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Sample records for catalysts substantially enhanced

  1. Substantial bulk photovoltaic effect enhancement via nanolayering.

    PubMed

    Wang, Fenggong; Young, Steve M; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M

    2016-01-01

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials' responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)(1-x)). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times due to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. This opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition. PMID:26791545

  2. Substantial bulk photovoltaic effect enhancement via nanolayering

    PubMed Central

    Wang, Fenggong; Young, Steve M.; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M.

    2016-01-01

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials' responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)1−x). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times due to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. This opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition. PMID:26791545

  3. Substantial bulk photovoltaic effect enhancement via nanolayering

    DOE PAGESBeta

    Wang, Fenggong; Young, Steve M.; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M.

    2016-01-21

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials’ responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)1–x). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times duemore » to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. Lastly, this opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition.« less

  4. Catalyst enhances Claus operations

    SciTech Connect

    Dupin, T.; Voizin, R.

    1982-11-01

    An improved Claus catalyst offers superior activity that emphasizes hydrolysis of CS/sub 2/ in the first converter. The catalyst is insensitive to oxygen action at concentrations generally found in Claus gas feeds. It also has an excellent resistance to hydrothermal shocks that may occur during shutdown of the sulfur line. Collectively, these properties make this catalyst the most active formula now available for optimum Claus yields and COS/CS/sub 2/ hydrolysis conversion.

  5. Oxidation catalyst

    DOEpatents

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  6. Enhanced catalyst for conversion of syngas to liquid motor fuels

    DOEpatents

    Coughlin, P.K.; Rabo, J.A.

    1985-12-03

    Synthesis gas comprising carbon monoxide and hydrogen is converted to C[sub 5][sup +] hydrocarbons suitable for use as liquid motor fuels by contact with a dual catalyst system capable of enhancing the selectivity of said conversion to motor fuel range hydrocarbons and the quality of the resulting motor fuel product. The catalyst composition employs a Fischer-Tropsch catalyst, together with a co-catalyst/support component comprising a SAPO silicoaluminophosphate, non-zeolitic molecular sieve catalyst.

  7. Enhanced catalyst for conversion of syngas to liquid motor fuels

    DOEpatents

    Coughlin, Peter K.; Rabo, Jule A.

    1985-01-01

    Synthesis gas comprising carbon monoxide and hydrogen is converted to C.sub.5.sup.+ hydrocarbons suitable for use as liquid motor fuels by contact with a dual catalyst system capable of enhancing the selectivity of said conversion to motor fuel range hydrocarbons and the quality of the resulting motor fuel product. The catalyst composition employs a Fischer-Tropsch catalyst, together with a co-catalyst/support component comprising SAPO silicoaluminophosphate, non-zeolitic molecular sieve catalyst.

  8. Palladium–platinum core-shell icosahedra with substantially enhanced activity and durability towards oxygen reduction

    SciTech Connect

    Wang, Xue; Choi, Sang-Il; Roling, Luke T.; Luo, Ming; Ma, Cheng; Zhang, Lei; Chi, Miaofang; Liu, Jingyue; Xie, Zhaoxiong; Herron, Jeffrey A.; Mavrikakis, Manos; Xia, Younan

    2015-07-02

    Conformal deposition of platinum as ultrathin shells on facet-controlled palladium nanocrystals offers a great opportunity to enhance the catalytic performance while reducing its loading. Here we report such a system based on palladium icosahedra. Owing to lateral confinement imposed by twin boundaries and thus vertical relaxation only, the platinum overlayers evolve into a corrugated structure under compressive strain. For the core-shell nanocrystals with an average of 2.7 platinum overlayers, their specific and platinum mass activities towards oxygen reduction are enhanced by eight- and sevenfold, respectively, relative to a commercial catalyst. Density functional theory calculations indicate that the enhancement can be attributed to the weakened binding of hydroxyl to the compressed platinum surface supported on palladium. After 10,000 testing cycles, the mass activity of the core-shell nanocrystals is still four times higher than the commercial catalyst. Ultimately, these results demonstrate an effective approach to the development of electrocatalysts with greatly enhanced activity and durability.

