier transform infrared spectroscopy indicates that molecular and/or dissociated water is inserted into the skeletal framework after long exposure times. Densification into pellets can slow the degradation of MOF-5 significantly, and may present a pathway to enhance the stability of some MOFs.

Crystallographic studies of gas sorption in metal–organic frameworks

PubMed Central

Carrington, Elliot J.; Vitórica-Yrezábal, Iñigo J.; Brammer, Lee

2014-01-01

Metal–organic frameworks (MOFs) are a class of porous crystalline materials of modular design. One of the primary applications of these materials is in the adsorption and separation of gases, with potential benefits to the energy, transport and medical sectors. In situ crystallography of MOFs under gas atmospheres has enabled the behaviour of the frameworks under gas loading to be investigated and has established the precise location of adsorbed gas molecules in a significant number of MOFs. This article reviews progress in such crystallographic studies, which has taken place over the past decade, but has its origins in earlier studies of zeolites, clathrates etc. The review considers studies by single-crystal or powder diffraction using either X-rays or neutrons. Features of MOFs that strongly affect gas sorption behaviour are discussed in the context of in situ crystallographic studies, specifically framework flexibility, and the presence of (organic) functional groups and unsaturated (open) metal sites within pores that can form specific interactions with gas molecules. PMID:24892587

Microporous rod metal-organic frameworks with diverse Zn/Cd-triazolate ribbons as secondary building units for CO2 uptake and selective adsorption of hydrocarbons.

PubMed

Zhang, Jian-Wei; Hu, Man-Cheng; Li, Shu-Ni; Jiang, Yu-Cheng; Zhai, Quan-Guo

2017-01-17

The synthetic design of new porous open-framework materials with pre-designed pore properties for desired applications such as gas adsorption and separation remains challenging. We proposed one such class of materials, rod metal-organic frameworks (rod MOFs), which can be tuned by using rod secondary building units (rod SBUs) with different geometrical and chemical features. Our approach takes advantage of the readily accessible metal-triazolate 1-D motifs as rod SBUs to combine with dicarboxylate ligands to prepare target rod MOFs. Herein we report three such metal-triazolate-dicarboxylate frameworks (SNNU-21, -22 and -23). During the formation of these three MOFs, Cd or Zn ions are firstly connected by 1,2,4-triazole through the N1,N2,N4-mode to form 1-D metal-organic ribbon-like rod SBUs, which further joint four adjacent rod SBUs via eight BDC linkers to give 3-D microporous frameworks. However, tuned by the different NH 2 groups from metal-triazolate rod SBUs, different space groups, pore sizes and shapes are observed for SNNU-21-23. All of these rod MOFs show not only remarkable CO 2 uptake capacity, but also high CO 2 over CH 4 and C 2 -hydrocarbons over CH 4 selectivity under ambient conditions. Specially, SNNU-23 exhibits a very high isosteric heat of adsorption (Q st ) for C 2 H 2 (62.2 kJ mol -1 ), which outperforms the values of all MOF materials reported to date including the famous MOF-74-Co.

Toward Metal–Organic Framework-Based Solar Cells: Enhancing Directional Exciton Transport by Collapsing Three-Dimensional Film Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goswami, Subhadip; Ma, Lin; Martinson, Alex B. F.

Owing to their ability to act as light-harvesting scaffolds, porphyrin-containing metal-organic frameworks (MOFs) are in the forefront of research on the application of highly ordered molecular materials to problems in solar-energy conversion. In this work, solvent-assisted linker exchange (SALE) is performed on a pillared paddlewheel porphyrin containing MOF thin film to collapse a 3D framework to a 2D framework. The change in dimensionality of the framework is confirmed by a decrease in the film thickness, the magnitude of which is in agreement with crystallographic parameters for related bulk materials. Furthermore, NMR spectroscopy performed on the digested sample suggests a similarmore » change in geometry is achieved in bulk MOF samples. The decreased distance between the porphyrin chromophores in the 2D MOF film compared to the 3D film results in enhanced energy transfer through the film. The extent of energy transport was probed by assembling MOF thin film where the outermost layers are palladium porphyrin (P2) units, which act as energy traps and fluorescence quenchers. Steady-state emission spectroscopy together with time-resolved emission spectroscopy indicates that excitons can travel through about 9-11 layers (porphyrin layers) in 2D films, whereas in 3D films energy transfer occurs through no more than about 6-8 layers. The results are difficult to understand if only changes in MOF interlayer spacing are considered but become much more understandable if dipole-dipole coupling distances are considered.« less

Drawing Sensors with Ball-Milled Blends of Metal-Organic Frameworks and Graphite

PubMed Central

Ko, Michael; Aykanat, Aylin; Smith, Merry K.

2017-01-01

The synthetically tunable properties and intrinsic porosity of conductive metal-organic frameworks (MOFs) make them promising materials for transducing selective interactions with gaseous analytes in an electrically addressable platform. Consequently, conductive MOFs are valuable functional materials with high potential utility in chemical detection. The implementation of these materials, however, is limited by the available methods for device incorporation due to their poor solubility and moderate electrical conductivity. This manuscript describes a straightforward method for the integration of moderately conductive MOFs into chemiresistive sensors by mechanical abrasion. To improve electrical contacts, blends of MOFs with graphite were generated using a solvent-free ball-milling procedure. While most bulk powders of pure conductive MOFs were difficult to integrate into devices directly via mechanical abrasion, the compressed solid-state MOF/graphite blends were easily abraded onto the surface of paper substrates equipped with gold electrodes to generate functional sensors. This method was used to prepare an array of chemiresistors, from four conductive MOFs, capable of detecting and differentiating NH3, H2S and NO at parts-per-million concentrations. PMID:28946624

Carbon with hierarchical pores from carbonized metal-organic frameworks for lithium sulphur batteries.

PubMed

Xi, Kai; Cao, Shuai; Peng, Xiaoyu; Ducati, Caterina; Kumar, R Vasant; Cheetham, Anthony K

2013-03-18

This paper presents a novel method and rationale for utilizing carbonized MOFs for sulphur loading to fabricate cathode structures for lithium-sulphur batteries. Unique carbon materials with differing hierarchical pore structures were synthesized from four types of zinc-containing metal-organic frameworks (MOFs). It is found that cathode materials made from MOFs-derived carbons with higher mesopore (2-50 nm) volumes exhibit increased initial discharge capacities, whereas carbons with higher micropore (<2 nm) volumes lead to cathode materials with better cycle stability.

Configurations, band structures and photocurrent responses of 4-(4-oxopyridin-1(4H)-yl)phthalic acid and its metal-organic frameworks

NASA Astrophysics Data System (ADS)

Yan, Xingxiu; Qiu, Xiandeng; Yan, Zhishuo; Li, Hongjiang; Gong, Yun; Lin, Jianhua

2016-05-01

4-(4-oxopyridin-1(4 H)-yl)phthalic acid (H2L) and three H2L-based metal-organic frameworks (MOFs) formulated as ZnL(DPE)(H2O)·H2O (DPE=(E)-1, 2-di(pyridine -4-yl)ethene) (1), CdL(H2O)2 (2) and CdL (3) were synthesized and structurally characterized by single-crystal X-ray diffraction. The free H2L ligand shows an enol-form and the L2- ligand in the three MOFs exists as the keto-form. Density functional theory (DFT) calculations indicate H2L and the three MOFs possess different band structures. Due to the existence of the N-donor, DPE in MOF 1, the conduction band (CB) minimum and band gap of MOF 1 are much lower than those of H2L. And MOF 1 yielded much larger photocurrent density than H2L upon visible light illumination. Electrochemical impedance spectroscopy (EIS) shows the interfacial charge transfer impedance in the presence of MOF 1 is lower than that in the presence of H2L. The hydrous MOF 2 and the anhydrous MOF 3 are both constructed by Cd(II) and L2-, and they can be reversibly transformed to each other. However, MOFs 2 and 3 possess different CB minimums and VB maximums, and their band gaps are much larger than that of MOF 1.

Highly sensitive and selective fluoride detection in water through fluorophore release from a metal-organic framework

PubMed Central

Hinterholzinger, Florian M.; Rühle, Bastian; Wuttke, Stefan; Karaghiosoff, Konstantin; Bein, Thomas

2013-01-01

The detection, differentiation and visualization of compounds such as gases, liquids or ions are key challenges for the design of selective optical chemosensors. Optical chemical sensors employ a transduction mechanism that converts a specific analyte recognition event into an optical signal. Here we report a novel concept for fluoride ion sensing where a porous crystalline framework serves as a host for a fluorescent reporter molecule. The detection is based on the decomposition of the host scaffold which induces the release of the fluorescent dye molecule. Specifically, the hybrid composite of the metal-organic framework NH2-MIL-101(Al) and fluorescein acting as reporter shows an exceptional turn-on fluorescence in aqueous fluoride-containing solutions. Using this novel strategy, the optical detection of fluoride is extremely sensitive and highly selective in the presence of many other anions. PMID:24008779

Multiaxis sensing using metal organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talin, Albert Alec; Allendorf, Mark D.; Leonard, Francois

2017-01-17

A sensor device including a sensor substrate; and a thin film comprising a porous metal organic framework (MOF) on the substrate that presents more than one transduction mechanism when exposed to an analyte. A method including exposing a porous metal organic framework (MOF) on a substrate to an analyte; and identifying more than one transduction mechanism in response to the exposure to the analyte.

Screening of metal-organic frameworks for carbon dioxide capture from flue gas using a combined experimental and modeling approach.

PubMed

Yazaydin, A Ozgür; Snurr, Randall Q; Park, Tae-Hong; Koh, Kyoungmoo; Liu, Jian; Levan, M Douglas; Benin, Annabelle I; Jakubczak, Paulina; Lanuza, Mary; Galloway, Douglas B; Low, John J; Willis, Richard R

2009-12-30

A diverse collection of 14 metal-organic frameworks (MOFs) was screened for CO(2) capture from flue gas using a combined experimental and modeling approach. Adsorption measurements are reported for the screened MOFs at room temperature up to 1 bar. These data are used to validate a generalized strategy for molecular modeling of CO(2) and other small molecules in MOFs. MOFs possessing a high density of open metal sites are found to adsorb significant amounts of CO(2) even at low pressure. An excellent correlation is found between the heat of adsorption and the amount of CO(2) adsorbed below 1 bar. Molecular modeling can aid in selection of adsorbents for CO(2) capture from flue gas by screening a large number of MOFs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talin, Albert Alec; Jones, Reese E.; Spataru, Dan Catalin

Metal organic frameworks (MOFs) are extended, nanoporous crystalline compounds consisting of metal ions interconnected by organic ligands. Their synthetic versatility suggest a disruptive class of opto - electronic materials with a high degree of electrical tunability and without the property - degrading disorder of organic conductors. In this project we determined the factors controlling charge and energy transport in MOFs and evaluated their potential for thermoelectric energy conversion. Two strategies for a chieving electronic conductivity in MOFs were explored: 1) using redox active 'guest' molecules introduced into the pores to dope the framework via charge - transfer coupling (Guest@MOF), 2)more » metal organic graphene analogs (MOGs) with dispersive band structur es arising from strong electronic overlap between the MOG metal ions and its coordinating linker groups. Inkjet deposition methods were developed to facilitate integration of the guest@MOF and MOG materials into practical devices.« less

Nanoarchitectures for Metal-Organic Framework-Derived Nanoporous Carbons toward Supercapacitor Applications.

PubMed

Salunkhe, Rahul R; Kaneti, Yusuf Valentino; Kim, Jeonghun; Kim, Jung Ho; Yamauchi, Yusuke

2016-12-20

The future advances of supercapacitors depend on the development of novel carbon materials with optimized porous structures, high surface area, high conductivity, and high electrochemical stability. Traditionally, nanoporous carbons (NPCs) have been prepared by a variety of methods, such as templated synthesis, carbonization of polymer precursors, physical and chemical activation, etc. Inorganic solid materials such as mesoporous silica and zeolites have been successfully utilized as templates to prepare NPCs. However, the hard-templating methods typically involve several synthetic steps, such as preparation of the original templates, formation of carbon frameworks, and removal of the original templates. Therefore, these methods are not favorable for large-scale production. Metal-organic frameworks (MOFs) with high surface areas and large pore volumes have been studied over the years, and recently, enormous efforts have been made to utilize MOFs for electrochemical applications. However, their low conductivity and poor stability still present major challenges toward their practical applications in supercapacitors. MOFs can be used as precursors for the preparation of NPCs with high porosity. Their parent MOFs can be prepared with endless combinations of organic and inorganic constituents by simple coordination chemistry, and it is possible to control their porous architectures, pore volumes, surface areas, etc. These unique properties of MOF-derived NPCs make them highly attractive for many technological applications. Compared with carbonaceous materials prepared using conventional precursors, MOF-derived carbons have significant advantages in terms of a simple synthesis with inherent diversity affording precise control over porous architectures, pore volumes, and surface areas. In this Account, we will summarize our recent research developments on the preparation of three-dimensional (3-D) MOF-derived carbons for supercapacitor applications. This Account will be divided into three main sections: (1) useful background on carbon materials for supercapacitor applications, (2) the importance of MOF-derived carbons, and (3) potential future developments of MOF-derived carbons for supercapacitors. This Account focuses mostly on carbons derived from two types of MOFs, namely, zeolite imidazolate framework-8 (ZIF-8) and ZIF-67. By using examples from our previous works, we will show the uniqueness of these carbons for achieving high performance by control of the chemical reactions/conditions as well proper utilization in asymmetric/symmetric supercapacitor configurations. This Account will promote further developments of MOF-derived multifunctional carbon materials with controlled porous architectures for optimization of their electrochemical performance toward supercapacitor applications.

Metal-organic framework nanosheets in polymer composite materials for gas separation

PubMed Central

Seoane, Beatriz; Miro, Hozanna; Corma, Avelino; Kapteijn, Freek; Llabrés i Xamena, Francesc X.; Gascon, Jorge

2014-01-01

Composites incorporating two-dimensional nanostructures within polymeric matrices hold potential as functional components for several technologies, including gas separation. Prospectively, employing metal-organic-frameworks (MOFs) as versatile nanofillers would notably broaden the scope of functionalities. However, synthesizing MOFs in the form of free standing nanosheets has proven challenging. We present a bottom-up synthesis strategy for dispersible copper 1,4-benzenedicarboxylate MOF lamellae of micrometer lateral dimensions and nanometer thickness. Incorporating MOF nanosheets into polymer matrices endows the resultant composites with outstanding CO2 separation performance from CO2/CH4 gas mixtures, together with an unusual and highly desired increment in the separation selectivity with pressure. As revealed by tomographic focused-ion-beam scanning-electron-microscopy, the unique separation behaviour stems from a superior occupation of the membrane cross-section by the MOF nanosheets as compared to isotropic crystals, which improves the efficiency of molecular discrimination and eliminates unselective permeation pathways. This approach opens the door to ultrathin MOF-polymer composites for various applications. PMID:25362353

Nanoporous metal organic frameworks as hybrid polymer-metal composites for drug delivery and biomedical applications.

PubMed

Beg, Sarwar; Rahman, Mahfoozur; Jain, Atul; Saini, Sumant; Midoux, Patrick; Pichon, Chantal; Ahmad, Farhan Jalees; Akhter, Sohail

2017-04-01

Metal organic frameworks (MOFs), porous hybrid polymer-metal composites at the nanoscale, are recent innovations in the field of chemistry; they are novel polymeric materials with diverse biomedical applications. MOFs are nanoporous materials, consisting of metal ions linked together by organic bridging ligands. The unique physical and chemical characteristics of MOFs have attracted wider attention from the scientific community, exploring their utility in the field of material science, biology, nanotechnology and drug delivery. The practical feasibility of MOFs is possible owing to their abilities for biodegradability, excellent porosity, high loading capacity, ease of surface modification, among others. In this regard, this review provides an account of various types of MOFs, their physiochemical characteristics and use in diverse disciplines of biomedical sciences - with special emphasis on drug delivery and theranostics. Moreover, this review also highlights the stability and toxicity issues of MOFs, along with their market potential for biomedical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metal-organic frameworks for thermoelectric energy-conversion applications

DOE PAGES

Talin, Albert Alec; Jones, Reese E.; Hopkins, Patrick E.

2016-11-07

Motivated by low cost, low toxicity, mechanical flexibility, and conformability over complex shapes, organic semiconductors are currently being actively investigated as thermoelectric (TE) materials to replace the costly, brittle, and non-eco-friendly inorganic TEs for near-ambient-temperature applications. Metal–organic frameworks (MOFs) share many of the attractive features of organic polymers, including solution processability and low thermal conductivity. A potential advantage of MOFs and MOFs with guest molecules (Guest@MOFs) is their synthetic and structural versatility, which allows both the electronic and geometric structure to be tuned through the choice of metal, ligand, and guest molecules. This could solve the long-standing challenge of findingmore » stable, high-TE-performance n-type organic semiconductors, as well as promote high charge mobility via the long-range crystalline order inherent in these materials. In this paper, we review recent advances in the synthesis of MOF and Guest@MOF TEs and discuss how the Seebeck coefficient, electrical conductivity, and thermal conductivity could be tuned to further optimize TE performance.« less

Dual-Function Metal-Organic Framework as a Versatile Catalyst for Detoxifying Chemical Warfare Agent Simulants.

PubMed

Liu, Yangyang; Moon, Su-Young; Hupp, Joseph T; Farha, Omar K

2015-12-22

The nanocrystals of a porphyrin-based zirconium(IV) metal-organic framework (MOF) are used as a dual-function catalyst for the simultaneous detoxification of two chemical warfare agent simulants at room temperature. Simulants of nerve agent (such as GD, VX) and mustard gas, dimethyl 4-nitrophenyl phosphate and 2-chloroethyl ethyl sulfide, have been hydrolyzed and oxidized, respectively, to nontoxic products via a pair of pathways catalyzed by the same MOF. Phosphotriesterase-like activity of the Zr6-containing node combined with photoactivity of the porphyrin linker gives rise to a versatile MOF catalyst. In addition, bringing the MOF crystals down to the nanoregime leads to acceleration of the catalysis.

A rare 3D chloro-laced Mn(II) metal-organic framework to show sensitive probing effect to Hg2+

NASA Astrophysics Data System (ADS)

Ming, Mei; Bai, Na

2017-10-01

Two 3D Mn(II) metal-organic frameworks (MOFs), [Mn(L-Cl)(DMA)](H2O) (1) and Mn(L-CH3)(DMA) (2) (H2L-Cl = 2,2'-dichloro-4,4'-azodibenzoic acid, H2L-CH3 = 2,2'-dimethyl-4,4'-azodibenzoic acid) were synthesized under similar solvothermal condition. Both MOFs crystallize in the orthorhombic system and show the 3D rod-packing networks in 2-fold interpenetrated pattern with sra topology. Due to the different substituent laces of MOFs (-Cl vs -CH3), only MOF 1 shows highly selective and sensitive fluorescence sensing effect for detecting Hg2+ ion.

Facile growth of a single-crystal pattern: a case study of HKUST-1.

PubMed

Li, Shaozhou; Lu, Guang; Huang, Xiao; Li, Hai; Sun, Yinghui; Zhang, Hua; Chen, Xiaodong; Huo, Fengwei

2012-12-18

In order to fabricate metal-organic framework (MOF) based devices, it is desirable to precisely position high-quality and mono-sized MOF crystals on supports. In this work, we demonstrate a facile solution procedure for the fabrication of oriented and monodispersed single-crystal MOF pattern. We expect that such capability will expand the scope of applications of MOFs to advanced fields.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qiu; Liu, Wenxian; Wang, Bingqing

Composites incorporating metal nanoparticles (MNPs) within metal-organic frameworks (MOFs) have broad applications in many fields. However, the controlled spatial distribution of the MNPs within MOFs remains a challenge for addressing key issues in catalysis, for example, the efficiency of catalysts due to the limitation of molecular diffusion within MOF channels. We report a facile strategy that enables MNPs to be encapsulated into MOFs with controllable spatial localization by using metal oxide both as support to load MNPs and as a sacrificial template to grow MOFs. This strategy is versatile to a variety of MNPs and MOF crystals. By localizing themore » encapsulated MNPs closer to the surface of MOFs, the resultant MNPs@MOF composites not only exhibit effective selectivity derived from MOF cavities, but also enhanced catalytic activity due to the spatial regulation of MNPs as close as possible to the MOF surface.« less

Design and construction of porous metal-organic frameworks based on flexible BPH pillars

NASA Astrophysics Data System (ADS)

Hao, Xiang-Rong; Yang, Guang-sheng; Shao, Kui-Zhan; Su, Zhong-Min; Yuan, Gang; Wang, Xin-Long

2013-02-01

Three metal-organic frameworks (MOFs), [Co2(BPDC)2(4-BPH)·3DMF]n (1), [Cd2(BPDC)2(4-BPH)2·2DMF]n (2) and [Ni2(BDC)2(3-BPH)2 (H2O)·4DMF]n (3) (H2BPDC=biphenyl-4,4'-dicarboxylic acid, H2BDC=terephthalic acid, BPH=bis(pyridinylethylidene)hydrazine and DMF=N,N'-dimethylformamide), have been solvothermally synthesized based on the insertion of heterogeneous BPH pillars. Framework 1 has "single-pillared" MOF-5-like motif with inner cage diameters of up to 18.6 Å. Framework 2 has "double pillared" MOF-5-like motif with cage diameters of 19.2 Å while 3 has "double pillared" 8-connected framework with channel diameters of 11.0 Å. Powder X-ray diffraction (PXRD) shows that 3 is a dynamic porous framework.

Hollow carbon nanobubbles: monocrystalline MOF nanobubbles and their pyrolysis† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6sc04903f Click here for additional data file.

PubMed Central

Zhang, Wei; Jiang, Xiangfen; Zhao, Yanyi; Carné-Sánchez, Arnau; Malgras, Victor; Kim, Jeonghun; Kim, Jung Ho; Wang, Shaobin; Jiang, Ji-Sen

2017-01-01

While bulk-sized metal–organic frameworks (MOFs) face limits to their utilization in various research fields such as energy storage applications, nanoarchitectonics is believed to be a possible solution. It is highly challenging to realize MOF nanobubbles with monocrystalline frameworks. By a spatially controlled etching approach, here, we can achieve the synthesis of zeolitic imidazolate framework (ZIF-8) nanobubbles with a uniform size of less than 100 nm. Interestingly, the ZIF-8 nanobubbles possess a monocrystalline nanoshell with a thickness of around 10 nm. Under optimal pyrolytic conditions, the ZIF-8 nanobubbles can be converted into hollow carbon nanobubbles while keeping their original shapes. The structure of the nanobubble enhances the fast Na+/K+ ion intercalation performance. Such remarkable improvement cannot be realized by conventional MOFs or their derived carbons. PMID:28580098

Achieving Amphibious Superprotonic Conductivity in a CuI Metal-Organic Framework by Strategic Pyrazinium Salt Impregnation.

PubMed

Khatua, Sajal; Bar, Arun Kumar; Sheikh, Javeed Ahmad; Clearfield, Abraham; Konar, Sanjit

2018-01-19

Treatment of a pyrazine (pz)-impregnated Cu I metal-organic framework (MOF) ([1⊃pz]) with HCl vapor renders an interstitial pyrazinium chloride salt-hybridized MOF ([1⊃pz⋅6 HCl]) that exhibits proton conductivity over 10 -2  S cm -1 both in anhydrous and under humid conditions. Framework [1⊃pz⋅6 HCl] features the highest anhydrous proton conductivity among the lesser-known examples of MOF-based materials exhibiting proton conductivity under both anhydrous and humid conditions. Moreover, [1⊃pz] and corresponding pyrazinium sulfate- and pyrazinium phosphate-hybridized MOFs also exhibit superprotonic conductivity over 10 -2  S cm -1 under humid conditions. The impregnated pyrazinium ions play a crucial role in protonic conductivity, which occurs through a Grotthuss mechanism. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A luminescent Cd(II)-based metal-organic framework for detection of Fe(III) ions in aqueous solution

NASA Astrophysics Data System (ADS)

Li, Fen-Fang; Zhu, Miao-Li; Lu, Li-Ping

2018-05-01

A novel Cd((II)-organic framework [Cd(Hcbic)]n (H3cbic = 1-(4-carboxybenz-yl)-1H-benzoim-idazole-5, 6-dicarboxylic acid) was assembled and characterized by X-ray single crystal analysis. The Cd-MOF features one-dimensional left and right-handed double helical chains with screw-pitch of about 4.727 Å and the 4-methyl benzoic acid groups of Hcbic2- ligands in MOF-1 play many ribbons distributing in the two sides of the 2D networks. It is found that MOF-1 shows high selectivity (KSV = 1.8 × 105 L / mol) for Fe3+ ions in water solution with luminescent quenching because of the existence of uncoordinated carboxyl groups within open frameworks, which indicates that MOF-1 is a simple and reliable detection sensing reagent for Fe3+ in practical applications.

Catalysis by metal-organic frameworks: fundamentals and opportunities.

PubMed

Ranocchiari, Marco; van Bokhoven, Jeroen Anton

2011-04-14

Crystalline porous materials are extremely important for developing catalytic systems with high scientific and industrial impact. Metal-organic frameworks (MOFs) show unique potential that still has to be fully exploited. This perspective summarizes the properties of MOFs with the aim to understand what are possible approaches to catalysis with these materials. We categorize three classes of MOF catalysts: (1) those with active site on the framework, (2) those with encapsulated active species, and (3) those with active sites attached through post-synthetic modification. We identify the tunable porosity, the ability to fine tune the structure of the active site and its environment, the presence of multiple active sites, and the opportunity to synthesize structures in which key-lock bonding of substrates occurs as the characteristics that distinguish MOFs from other materials. We experience a unique opportunity to imagine and design heterogeneous catalysts, which might catalyze reactions previously thought impossible.

Multifaceted Modularity: A Key for Stepwise Building of Hierarchical Complexity in Actinide Metal–Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgopolova, Ekaterina A.; Ejegbavwo, Otega A.; Martin, Corey R.

Growing necessity for efficient nuclear waste management is a driving force for development of alternative architectures towards fundamental understanding of mechanisms involved in actinide integration inside extended structures. In this manuscript, metal-organic frameworks (MOFs) were investigated as a model system for engineering radionuclide containing materials through utilization of unprecedented MOF modularity, which cannot be replicated in any other type of materials. Through the implementation of recent synthetic advances in the MOF field, hierarchical complexity of An-materials were built stepwise, which was only feasible due to preparation of the first examples of actinide-based frameworks with “unsaturated” metal nodes. The first successfulmore » attempts of solid-state metathesis and metal node extension in An-MOFs are reported, and the results of the former approach revealed drastic differences in chemical behavior of extended structures versus molecular species. Successful utilization of MOF modularity also allowed us to structurally characterize the first example of bimetallic An-An nodes. To the best of our knowledge, through combination of solid-state metathesis, guest incorporation, and capping linker installation, we were able to achieve the highest Th wt% in mono- and bi-actinide frameworks with minimal structural density. Overall, combination of a multistep synthetic approach with homogeneous actinide distribution and moderate solvothermal conditions could make MOFs an exceptionally powerful tool to address fundamental questions responsible for chemical behavior of An-based extended structures, and therefore, shed light on possible optimization of nuclear waste administration.« less

Multifaceted Modularity: A Key for Stepwise Building of Hierarchical Complexity in Actinide Metal-Organic Frameworks.

PubMed

Dolgopolova, Ekaterina A; Ejegbavwo, Otega A; Martin, Corey R; Smith, Mark D; Setyawan, Wahyu; Karakalos, Stavros G; Henager, Charles H; Zur Loye, Hans-Conrad; Shustova, Natalia B

2017-11-22

Growing necessity for efficient nuclear waste management is a driving force for development of alternative architectures toward fundamental understanding of mechanisms involved in actinide (An) integration inside extended structures. In this manuscript, metal-organic frameworks (MOFs) were investigated as a model system for engineering radionuclide containing materials through utilization of unprecedented MOF modularity, which cannot be replicated in any other type of materials. Through the implementation of recent synthetic advances in the MOF field, hierarchical complexity of An-materials was built stepwise, which was only feasible due to preparation of the first examples of actinide-based frameworks with "unsaturated" metal nodes. The first successful attempts of solid-state metathesis and metal node extension in An-MOFs are reported, and the results of the former approach revealed drastic differences in chemical behavior of extended structures versus molecular species. Successful utilization of MOF modularity also allowed us to structurally characterize the first example of bimetallic An-An nodes. To the best of our knowledge, through combination of solid-state metathesis, guest incorporation, and capping linker installation, we were able to achieve the highest Th wt % in mono- and biactinide frameworks with minimal structural density. Overall, the combination of a multistep synthetic approach with homogeneous actinide distribution and moderate solvothermal conditions could make MOFs an exceptionally powerful tool to address fundamental questions responsible for chemical behavior of An-based extended structures and, therefore, shed light on possible optimization of nuclear waste administration.

Chemically Active, Porous 3D-Printed Thermoplastic Composites.

PubMed

Evans, Kent A; Kennedy, Zachary C; Arey, Bruce W; Christ, Josef F; Schaef, Herbert T; Nune, Satish K; Erikson, Rebecca L

2018-05-02

Metal-organic frameworks (MOFs) exhibit exceptional properties and are widely investigated because of their structural and functional versatility relevant to catalysis, separations, and sensing applications. However, their commercial or large-scale application is often limited by their powder forms which make integration into devices challenging. Here, we report the production of MOF-thermoplastic polymer composites in well-defined and customizable forms and with complex internal structural features accessed via a standard three-dimensional (3D) printer. MOFs (zeolitic imidazolate framework; ZIF-8) were incorporated homogeneously into both poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU) matrices at high loadings (up to 50% by mass), extruded into filaments, and utilized for on-demand access to 3D structures by fused deposition modeling. Printed, rigid PLA/MOF composites display a large surface area (SA avg = 531 m 2 g -1 ) and hierarchical pore features, whereas flexible TPU/MOF composites achieve a high surface area (SA avg = 706 m 2 g -1 ) by employing a simple method developed to expose obstructed micropores postprinting. Critically, embedded particles in the plastic matrices retain their ability to participate in chemical interactions characteristic of the parent framework. The fabrication strategies were extended to other MOFs and illustrate the potential of 3D printing to create unique porous and high surface area chemically active structures.

IM-19: a new flexible microporous gallium based-MOF framework with pressure- and temperature-dependent openings.

PubMed

Chaplais, Gérald; Simon-Masseron, Angélique; Porcher, Florence; Lecomte, Claude; Bazer-Bachi, Delphine; Bats, Nicolas; Patarin, Joël

2009-07-14

Five metal-organic frameworks (MOFs) based on the same three-dimensional gallium terephthalate network (IM-19) are described, and an incommensurate structure (for the as-synthesized form) as well as two remarkable guest-free polymorphs (open and closed) are highlighted.

On the electrochemical deposition of metal–organic frameworks

DOE PAGES

Campagnol, Nicolo; Van Assche, Tom R. C.; Li, Minyuan; ...

2016-02-11

In this paper we study and compare the anodic and cathodic electrodeposition of Metal–Organic Frameworks (MOFs) and suggest guidelines for the electrodeposition of new MOFs with this technique. KHUST-1 was electrodeposited both anodically and cathodically and a four step mechanism is proposed to explain the anodic synthesis.

A high surface area Zr(IV)-based metal–organic framework showing stepwise gas adsorption and selective dye uptake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lv, Xiu-Liang; Tong, Minman; Huang, Hongliang

2015-03-15

Exploitation of new metal–organic framework (MOF) materials with high surface areas has been attracting great attention in related research communities due to their broad potential applications. In this work, a new Zr(IV)-based MOF, [Zr{sub 6}O{sub 4}(OH){sub 4}(eddb){sub 6}] (BUT-30, H{sub 2}eddb=4,4′-(ethyne-1,2-diyl)dibenzoic acid) has been solvothermally synthesized, characterized, and explored for gases and dyes adsorptions. Single-crystal X-ray diffraction analysis demonstrates a three-dimensional cubic framework structure of this MOF, in which each Zr{sub 6}O{sub 4}(OH){sub 4} building unit is linked by 12 linear eddb ligands. BUT-30 has been found stable up to 400 °C and has a Brunauer–Emmett–Teller (BET) surface area asmore » high as 3940.6 m{sup 2} g{sup −1} (based on the N{sub 2} adsorption at 77 K) and total pore volume of 1.55 cm{sup 3} g{sup −1}. It is more interesting that this MOF exhibits stepwise adsorption behaviors for Ar, N{sub 2}, and CO{sub 2} at low temperatures, and selective uptakes towards different ionic dyes. - Graphical abstract: A new Zr(IV)-based MOF with high surface area has been synthesized and structurally characterized, which shows stepwise gas adsorption at low temperature and selective dye uptake from solution. - Highlights: • A new Zr-based MOF was synthesized and structurally characterized. • This MOF shows a higher surface area compared with its analogous UiO-67 and 68. • This MOF shows a rare stepwise adsorption towards light gases at low temperature. • This MOF performs selective uptakes towards cationic dyes over anionic ones. • Using triple-bond spacer is confirmed feasible in enhancing MOF surface areas.« less

UiO-66-NH2 Metal-Organic Framework (MOF) Nucleation on TiO2, ZnO, and Al2O3 Atomic Layer Deposition-Treated Polymer Fibers: Role of Metal Oxide on MOF Growth and Catalytic Hydrolysis of Chemical Warfare Agent Simulants.

PubMed

Lee, Dennis T; Zhao, Junjie; Oldham, Christopher J; Peterson, Gregory W; Parsons, Gregory N

2017-12-27

Metal-organic frameworks (MOFs) chemically bound to polymeric microfibrous textiles show promising performance for many future applications. In particular, Zr-based UiO-66-family MOF-textiles have been shown to catalytically degrade highly toxic chemical warfare agents (CWAs), where favorable MOF/polymer bonding and adhesion are attained by placing a nanoscale metal-oxide layer on the polymer fiber preceding MOF growth. To date, however, the nucleation mechanism of Zr-based MOFs on different metal oxides and how product performance is affected are not well understood. Herein, we provide new insight into how different inorganic nucleation films (i.e., Al 2 O 3 , ZnO, or TiO 2 ) conformally coated on polypropylene (PP) nonwoven textiles via atomic layer deposition (ALD) influence the quality, overall surface area, and the fractional yield of UiO-66-NH 2 MOF crystals solvothermally grown on fiber substrates. Of the materials explored, we find that TiO 2 ALD layers lead to the most effective overall MOF/fiber adhesion, uniformity, and a rapid catalytic degradation rate for a CWA simulant, dimethyl p-nitrophenyl phosphate (DMNP) with t 1/2 = 15 min, 580-fold faster than the catalytic performance of untreated PP textiles. Interestingly, compared to ALD TiO 2 and Al 2 O 3 , ALD ZnO induces a larger MOF yield in solution and mass loading on PP fibrous mats. However, this larger MOF yield is ascribed to chemical instability of the ZnO layer under MOF formation condition, leading to Zn 2+ ions that promote further homogeneous MOF growth. Insights presented here improve understanding of compatibility between active MOF materials and substrate surfaces, which we believe will help advanced MOF composite materials for a variety of useful functions.

Smart Nanocomposites of Cu-Hemin Metal-Organic Frameworks for Electrochemical Glucose Biosensing

PubMed Central

He, Juan; Yang, Han; Zhang, Yayun; Yu, Jie; Miao, Longfei; Song, Yonghai; Wang, Li

2016-01-01

Herein, a smart porous material, Cu-hemin metal-organic-frameworks (Cu-hemin MOFs), was synthesized via assembling of Cu2+ with hemin to load glucose oxidase (GOD) for electrochemical glucose biosensing for the first time. The formation of the Cu-hemin MOFs was verified by scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, N2 adsorption/desorption isotherms, UV-vis absorption spectroscopy, fluorescence spectroscopy, thermal analysis and electrochemical techniques. The results indicated that the Cu-hemin MOFs showed a ball-flower-like hollow cage structure with a large specific surface area and a large number of mesopores. A large number of GOD molecules could be successfully loaded in the pores of Cu-hemin MOFs to keep their bioactivity just like in a solution. The GOD/Cu-hemin MOFs exhibited both good performance toward oxygen reduction reaction via Cu-hemin MOFs and catalytic oxidation of glucose via GOD, superior to other GOD/MOFs and GOD/nanomaterials. Accordingly, the performance of GOD/Cu-hemin MOFs-based electrochemical glucose sensor was enhanced greatly, showing a wide linear range from 9.10 μM to 36.0 mM and a low detection limit of 2.73 μM. Moreover, the sensor showed satisfactory results in detection of glucose in human serum. This work provides a practical design of new electrochemical sensing platform based on MOFs and biomolecules. PMID:27811998

Recent Progress in Metal-Organic Frameworks and Their Derived Nanostructures for Energy and Environmental Applications.