  9. Palladium-platinum core-shell icosahedra with substantially enhanced activity and durability towards oxygen reduction

    NASA Astrophysics Data System (ADS)

    Wang, Xue; Choi, Sang-Il; Roling, Luke T.; Luo, Ming; Ma, Cheng; Zhang, Lei; Chi, Miaofang; Liu, Jingyue; Xie, Zhaoxiong; Herron, Jeffrey A.; Mavrikakis, Manos; Xia, Younan

    2015-07-01

    Conformal deposition of platinum as ultrathin shells on facet-controlled palladium nanocrystals offers a great opportunity to enhance the catalytic performance while reducing its loading. Here we report such a system based on palladium icosahedra. Owing to lateral confinement imposed by twin boundaries and thus vertical relaxation only, the platinum overlayers evolve into a corrugated structure under compressive strain. For the core-shell nanocrystals with an average of 2.7 platinum overlayers, their specific and platinum mass activities towards oxygen reduction are enhanced by eight- and sevenfold, respectively, relative to a commercial catalyst. Density functional theory calculations indicate that the enhancement can be attributed to the weakened binding of hydroxyl to the compressed platinum surface supported on palladium. After 10,000 testing cycles, the mass activity of the core-shell nanocrystals is still four times higher than the commercial catalyst. These results demonstrate an effective approach to the development of electrocatalysts with greatly enhanced activity and durability.

  10. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, Wolfgang M. H.; Tzou, Ming-Shin; Jiang, Hui-Jong

    1987-01-01

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  11. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, W.M.H.; Tzou, M.S.; Jiang, H.J.

    1987-03-31

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  12. Palladium-platinum core-shell icosahedra with substantially enhanced activity and durability towards oxygen reduction.

    PubMed

    Wang, Xue; Choi, Sang-Il; Roling, Luke T; Luo, Ming; Ma, Cheng; Zhang, Lei; Chi, Miaofang; Liu, Jingyue; Xie, Zhaoxiong; Herron, Jeffrey A; Mavrikakis, Manos; Xia, Younan

    2015-01-01

    Conformal deposition of platinum as ultrathin shells on facet-controlled palladium nanocrystals offers a great opportunity to enhance the catalytic performance while reducing its loading. Here we report such a system based on palladium icosahedra. Owing to lateral confinement imposed by twin boundaries and thus vertical relaxation only, the platinum overlayers evolve into a corrugated structure under compressive strain. For the core-shell nanocrystals with an average of 2.7 platinum overlayers, their specific and platinum mass activities towards oxygen reduction are enhanced by eight- and sevenfold, respectively, relative to a commercial catalyst. Density functional theory calculations indicate that the enhancement can be attributed to the weakened binding of hydroxyl to the compressed platinum surface supported on palladium. After 10,000 testing cycles, the mass activity of the core-shell nanocrystals is still four times higher than the commercial catalyst. These results demonstrate an effective approach to the development of electrocatalysts with greatly enhanced activity and durability. PMID:26133469

  13. Palladium–platinum core-shell icosahedra with substantially enhanced activity and durability towards oxygen reduction

    DOE PAGESBeta

    Wang, Xue; Choi, Sang-Il; Roling, Luke T.; Luo, Ming; Ma, Cheng; Zhang, Lei; Chi, Miaofang; Liu, Jingyue; Xie, Zhaoxiong; Herron, Jeffrey A.; et al

    2015-07-02

    Conformal deposition of platinum as ultrathin shells on facet-controlled palladium nanocrystals offers a great opportunity to enhance the catalytic performance while reducing its loading. Here we report such a system based on palladium icosahedra. Owing to lateral confinement imposed by twin boundaries and thus vertical relaxation only, the platinum overlayers evolve into a corrugated structure under compressive strain. For the core-shell nanocrystals with an average of 2.7 platinum overlayers, their specific and platinum mass activities towards oxygen reduction are enhanced by eight- and sevenfold, respectively, relative to a commercial catalyst. Density functional theory calculations indicate that the enhancement can bemore » attributed to the weakened binding of hydroxyl to the compressed platinum surface supported on palladium. After 10,000 testing cycles, the mass activity of the core-shell nanocrystals is still four times higher than the commercial catalyst. Ultimately, these results demonstrate an effective approach to the development of electrocatalysts with greatly enhanced activity and durability.« less

  14. Enhanced catalyst stability for cyclic co methanation operations

    DOEpatents

    Risch, Alan P.; Rabo, Jule A.

    1983-01-01

    Carbon monoxide-containing gas streams are passed over a catalyst to deposit a surface layer of active surface carbon thereon essentially without the formation of inactive coke. The active carbon is thereafter reacted with steam or hydrogen to form methane. Enhanced catalyst stability for long term, cyclic operation is obtained by the incorporation of an alkali or alkaline earth dopant in a silica binding agent added to the catalyst-support additive composition.

  15. Enhanced catalyst for converting synthesis gas to liquid motor fuels

    DOEpatents

    Coughlin, Peter K.