PubMed

Xie, Zhiqiang; Xu, Wangwang; Cui, Xiaodan; Wang, Ying

2017-04-22

Metal-organic frameworks (MOFs), as a very promising category of porous materials, have attracted increasing interest from research communities due to their extremely high surface areas, diverse nanostructures, and unique properties. In recent years, there is a growing body of evidence to indicate that MOFs can function as ideal templates to prepare various nanostructured materials for energy and environmental cleaning applications. Recent progress in the design and synthesis of MOFs and MOF-derived nanomaterials for particular applications in lithium-ion batteries, sodium-ion batteries, supercapacitors, dye-sensitized solar cells, and heavy-metal-ion detection and removal is reviewed herein. In addition, the remaining major challenges in the above fields are discussed and some perspectives for future research efforts in the development of MOFs are also provided. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single Pt Atoms Confined into a Metal-Organic Framework for Efficient Photocatalysis.

PubMed

Fang, Xinzuo; Shang, Qichao; Wang, Yu; Jiao, Long; Yao, Tao; Li, Yafei; Zhang, Qun; Luo, Yi; Jiang, Hai-Long

2018-02-01

It is highly desirable yet remains challenging to improve the dispersion and usage of noble metal cocatalysts, beneficial to charge transfer in photocatalysis. Herein, for the first time, single Pt atoms are successfully confined into a metal-organic framework (MOF), in which electrons transfer from the MOF photosensitizer to the Pt acceptor for hydrogen production by water splitting under visible-light irradiation. Remarkably, the single Pt atoms exhibit a superb activity, giving a turnover frequency of 35 h -1 , ≈30 times that of Pt nanoparticles stabilized by the same MOF. Ultrafast transient absorption spectroscopy further unveils that the single Pt atoms confined into the MOF provide highly efficient electron transfer channels and density functional theory calculations indicate that the introduction of single Pt atoms into the MOF improves the hydrogen binding energy, thus greatly boosting the photocatalytic H 2 production activity. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supercapacitors of nanocrystalline metal-organic frameworks.

PubMed

Choi, Kyung Min; Jeong, Hyung Mo; Park, Jung Hyo; Zhang, Yue-Biao; Kang, Jeung Ku; Yaghi, Omar M

2014-07-22

The high porosity of metal-organic frameworks (MOFs) has been used to achieve exceptional gas adsorptive properties but as yet remains largely unexplored for electrochemical energy storage devices. This study shows that MOFs made as nanocrystals (nMOFs) can be doped with graphene and successfully incorporated into devices to function as supercapacitors. A series of 23 different nMOFs with multiple organic functionalities and metal ions, differing pore sizes and shapes, discrete and infinite metal oxide backbones, large and small nanocrystals, and a variety of structure types have been prepared and examined. Several members of this series give high capacitance; in particular, a zirconium MOF exhibits exceptionally high capacitance. It has the stack and areal capacitance of 0.64 and 5.09 mF cm(-2), about 6 times that of the supercapacitors made from the benchmark commercial activated carbon materials and a performance that is preserved over at least 10000 charge/discharge cycles.

A novel hybrid metal-organic framework-polymeric monolith for solid-phase microextraction.

PubMed

Lin, Chen-Lan; Lirio, Stephen; Chen, Ya-Ting; Lin, Chia-Her; Huang, Hsi-Ya

2014-03-17

This study describes the fabrication of a novel hybrid metal-organic framework- organic polymer (MOF-polymer) for use as a stationary phase in fritless solid-phase microextraction (SPME) for validating analytical methods. The MOF-polymer was prepared by using ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and an imidazolium-based ionic liquid as porogenic solvent followed by microwave-assisted polymerization with the addition of 25 % MOF. This novel hybrid MOF-polymer was used to extract penicillin (penicillin G, penicillin V, oxacillin, cloxacillin, nafcillin, dicloxacillin) under different conditions. Quantitative analysis of the extracted penicillin samples using the MOF-organic polymer for SPME was conducted by using capillary electrochromatography (CEC) coupled with UV analysis. The penicillin recovery was 63-96.2 % with high reproducibility, sensitivity, and reusability. The extraction time with the proposed fabricated SPME was only 34 min. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Centimetre-scale micropore alignment in oriented polycrystalline metal-organic framework films via heteroepitaxial growth.

PubMed

Falcaro, Paolo; Okada, Kenji; Hara, Takaaki; Ikigaki, Ken; Tokudome, Yasuaki; Thornton, Aaron W; Hill, Anita J; Williams, Timothy; Doonan, Christian; Takahashi, Masahide

2017-03-01

The fabrication of oriented, crystalline films of metal-organic frameworks (MOFs) is a critical step toward their application to advanced technologies such as optics, microelectronics, microfluidics and sensing. However, the direct synthesis of MOF films with controlled crystalline orientation remains a significant challenge. Here we report a one-step approach, carried out under mild conditions, that exploits heteroepitaxial growth for the rapid fabrication of oriented polycrystalline MOF films on the centimetre scale. Our methodology employs crystalline copper hydroxide as a substrate and yields MOF films with oriented pore channels on scales that primarily depend on the dimensions of the substrate. To demonstrate that an anisotropic crystalline morphology can translate to a functional property, we assembled a centimetre-scale MOF film in the presence of a dye and showed that the optical response could be switched 'ON' or 'OFF' by simply rotating the film.

High-internal-phase emulsions stabilized by metal-organic frameworks and derivation of ultralight metal-organic aerogels

PubMed Central

Zhang, Bingxing; Zhang, Jianling; Liu, Chengcheng; Peng, Li; Sang, Xinxin; Han, Buxing; Ma, Xue; Luo, Tian; Tan, Xiuniang; Yang, Guanying

2016-01-01

To design high-internal-phase emulsion (HIPE) systems is of great interest from the viewpoints of both fundamental researches and practical applications. Here we demonstrate for the first time the utilization of metal-organic framework (MOF) for HIPE formation. By stirring the mixture of water, oil and MOF at room temperature, the HIPE stabilized by the assembly of MOF nanocrystals at oil-water interface could be formed. The MOF-stabilized HIPE provides a novel route to produce highly porous metal-organic aerogel (MOA) monolith. After removing the liquids from the MOF-stabilized HIPE, the ultralight MOA with density as low as 0.01 g·cm−3 was obtained. The HIPE approach for MOA formation has unique advantages and is versatile in producing different kinds of ultralight MOAs with tunable porosities and structures. PMID:26892258

Remote Stabilization of Copper Paddlewheel Based Molecular Building Blocks in Metal-Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Wen-Yang; Cai, Rong; Pham, Tony

Copper paddlewheel based molecular building blocks (MBBs) are ubiquitous and have been widely employed for the construction of highly porous metal–organic frameworks (MOFs). However, most copper paddlewheel based MOFs fail to retain their structural integrity in the presence of water. This instability is directly correlated to the plausible displacement of coordinating carboxylates in the copper paddlewheel MBB, [Cu₂(O₂C-)₄], by the strongly coordinating water molecules. In this comprehensive study, we illustrate the chemical stability control in the rht-MOF platform via strengthening the coordinating bonds within the triangular inorganic MBB, [Cu₃O(N 4–x(CH) xC-)₃] (x = 0, 1, or 2). Remotely, the chemicalmore » stabilization propagated into the paddlewheel MBB to afford isoreticular rht-MOFs with remarkably enhanced water/chemical stabilities compared to the prototypal rht-MOF-1.« less

Guest-Induced Switchable Breathing Behavior in a Flexible Metal-Organic Framework with Pronounced Negative Gas Pressure.

PubMed

Shi, Yi-Xiang; Li, Wu-Xiang; Zhang, Wen-Hua; Lang, Jian-Ping

2018-06-29

Flexible metal-organic frameworks (MOFs) have attracted great interest for their dynamically structural transformability in response to external stimuli. Herein, we report a switchable "breathing" or "gate-opening" behavior associated with the phase transformation between a narrow pore (np) and a large pore (lp) in a flexible pillared-layered MOF, denoted as MOF-1 as, which is also confirmed by SCXRD and PXRD. The desolvated phase (MOF-1 des) features a unique stepwise adsorption isotherm for N 2 coupled with a pronounced negative gas adsorption pressure. For comparison, however, no appreciable CO 2 adsorption and gate-opening phenomenon with stepwise sorption can be observed. Furthermore, the polar micropore walls decorated with thiophene groups in MOF-1 des reveals the selective sorption of toluene over benzene and p-xylene associated with self-structural adjustment in spite of the markedly similar physicochemical properties of these vapor molecules.

Highly stable aluminum-based metal-organic frameworks as biosensing platforms for assessment of food safety.

PubMed

Liu, Chun-Sen; Sun, Chun-Xiao; Tian, Jia-Yue; Wang, Zhuo-Wei; Ji, Hong-Fei; Song, Ying-Pan; Zhang, Shuai; Zhang, Zhi-Hong; He, Ling-Hao; Du, Miao

2017-05-15

Two unique immunosensors made of aluminum-based metal-organic frameworks (MOFs), namely, 515- and 516-MOFs, with 4,4',4''-nitrilotribenzoic acid (H 3 NTB) were successfully obtained to efficiently assess food safety. The as-prepared 515- and 516-MOFs exhibited superior thermal and physicochemical stability, high electrochemical activity, and good biocompatibility. Among these immunosensors, 516-MOF showed a preferable biosensing ability toward analytes determined by electrochemical techniques. The developed 516-MOF-based electrochemical biosensor not only demonstrated high sensitivity with low detection limits of 0.70 and 0.40pgmL -1 toward vomitoxin and salbutamol, respectively, but also showed good selectivity in the presence of other interferences. Therefore, with the advantages of high sensitivity, good selectivity, and simple operation, this new strategy is believed to exhibit great potential for simple and convenient detection of poisonous and harmful residues in food. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrogen sensing properties of nanocomposite graphene oxide/Co-based metal organic frameworks (Co-MOFs@GO)

NASA Astrophysics Data System (ADS)

Fardindoost, Somayeh; Hatamie, Shadie; Iraji Zad, Azam; Razi Astaraei, Fatemeh

2018-01-01

This paper reports on hydrogen sensing based graphene oxide hybrid with Co-based metal organic frameworks (Co-MOFs@GO) prepared by the hydrothermal process. The texture and morphology of the hybrid were characterized by powder x-ray diffraction, scanning electron microscopy and Brunauer-Emmett-Teller analysis. Porous flower like structures assembled from Co-MOFs and GO flakes with sufficient specific surface area are obtained, which are ideal for gas molecules diffusion and interactions. Sensing performance of Co-MOFs@GO were tested and also improved by sputtering platinum (Pt) as a catalyst. The Pt-sputtered Co-MOFs@GO show outstanding hydrogen resistive-sensing with response and recovery times below 12 s at 15 °C. Also, they show stable, repeatable and selective responses to the target gas which make it suitable for the development of a high performance hydrogen sensor.

Molecular Building Block-Based Electronic Charges for High-Throughput Screening of Metal-Organic Frameworks for Adsorption Applications.

PubMed

Argueta, Edwin; Shaji, Jeena; Gopalan, Arun; Liao, Peilin; Snurr, Randall Q; Gómez-Gualdrón, Diego A

2018-01-09

Metal-organic frameworks (MOFs) are porous crystalline materials with attractive properties for gas separation and storage. Their remarkable tunability makes it possible to create millions of MOF variations but creates the need for fast material screening to identify promising structures. Computational high-throughput screening (HTS) is a possible solution, but its usefulness is tied to accurate predictions of MOF adsorption properties. Accurate adsorption simulations often require an accurate description of electrostatic interactions, which depend on the electronic charges of the MOF atoms. HTS-compatible methods to assign charges to MOF atoms need to accurately reproduce electrostatic potentials (ESPs) and be computationally affordable, but current methods present an unsatisfactory trade-off between computational cost and accuracy. We illustrate a method to assign charges to MOF atoms based on ab initio calculations on MOF molecular building blocks. A library of building blocks with built-in charges is thus created and used by an automated MOF construction code to create hundreds of MOFs with charges "inherited" from the constituent building blocks. The molecular building block-based (MBBB) charges are similar to REPEAT charges-which are charges that reproduce ESPs obtained from ab initio calculations on crystallographic unit cells of nanoporous crystals-and thus similar predictions of adsorption loadings, heats of adsorption, and Henry's constants are obtained with either method. The presented results indicate that the MBBB method to assign charges to MOF atoms is suitable for use in computational high-throughput screening of MOFs for applications that involve adsorption of molecules such as carbon dioxide.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, Jun-Sheng; Yuan, Shuai; Lollar, Christina

Recent years have witnessed the exploration and synthesis of an increasing number of metal–organic frameworks (MOFs). The utilization of stable MOFs as a platform for catalysis and biomimetics is discussed.

A New Class of Metal-Cyclam-Based Zirconium Metal–Organic Frameworks for CO 2 Adsorption and Chemical Fixation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Jie; Usov, Pavel M.; Xu, Wenqian

Metal–organic frameworks (MOFs) have shown great promise in catalysis, mainly due to their high content of active centers, large internal surface areas, tunable pore size, and versatile chemical functionalities. However, it is a challenge to rationally design and construct MOFs that can serve as highly stable and reusable heterogeneous catalysts. Here two new robust 3D porous metal-cyclam-based zirconium MOFs, denoted VPI-100 (Cu) and VPI-100 (Ni), have been prepared by a modulated synthetic strategy. The frameworks are assembled by eight-connected Zr 6 clusters and metallocyclams as organic linkers. Importantly, the cyclam core has accessible axial coordination sites for guest interactions andmore » maintains the electronic properties exhibited by the parent cyclam ring. The VPI-100 MOFs exhibit excellent chemical stability in various organic and aqueous solvents over a wide pH range and show high CO 2 uptake capacity (up to ~9.83 wt% adsorption at 273 K under 1 atm). Moreover, VPI-100 MOFs demonstrate some of the highest reported catalytic activity values (turnover frequency and conversion efficiency) among Zr-based MOFs for the chemical fixation of CO 2 with epoxides, including sterically hindered epoxides. Thus, the MOFs, which bear dual catalytic sites (Zr and Cu/Ni), enable chemistry not possible with the cyclam ligand under the same conditions and can be used as recoverable stable heterogeneous catalysts without losing performance.« less

A New Class of Metal-Cyclam-Based Zirconium Metal–Organic Frameworks for CO 2 Adsorption and Chemical Fixation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Jie; Usov, Pavel M.; Xu, Wenqian

Metal-organic frameworks (MOFs) have shown great promise in catalysis, mainly due to their high content of active centers, large internal surface areas, tunable pore size, and versatile chemical functionalities. However, it is a challenge to rationally design and construct MOFs that can serve as highly stable and reusable heterogeneous catalysts. Here two new robust 3D porous metal-cyclam-based zirconium MOFs, denoted VPI-100 (Cu) and VPI-100 (Ni), have been prepared by a modulated synthetic strategy. The frameworks are assembled by eight-connected Zr-6 clusters and metallocyclams as organic linkers. Importantly, the cyclam core has accessible axial coordination sites for guest interactions and maintainsmore » the electronic properties exhibited by the parent cyclam ring. The VPI-100 MOFs exhibit excellent chemical stability in various organic and aqueous solvents over a wide pH range and show high CO2 uptake capacity (up to similar to 9.83 wt% adsorption at 273 K under 1 atm). Moreover, VPI-100 MOFs demonstrate some of the highest reported catalytic activity values (turnover frequency and conversion efficiency) among Zr-based MOFs for the chemical fixation of CO2 with epoxides, including sterically hindered epoxides. The MOFs, which bear dual catalytic sites (Zr and Cu/Ni), enable chemistry not possible with the cyclam ligand under the same conditions and can be used as recoverable stable heterogeneous catalysts without losing performance.« less

A New Class of Metal-Cyclam-Based Zirconium Metal–Organic Frameworks for CO 2 Adsorption and Chemical Fixation

DOE PAGES

Zhu, Jie; Usov, Pavel M.; Xu, Wenqian; ...

2017-12-22

Metal–organic frameworks (MOFs) have shown great promise in catalysis, mainly due to their high content of active centers, large internal surface areas, tunable pore size, and versatile chemical functionalities. However, it is a challenge to rationally design and construct MOFs that can serve as highly stable and reusable heterogeneous catalysts. Here two new robust 3D porous metal-cyclam-based zirconium MOFs, denoted VPI-100 (Cu) and VPI-100 (Ni), have been prepared by a modulated synthetic strategy. The frameworks are assembled by eight-connected Zr 6 clusters and metallocyclams as organic linkers. Importantly, the cyclam core has accessible axial coordination sites for guest interactions andmore » maintains the electronic properties exhibited by the parent cyclam ring. The VPI-100 MOFs exhibit excellent chemical stability in various organic and aqueous solvents over a wide pH range and show high CO 2 uptake capacity (up to ~9.83 wt% adsorption at 273 K under 1 atm). Moreover, VPI-100 MOFs demonstrate some of the highest reported catalytic activity values (turnover frequency and conversion efficiency) among Zr-based MOFs for the chemical fixation of CO 2 with epoxides, including sterically hindered epoxides. Thus, the MOFs, which bear dual catalytic sites (Zr and Cu/Ni), enable chemistry not possible with the cyclam ligand under the same conditions and can be used as recoverable stable heterogeneous catalysts without losing performance.« less

A supermolecular building approach for the design and construction of metal-organic frameworks.

PubMed

Guillerm, Vincent; Kim, Dongwook; Eubank, Jarrod F; Luebke, Ryan; Liu, Xinfang; Adil, Karim; Lah, Myoung Soo; Eddaoudi, Mohamed

2014-08-21

In this review, we describe two recently implemented conceptual approaches facilitating the design and deliberate construction of metal–organic frameworks (MOFs), namely supermolecular building block (SBB) and supermolecular building layer (SBL) approaches. Our main objective is to offer an appropriate means to assist/aid chemists and material designers alike to rationally construct desired functional MOF materials, made-to-order MOFs. We introduce the concept of net-coded building units (net-cBUs), where precise embedded geometrical information codes uniquely and matchlessly a selected net, as a compelling route for the rational design of MOFs. This concept is based on employing pre-selected 0-periodic metal–organic polyhedra or 2-periodic metal–organic layers, SBBs or SBLs respectively, as a pathway to access the requisite net-cBUs. In this review, inspired by our success with the original rht-MOF, we extrapolated our strategy to other known MOFs via their deconstruction into more elaborate building units (namely polyhedra or layers) to (i) elucidate the unique relationship between edge-transitive polyhedra or layers and minimal edge-transitive 3-periodic nets, and (ii) illustrate the potential of the SBB and SBL approaches as a rational pathway for the design and construction of 3-periodic MOFs. Using this design strategy, we have also identified several new hypothetical MOFs which are synthetically targetable.

Robust and Porous β-Diketiminate-Functionalized Metal–Organic Frameworks for Earth-Abundant-Metal-Catalyzed C–H Amination and Hydrogenation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thacker, Nathan C.; Lin, Zekai; Zhang, Teng

We have designed a strategy for postsynthesis installation of the β-diketiminate (NacNac) functionality in a metal–organic framework (MOF) of UiO-topology. Metalation of the NacNac-MOF (I) with earth-abundant metal salts afforded the desired MOF-supported NacNac-M complexes (M = Fe, Cu, and Co) with coordination environments established by detailed EXAFS studies. The NacNac-Fe-MOF catalyst, I•Fe(Me), efficiently catalyzed the challenging intramolecular sp 3 C–H amination of a series of alkyl azides to afford α-substituted pyrrolidines. The NacNac-Cu-MOF catalyst, I•Cu(THF), was effective in promoting the intermolecular sp 3 C–H amination of cyclohexene using unprotected anilines to provide access to secondary amines in excellent selectivity.more » Finally, the NacNac-Co-MOF catalyst, I•Co(H), was used to catalyze alkene hydrogenation with turnover numbers (TONs) as high as 700 000. All of the NacNac-M-MOF catalysts were more effective than their analogous homogeneous catalysts and could be recycled and reused without a noticeable decrease in yield. The NacNac-MOFs thus provide a novel platform for engineering recyclable earth-abundant-element-based single-site solid catalysts for many important organic transformations.« less

Combi-metal organic framework (Combi-MOF) of α-amylase and glucoamylase for one pot starch hydrolysis.

PubMed

Salgaonkar, Manish; Nadar, Shamraja S; Rathod, Virendra K

2018-07-01

The multi-enzyme biocatalyst allows to run in vitro multi-step cascade reactions in single pot. An efficient combi-metal organic frameworks (combi-MOF) of α-amylase and glucoamylase for one pot starch hydrolysis was constructed by mixing zinc acetate and 2‑methylimmidazole with enzyme mixture in one pot under biocompatible conditions. The prepared combi-MOF was characterized and analyzed by powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Thermo-stability was evaluated for combi-MOF in the range of 55 to 75°C which showed three folds improved stability in terms of half-life. In kinetic parameter studies, rate of starch hydrolysis (V max ) of combi-MOF was found to be enhanced after co-immobilization. Further, combi-MOF was recycled in batch mode which retained up to 52% residual activity after five successive cycles of reuse. In addition to that, combi-MOF exhibited extraordinary storage stability till 24days. At the end, starch hydrolytic activity of combi-MOF was tested for different sources of starch (corn, rice, wheat and potato) which exhibited higher rate of hydrolysis than mixture of free enzymes due to spatially co-localized multi-enzymatic systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Crystal Engineering of an nbo Topology Metal-Organic Framework for Chemical Fixation of CO₂ under Ambient Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Wen-Yang; Chen, Yao; Niu, Youhong

Crystal engineering of the nbo metal–organic framework (MOF) platform MOF-505 with a custom-designed azamacrocycle ligand (1,4,7,10-tetrazazcyclododecane-N,N',N'',N'''-tetra-p-methylbenzoic acid) leads to a high density of well-oriented Lewis active sites within the cuboctahedral cage in MMCF-2, [Cu₂(Cu-tactmb)(H₂O)₃(NO₃)₂]. This MOF demonstrates high catalytic activity for the chemical fixation of CO₂ into cyclic carbonates at room temperature under 1 atm pressure.

Review of Peer Evaluation Research

DTIC Science & Technology

1978-10-01

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Photocatalytic Performance of a Novel MOF/BiFeO₃ Composite.

PubMed

Si, Yunhui; Li, Yayun; Zou, Jizhao; Xiong, Xinbo; Zeng, Xierong; Zhou, Ji

2017-10-10

In this study, MOF/BiFeO₃ composite (MOF, metal-organic framework) has been synthesized successfully through a one-pot hydrothermal method. The MOF/BiFeO₃ composite samples, pure MOF samples and BiFeO₃ samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and by UV-vis spectrophotometry. The results and analysis reveal that MOF/BiFeO₃ composite has better photocatalytic behavior for methylene blue (MB) compared to pure MOF and pure BiFeO₃. The enhancement of photocatalytic performance should be due to the introduction of MOF change the surface morphology of BiFeO 3, which will increase the contact area with MB. This composing strategy of MOF/BiFeO₃ composite may bring new insight into the designing of highly efficient photocatalysts.

Highly Efficient Cooperative Catalysis by Co III (Porphyrin) Pairs in Interpenetrating Metal-Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Zekai; Zhang, Zhi-Ming; Chen, Yu-Sheng

2016-12-02

A series of porous twofold interpenetrated In-Co III(porphyrin) metal–organic frameworks (MOFs) were constructed by in situ metalation of porphyrin bridging ligands and used as efficient cooperative catalysts for the hydration of terminal alkynes. The twofold interpenetrating structure brings adjacent Co III(porphyrins) in the two networks parallel to each other with a distance of about 8.8 Å, an ideal distance for the simultaneous activation of both substrates in alkyne hydration reactions. As a result, the In-Co III(porphyrin) MOFs exhibit much higher (up to 38 times) catalytic activity than either homogeneous catalysts or MOF controls with isolated Co III(porphyrin) centers, thus highlightingmore » the potential application of MOFs in cooperative catalysis.« less

Molecular simulation of separation of CO{sub 2} from flue gases in Cu-BTC metal-organic framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Q.Y.; Xue, C.Y.; Zhong, C.L.

2007-11-15

In this work, a computational study was performed on the adsorption separation of CO{sub 2} from flue gases (mixtures of CO{sub 2}/N{sub 2}/O{sub 2}) in Cu-BTC metal-organic framework (MOF) to investigate the applicability of MOFs to this important industrial system. The computational results showed that Cu-BTC is a promising material for separation of CO{sub 2} from flue gases, and the macroscopic separation behaviors of the MOF were elucidated at a molecular level to give insight into the underlying mechanisms. The present work not only provided useful information for understanding the separation characteristics of MOFs, but also showed their potential applicationsmore » in chemical industry.« less

Facile synthesis of nickel-based metal organic framework [Ni3(HCOO)6] by microwave method and application for supercapacitor

NASA Astrophysics Data System (ADS)

Luo, Jujie; Yang, Xing; Wang, Shumin; Bi, Yuhong; Nautiyal, Amit; Zhang, Xinyu

The metal organic framework (MOF) [Ni3(HCOO)6] was synthesized via the simple and fast microwave method, and the effect of irradiation power on crystallinity of synthesized Ni-based MOF was studied. The samples were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The synthesized Ni-based MOF was electrochemically characterized by using galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques. The synthesized MOF showed the highest specific capacitance of 1196.2F/g at 1A/g with excellent cyclability (86.04% capacitance retention after 2,000 cycles), thereby demonstrating its potential application in supercapacitors.

Chemically Active, Porous 3D-Printed Thermoplastic Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Kent A.; Kennedy, Zachary C.; Arey, Bruce W.

Metal-organic frameworks (MOFs) exhibit exceptional properties and are widely investigated because of their structural and functional versatility relevant to catalysis, separations, and sensing applications. However, their commercial or large-scale application is often limited by their powder forms. To address this, we report the production of MOF-thermoplastic polymer composites accessed via a standard 3D printer. MOFs (Zeolitic imidazolate framework; ZIF-8) were successfully incorporated homogeneously into both poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU) matrices, extruded into filaments, and utilized for on-demand access to 3D structures by fused-deposition modeling. Printed rigid PLA-MOF composites displayed good structural integrity, high surface area ((SA)avg =more » 531 m2 g-1) and hierarchical pore features. Flexible TPU-MOF composites (SAavg = 706 m2 g-1) were achieved by employing a sacrificial fluoropolymer readily removed post-printing. Critically, embedded particles in the plastic matrices retain their ability to participate in chemical interactions characteristic of the parent MOF. The fabrication strategies can be extended to other MOFs and illustrate the potential of 3D printing to create unique porous and high surface area chemically-active structures.« less

Synthesis and Small Molecule Exchange Studies of a Magnesium Bisformate Metal-Organic Framework: An Experiment in Host-Guest Chemistry for the Undergraduate Laboratory

ERIC Educational Resources Information Center

Rood, Jeffrey A.; Henderson, Kenneth W.

2013-01-01

concepts of host-guest chemistry and size exclusion in porous metal-organic frameworks (MOFs). The experiment has been successfully carried out in both introductory and advanced-level inorganic chemistry laboratories. Students synthesized the porous MOF, alpha-Mg[subscript…

Crystal conversion between metal-organic frameworks with different crystal topologies for efficient crystal design on two-dimensional substrates

NASA Astrophysics Data System (ADS)

Tsuruoka, Takaaki; Inoue, Kohei; Miyanaga, Ayumi; Tobiishi, Kaho; Ohhashi, Takashi; Hata, Manami; Takashima, Yohei; Akamatsu, Kensuke

2018-04-01

Crystal conversion of metal-organic frameworks (MOFs) between different crystal topologies on a polymer substrate has been successfully achieved by localized dissolution of MOF crystals followed by a rapid self-assembly of framework components. Upon addition of the desired organic linkers to the reaction system containing MOF crystals on the substrate, reversible crystal conversion between the [Cu2(btc)3]n and [Cu2(ndc)2(dabco)]n frameworks (btc = 1,3,5-benzene tricarboxylate, ndc = 1,4-naphthalene dicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane) could be routinely achieved in high yields. Most surprisingly, in the case of conversion from the [Cu2(ndc)2(dabco)]n to [Cu2(btc)3]n frameworks, the [Cu2(btc)3]n crystals with unique shapes (cuboctahedron and truncated cube) could be prepared using butanol as a reaction medium.

Templated and template-free fabrication strategies for zero-dimensional hollow MOF superstructures.

PubMed

Kim, Hyehyun; Lah, Myoung Soo

2017-05-16

Various fabrication strategies for hollow metal-organic framework (MOF) superstructures are reviewed and classified using various types of external templates and their properties. Hollow MOF superstructures have also been prepared without external templates, wherein unstable intermediates obtained during reactions convert to the final hollow MOF superstructures. Many hollow MOF superstructures have been fabricated using hard templates. After the core-shell core@MOF structure was prepared using a hard template, the core was selectively etched to generate a hollow MOF superstructure. Another approach for generating hollow superstructures is to use a solid reactant as a sacrificial template; this method requires no additional etching process. Soft templates such as discontinuous liquid/emulsion droplets and gas bubbles in a continuous soft phase have also been employed to prepare hollow MOF superstructures.

Synthesis, structural characterization and selectively catalytic properties of metal-organic frameworks with nano-sized channels: A modular design strategy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu Lingguang; Gu Lina; Hu Gang

2009-03-15

Modular design method for designing and synthesizing microporous metal-organic frameworks (MOFs) with selective catalytical activity was described. MOFs with both nano-sized channels and potential catalytic activities could be obtained through self-assembly of a framework unit and a catalyst unit. By selecting hexaaquo metal complexes and the ligand BTC (BTC=1,3,5-benzenetricarboxylate) as framework-building blocks and using the metal complex [M(phen){sub 2}(H{sub 2}O){sub 2}]{sup 2+} (phen=1,10-phenanthroline) as a catalyst unit, a series of supramolecular MOFs 1-7 with three-dimensional nano-sized channels, i.e. [M{sup 1}(H{sub 2}O){sub 6}].[M{sup 2}(phen){sub 2}(H{sub 2}O){sub 2}]{sub 2}.2(BTC).xH{sub 2}O (M{sup 1}, M{sup 2}=Co(II), Ni(II), Cu(II), Zn(II), or Mn(II), phen=1,10-phenanthroline, BTC=1,3,5-benzenetricarboxylate, x=22-24),more » were synthesized through self-assembly, and their structures were characterized by IR, elemental analysis, and single-crystal X-ray diffraction. These supramolecular microporous MOFs showed significant size and shape selectivity in the catalyzed oxidation of phenols, which is due to catalytic reactions taking place in the channels of the framework. Design strategy, synthesis, and self-assembly mechanism for the construction of these porous MOFs were discussed. - Grapical abstract: A modular design strategy has been developed to synthesize microporous metal-organic frameworks with potential catalytic activity by self-assembly of the framework-building blocks and the catalyst unit.« less

Water-Stable In(III)-Based Metal-Organic Frameworks with Rod-Shaped Secondary Building Units: Single-Crystal to Single-Crystal Transformation and Selective Sorption of C2H2 over CO2 and CH4.

PubMed

Guo, Zhen-Ji; Yu, Jiamei; Zhang, Yong-Zheng; Zhang, Jian; Chen, Ya; Wu, Yufeng; Xie, Lin-Hua; Li, Jian-Rong

2017-02-20

Three new water-stable In(III)-based metal-organic frameworks, namely, [In 3 (TTTA) 2 (OH) 3 (H 2 O)]·(DMA) 3 (BUT-70, DMA = N,N-dimethylacetamide), [In 3 (TTTA) 2 (CH 3 O) 3 ] (BUT-70A), and [In 3 (TTTA) 2 (OH) 3 ] (BUT-70B), with rod-shaped secondary building units (SBUs) and an new acrylate-based ligand, (2E,2'E,2″E)-3,3',3″-(2,4,6-trimethylbenzene-1,3,5-triyl)-triacrylate (TTTA 3- ) were obtained and structurally characterized. BUT-70A and -70B were generated in a single-crystal to single-crystal transformation fashion from BUT-70 through guest exchange followed by their removal. The solvents used for guest exchange were methanol and dichloromethane, respectively. Single-crystal structure analyses show that the guest exchange and removal process is accompanied by the substitution of coordinated water molecules of In(III) centers with uncoordinated carboxylate O atoms of TTTA 3- ligands. Moreover, hydroxyl groups bridging two In(III) centers are also replaced by methoxyl groups in the transformation from BUT-70 to -70A. Overall, three metal-organic frameworks (MOFs) are constructed by infinite chains consisting of corner-sharing InO 4 (OR) 2 (R = H or Me) octahedral entities, which are interconnected by TTTA 3- ligands to form three-dimensional frameworks. Unlike most reported MOFs with infinite chains as SBUs, such as well-known MIL-53 and M-MOF-74, which have one-dimensional channels along the chain direction, the BUT-70 series contain two-dimensional intersecting channels. The Brunauer-Emmett-Teller surface area and pore volume of BUT-70A were estimated to be 460 m 2 g -1 and 0.18 cm 3 g -1 , respectively, which are obviously lower than those of BUT-70B (695 m 2 g -1 and 0.29 cm 3 g -1 ). Gas adsorption experiments demonstrated that BUT-70A and -70B are able to selectively adsorb C 2 H 2 over CO 2 and CH 4 . At 1 atm and 298 K, BUT-70A uptakes 3.1 mmol g -1 C 2 H 2 , which is 3.6 times that of the CO 2 uptake and 7.2 times that of the CH 4 uptake. Compared with BUT-70A, BUT-70B presents an even higher C 2 H 2 uptake of 3.9 mmol g -1 at the same conditions, but slightly lower Ideal Adsorbed Solution Theory C 2 H 2 /CO 2 and C 2 H 2 /CH 4 selectivities.

Complex Nanostructures from Materials based on Metal-Organic Frameworks for Electrochemical Energy Storage and Conversion.

PubMed

Guan, Bu Yuan; Yu, Xin Yao; Wu, Hao Bin; Lou, Xiong Wen David

2017-12-01

Metal-organic frameworks (MOFs) have drawn tremendous attention because of their abundant diversity in structure and composition. Recently, there has been growing research interest in deriving advanced nanomaterials with complex architectures and tailored chemical compositions from MOF-based precursors for electrochemical energy storage and conversion. Here, a comprehensive overview of the synthesis and energy-related applications of complex nanostructures derived from MOF-based precursors is provided. After a brief summary of synthetic methods of MOF-based templates and their conversion to desirable nanostructures, delicate designs and preparation of complex architectures from MOFs or their composites are described in detail, including porous structures, single-shelled hollow structures, and multishelled hollow structures, as well as other unusual complex structures. Afterward, their applications are discussed as electrode materials or catalysts for lithium-ion batteries, hybrid supercapacitors, water-splitting devices, and fuel cells. Lastly, the research challenges and possible development directions of complex nanostructures derived from MOF-based-templates for electrochemical energy storage and conversion applications are outlined. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effective Recovery of Vanadium from Oil Refinery Waste into Vanadium-Based Metal-Organic Frameworks.

PubMed

Zhan, Guowu; Ng, Wei Cheng; Lin, Wenlin Yvonne; Koh, Shin Nuo; Wang, Chi-Hwa

2018-03-06

Carbon black waste, an oil refinery waste, contains a high concentration of vanadium(V) leftover from the processing of crude oil. For the sake of environmental sustainability, it is therefore of interest to recover the vanadium as useful products instead of disposing of it. In this work, V was recovered in the form of vanadium-based metal-organic frameworks (V-MOFs) via a novel pathway by using the leaching solution of carbon black waste instead of commercially available vanadium chemicals. Two different types of V-MOFs with high levels of crystallinity and phase purity were fabricated in very high yields (>98%) based on a coordination modulation method. The V-MOFs exhibited well-defined and controlled shapes such as nanofibers (length: > 10 μm) and nanorods (length: ∼270 nm). Furthermore, the V-MOFs showed high catalytic activities for the oxidation of benzyl alcohol to benzaldehyde, indicating the strong potential of the waste-derived V-MOFs in catalysis applications. Overall, our work offers a green synthesis pathway for the preparation of V-MOFs by using heavy metals of industrial waste as the metal source.