    1986-01-01

    The conversion of synthesis gas to liquid molar fuels by means of a cobalt Fischer-Tropsch catalyst composition is enhanced by the addition of molybdenum, tungsten or a combination thereof as an additional component of said composition. The presence of the additive component increases the olefinic content of the hydrocarbon products produced. The catalyst composition can advantageously include a support component, such as a molecular sieve, co-catalyst/support component or a combination of such support components.

  16. Enhanced Oxidation Catalysts for Water Reclamation

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.

    1999-01-01

    This effort seeks to develop and test high-performance, long operating life, physically stable catalysts for use in spacecraft water reclamation systems. The primary goals are to a) reduce the quantity of expendable water filters used to purify water aboard spacecraft, b) to extend the life of the oxidation catalysts used for eliminating organic contaminants in the water reclamation systems, and c) reduce the weight/volume of the catalytic oxidation systems (e.g. VRA) used. This effort is targeted toward later space station utilization and will consist of developing flight-qualifiable catalysts and long-term ground tests of the catalyst prior to their utilization in flight. Fixed -bed catalytic reactors containing 5% platinum on granular activated carbon have been subjected to long-term dynamic column tests to measure catalyst stability vs throughput. The data generated so far indicate that an order of magnitude improvement can be obtained with the treated catalysts vs the control catalyst, at only a minor loss (approx 10%) in the initial catalytic activity.

  17. Nanoscale Catalysts for NMR Signal Enhancement by Reversible Exchange

    PubMed Central

    Shi, Fan; Coffey, Aaron M.; Waddell, Kevin W.; Chekmenev, Eduard Y.; Goodson, Boyd M.

    2015-01-01

    Two types of nanoscale catalysts were created to explore NMR signal enhancement via reversible exchange (SABRE) at the interface between heterogeneous and homogeneous conditions. Nanoparticle and polymer comb variants were synthesized by covalently tethering Ir-based organometallic catalysts to support materials comprised of TiO2/PMAA (poly methacrylic acid) and PVP (polyvinyl pyridine), respectively, and characterized by AAS, NMR, and DLS. Following parahydrogen (pH2) gas delivery to mixtures containing one type of “nano-SABRE” catalyst particles, a target substrate, and ethanol, up to ~(−)40-fold and ~(−)7-fold 1H NMR signal enhancements were observed for pyridine substrates using the nanoparticle and polymer comb catalysts, respectively, following transfer to high field (9.4 T). These enhancements appear to result from intact particles and not from any catalyst molecules leaching from their supports; unlike the case with homogeneous SABRE catalysts, high-field (in situ) SABRE effects were generally not observed with the nanoscale catalysts. The potential for separation and reuse of such catalyst particles is also demonstrated. Taken together, these results support the potential utility of rational design at molecular, mesoscopic, and macroscopic/engineering levels for improving SABRE and HET-SABRE (heterogeneous-SABRE) for applications varying from fundamental studies of catalysis to biomedical imaging. PMID:26185545

  18. Substantial optical dielectric enhancement by volume compression in LiAsSe2

    NASA Astrophysics Data System (ADS)

    Zheng, Fan; Brehm, John A.; Young, Steve M.; Kim, Youngkuk; Rappe, Andrew M.

    2016-05-01

    Based on first-principles calculations, we predict a substantial increase in the optical dielectric function of LiAsSe2 under pressure. We find that the optical dielectric constant is enhanced threefold under compression along all three axes by 3%. This enhancement is mainly due to the dimerization strength reduction of the one-dimensional (1D) As-Se chains in LiAsSe2, which significantly alters the wave function phase mismatch between two neighboring chains and changes the transition intensity. By developing a tight-binding model of the interacting 1D chains, the essential features of the low-energy electronic structure of LiAsSe2 are captured. Our findings are important for understanding the fundamental physics of LiAsSe2 and provide a feasible way to enhance the material optical response that can be applied to light harvesting for energy applications.