Self-Template-Directed Metal-Organic Frameworks Network and the Derived Honeycomb-Like Carbon Flakes via Confinement Pyrolysis.

PubMed

Wang, Jie; Tang, Jing; Ding, Bing; Chang, Zhi; Hao, Xiaodong; Takei, Toshiaki; Kobayashi, Naoya; Bando, Yoshio; Zhang, Xiaogang; Yamauchi, Yusuke

2018-04-01

Metal-organic frameworks (MOFs) have become a research hotspot since they have been explored as convenient precursors for preparing various multifunctional nanomaterials. However, the preparation of MOF networks with controllable flake morphology in large scale is not realized yet. Herein, a self-template strategy is developed to prepare MOF networks. In this work, layered double-metal hydroxide (LDH) and other layered metal hydroxides are used not only as a scaffold but also as a self-sacrificed metal source. After capturing the abundant metal cations identically from the LDH by the organic linkers, MOF networks are in situ formed. It is interesting that the MOF network-derived carbon materials retain the flake morphology and exhibit a unique honeycomb-like macroporous structure due to the confined shrinkage of the polyhedral facets. The overall properties of the carbon networks are adjustable according to the tailored metal compositions in LDH and the derived MOFs, which are desirable for target-oriented applications as exemplified by the electrochemical application in supercapacitors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adsorptive desulfurization with metal-organic frameworks: A density functional theory investigation

NASA Astrophysics Data System (ADS)

Chen, Zhiping; Ling, Lixia; Wang, Baojun; Fan, Huiling; Shangguan, Ju; Mi, Jie

2016-11-01

The contribution of each fragment of metal-organic frameworks (MOFs) to the adsorption of sulfur compounds were investigated using density functional theory (DFT). The involved sulfur compounds are dimethyl sulfide (CH3SCH3), ethyl mercaptan (CH3CH2SH) and hydrogen sulfide (H2S). MOFs with different organic ligands (NH2-BDC, BDC and NDC), metal centers structures (M, M-M and M3O) and metal ions (Zn, Cu and Fe) were used to study their effects on sulfur species adsorption. The results revealed that, MOFs with coordinatively unsaturated sites (CUS) have the strongest binding strength with sulfur compounds, MOFs with NH2-BDC substituent group ligand comes second, followed by that with saturated metal center, and the organic ligands without substituent group has the weakest adsorption strength. Moreover, it was also found that, among different metal ions (Fe, Zn and Cu), MOFs with unsaturated Fe has the strongest adsorption strength for sulfur compounds. These results are consistent with our previous experimental observations, and therefore provide insights on the better design of MOFs for desulfurization application.

Alternative synthetic approaches for metal-organic frameworks: transformation from solid matters.

PubMed

Zhan, Guowu; Zeng, Hua Chun

2016-12-20

Developing economic and sustainable synthetic strategies for metal-organic frameworks (MOFs) is imperative for promoting MOF materials into large scale industrial use. Very recently, an alternative strategy for MOF synthesis by using solvent-insoluble "solid matters" as cation reservoirs and/or templates has been developed to accomplish this goal, in which the solid matters often refer to metals, metal oxides, hydroxides, carbonates, and so forth, but excluding the soluble metal salts which have been prevailingly used in MOF synthesis. Although most of the pioneering activities in this field have just started in the past 5 years, remarkable achievements have been made covering the synthesis, functionalization, positioning, and applications. A great number of MOFs in powder form, thin-films, or membranes, have been prepared through such solid-to-MOF transformations. This field is rapidly developing and expanding, and the number of related scientific publications has strikingly increased over the last few years. The aim of this review is to summarise the latest developments, highlight the present state-of-the-art, and also provide an overview for future research directions.

Robust and conductive two-dimensional metal-organic frameworks with exceptionally high volumetric and areal capacitance

DOE PAGES

Feng, Dawei; Lei, Ting; Lukatskaya, Maria R.; ...

2018-01-01

For miniaturized capacitive energy storage, volumetric and areal capacitances are more important metrics than gravimetric ones because of the constraints imposed by device volume and chip area. Typically used in commercial supercapacitors, porous carbons, although they provide a stable and reliable performance, lack volumetric performance because of their inherently low density and moderate capacitances. In this paper, we report a high-performing electrode based on conductive hexaaminobenzene (HAB)-derived two-dimensional metal-organic frameworks (MOFs). In addition to possessing a high packing density and hierarchical porous structure, these MOFs also exhibit excellent chemical stability in both acidic and basic aqueous solutions, which is inmore » sharp contrast to conventional MOFs. Submillimetre-thick pellets of HAB MOFs showed high volumetric capacitances up to 760 F cm -3 and high areal capacitances over 20 F cm -2. Furthermore, the HAB MOF electrodes exhibited highly reversible redox behaviours and good cycling stability with a capacitance retention of 90% after 12,000 cycles. In conclusion, these promising results demonstrate the potential of using redox-active conductive MOFs in energy-storage applications.« less

Porous Pt-Ni Nanowires within In Situ Generated Metal-Organic Frameworks for Highly Chemoselective Cinnamaldehyde Hydrogenation.

PubMed

Zhang, Nan; Shao, Qi; Wang, Pengtang; Zhu, Xing; Huang, Xiaoqing

2018-05-01

Although chemoselective hydrogenation of unsaturated aldehydes is the major route to highly valuable industrially demanded unsaturated alcohols, it is still challenging, as the production of saturated aldehydes is more favorable over unsaturated alcohols from the view of thermodynamics. By combining the structural features of porous nanowires (NWs) and metal-organic frameworks (MOFs), a unique class of porous Pt-Ni NWs in situ encapsuled by MOFs (Pt-Ni NWs@Ni/Fex-MOFs) is designed to enhance the unsaturated alcohols selectivity in the cinnamaldehyde (CAL) hydrogenation. A detailed catalytic study shows that the porous Pt-Ni NWs@Ni/Fe x -MOFs exhibit volcano-type activity and selectivity in CAL hydrogenation as a function of Fe content. The optimized porous PtNi 2.20 NWs@Ni/Fe 4 -MOF is highly active and selective with 99.5% CAL conversion and 83.3% cinnamyl alcohol selectivity due to the confinement effect, appropriate thickness of MOF and its optimized electronic structure, and excellent durability with negligible activity and selectivity loss after five runs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Robust and conductive two-dimensional metal-organic frameworks with exceptionally high volumetric and areal capacitance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Dawei; Lei, Ting; Lukatskaya, Maria R.

For miniaturized capacitive energy storage, volumetric and areal capacitances are more important metrics than gravimetric ones because of the constraints imposed by device volume and chip area. Typically used in commercial supercapacitors, porous carbons, although they provide a stable and reliable performance, lack volumetric performance because of their inherently low density and moderate capacitances. In this paper, we report a high-performing electrode based on conductive hexaaminobenzene (HAB)-derived two-dimensional metal-organic frameworks (MOFs). In addition to possessing a high packing density and hierarchical porous structure, these MOFs also exhibit excellent chemical stability in both acidic and basic aqueous solutions, which is inmore » sharp contrast to conventional MOFs. Submillimetre-thick pellets of HAB MOFs showed high volumetric capacitances up to 760 F cm -3 and high areal capacitances over 20 F cm -2. Furthermore, the HAB MOF electrodes exhibited highly reversible redox behaviours and good cycling stability with a capacitance retention of 90% after 12,000 cycles. In conclusion, these promising results demonstrate the potential of using redox-active conductive MOFs in energy-storage applications.« less

Gel-based morphological design of zirconium metal-organic frameworks.

PubMed

Bueken, Bart; Van Velthoven, Niels; Willhammar, Tom; Stassin, Timothée; Stassen, Ivo; Keen, David A; Baron, Gino V; Denayer, Joeri F M; Ameloot, Rob; Bals, Sara; De Vos, Dirk; Bennett, Thomas D

2017-05-01

The ability of metal-organic frameworks (MOFs) to gelate under specific synthetic conditions opens up new opportunities in the preparation and shaping of hierarchically porous MOF monoliths, which could be directly implemented for catalytic and adsorptive applications. In this work, we present the first examples of xero- or aerogel monoliths consisting solely of nanoparticles of several prototypical Zr 4+ -based MOFs: UiO-66-X (X = H, NH 2 , NO 2 , (OH) 2 ), UiO-67, MOF-801, MOF-808 and NU-1000. High reactant and water concentrations during synthesis were observed to induce the formation of gels, which were converted to monolithic materials by drying in air or supercritical CO 2 . Electron microscopy, combined with N 2 physisorption experiments, was used to show that irregular nanoparticle packing leads to pure MOF monoliths with hierarchical pore systems, featuring both intraparticle micropores and interparticle mesopores. Finally, UiO-66 gels were shaped into monolithic spheres of 600 μm diameter using an oil-drop method, creating promising candidates for packed-bed catalytic or adsorptive applications, where hierarchical pore systems can greatly mitigate mass transfer limitations.

Structural and Dielectric Properties of Ionic Liquid Doped Metal Organic Framework based Polymer Electrolyte Nanocomposites

NASA Astrophysics Data System (ADS)

Dutta, Rituraj; Kumar, Ashok

2016-10-01

Metal Organic Frameworks (MOFs) are mesoporous materials that can be treated as potential hosts for trapping guest molecules in their pores. Ion conduction and phase behavior dynamics of Ionic Liquids (ILs) can be controlled by tunable interactions of MOFs with the ILs. MOFs incorporated with ionic liquid can be dispersed in the polymers to synthesize polymer electrolyte nanocomposites with high ionic conductivity, electrochemical and thermal stability for applications in energy storage and conversion devices such as rechargeable Li-ion batteries. In the present work we have synthesized Cu-based MOF [Cu3(l,3,5-benzene tricarboxylate)2(H2O)] incorporated with the ionic liquid 1-Butyl-3-methylimidazolium bromide at different weight ratios of MOF and IL. The synthesized MOF-IL composites are dispersed in Poly (ethylene oxide) (PEO). Frequency dependent behavior of permittivity and dielectric loss of the nanocomposites depict the non-Debye dielectric relaxation mechanism. The room temperature Nyquist plots reveal decreasing bulk resistance upto 189 Ω with optimum ionic conductivity of 1.3×10-3S cm-1at maximum doping concentration of IL in the nanocomposite system.

Robust and conductive two-dimensional metal-organic frameworks with exceptionally high volumetric and areal capacitance

NASA Astrophysics Data System (ADS)

Feng, Dawei; Lei, Ting; Lukatskaya, Maria R.; Park, Jihye; Huang, Zhehao; Lee, Minah; Shaw, Leo; Chen, Shucheng; Yakovenko, Andrey A.; Kulkarni, Ambarish; Xiao, Jianping; Fredrickson, Kurt; Tok, Jeffrey B.; Zou, Xiaodong; Cui, Yi; Bao, Zhenan

2018-01-01

For miniaturized capacitive energy storage, volumetric and areal capacitances are more important metrics than gravimetric ones because of the constraints imposed by device volume and chip area. Typically used in commercial supercapacitors, porous carbons, although they provide a stable and reliable performance, lack volumetric performance because of their inherently low density and moderate capacitances. Here we report a high-performing electrode based on conductive hexaaminobenzene (HAB)-derived two-dimensional metal-organic frameworks (MOFs). In addition to possessing a high packing density and hierarchical porous structure, these MOFs also exhibit excellent chemical stability in both acidic and basic aqueous solutions, which is in sharp contrast to conventional MOFs. Submillimetre-thick pellets of HAB MOFs showed high volumetric capacitances up to 760 F cm-3 and high areal capacitances over 20 F cm-2. Furthermore, the HAB MOF electrodes exhibited highly reversible redox behaviours and good cycling stability with a capacitance retention of 90% after 12,000 cycles. These promising results demonstrate the potential of using redox-active conductive MOFs in energy-storage applications.

Flexible and Hierarchical Metal-Organic Framework Composites for High-Performance Catalysis.

PubMed

Huang, Ning; Drake, Hannah; Li, Jialuo; Pang, Jiangdong; Wang, Ying; Yuan, Shuai; Wang, Qi; Cai, Peiyu; Qin, Junsheng; Zhou, Hong-Cai

2018-05-18

The development of new types of porous composite materials is of great significance owing to their potentially improved performance over those of individual components and extensive applications in separation, energy storage, and heterogeneous catalysis. In this work, we integrated mesoporous metal-organic frameworks (MOFs) with macroporous melamine foam (MF) using a one-pot process, generating a series of MOF/MF composite materials with preserved crystallinity, hierarchical porosity, and increased stability over that of melamine foam. The MOF nanocrystals were threaded by the melamine foam networks, resembling a ball-and-stick model overall. As a proof-of-concept study, the resulting MOF/MF composite materials were employed as an effective heterogeneous catalyst for the epoxidation of cholesteryl esters. Combining the advantages of interpenetrative mesoporous and macroporous structures, the MOF/melamine foam composite provided higher dispersibility and more accessibility of catalytic sites, exhibiting excellent catalytic performance. This strategy constitutes an important step forward the development of other MOF composites and exploration of their high-performance catalysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Facile synthesis of glucoamylase embedded metal-organic frameworks (glucoamylase-MOF) with enhanced stability.

PubMed

Nadar, Shamraja S; Rathod, Virendra K

2017-02-01

The self-assembled glucoamylase metal-organic framework (glucoamylase-MOF) was synthesized by facile one-step method within 20min by simply mixing aqueous solution of 2-methylimidazole (160mM), glucoamylase (5mg/mL) and zinc acetate (40mM) at room temperature (28±2°C). The prepared glucoamylase-MOF was characterized by using FT-IR, confocal scanning laser microscopy, XRD and SEM. The robustness and thermal stability of glucoamylase embedded MOF was evaluated in terms of half-life (in the range of 60-80°C) which showed 6 folds increment as against free form. Further, in Michaelis-Menten kinetics studies, glucoamylase entrapped MOF exhibited higher K m value and lower V max value as compared to native enzyme. Moreover, the immobilized glucoamylase exhibited up to 57% of residual activity after six consecutive cycles of reuse, whereas it retained 91% of residual activity till 25days of storage. Finally, the conformational changes occurred after the encapsulation of glucoamylase in the interior of MOF, which was analyzed by using FT-IR data analysis tools. Copyright © 2016 Elsevier B.V. All rights reserved.

Cobalt doping of the MOF-5 framework and its effect on gas-adsorption properties.

PubMed

Botas, Juan A; Calleja, Guillermo; Sánchez-Sánchez, Manuel; Orcajo, M Gisela

2010-04-20

Partial isomorphic substitution of Zn in IRMOF metal clusters by cobalt ions is described for the first time. Specifically, different numbers of Co(2+) ions have been incorporated during solvothermal crystallization into the Zn-based MOF-5 (IRMOF-1) framework, which is one of the most studied MOF materials. The amount of Zn that can be substituted seems to be limited, being no more than 25% of total metal content, that is, no more than one Co atom inside every metal cluster formed by four transition-metal ions, on average. Several characterization techniques, including X-ray diffraction, DR UV-visible spectroscopy, N(2) adsorption isotherms, and thermogravimetrical analysis, strongly support the effective incorporation of Co into the material framework. As-synthesized CoMOF-5 has cobalt ions in octahedral coordination, changing to tetrahedral by simple evacuation, presumably by the removal of two diethylformamide molecules per Co ion. Moreover, the H(2), CH(4), and CO(2) uptake of MOF-5 materials systematically increases with the Co content, particularly at high pressure. Such an increase is moderate anyway, considering that Co is incorporated into unexposed metal sites that are less accessible to gas molecules.

Configurations, band structures and photocurrent responses of 4-(4-oxopyridin-1(4H)-yl)phthalic acid and its metal-organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Xingxiu; Qiu, Xiandeng; Yan, Zhishuo

2016-05-15

4-(4-oxopyridin-1(4 H)-yl)phthalic acid (H{sub 2}L) and three H{sub 2}L-based metal-organic frameworks (MOFs) formulated as ZnL(DPE)(H{sub 2}O)·H{sub 2}O (DPE=(E)-1, 2-di(pyridine −4-yl)ethene) (1), CdL(H{sub 2}O){sub 2} (2) and CdL (3) were synthesized and structurally characterized by single-crystal X-ray diffraction. The free H{sub 2}L ligand shows an enol-form and the L{sup 2−} ligand in the three MOFs exists as the keto-form. Density functional theory (DFT) calculations indicate H{sub 2}L and the three MOFs possess different band structures. Due to the existence of the N-donor, DPE in MOF 1, the conduction band (CB) minimum and band gap of MOF 1 are much lower thanmore » those of H{sub 2}L. And MOF 1 yielded much larger photocurrent density than H{sub 2}L upon visible light illumination. Electrochemical impedance spectroscopy (EIS) shows the interfacial charge transfer impedance in the presence of MOF 1 is lower than that in the presence of H{sub 2}L. The hydrous MOF 2 and the anhydrous MOF 3 are both constructed by Cd(II) and L{sup 2−}, and they can be reversibly transformed to each other. However, MOFs 2 and 3 possess different CB minimums and VB maximums, and their band gaps are much larger than that of MOF 1. - Graphical abstract: The free ligand, 4-(4-oxopyridin-1(4H)-yl)phthalic acid (H{sub 2}L) shows different configuration from its three MOFs, and they possess different band structures. MOF 1 yielded much larger visible-light-driven photocurrent density than H{sub 2}L. The hydrous MOF 2 and the anhydrous MOF 3 can be transformed to each other, and they have larger band gaps than MOF 1.« less

Liquid/vapor-induced reversible dynamic structural transformation of a three-dimensional Cu-based MOF to a one-dimensional MOF showing gate adsorption.

PubMed

Kondo, Atsushi; Suzuki, Takayuki; Kotani, Ryosuke; Maeda, Kazuyuki

2017-05-23

A new 3D metal-organic framework (MOF), in which 2D layers are interlaced to form a 3D architecture, was synthesized by a reaction of Cu(BF 4 ) 2 and 1,3-bis(4-pyridyl)propane (bpp) in a water/1-hexanol solvent system, and the crystal structure of the MOF was successfully solved. The MOF is reversibly transformed to a 1D chain MOF, which shows gate adsorption properties. The dynamic transformation gives crystal size reduction resulting in a slight change in CO 2 adsorption isotherms. The 1D MOF shows selective adsorption/separation properties on benzene and its analogues with similar sizes and shapes (benzene, toluene, and cyclohexane).