  19. Prolonging the hydration and active metabolism from light periods into nights substantially enhances lichen growth.

    PubMed

    Bidussi, Massimo; Gauslaa, Yngvar; Solhaug, Knut Asbjørn

    2013-05-01

    This study investigates how hydration during light and dark periods influences growth in two epiphytic old forest lichens, the green algal Lobaria pulmonaria and the cyanobacterial L. scrobiculata. The lichens were cultivated in growth chambers for 14 days (200 μmol m(-1) s(-2); 12 h photoperiod) at four temperature regimes (25/20 °C, 21/16 °C, 13/8 °C, and 6/1 °C; day/night temperatures) and two hydration regimes (12 h day-time hydration; 12 h day-time + 12 h night-time hydration). Growth was highly dynamic, showing that short-term growth experiments in growth cabinets have a high, but largely unexplored potential in functional lichen studies. The highest measured growth rates were not far from the maximal dry matter gain estimated from published net photosynthetic CO2 uptake data. For the entire data set, photobiont type, temperature, hydration regime and specific thallus mass accounted for 46.6 % of the variation in relative growth rate (RGR). Both species showed substantially higher relative growth rates based on both biomass (RGR) and thallus area (RTAGR) when they were hydrated day and night compared to hydration in light only. Chronic photoinhibition was substantial in thalli hydrated only during the day time and kept at the highest and lowest temperature regimes, resulting in exponential increases in RGR with increasing maximal PSII efficiency (F v/F m) in both species. However, the depression in F v/F m was stronger for the cyanolichen than for the cephalolichen at extreme temperatures. The growth-stimulating effect of night-time hydration suggests that nocturnal metabolic activity improves recovery of photoinhibition and/or enhances the conversion rate of photosynthates into thallus extension. PMID:23389675

  20. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Thomas K. Gale

    2006-06-30

    Catalysis is the key fundamental ingredient to convert elemental mercury in coal-fired power stations into its oxidized forms that are more easily captured by sorbents, ESPs, baghouses, and wet scrubbers, whether the catalyst be unburned carbon (UBC) in the ash or vanadium pentoxide in SCR catalysts. This project has investigated several different types of catalysts that enhance mercury oxidation in several different ways. The stated objective of this project in the Statement of Objectives included testing duct-injection catalysts, catalyst-sorbent hybrids, and coated low-pressure-drop screens. Several different types of catalysts were considered for duct injection, including different forms of iron and carbon. Duct-injection catalysts would have to be inexpensive catalysts, as they would not be recycled. Iron and calcium had been shown to catalyze mercury oxidation in published bench-scale tests. However, as determined from results of an on-going EPRI/EPA project at Southern Research, while iron and calcium did catalyze mercury oxidation, the activity of these catalysts was orders of magnitude below that of carbon and had little impact in the short residence times available for duct-injected catalysts or catalyst-sorbent hybrids. In fact, the only catalyst found to be effective enough for duct injection was carbon, which is also used to capture mercury and remove it from the flue gas. It was discovered that carbon itself is an effective catalyst-sorbent hybrid. Bench-scale carbon-catalyst tests were conducted, to obtain kinetic rates of mercury adsorption (a key step in the catalytic oxidation of mercury by carbon) for different forms of carbon. All carbon types investigated behaved in a similar manner with respect to mercury sorption, including the effect of temperature and chlorine concentration. Activated carbon was more effective at adsorbing mercury than carbon black and unburned carbon (UBC), because their internal surface area of activated carbon was

  1. Surface Modified Coals for Enhanced Catalyst Dispersion and Liquefaction

    SciTech Connect

    Yaw D. Yeboah

    1998-12-04

    The aim of this study is to enhance catalyst loading and dispersion in coal for improved liquefaction by preadsorption of surfactants and catalysts on to the coal. During this reporting period, liquefaction experiments were conducted with the raw coal and catalyst loaded samples. Pretreatment of the coal and catalyst-loaded samples were done using the surfactants presented in previous reports. Liquefaction samples were tested using 6.6 g of solvent, 3.3 g coal, 6.9 MPa ambient hydrogen pressure, 425 0 C and 30 minutes. The liquid and solid products were removed from the reactor using tetrahydrofuran (THF). Coal conversions were calculated based on THF and heptane solubility. The results showed that in the absence of a catalyst, 33.8% heptane solubles was obtained with the parent coal compared to 27.8% and 27.3% with the SDS and DDAB surfactants. The presence of molybdenum, as expected, resulted in enhanced heptane solubles with or without surfactants. In the absence of surfactants, 50% heptane solubles was obtained compared to 40-47% with surfactants. Thus, it appears that pretreatment, unexpectedly, had a negative effect on liquefaction activity. It is unclear if the observed differences in results are significant. Clearly, additional experiments are needed before any firm deductions and conclusions can be drawn from the results.