Synthesis, characterization and heterogeneous base catalysis of amino functionalized lanthanide metal-organic frameworks

NASA Astrophysics Data System (ADS)

Huang, Jinping; Li, Chunmei; Tao, Lingling; Zhu, Huilin; Hu, Gang

2017-10-01

Lanthanide metal-organic frameworks (Ln-MOFs) are featured by their tolerance to water and dense structure. In this work, an amine-functionalized Ln-MOF was facilely synthesized by coordination of terbium with 2-aminoterephthalic acid under the condition of microwave irradiation. The crystal structure was characterized by single crystal X-ray diffraction, FT-IR, Raman, TG-DTA and XPS analysis. The basic catalytic activity of the NH2-Tb-MOF was evaluated for Knoevenagel condensation and Henry reactions. Apart from the high activity and 100% selectivity to the condensation product, the NH2-Tb-MOF catalyst could be easily recycled and reused owing to the high stability of the MOF framework formed by coordination of Tb3+ with carboxylic groups. Remarkably, the NH2-Tb-MOF exhibited size-selective catalysis to substrates. For the small-sized reactants, it displayed comparable activity to the homogeneous catalyst of aniline owing to the high dispersion of NH2- active sites and the low diffusion limits. However, in the same reaction system, extremely poor activity in Knoevenagel condensation and Henry reaction for the bulky substrate 4-(tert-butyl) benzaldehyde was observed due to the both effects of substitute and inhibition of diffusion into the micropores. Crystal structure analysis provided a mechanistic evidence that the heterogeneous base catalysis arose from the amino groups densely distributed inside the micropores.

Ultrasound assisted combined molecularly imprinted polymer for selective extraction of nicotinamide in human urine and milk samples: Spectrophotometric determination and optimization study.

PubMed

Asfaram, Arash; Ghaedi, Mehrorang; Dashtian, Kheibar

2017-01-01

Ultrasound-assisted dispersive solid phase microextraction followed by UV-vis spectrophotometer (UA-DSPME-UV-vis) was designed for extraction and preconcentration of nicotinamide (vitamin B 3 ) by HKUST-1 metal organic framework (MOF) based molecularly imprinted polymer (MIP). This new material was characterized by FTIR and FE-SEM techniques. The preliminary Plackett-Burman design was used for screening and subsequently the central composite design justifies significant terms and possible construction of mathematical equation which give the individual and cooperative contribution of variables like HKUST-1-MOF-NA-MIP mass, sonication time, temperature, eluent volume, pH and vortex time. Accordingly the optimum condition was set as: 2.0mg HKUST-1-MOF-NA-MIP, 200μL eluent and 5.0min sonication time in center points other variables were determined as the best conditions to reach the maximum recovery of the analyte. The UA-DSPME-UV-vis method performances like excellent linearity (LR), limits of detection (LOD), limits of quantification of 10-5000μgL -1 with R 2 of 0.99, LOD (1.96ngmL -1 ), LOQ (6.53μgL -1 ), respectively show successful and accurate applicability of the present method for monitoring analytes with within- and between-day precision of 0.96-3.38%. The average absolute recoveries of the nicotinamide extracted from the urine, milk and water samples were 95.85-101.27%. Copyright © 2016 Elsevier B.V. All rights reserved.

UiO-66-Type Metal-Organic Framework with Free Carboxylic Acid: Versatile Adsorbents via H-bond for Both Aqueous and Nonaqueous Phases.

PubMed

Song, Ji Yoon; Ahmed, Imteaz; Seo, Pill Won; Jhung, Sung Hwa

2016-10-03

The metal-organic framework (MOF) UiO-66 was synthesized in one step from zirconium chloride and isophthalic acid (IPA), together with the usual link material, terephthalic acid (TPA). UiO-66 with free -COOH can be obtained in a facile way by replacing up to 30% of the TPA with IPA. However, the chemical and thermal stability of the synthesized MOFs decreased with increasing IPA content used in the syntheses, suggesting an increase in the population of imperfect bonds in the MOFs because of the asymmetrical structure of IPA. The obtained MOFs with free -COOH were applied in liquid-phase adsorptions from both water and model fuel to not only estimate the potential applications but also confirm the presence of -COOH in the MOFs. The adsorbed amounts of several organics (triclosan and oxybenzone from water and indole and pyrrole from fuel) increased monotonously with increasing IPA content applied in MOF synthesis (or -COOH in the MOFs). The favorable contribution of free -COOH to adsorption can be explained by H-bonding, and the direction of H-bonds (adsorbates: H donor; MOFs: H acceptor) was confirmed by the adsorption of oxybenzone in a wide pH range. The versatile applications of the MOFs with -COOH in adsorptions from both polar and nonpolar phases are remarkable considering that hydrophobic and hydrophilic adsorbents are generally required for water and fuel purification, respectively. Finally, the presence of free -COOH in the MOFs was confirmed by liquid-phase adsorptions together with general Fourier transform infrared analyses and decreased chemical and thermal stability.

Liquid metal-organic frameworks

NASA Astrophysics Data System (ADS)

Gaillac, Romain; Pullumbi, Pluton; Beyer, Kevin A.; Chapman, Karena W.; Keen, David A.; Bennett, Thomas D.; Coudert, François-Xavier

2017-11-01

Metal-organic frameworks (MOFs) are a family of chemically diverse materials, with applications in a wide range of fields, covering engineering, physics, chemistry, biology and medicine. Until recently, research has focused almost entirely on crystalline structures, yet now a clear trend is emerging, shifting the emphasis onto disordered states, including `defective by design’ crystals, as well as amorphous phases such as glasses and gels. Here we introduce a strongly associated MOF liquid, obtained by melting a zeolitic imidazolate framework. We combine in situ variable temperature X-ray, ex situ neutron pair distribution function experiments, and first-principles molecular dynamics simulations to study the melting phenomenon and the nature of the liquid obtained. We demonstrate from structural, dynamical, and thermodynamical information that the chemical configuration, coordinative bonding, and porosity of the parent crystalline framework survive upon formation of the MOF liquid.

Liquid metal-organic frameworks.

PubMed

Gaillac, Romain; Pullumbi, Pluton; Beyer, Kevin A; Chapman, Karena W; Keen, David A; Bennett, Thomas D; Coudert, François-Xavier

2017-11-01

Metal-organic frameworks (MOFs) are a family of chemically diverse materials, with applications in a wide range of fields, covering engineering, physics, chemistry, biology and medicine. Until recently, research has focused almost entirely on crystalline structures, yet now a clear trend is emerging, shifting the emphasis onto disordered states, including 'defective by design' crystals, as well as amorphous phases such as glasses and gels. Here we introduce a strongly associated MOF liquid, obtained by melting a zeolitic imidazolate framework. We combine in situ variable temperature X-ray, ex situ neutron pair distribution function experiments, and first-principles molecular dynamics simulations to study the melting phenomenon and the nature of the liquid obtained. We demonstrate from structural, dynamical, and thermodynamical information that the chemical configuration, coordinative bonding, and porosity of the parent crystalline framework survive upon formation of the MOF liquid.

Liquid metal–organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaillac, Romain; Pullumbi, Pluton; Beyer, Kevin A.

Metal–organic frameworks (MOFs) are a family of chemically diverse materials, with applications in a wide range of fields, covering engineering, physics, chemistry, biology and medicine. Until recently, research has focused almost entirely on crystalline structures, yet now a clear trend is emerging, shifting the emphasis onto disordered states, including ‘defective by design’ crystals, as well as amorphous phases such as glasses and gels. Here we introduce a strongly associated MOF liquid, obtained by melting a zeolitic imidazolate framework. We combine in situ variable temperature X-ray, ex situ neutron pair distribution function experiments, and first-principles molecular dynamics simulations to study themore » melting phenomenon and the nature of the liquid obtained. We demonstrate from structural, dynamical, and thermodynamical information that the chemical configuration, coordinative bonding, and porosity of the parent crystalline framework survive upon formation of the MOF liquid.« less

Metal-organic frameworks for lithium ion batteries and supercapacitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ke, Fu-Sheng; Wu, Yu-Shan; Deng, Hexiang, E-mail: hdeng@whu.edu.cn

2015-03-15

Porous materials have been widely used in batteries and supercapacitors attribute to their large internal surface area (usually 100–1000 m{sup 2} g{sup −1}) and porosity that can favor the electrochemical reaction, interfacial charge transport, and provide short diffusion paths for ions. As a new type of porous crystalline materials, metal-organic frameworks (MOFs) have received huge attention in the past decade due to their unique properties, i.e. huge surface area (up to 7000 m{sup 2} g{sup −1}), high porosity, low density, controllable structure and tunable pore size. A wide range of applications including gas separation, storage, catalysis, and drug delivery benefitmore » from the recent fast development of MOFs. However, their potential in electrochemical energy storage has not been fully revealed. Herein, the present mini review appraises recent and significant development of MOFs and MOF-derived materials for rechargeable lithium ion batteries and supercapacitors, to give a glimpse into these potential applications of MOFs. - Graphical abstract: MOFs with large surface area and high porosity can offer more reaction sites and charge carriers diffusion path. Thus MOFs are used as cathode, anode, electrolyte, matrix and precursor materials for lithium ion battery, and also as electrode and precursor materials for supercapacitors. - Highlights: • MOFs have potential in electrochemical area due to their high porosity and diversity. • We summarized and compared works on MOFs for lithium ion battery and supercapacitor. • We pointed out critical challenges and provided possible solutions for future study.« less

CO2/H2O adsorption equilibrium and rates on metal-organic frameworks: HKUST-1 and Ni/DOBDC.

PubMed

Liu, Jian; Wang, Yu; Benin, Annabelle I; Jakubczak, Paulina; Willis, Richard R; LeVan, M Douglas

2010-09-07

Metal-organic frameworks (MOFs) have recently attracted intense research interest because of their permanent porous structures, huge surface areas, and potential applications as novel adsorbents and catalysts. In order to provide a basis for consideration of MOFs for removal of carbon dioxide from gases containing water vapor, such as flue gas, we have studied adsorption equilibrium of CO(2), H(2)O vapor, and their mixtures and also rates of CO(2) adsorption in two MOFs: HKUST-1 (CuBTC) and Ni/DOBDC (CPO-27-Ni or Ni/MOF-74). The MOFs were synthesized via solvothermal methods, and the as-synthesized products were solvent exchanged and regenerated before experiments. Pure component adsorption equilibria and CO(2)/H(2)O binary adsorption equilibria were studied using a volumetric system. The effects of H(2)O adsorption on CO(2) adsorption for both MOF samples were determined, and the results for 5A and NaX zeolites were included for comparison. The hydrothermal stabilities for the two MOFs over the course of repetitive measurements of H(2)O and CO(2)/H(2)O mixture equilibria were also studied. CO(2) adsorption rates from helium for the MOF samples were investigated by using a unique concentration-swing frequency response (CSFR) system. Mass transfer into the MOFs is rapid with the controlling resistance found to be macropore diffusion, and rate parameters were established for the mechanism.

A porphyrin-based metal–organic framework as a pH-responsive drug carrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Wenxin; Hu, Quan; Jiang, Ke

A low cytotoxic porphyrin-based metal–organic framework (MOF) PCN-221, which exhibited high PC12 cell viability via 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyl tetrazolium (MTT) assay, was selected as an oral drug carrier. Methotrexate (MTX) was chosen as the model drug molecule which was absorbed into inner pores and channels of MOFs by diffusion. PCN-221 showed high drug loading and sustained release behavior under physiological environment without “burst effect”. The controlled pH-responsive release of drugs by PCN-221 revealed its promising application in oral drug delivery. - Graphical abstract: The porous crystals PCN-221 with pore openings (MOF) PCN-221 was prepared exhibiting low cytotoxicity. PCN-221 showed high drug Methotrexatemore » loading and controlled pH-responsive release of Methotrexate. - Highlights: • A porphyrin-based metal–organic framework (MOF) PCN-221 was prepared showing low cytotoxicity. • PCN-221 showed high drug Methotrexate loading. • PCN-221 showed controlled pH-responsive release of Methotrexate.« less

A Sr2+-metal-organic framework with high chemical stability: synthesis, crystal structure and photoluminescence property.

PubMed

Jia, Yan-Yuan; Liu, Xiao-Ting; Wang, Wen-He; Zhang, Li-Zhu; Zhang, Ying-Hui; Bu, Xian-He

2017-01-13

Metal-organic frameworks (MOFs) are typically built by assembly of metal centres and organic linkers, and have emerged as promising crystalline materials in a variety of fields. However, the stability of MOFs is a key limitation for their practical applications. Herein, we report a novel Sr 2+: -MOF [Sr 4 (Tdada) 2 (H 2 O) 3 (DMF) 2 ] (denoted as NKU- 105: , NKU = Nankai University; H 4 Tdada = 5,5'-((thiophene-2,5-dicar bonyl)bis(azanediyl))diisophthalic acid; DMF = N,N-dimethylformamide) featuring an open square channel of about 6 Å along the c-axis. Notably, NKU- 105: exhibits much outstanding chemical stability against common organic solvents, boiling water, acids and bases, relative to most MOF materials. Furthermore, NKU- 105: is an environment-friendly luminescent material with a bright cyan emission.This article is part of the themed issue 'Coordination polymers and metal-organic frameworks: materials by design'. © 2016 The Author(s).

A Sr2+-metal–organic framework with high chemical stability: synthesis, crystal structure and photoluminescence property

PubMed Central

Jia, Yan-Yuan; Liu, Xiao-Ting; Wang, Wen-He; Zhang, Li-Zhu; Bu, Xian-He

2017-01-01

Metal–organic frameworks (MOFs) are typically built by assembly of metal centres and organic linkers, and have emerged as promising crystalline materials in a variety of fields. However, the stability of MOFs is a key limitation for their practical applications. Herein, we report a novel Sr2+-MOF [Sr4(Tdada)2(H2O)3(DMF)2] (denoted as NKU-105, NKU = Nankai University; H4Tdada = 5,5'-((thiophene-2,5-dicar bonyl)bis(azanediyl))diisophthalic acid; DMF = N,N-dimethylformamide) featuring an open square channel of about 6 Å along the c-axis. Notably, NKU-105 exhibits much outstanding chemical stability against common organic solvents, boiling water, acids and bases, relative to most MOF materials. Furthermore, NKU-105 is an environment-friendly luminescent material with a bright cyan emission. This article is part of the themed issue ‘Coordination polymers and metal–organic frameworks: materials by design’. PMID:27895256

A facile strategy for enzyme immobilization with highly stable hierarchically porous metal-organic frameworks.

PubMed

Liu, Xiao; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

2017-11-16

Metal-organic frameworks (MOFs) have drawn extensive research interest as candidates for enzyme immobilization owing to their tunable porosity, high surface area, and excellent chemical/thermal stability. Herein, we report a facile and universal strategy for enzyme immobilization using highly stable hierarchically porous metal-organic frameworks (HP-MOFs). The HP-MOFs were stable over a wide pH range (pH = 2-11 for HP-DUT-5) and met the catalysis conditions of most enzymes. The as-prepared hierarchical micro/mesoporous MOFs with mesoporous defects showed a superior adsorption capacity towards enzymes. The maximum adsorption capacity of HP-DUT-5 for glucose oxidase (GOx) and uricase was 208 mg g -1 and 225 mg g -1 , respectively. Furthermore, we constructed two multi-enzyme biosensors for glucose and uric acid (UA) by immobilizing GOx and uricase with horseradish peroxidase (HRP) on HP-DUT-5, respectively. These sensors were efficiently applied in the colorimetric detection of glucose and UA and showed good sensitivity, selectivity, and recyclability.

Unravelling surface and interfacial structures of a metal-organic framework by transmission electron microscopy.

PubMed

Zhu, Yihan; Ciston, Jim; Zheng, Bin; Miao, Xiaohe; Czarnik, Cory; Pan, Yichang; Sougrat, Rachid; Lai, Zhiping; Hsiung, Chia-En; Yao, Kexin; Pinnau, Ingo; Pan, Ming; Han, Yu

2017-05-01

Metal-organic frameworks (MOFs) are crystalline porous materials with designable topology, porosity and functionality, having promising applications in gas storage and separation, ion conduction and catalysis. It is challenging to observe MOFs with transmission electron microscopy (TEM) due to the extreme instability of MOFs upon electron beam irradiation. Here, we use a direct-detection electron-counting camera to acquire TEM images of the MOF ZIF-8 with an ultralow dose of 4.1 electrons per square ångström to retain the structural integrity. The obtained image involves structural information transferred up to 2.1 Å, allowing the resolution of individual atomic columns of Zn and organic linkers in the framework. Furthermore, TEM reveals important local structural features of ZIF-8 crystals that cannot be identified by diffraction techniques, including armchair-type surface terminations and coherent interfaces between assembled crystals. These observations allow us to understand how ZIF-8 crystals self-assemble and the subsequent influence of interfacial cavities on mass transport of guest molecules.

Solvothermal synthesis and structure of 3D frameworks of Nd(III) and Y(III) with thiophene-2,5-dicarboxylate and N,N‧-diethylformamide

NASA Astrophysics Data System (ADS)

Sharma, Swati; Yawer, Mohd; Kariem, Mukaddus; Sheikh, Haq Nawaz

2016-08-01

Two new 3D MOFs [Nd2(TDA)3(DEF)2(H2O)]n (1) and [Y4(TDA)6(DEF)4]n (2) [Thiophene-2,5-dicarboxylic acid (H2TDA) and N,N‧-diethylformamide (DEF)] were synthesized by solvothermal method. They were characterized by elemental analyses, infrared spectroscopy and single crystal X-ray diffraction studies. The two MOFs (1) and (2) belong to the monoclinic system with space group P21/n and C 2 respectively. Structural characterizations by single-crystal X-ray crystallography reveal that 1 and 2 adopt three-dimensional frameworks constructed by cross-linking of rod shaped infinite chain secondary building unit (SBU) by thiophene-2,5-dicarboxylates as linker. These frameworks feature rhomboidal channels, inside which coordinated DEF/H2O solvent molecules are located. DEF plays pivotal role in reaction and design of MOFs. Thermogravimetric analysis shows that both MOFs are thermally robust.

Unravelling surface and interfacial structures of a metal-organic framework by transmission electron microscopy

NASA Astrophysics Data System (ADS)

Zhu, Yihan; Ciston, Jim; Zheng, Bin; Miao, Xiaohe; Czarnik, Cory; Pan, Yichang; Sougrat, Rachid; Lai, Zhiping; Hsiung, Chia-En; Yao, Kexin; Pinnau, Ingo; Pan, Ming; Han, Yu

2017-05-01

Metal-organic frameworks (MOFs) are crystalline porous materials with designable topology, porosity and functionality, having promising applications in gas storage and separation, ion conduction and catalysis. It is challenging to observe MOFs with transmission electron microscopy (TEM) due to the extreme instability of MOFs upon electron beam irradiation. Here, we use a direct-detection electron-counting camera to acquire TEM images of the MOF ZIF-8 with an ultralow dose of 4.1 electrons per square ångström to retain the structural integrity. The obtained image involves structural information transferred up to 2.1 Å, allowing the resolution of individual atomic columns of Zn and organic linkers in the framework. Furthermore, TEM reveals important local structural features of ZIF-8 crystals that cannot be identified by diffraction techniques, including armchair-type surface terminations and coherent interfaces between assembled crystals. These observations allow us to understand how ZIF-8 crystals self-assemble and the subsequent influence of interfacial cavities on mass transport of guest molecules.

Rigidifying fluorescent linkers by metal-organic framework formation for fluorescence blue shift and quantum yield enhancement.

PubMed

Wei, Zhangwen; Gu, Zhi-Yuan; Arvapally, Ravi K; Chen, Ying-Pin; McDougald, Roy N; Ivy, Joshua F; Yakovenko, Andrey A; Feng, Dawei; Omary, Mohammad A; Zhou, Hong-Cai

2014-06-11

We demonstrate that rigidifying the structure of fluorescent linkers by structurally constraining them in metal-organic frameworks (MOFs) to control their conformation effectively tunes the fluorescence energy and enhances the quantum yield. Thus, a new tetraphenylethylene-based zirconium MOF exhibits a deep-blue fluorescent emission at 470 nm with a unity quantum yield (99.9 ± 0.5%) under Ar, representing ca. 3600 cm(-1) blue shift and doubled radiative decay efficiency vs the linker precursor. An anomalous increase in the fluorescence lifetime and relative intensity takes place upon heating the solid MOF from cryogenic to ambient temperatures. The origin of these unusual photoluminescence properties is attributed to twisted linker conformation, intramolecular hindrance, and framework rigidity.

Plasmonic nanopatch array with integrated metal–organic framework for enhanced infrared absorption gas sensing

DOE PAGES

Chong, Xinyuan; Kim, Ki-joong; Zhang, Yujing; ...

2017-06-06

In this letter, we present a nanophotonic device consisting of plasmonic nanopatch array (NPA) with integrated metal–organic framework (MOF) for enhanced infrared absorption gas sensing. By designing a gold NPA on a sapphire substrate, we are able to achieve enhanced optical field that spatially overlaps with the MOF layer, which can adsorb carbon dioxide (CO 2) with high capacity. Additionally, experimental results show that this hybrid plasmonic–MOF device can effectively increase the infrared absorption path of on-chip gas sensors by more than 1100-fold. Lastly, the demonstration of infrared absorption spectroscopy of CO 2 using the hybrid plasmonic–MOF device proves amore » promising strategy for future on-chip gas sensing with ultra-compact size.« less

Solvent-induced controllable synthesis, single-crystal to single-crystal transformation and encapsulation of Alq3 for modulated luminescence in (4,8)-connected metal-organic frameworks.

PubMed

Lan, Ya-Qian; Jiang, Hai-Long; Li, Shun-Li; Xu, Qiang

2012-07-16

In this work, for the first time, we have systematically demonstrated that solvent plays crucial roles in both controllable synthesis of metal-organic frameworks (MOFs) and their structural transformation process. With solvent as the only variable, five new MOFs with different structures have been constructed, in which one MOF undergoes solvent-induced single-crystal to single-crystal (SCSC) transformation that involves not only solvent exchange but also the cleavage and formation of coordination bonds. Particularly, a significant crystallographic change has been realized through an unprecedented three-step SCSC transformation process. Furthermore, we have demonstrated that the obtained MOF could be an excellent host for chromophores such as Alq3 for modulated luminescent properties.

Controlled uptake and release of imatinib from ultrasound nanoparticles Cu3(BTC)2 metal-organic framework in comparison with bulk structure.

PubMed

Abbasi, Amir Reza; Rizvandi, Maryam; Azadbakht, Azadeh; Rostamnia, Sadegh

2016-06-01

The porosity of metal-organic frameworks (MOFs) is an important point concerning the possible use of such functional materials for different purposes. In this work, we study uptake and release properties of imatinib (IM) from nano Cu(II)-MOF in comparison with bulk Cu(II)-MOF. To explore the absorption ability of the Cu(II)-MOF to IM, fresh sample of Cu3(BTC)2 was immersed in an aqueous solution of IM and were monitored in real time with UV/vis spectroscopy. Results show that the adsorbed quantity of IM over nano Cu3(BTC)2 (I) is much higher than those over a bulk Cu3(BTC)2 (II). Copyright © 2016. Published by Elsevier Inc.

Plasmonic nanopatch array with integrated metal–organic framework for enhanced infrared absorption gas sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chong, Xinyuan; Kim, Ki-joong; Zhang, Yujing

In this letter, we present a nanophotonic device consisting of plasmonic nanopatch array (NPA) with integrated metal–organic framework (MOF) for enhanced infrared absorption gas sensing. By designing a gold NPA on a sapphire substrate, we are able to achieve enhanced optical field that spatially overlaps with the MOF layer, which can adsorb carbon dioxide (CO 2) with high capacity. Additionally, experimental results show that this hybrid plasmonic–MOF device can effectively increase the infrared absorption path of on-chip gas sensors by more than 1100-fold. Lastly, the demonstration of infrared absorption spectroscopy of CO 2 using the hybrid plasmonic–MOF device proves amore » promising strategy for future on-chip gas sensing with ultra-compact size.« less

Vapor-Phase Deposition and Modification of Metal-Organic Frameworks: State-of-the-Art and Future Directions.

PubMed

Stassen, Ivo; De Vos, Dirk; Ameloot, Rob

2016-10-04

Materials processing, and thin-film deposition in particular, is decisive in the implementation of functional materials in industry and real-world applications. Vapor processing of materials plays a central role in manufacturing, especially in electronics. Metal-organic frameworks (MOFs) are a class of nanoporous crystalline materials on the brink of breakthrough in many application areas. Vapor deposition of MOF thin films will facilitate their implementation in micro- and nanofabrication research and industries. In addition, vapor-solid modification can be used for postsynthetic tailoring of MOF properties. In this context, we review the recent progress in vapor processing of MOFs, summarize the underpinning chemistry and principles, and highlight promising directions for future research. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Encapsulation of Hemin in Metal-Organic Frameworks for Catalyzing the Chemiluminescence Reaction of the H2O2-Luminol System and Detecting Glucose in the Neutral Condition.

PubMed

Luo, Fenqiang; Lin, Yaolin; Zheng, Liyan; Lin, Xiaomei; Chi, Yuwu

2015-06-03

Novel metal-organic frameworks (MOFs) based solid catalysts have been synthesized by encapsulating Hemin into the HKUST-1 MOF materials. These have been first applied in the chemiluminescence field with outstanding performance. The functionalized MOFs not only maintain an excellent catalytic activity inheriting from Hemin but also can be cyclically utilized as solid mimic peroxidases in the neutral condition. The synthesized Hemin@HKUST-1 composites have been used to develop practical sensors for H2O2 and glucose with wide response ranges and low detection limits. It was envisioned that catalyst-functionalized MOFs for chemiluminescence sensing would have promising applications in green, selective, and sensitive detection of target analytes in the future.

Diffusion Control in the in Situ Synthesis of Iconic Metal-Organic Frameworks within an Ionic Polymer Matrix.

PubMed

Lim, Jungho; Lee, Eun Ji; Choi, Jae Sun; Jeong, Nak Cheon

2018-01-31

Ionic polymers that possess ion-exchangeable sites have been shown to be a greatly useful platform to fabricate mixed matrices (MMs) where metal-organic frameworks (MOFs) can be in situ synthesized, although the in situ synthesis of MOF has been rarely studied. In this study, alginate (ALG), an anionic green polymer that possesses metal-ion-exchangeable sites, is employed as a platform of MMs for the in situ synthesis of iconic MOFs, HKUST-1, and MOF-74(Zn). We demonstrate for the first time that the sequential order of supplying MOF ingredients (metal ion and deprotonated ligand) into the alginate matrix leads to substantially different results because of a difference in the diffusion of the MOF components. For the examples examined, whereas the infusion of BTC 3- ligand into Cu 2+ -exchanged ALG engendered the eggshell-shaped HKUST-1 layers on the surface of MM spheres, the infusion of Cu 2+ ions into BTC 3- -included alginate engendered the high dispersivity and junction contact of HKUST-1 crystals in the alginate matrix. This fundamental property has been exploited to fabricate a flexible MOF-containing mixed matrix membrane by coincorporating poly(vinyl alcohol). Using two molecular dyes, namely, methylene blue and rhodamine 6G, further, we show that this in situ strategy is suitable for fabricating an MOF-MM that exhibits size-selective molecular uptake.

Temperature Treatment of Highly Porous Zirconium-Containing Metal-Organic Frameworks Extends Drug Delivery Release.

PubMed

Teplensky, Michelle H; Fantham, Marcus; Li, Peng; Wang, Timothy C; Mehta, Joshua P; Young, Laurence J; Moghadam, Peyman Z; Hupp, Joseph T; Farha, Omar K; Kaminski, Clemens F; Fairen-Jimenez, David

2017-06-07

Utilizing metal-organic frameworks (MOFs) as a biological carrier can lower the amount of the active pharmaceutical ingredient (API) required in cancer treatments to provide a more efficacious therapy. In this work, we have developed a temperature treatment process for delaying the release of a model drug compound from the pores of NU-1000 and NU-901, while taking care to utilize these MOFs' large pore volume and size to achieve exceptional model drug loading percentages over 35 wt %. Video-rate super-resolution microscopy reveals movement of MOF particles when located outside of the cell boundary, and their subsequent immobilization when taken up by the cell. Through the use of optical sectioning structured illumination microscopy (SIM), we have captured high-resolution 3D images showing MOF uptake by HeLa cells over a 24 h period. We found that addition of a model drug compound into the MOF and the subsequent temperature treatment process does not affect the rate of MOF uptake by the cell. Endocytosis analysis revealed that MOFs are internalized by active transport and that inhibiting the caveolae-mediated pathway significantly reduced cellular uptake of MOFs. Encapsulation of an anticancer therapeutic, alpha-cyano-4-hydroxycinnamic acid (α-CHC), and subsequent temperature treatment produced loadings of up to 81 wt % and demonstrated efficacy at killing cells beyond the burst release effect.

Computational Design of Functionalized Metal–Organic Framework Nodes for Catalysis

PubMed Central

2017-01-01

Recent progress in the synthesis and characterization of metal–organic frameworks (MOFs) has opened the door to an increasing number of possible catalytic applications. The great versatility of MOFs creates a large chemical space, whose thorough experimental examination becomes practically impossible. Therefore, computational modeling is a key tool to support, rationalize, and guide experimental efforts. In this outlook we survey the main methodologies employed to model MOFs for catalysis, and we review selected recent studies on the functionalization of their nodes. We pay special attention to catalytic applications involving natural gas conversion. PMID:29392172

Directing the breathing behavior of pillared-layered metal-organic frameworks via a systematic library of functionalized linkers bearing flexible substituents.

PubMed

Henke, Sebastian; Schneemann, Andreas; Wütscher, Annika; Fischer, Roland A

2012-06-06

Flexible metal-organic frameworks (MOFs), also referred to as soft porous crystals (SPCs), show reversible structural transitions dependent on the nature and quantity of adsorbed guest molecules. In recent studies it has been reported that covalent functionalization of the organic linker can influence or even integrate framework flexibility ("breathing") in MOFs. However, rational fine-tuning of such responsive properties is very desirable but challenging as well. Here we present a powerful approach for the targeted manipulation of responsiveness and framework flexibility of an important family of pillared-layered MOFs based on the parent structure [Zn(2)(bdc)(2)(dabco)](n) (bdc = 1,4-benzenedicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane). A library of functionalized bdc-type linkers (fu-bdc), which bear additional dangling side groups at different positions of the benzene core (alkoxy groups of varying chain length with diverse functionalities and polarity), was generated. Synthesis of the materials [Zn(2)(fu-bdc)(2)(dabco)](n) yields the respective collection of highly responsive MOFs. The parent MOF is only weakly flexible; however, the substituted frameworks of [Zn(2)(fu-bdc)(2)(dabco)](n) contract drastically upon guest removal and expand again upon adsorption of DMF (N,N-dimethylformamide), EtOH, or CO(2), etc., while N(2) is hardly adsorbed and does not open the narrow-pored form. These "breathing" dynamics are attributed to the dangling side chains that act as immobilized "guests", which interact with mobile guest molecules as well as with themselves and with the framework backbone. The structural details of the guest-free, contracted form and the gas sorption behavior (phase transition pressure, hysteresis loop) are highly dependent on the nature of the substituent at the linker and can therefore be adjusted using our approach. Combining our library of functionalized linkers with the concept of mixed-component MOFs (solid solutions) offers very rich additional dimensions of tailoring the structural dynamics and responsiveness. Implementation of two differently functionalized linkers in varying ratios yields multicomponent single-phased [Zn(2)(fu-bdc')(2x)(fu-bdc″)(2-2x)(dabco)](n) MOFs (0 < x < 1) of increased inherent complexity, which feature a non-linear dependence of their gas sorption properties on the applied ratio of components. Hence, the responsive behavior of such pillared-layered MOFs can be extensively tuned via an intelligent combination of functionalized linkers.

Submicron sized water-stable metal organic framework (bio-MOF-11) for catalytic degradation of pharmaceuticals and personal care products.

PubMed

Azhar, Muhammad Rizwan; Vijay, Periasamy; Tadé, Moses O; Sun, Hongqi; Wang, Shaobin

2018-04-01

Water-stable and active metal organic frameworks (MOFs) are important materials for mitigation of water contaminants via adsorption and catalytic reactions. In this study, a highly water-stable Co-based MOF, namely bio-MOF-11-Co, was synthesized by a simplified benign method. Moreover, it was used as a catalyst in successful activation of peroxymonsulfate for catalytic degradation of sulfachloropyradazine (SCP) and para-hydroxybenzoic acid (p-HBA) as representatives of pharmaceuticals and personal care products, respectively. The bio-MOF-11-Co showed rapid degradation of both p-HBA and SCP and could be reused multiple times without losing the activity by simply water washing. The effects of catalyst and PMS loadings as well as temperature were further studied, showing that high catalyst and PMS loadings as well as temperature produced faster kinetic degradation of p-HBA and SCP. The generation of highly reactive and HO radicals during the degradation was investigated by quenching tests and electron paramagnetic resonance. A plausible degradation mechanism was proposed based on the functionalities in the bio-MOF-11-Co. The availability of electron rich nucleobase adenine reinforced the reaction kinetics by electron donation along with cobalt atoms in the bio-MOF-11-Co structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

General and Direct Method for Preparing Oligonucleotide-Functionalized Metal-Organic Framework Nanoparticles.

PubMed

Wang, Shunzhi; McGuirk, C Michael; Ross, Michael B; Wang, Shuya; Chen, Pengcheng; Xing, Hang; Liu, Yuan; Mirkin, Chad A

2017-07-26

Metal-organic frameworks (MOFs) are a class of modular, crystalline, and porous materials that hold promise for storage and transport of chemical cargoes. Though MOFs have been studied in bulk forms, ways of deliberately manipulating the external surface functionality of MOF nanoparticles are less developed. A generalizable approach to modify their surfaces would allow one to impart chemical functionality onto the particle surface that is independent of the bulk MOF structure. Moreover, the use of a chemically programmable ligand, such as DNA, would allow for the manipulation of interparticle interactions. Herein, we report a coordination chemistry-based strategy for the surface functionalization of the external metal nodes of MOF nanoparticles with terminal phosphate-modified oligonucleotides. The external surfaces of nine distinct archetypical MOF particles containing four different metal species (Zr, Cr, Fe, and Al) were successfully functionalized with oligonucleotides, illustrating the generality of this strategy. By taking advantage of the programmable and specific interactions of DNA, 11 distinct MOF particle-inorganic particle core-satellite clusters were synthesized. In these hybrid nanoclusters, the relative stoichiometry, size, shape, and composition of the building blocks can all be independently controlled. This work provides access to a new set of nucleic acid-nanoparticle conjugates, which may be useful as programmable material building blocks and as probes for measuring and manipulating intracellular processes.

Metal-organic framework mixed-matrix disks: Versatile supports for automated solid-phase extraction prior to chromatographic separation.

PubMed

Ghani, Milad; Font Picó, Maria Francesca; Salehinia, Shima; Palomino Cabello, Carlos; Maya, Fernando; Berlier, Gloria; Saraji, Mohammad; Cerdà, Víctor; Turnes Palomino, Gemma

2017-03-10

We present for the first time the application of metal-organic framework (MOF) mixed-matrix disks (MMD) for the automated flow-through solid-phase extraction (SPE) of environmental pollutants. Zirconium terephthalate UiO-66 and UiO-66-NH 2 MOFs with different size (90, 200 and 300nm) have been incorporated into mechanically stable polyvinylidene difluoride (PVDF) disks. The performance of the MOF-MMDs for automated SPE of seven substituted phenols prior to HPLC analysis has been evaluated using the sequential injection analysis technique. MOF-MMDs enabled the simultaneous extraction of phenols with the concomitant size exclusion of molecules of larger size. The best extraction performance was obtained using a MOF-MMD containing 90nm UiO-66-NH 2 crystals. Using the selected MOF-MMD, detection limits ranging from 0.1 to 0.2μgL -1 were obtained. Relative standard deviations ranged from 3.9 to 5.3% intra-day, and 4.7-5.7% inter-day. Membrane batch-to-batch reproducibility was from 5.2 to 6.4%. Three different groundwater samples were analyzed with the proposed method using MOF-MMDs, obtaining recoveries ranging from 90 to 98% for all tested analytes. Copyright © 2017 Elsevier B.V. All rights reserved.