  2. The use of catalyst to enhance the wet oxidation process.

    PubMed

    Maugans, C; Kumfer, B

    2007-01-01

    Wet oxidation tests were performed on two pure compound streams: acetic acid and ammonia; and on two wastewater streams: acrylic acid wastewater and sulphide laden spent caustic. Test results showed that Mn/Ce and Pt/TiO2 were effective catalysts that greatly enhanced acetic acid, ammonia and acrylic acid wastewater destruction. However, the Mn/Ce catalyst performance appears to be inhibited by concentrated salts dissolved in solution. This could limit the applicability of this catalyst for the treatment of brackish wastewaters. Zr, Ce and Ce nanoparticles were also shown to exhibit some catalytic activity, however not to the extent of the Mn/Ce and the Pt/TiO2. PMID:17674847

  3. SURFACE-MODIFIED COALS FOR ENHANCED CATALYST DISPERSION AND LIQUEFACTION

    SciTech Connect

    Dr. Yaw D. Yeboah

    1999-09-01

    This is the final report of the Department of Energy Sponsored project DE-FGF22-95PC95229 entitled, surface modified coals for enhanced catalyst dispersion and liquefaction. The aims of the study were to enhance catalyst loading and dispersion in coal for improved liquefaction by preadsorption of surfactants and catalysts on the coal and to train and educate minority scientists in catalysts and separation science. Illinois No. 6 Coal (DEC-24) was selected for the study. The surfactants investigated included dodecyl dimethyl ethyl ammonium bromide (DDAB), a cationic surfactant, sodium dodecyl sulfate, an anionic surfactant, and Triton x-100, a neutral surfactant. Ammonium molybdate tetrahydrate was used as the molybdenum catalyst precursor. Zeta potential, BET, FTIR, AFM, UV-Vis and luminescence intensity measurements were undertaken to assess the surface properties and the liquefaction activities of the coal. The parent coal had a net negative surface charge over the pH range 2-12. However, in the presence of DDAB the negativity of the surface charge decreased. At higher concentrations of DDAB, a positive surface charge resulted. In contrast to the effect of DDAB, the zeta potential of the coal became more negative than the parent coal in the presence of SDS. Adsorption of Triton reduced the net negative charge density of the coal samples. The measured surface area of the coal surface was about 30 m{sup 2}/g compared to 77m{sup 2}/g after being washed with deionized water. Addition of the surfactants decreased the surface area of the samples. Adsorption of the molybdenum catalyst increased the surface area of the coal sample. The adsorption of molybdenum on the coal was significantly promoted by preadsorption of DDAB and SDS. Molybdenum adsorption showed that, over a wide range of concentrations and pH values, the DDAB treated coal adsorbed a higher amount of molybdenum than the samples treated with SDS. The infrared spectroscopy (FTIR) and the atomic force

  4. Immobilized catalysts for iridium-catalyzed allylic amination: rate enhancement by immobilization.

    PubMed

    Malakar, Chandi C; Helmchen, Günter

    2015-05-01

    The first immobilized catalyst for Ir-catalyzed asymmetric allylic aminations is described. The catalyst is a cationic (π-allyl)Ir complex bound by cation exchange to an anionic silica gel support. Preparation of the catalyst is facile, and the supported catalyst displayed considerably enhanced activity compared with the parent homogeneous catalyst. Up to 43 consecutive amination runs were possible in recycling experiments. PMID:25787122

  5. Surface modified coals for enhanced catalyst dispersion and liquefaction

    SciTech Connect

    Dr. Yaw D. Yeboah

    1998-10-29

    The aim of the study is to enhance catalyst loading and dispersion in coal for improved liquefaction by preadsorption of surfactants and catalysts on to the coal. During this reporting period, zeta potential measurements were conducted to assess the surface charge on the raw, pretreated and catalyzed coal samples. The surface area, transmission spectroscopy and luminescence intensity of the raw coal and pretreated coal samples were also determined to assess the quality of the coal surface. Across a broad range of pH values, the raw coal had an overall negative charge. Coal treated with anionic surfactant SDS maintained an overall net negative surface negative charge. The interaction between the coal and cationic surfactant DDAB caused the opposite effect resulting in a more positive coal surface charge. Although one would have expected little or no effect of the neutral surfactant Triton X-100, there appears to be some difference in the results of the raw coal and the coal treated with Triton X-100. The authors believe that the Triton not only binds to the nonpolar sites but also has a strong affinity for the polar sites through electrostatic bonding and interaction between the hydrophobic tails. The addition of molybdenum to coal pretreated with DDAB caused a reduction in the positive charge of the coal surface probably due to possible ionic interaction between the coal surface, the surfactant and the catalyst. The adsorption isotherm of the coal was characteristic of isotherms for porous samples and the surface area of the coal increased from 30 m{sup 2}/g to 77 m{sup 2}/g when washed with deionized water. This suggests coal washing may be one method of increasing the surface area for surfactant adsorption. Although the transmission measurements provided valuable information about the coal it resulted in little information on the amount of adsorbed Triton. However, the maximum solid-liquid ratio for optimum surfactant loading of Triton X-100 was determined via