Are metal-organic frameworks able to provide a new generation of solid-phase microextraction coatings? - A review.

PubMed

Rocío-Bautista, Priscilla; Pacheco-Fernández, Idaira; Pasán, Jorge; Pino, Verónica

2016-10-05

Solid-phase microextraction (SPME) is a powerful technique commonly used in sample preparation for extraction/preconcentration of analytes from a wide variety of samples. Among the trends in improving SPME applications, current investigations are focused on the development of novel coatings able to improve the extraction efficiency, sensitivity, and thermal and mechanical stability, within other properties, of current commercial SPME fibers. Metal-organic frameworks (MOFs) merit to be highlighted as promising sorbent materials in SPME schemes. MOFs are porous hybrid materials composed by metal ions and organic linkers, presenting the highest surface areas known, with ease synthesis and high tuneability, together with adequate chemical and thermal stability. For MOF based-SPME fibers, it results important to pretreat adequately the SPME supports to ensure the correct formation of the MOF onto the fiber or the attachment MOF-support. This, in turn, will increase the final stability of the fiber while generating uniform coatings. This review provides a critical overview of the current state of the use of MOFs as SPME coatings, not only highlighting the advantages of these materials versus commercial SPME coatings in terms of stability, selectivity, and sensitivity; but also insightfully describing the current methods to obtain reproducible MOF-based SPME coatings. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and Transport Properties of Novel MOF/PIM-1/MOF Sandwich Membranes for Gas Separation

PubMed Central

Fuoco, Alessio; Khdhayyer, Muhanned R.; Attfield, Martin P.; Esposito, Elisa; Jansen, Johannes C.; Budd, Peter M.

2017-01-01

Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes. The pure gas permeabilities of He, H2, O2, N2, CH4, CO2 were studied to understand the effect of the surface modification on the basic transport properties and evaluate the potential use of these membranes for industrially relevant gas separations. The pure gas transport was discussed in terms of permeability and selectivity, highlighting the effect of the MOF growth on the diffusion coefficients of the gas in the new composite polymer membranes. The results confirm that the growth of MOFs on polymer membranes can enhance the selectivity of the appropriately functionalized PIM-1, without a dramatic decrease of the permeability. PMID:28208658

Hybrid micro-/nano-structures derived from metal-organic frameworks: preparation and applications in energy storage and conversion.

PubMed

Cao, Xiehong; Tan, Chaoliang; Sindoro, Melinda; Zhang, Hua

2017-05-22

Metal-organic frameworks (MOFs), an important class of inorganic-organic hybrid crystals with intrinsic porous structures, can be used as versatile precursors or sacrificial templates for preparation of numerous functional nanomaterials for various applications. Recent developments of MOF-derived hybrid micro-/nano-structures, constructed by more than two components with varied functionalities, have revealed their extensive capabilities to overcome the weaknesses of the individual counterparts and thus give enhanced performance for energy storage and conversion. In this tutorial review, we summarize the recent advances in MOF-derived hybrid micro-/nano-structures. The synthetic strategies for preparing MOF-derived hybrid micro-/nano-structures are first introduced. Focusing on energy storage and conversion, we then discuss their potential applications in lithium-ion batteries, lithium-sulfur batteries, supercapacitors, lithium-oxygen batteries and fuel cells. Finally, we give our personal insights into the challenges and opportunities for the future research of MOF-derived hybrid micro-/nano-structures.

Text Mining Metal-Organic Framework Papers.

PubMed

Park, Sanghoon; Kim, Baekjun; Choi, Sihoon; Boyd, Peter G; Smit, Berend; Kim, Jihan

2018-02-26

We have developed a simple text mining algorithm that allows us to identify surface area and pore volumes of metal-organic frameworks (MOFs) using manuscript html files as inputs. The algorithm searches for common units (e.g., m 2 /g, cm 3 /g) associated with these two quantities to facilitate the search. From the sample set data of over 200 MOFs, the algorithm managed to identify 90% and 88.8% of the correct surface area and pore volume values. Further application to a test set of randomly chosen MOF html files yielded 73.2% and 85.1% accuracies for the two respective quantities. Most of the errors stem from unorthodox sentence structures that made it difficult to identify the correct data as well as bolded notations of MOFs (e.g., 1a) that made it difficult identify its real name. These types of tools will become useful when it comes to discovering structure-property relationships among MOFs as well as collecting a large set of data for references.

Mechanical Properties in Metal-Organic Frameworks: Emerging Opportunities and Challenges for Device Functionality and Technological Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burtch, Nicholas C.; Heinen, Jurn; Bennett, Thomas D.

We report that some of the most remarkable recent developments in metal–organic framework (MOF) performance properties can only be rationalized by the mechanical properties endowed by their hybrid inorganic–organic nanoporous structures. While these characteristics create intriguing application prospects, the same attributes also present challenges that will need to be overcome to enable the integration of MOFs with technologies where these promising traits can be exploited. In this review, emerging opportunities and challenges are identified for MOF-enabled device functionality and technological applications that arise from their fascinating mechanical properties. This is discussed not only in the context of their more well-studiedmore » gas storage and separation applications, but also for instances where MOFs serve as components of functional nanodevices. Recent advances in understanding MOF mechanical structure–property relationships due to attributes such as defects and interpenetration are highlighted, and open questions related to state-of-the-art computational approaches for quantifying their mechanical properties are critically discussed.« less

Porous Iron-Carboxylate Metal-Organic Framework: A Novel Bioplatform with Sustained Antibacterial Efficacy and Nontoxicity.

PubMed

Lin, Sha; Liu, Xiangmei; Tan, Lei; Cui, Zhenduo; Yang, Xianjin; Yeung, Kelvin W K; Pan, Haobo; Wu, Shuilin

2017-06-07

Sustained drug release plays a critical role in targeting the therapy of local diseases such as bacterial infections. In the present work, porous iron-carboxylate metal-organic framework [MOF-53(Fe)] nanoparticles (NPs) were designed to entrap the vancomycin (Van) drugs. This system exhibited excellent chemical stability under acidic conditions (pH 7.4, 6.5, and 5.5) and much higher drug-loading capability because of the high porosity and large surface area of MOF NPs. The results showed that the drug-loading ratio of Van could reach 20 wt % and that the antibacterial ratio of the MOF-53(Fe)/Van system against Staphylococcus aureus could reach up to 90%. In addition, this MOF-53(Fe)/Van system exhibited excellent biocompatibility because of its chemical stability and sustained release of iron ions. Hence, these porous MOF NPs are a promising bioplatform not only for local therapy of bacterial infections but also for other biomedical therapies for tissue regeneration.

Mechanical Properties in Metal-Organic Frameworks: Emerging Opportunities and Challenges for Device Functionality and Technological Applications

DOE PAGES

Burtch, Nicholas C.; Heinen, Jurn; Bennett, Thomas D.; ...

2017-11-17

We report that some of the most remarkable recent developments in metal–organic framework (MOF) performance properties can only be rationalized by the mechanical properties endowed by their hybrid inorganic–organic nanoporous structures. While these characteristics create intriguing application prospects, the same attributes also present challenges that will need to be overcome to enable the integration of MOFs with technologies where these promising traits can be exploited. In this review, emerging opportunities and challenges are identified for MOF-enabled device functionality and technological applications that arise from their fascinating mechanical properties. This is discussed not only in the context of their more well-studiedmore » gas storage and separation applications, but also for instances where MOFs serve as components of functional nanodevices. Recent advances in understanding MOF mechanical structure–property relationships due to attributes such as defects and interpenetration are highlighted, and open questions related to state-of-the-art computational approaches for quantifying their mechanical properties are critically discussed.« less

A flexible ligand-based wavy layered metal-organic framework for lithium-ion storage.

PubMed

An, Tiance; Wang, Yuhang; Tang, Jing; Wang, Yang; Zhang, Lijuan; Zheng, Gengfeng

2015-05-01

A substantial challenge for direct utilization of metal-organic frameworks (MOFs) as lithium-ion battery anodes is to maintain the rigid MOF structure during lithiation/delithiation cycles. In this work, we developed a flexible, wavy layered nickel-based MOF (C20H24Cl2N8Ni, designated as Ni-Me4bpz) by a solvothermal approach of 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H2Me4bpz) with nickel(II) chloride hexahydrate. The obtained MOF materials (Ni-Me4bpz) with metal azolate coordination mode provide 2-dimensional layered structure for Li(+) intercalation/extraction, and the H2Me4bpz ligands allow for flexible rotation feature and structural stability. Lithium-ion battery anodes made of the Ni-Me4bpz material demonstrate excellent specific capacity and cycling performance, and the crystal structure is well preserved after the electrochemical tests, suggesting the potential of developing flexible layered MOFs for efficient and stable electrochemical storage. Copyright © 2015 Elsevier Inc. All rights reserved.

Mechanical Properties in Metal-Organic Frameworks: Emerging Opportunities and Challenges for Device Functionality and Technological Applications.

PubMed

Burtch, Nicholas C; Heinen, Jurn; Bennett, Thomas D; Dubbeldam, David; Allendorf, Mark D

2017-11-17

Some of the most remarkable recent developments in metal-organic framework (MOF) performance properties can only be rationalized by the mechanical properties endowed by their hybrid inorganic-organic nanoporous structures. While these characteristics create intriguing application prospects, the same attributes also present challenges that will need to be overcome to enable the integration of MOFs with technologies where these promising traits can be exploited. In this review, emerging opportunities and challenges are identified for MOF-enabled device functionality and technological applications that arise from their fascinating mechanical properties. This is discussed not only in the context of their more well-studied gas storage and separation applications, but also for instances where MOFs serve as components of functional nanodevices. Recent advances in understanding MOF mechanical structure-property relationships due to attributes such as defects and interpenetration are highlighted, and open questions related to state-of-the-art computational approaches for quantifying their mechanical properties are critically discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Targeted Single-Site MOF Node Modification: Trivalent Metal Loading via Atomic Layer Deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, In Soo; Borycz, Joshua; Platero-Prats, Ana E.

Postsynthetic functionalization of metal organic frameworks (MOFs) enables the controlled, high-density incorporation of new atoms on a crystallographically precise framework. Leveraging the broad palette of known atomic layer deposition (ALD) chemistries, ALD in MOFs (AIM) is one such targeted approach to construct diverse, highly functional, few-atom clusters. We here demonstrate the saturating reaction of trimethylindium (InMe3) with the node hydroxyls and ligated water of NU-1000, which takes place without significant loss of MOF crystallinity or internal surface area. We computationally identify the elementary steps by which trimethylated trivalent metal compounds (ALD precursors) react with this Zr-based MOF node to generatemore » a uniform and well characterized new surface layer on the node itself, and we predict a final structure that is fully consistent with experimental X-ray pair distribution function (PDF) analysis. We further demonstrate tunable metal loading through controlled number density of the reactive handles (-OH and -OH2) achieved through node dehydration at elevated temperatures.« less

Stable metal–organic framework-supported niobium catalysts

DOE PAGES

Ahn, Sol; Thornburg, Nicholas E.; Li, Zhanyong; ...

2016-10-31

In this study by developing structurally well-defined, supported oxide catalysts remains a significant challenge. Here, we report the grafting of Nb(V) oxide sites onto the nodes of the Zr-based metal organic framework (MOF) NU-1000 as a stable, well-defined catalyst support. Nb(V) oxide was deposited with loadings up to 1.6 mmol/g via two post-synthetic methods: atomic layer deposition in a MOF (AIM), and solution-phase grafting in a MOF (SIM). Difference envelope density (DED) measurements indicated that the two synthetic methods resulted in different local structures of the Nb(V) ions within NU-1000. Despite their high Nb(V) loadings, which were equivalent to >60%more » surface coverage, nearly all Nb(V) sites of the MOF-supported catalysts were active sites for alkene epoxidation, as confirmed by phenylphosphonic acid titration. The MOF-supported catalysts were more selective than the control Nb-ZrO 2 catalyst for cyclohexene epoxidation with aqueous H 2O 2, and were far more active on a gravimetric basis.« less

Fabrication of zinc-dicarboxylate- and zinc-pyrazolate-carboxylate-framework thin films through vapour-solid deposition.

PubMed

Medishetty, Raghavender; Zhang, Zongji; Sadlo, Alexander; Cwik, Stefan; Peeters, Daniel; Henke, Sebastian; Mangayarkarasi, Nagarathinam; Devi, Anjana

2018-05-17

Fabrication of three-dimensional metal-organic framework (MOF) thin films has been investigated for the first time through the conversion of a ZnO layer via a pure vapour-solid deposition reaction at ambient pressure. The fabrication of MOF thin films with a dicarboxylate linker, (DMA)2[Zn3(bdc)4] (1) (bdc = 1,4-benzenedicarboxylate), and a carboxy-pyrazolate linker, [Zn4O(dmcapz)6] (2) (dmcapz = 3,5-dimethyl-4-carboxypyrazole), involves the deposition of the linker and/or the preparation of a composite film preliminarily and its subsequent conversion into a MOF film using closed cell thermal treatment. Furthermore, it was possible to isolate thin films with a MOF-5 isotype structure grown along the [110] direction, using a carboxy-pyrazolate linker. This was achieved just by the direct reaction of the ZnO film and the organic linker vapors, employing a simple route that demonstrates the feasibility of MOF thin film fabrication using inexpensive routes at ambient pressure.

Water depollution using metal-organic frameworks-catalyzed advanced oxidation processes: A review.

PubMed

Sharma, Virender K; Feng, Mingbao

2017-09-28

This paper presents a review on the environmental applications of metal-organic frameworks (MOFs), which are inorganic-organic hybrid highly porous crystalline materials, prepared from metal ion/clusters and multidentate organic ligands. The emphases are made on the enhancement of the performance of advanced oxidation processes (AOPs) (photocatalysis, Fenton reaction methods, and sulfate radical (SO 4 - )-mediated oxidations) using MOFs materials. MOFs act as adsorption and light absorbers, leading to superior performance of photocatalytic processes. More recent examples of photocatalytic degradation of dyes are presented. Additionally, it is commonly shown that Fe-based MOFs exhibited excellent catalytic performance on the Fenton-based and SO 4 •- -mediated oxidations of organic pollutants (e.g., dyes, phenol and pharmaceuticals). The significantly enhanced generation of reactive species such as OH and/or SO 4 - by both homogeneous and heterogeneous catalysis was proposed as the possible mechanism for water depollution. Based on the existing literature, the challenge and future perspectives in MOF-based AOPs are addressed. Copyright © 2017 Elsevier B.V. All rights reserved.

Nanomaterials derived from metal-organic frameworks

NASA Astrophysics Data System (ADS)

Dang, Song; Zhu, Qi-Long; Xu, Qiang

2018-01-01

The thermal transformation of metal-organic frameworks (MOFs) generates a variety of nanostructured materials, including carbon-based materials, metal oxides, metal chalcogenides, metal phosphides and metal carbides. These derivatives of MOFs have characteristics such as high surface areas, permanent porosities and controllable functionalities that enable their good performance in sensing, gas storage, catalysis and energy-related applications. Although progress has been made to tune the morphologies of MOF-derived structures at the nanometre scale, it remains crucial to further our knowledge of the relationship between morphology and performance. In this Review, we summarize the synthetic strategies and optimized methods that enable control over the size, morphology, composition and structure of the derived nanomaterials. In addition, we compare the performance of materials prepared by the MOF-templated strategy and other synthetic methods. Our aim is to reveal the relationship between the morphology and the physico-chemical properties of MOF-derived nanostructures to optimize their performance for applications such as sensing, catalysis, and energy storage and conversion.

Bimetallic Metal-Organic Frameworks for Controlled Catalytic Graphitization of Nanoporous Carbons

PubMed Central

Tang, Jing; Salunkhe, Rahul R.; Zhang, Huabin; Malgras, Victor; Ahamad, Tansir; Alshehri, Saad M.; Kobayashi, Naoya; Tominaka, Satoshi; Ide, Yusuke; Kim, Jung Ho; Yamauchi, Yusuke

2016-01-01

Single metal-organic frameworks (MOFs), constructed from the coordination between one-fold metal ions and organic linkers, show limited functionalities when used as precursors for nanoporous carbon materials. Herein, we propose to merge the advantages of zinc and cobalt metals ions into one single MOF crystal (i.e., bimetallic MOFs). The organic linkers that coordinate with cobalt ions tend to yield graphitic carbons after carbonization, unlike those bridging with zinc ions, due to the controlled catalytic graphitization by the cobalt nanoparticles. In this work, we demonstrate a feasible method to achieve nanoporous carbon materials with tailored properties, including specific surface area, pore size distribution, degree of graphitization, and content of heteroatoms. The bimetallic-MOF-derived nanoporous carbon are systematically characterized, highlighting the importance of precisely controlling the properties of the carbon materials. This can be done by finely tuning the components in the bimetallic MOF precursors, and thus designing optimal carbon materials for specific applications. PMID:27471193

Topologically Guided, Automated Construction of Metal–Organic Frameworks and Their Evaluation for Energy-Related Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colón, Yamil J.; Gómez-Gualdrón, Diego A.; Snurr, Randall Q.

Metal-organic frameworks (MOFs) are promising materials for a range of energy and environmental applications. Here we describe in detail a computational algorithm and code to generate MOFs based on edge-transitive topological nets for subsequent evaluation via molecular simulation. This algorithm has been previously used by us to construct and evaluate 13 512 MOFs of 41 different topologies for cryo-adsorbed hydrogen storage. Grand canonical Monte Carlo simulations are used here to evaluate the 13 512 structures for the storage of gaseous fuels such as hydrogen and methane and nondistillative separation of xenon/krypton mixtures at various operating conditions. MOF performance for bothmore » gaseous fuel storage and xenon/krypton separation is influenced by topology. Simulation data suggest that gaseous fuel storage performance is topology-dependent due to MOF properties such as void fraction and surface area combining differently in different topologies, whereas xenon/krypton separation performance is topology-dependent due to how topology constrains the pore size distribution.« less