  6. Lipid Cross-Linking of Nanolipoprotein Particles Substantially Enhances Serum Stability and Cellular Uptake.

    PubMed

    Gilmore, Sean F; Blanchette, Craig D; Scharadin, Tiffany M; Hura, Greg L; Rasley, Amy; Corzett, Michele; Pan, Chong-Xian; Fischer, Nicholas O; Henderson, Paul T

    2016-08-17

    Nanolipoprotein particles (NLPs) consist of a discoidal phospholipid lipid bilayer confined by an apolipoprotein belt. NLPs are a promising platform for a variety of biomedical applications due to their biocompatibility, size, definable composition, and amphipathic characteristics. However, poor serum stability hampers the use of NLPs for in vivo applications such as drug formulation. In this study, NLP stability was enhanced upon the incorporation and subsequent UV-mediated intermolecular cross-linking of photoactive DiynePC phospholipids in the lipid bilayer, forming cross-linked nanoparticles (X-NLPs). Both the concentration of DiynePC in the bilayer and UV exposure time significantly affected the resulting X-NLP stability in 100% serum, as assessed by size exclusion chromatography (SEC) of fluorescently labeled particles. Cross-linking did not significantly impact the size of X-NLPs as determined by dynamic light scattering and SEC. X-NLPs had essentially no degradation over 48 h in 100% serum, which is a drastic improvement compared to non-cross-linked NLPs (50% degradation by ∼10 min). X-NLPs had greater uptake into the human ATCC 5637 bladder cancer cell line compared to non-cross-linked particles, indicating their potential utility for targeted drug delivery. X-NLPs also exhibited enhanced stability following intravenous administration in mice. These results collectively support the potential utility of X-NLPs for a variety of in vivo applications. PMID:27411034

  7. Pre-dawn stomatal opening does not substantially enhance early-morning photosynthesis in Helianthus annuus.

    PubMed

    Auchincloss, Lisa; Easlon, Hsien M; Levine, Diedre; Donovan, Lisa; Richards, James H

    2014-06-01

    Most C3 plant species have partially open stomata during the night especially in the 3-5 h before dawn. This pre-dawn stomatal opening has been hypothesized to enhance early-morning photosynthesis (A) by reducing diffusion limitations to CO2 at dawn. We tested this hypothesis in cultivated Helianthus annuus using whole-shoot gas exchange, leaf level gas exchange and modelling approaches. One hour pre-dawn low-humidity treatments were used to reduce pre-dawn stomatal conductance (g). At the whole-shoot level, a difference of pre-dawn g (0.40 versus 0.17 mol m(-2) s(-1)) did not significantly affect A during the first hour after dawn. Shorter term effects were investigated with leaf level gas exchange measurements and a difference of pre-dawn g (0.10 versus 0.04 mol m(-2) s(-1)) affected g and A for only 5 min after dawn. The potential effects of a wider range of stomatal apertures were explored with an empirical model of the relationship between A and intercellular CO2 concentration during the half-hour after dawn. Modelling results demonstrated that even extremely low pre-dawn stomatal conductance values have only a minimal effect on early-morning A for a few minutes after dawn. Thus, we found no evidence that pre-dawn stomatal opening enhances A. PMID:24895756

  8. Arginine-Containing Ligands Enhance H-2 Oxidation Catalyst Performance

    SciTech Connect

    Dutta, Arnab; Roberts, John A.; Shaw, Wendy J.

    2014-06-16

    In H2 fuel cells, performance depends on factors controlling turnover frequency and energy efficiency in the electrocatalytic oxidation of H2. Nature uses the hydrogenase enzymes to oxidize H2 at high turnover frequencies (up to 20,000 s-1) and low overpotentials (<100 mV), while the fastest synthetic catalyst reported to date only oxidizes H2 at 50 s-1 under 1 atm H2. Here we report a water-soluble complex incorporating the amino acid arginine, [NiII(PCy2NArg2)2]6+, that operates at 210 s-1 (180 mV overpotential) under 1 atm H2 and 144,000 s-1 (460 mV overpotential) under 133 atm H2. The complex functions from pH 0-14 with rates increasing at lower pH values. The arginine groups impart water solubility and play a critical role in enhancing turnover frequency, most consistent with an intramolecular Arg-Arg interaction that controls the structure of the catalyst active site. This work was funded by the Office of Science Early Career Research Program through the US DOE, BES (AD, WJS), and the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US DOE, BES (JASR). PNNL is operated by Battelle for the US DOE.

  9. Enhancement of alkylation catalysts for improved supercritical fluid regeneration

    DOEpatents

    Ginosar, Daniel M.; Petkovic, Lucia

    2009-09-22

    A method of modifying an alkylation catalyst to reduce the formation of condensed hydrocarbon species thereon. The method comprises providing an alkylation catalyst comprising a plurality of active sites. The plurality of active sites on the alkylation catalyst may include a plurality of weakly acidic active sites, intermediate acidity active sites, and strongly acidic active sites. A base is adsorbed to a portion of the plurality of active sites, such as the strongly acidic active sites, selectively poisoning the strongly acidic active sites. A method of modifying the alkylation catalyst by providing an alkylation catalyst comprising a pore size distribution that sterically constrains formation of the condensed hydrocarbon species on the alkylation catalyst or by synthesizing the alkylation catalyst to comprise a decreased number of strongly acidic active sites is also disclosed, as is a method of improving a regeneration efficiency of the alkylation catalyst.

  10. Enhancement of alkylation catalysts for improved supercritical fluid regeneration

    DOEpatents

    Ginosar, Daniel M.; Petkovic, Lucia M.

    2010-12-28

    A method of modifying an alkylation catalyst to reduce the formation of condensed hydrocarbon species thereon. The method comprises providing an alkylation catalyst comprising a plurality of active sites. The plurality of active sites on the alkylation catalyst may include a plurality of weakly acidic active sites, intermediate acidity active sites, and strongly acidic active sites. A base is adsorbed to a portion of the plurality of active sites, such as the strongly acidic active sites, selectively poisoning the strongly acidic active sites. A method of modifying the alkylation catalyst by providing an alkylation catalyst comprising a pore size distribution that sterically constrains formation of the condensed hydrocarbon species on the alkylation catalyst or by synthesizing the alkylation catalyst to comprise a decreased number of strongly acidic active sites is also disclosed, as is a method of improving a regeneration efficiency of the alkylation catalyst.

  11. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Jared W. Cannon; Thomas K. Gale

    2004-12-31

    Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. Three different SCR catalysts are being studied. These are honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts are manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Test methods and experimental procedures were developed for current and future testing. The methods and procedures equalize factors influencing mercury adsorption and oxidation (surface area, catalyst activity, and pore structure) that normally differ for each catalyst type. Initial testing was performed to determine the time necessary for each catalyst to reach surface-adsorption equilibrium. In addition, the fraction of Hg oxidized by each of the SCR catalyst types is being investigated, for a given amount of catalyst and flow rate of mercury and flue gas. The next major effort will be to examine the kinetics of mercury oxidation across the SCR catalysts with respect to changes in mercury concentration and with respect to HCl concentration. Hg-sorption equilibrium times will also be investigated with respect to ammonia concentration in the simulated flue gas.

  12. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Thomas K. Gale

    2005-12-31

    Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. Three different SCR catalysts are currently being studied in this project--honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Future work to characterize flue gas simulations typically derived from low and high sulfur bituminous coal are being performed in a stepwise manner, to avoid the constant interruptions in testing that occur when leaks in the system are generated during temperature transitions. Specifically, chlorine concentration vs. mercury oxidation correlations will be developed for each catalyst. The contributions of temperature are also being investigated. SO2 oxidation is also being investigated for each test condition.

  13. Enhanced catalyst and process for converting synthesis gas to liquid motor fuels

    DOEpatents

    Coughlin, Peter K.

    1986-01-01

    The conversion of synthesis gas to liquid molar fuels by means of a cobalt Fischer-Tropsch catalyst composition is enhanced by the addition of molybdenum, tungsten or a combination thereof as an additional component of said composition. The presence of the additive component increases the olefinic content of the hydrocarbon products produced. The catalyst composition can advantageously include a support component, such as a molecular sieve, co-catalyst/support component or a combination of such support components.

  14. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Alex J. Berry; Thomas K. Gale

    2005-09-30

    Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. The testing was performed at Southern Research's Catalyst Test Facility, a bench-scale reactor capable of simulating gas-phase reactions occurring in coal-fired utility pollution-control equipment. Three different SCR catalysts are currently being studied in this project - honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Methods and procedures for experimental testing continue to be developed to produce the highest quality mercury-oxidation data. Most experiments so far have focused on testing the catalysts in a simulated Powder River Basin (PRB) flue-gas environment, which contains lower sulfur and chlorine than produced by other coals. Future work to characterize flue gas simulations typically derived from low and high sulfur bituminous coal will be performed in a stepwise manner, to avoid the constant interruptions in testing that occur when leaks in the system are generated during temperature transitions. Specifically, chlorine concentration vs. mercury oxidation graph will be developed for each catalyst. The contributions of temperature and later sulfur will be investigated after this is complete. Also, last quarter's tests showed a potential linear relationship between SO3 conversion and mercury oxidation. As a result, SO3 samples will be taken more frequently to investigate each catalyst's ability to selectively oxidize mercury.

  15. -based catalysts with engineered morphologies for soot oxidation to enhance soot-catalyst contact

    NASA Astrophysics Data System (ADS)

    Miceli, Paolo; Bensaid, Samir; Russo, Nunzio; Fino, Debora

    2014-05-01

    As morphology plays a relevant role in solid/solid catalysis, where the number of contact points is a critical feature in this kind of reaction, three different ceria morphologies have been investigated in this work as soot oxidation catalysts: ceria nanofibers, which can become organized as a catalytic network inside diesel particulate filter channels and thus trap soot particles at several contact points but have a very low specific surface area (4 m2/g); solution combustion synthesis ceria, which has an uncontrolled morphology but a specific surface area of 31 m2/g; and three-dimensional self-assembled (SA) ceria stars, which have both high specific surface area (105 m2/g) and a high availability of contact points. A high microporous volume of 0.03 cm3/g and a finer crystallite size compared to the other morphologies suggested that self-assembled stars could improve their redox cycling capability and their soot oxidation properties. In this comparison, self-assembled stars have shown the best tendency towards soot oxidation, and the temperature of non-catalytic soot oxidation has dropped from 614°C to 403°C in tight and to 552°C in loose contact conditions, respectively. As far as the loose contact results are concerned, this condition being the most realistic and hence the most significant, self-assembled stars have exhibited the lowest T 10% onset temperature of this trio (even after ageing), thus proving their higher intrinsic activity. Furthermore, the three-dimensional shape of self-assembled stars may involve more of the soot cake layer than the solution combustion synthesis or nanofibers of ceria and thus enhance the total number of contact points. The results obtained through this work have encouraged our efforts to understand soot oxidation and to transpose these results to real diesel particulate filters.

  16. Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity

    SciTech Connect

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2000-07-01

    This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations.

  17. Novel Intermetallic Catalysts to Enhance PEM Membrane Durability

    SciTech Connect

    Francis J. DiSalvo

    2009-01-06

    The research examined possible sources of degradation of platinum based anode catalysts under long term use. Scientists at the United Technologies Research Center had shown that the anode as well as the cathode catalysts degrade in hydrogen fuel cells. This goal of this research was to see if mechanisms of anode degradation could be understood using forefront electrochemical techniques in an aqueous system. We found that this method is limited by the very low levels of impurities (perhaps less than a part per trillion) in the electrolyte. This limitation comes from the relatively small catalyst surface area (a few sq cm or less) compared to the electrolyte volume of 10 to 25 ml. In real fuel cells this ratio is completelyreversed: high catalyst surface area and low electrolyte violume, making the system much less sensitive to impurities in the electrolyte. We conclude that degradation mechanisms should be studied in real fuel cell systems, rather than in ex-situ, large electrolyte volume experiments.

  18. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Jared W. Cannon; Thomas K. Gale

    2005-06-30

    Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. The testing was performed at Southern Research's Catalyst Test Facility, a bench-scale reactor capable of simulating gas-phase reactions occurring in coal-fired utility pollution-control equipment. Three different SCR catalysts are currently being studied in this project--honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Methods and procedures for experimental testing continue to be developed to produce the highest quality mercury-oxidation data. During this past quarter, it was discovered that long periods (12 - 24 hours) are required to equilibrate the catalysts in the system. In addition, after the system has been equilibrated, operational changes to temperature, gas concentration, or flow rate shifts the equilibrium, and steady-state must be reestablished, which can require as much as twelve additional hours per condition change. In the last quarter of testing, it was shown that the inclusion of ammonia had a strong effect on the oxidation of mercury by SCR catalysts, both in the short-term (a transitional period of elemental and oxidized mercury off gassing) and the long-term (less steady-state mercury oxidation). All experiments so far have focused on testing the catalysts in a simulated Powder River Basin (PRB) flue-gas environment, which contains lower sulfur and chlorine than produced by other coals. In the next quarter, parametric testing will be expanded to include flue gases simulating power plants burning

  19. Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity

    DOEpatents

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2002-01-01

    A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime, high frequency, high power bursts of low-duty factor microwaves sufficient to generate a plasma discharge and passing a gas to be treated through the discharge so as to cause dissociative reduction of the exhaust gases and enhanced catalyst reactivity through application of the pulsed microwave fields directly to the catalyst material sufficient to cause a polarizability catastrophe and enhanced heating of the metal crystallite particles of the catalyst, and in the presence or absence of the plasma. The invention also includes a reactor for aftertreatment of exhaust gases.

  20. Robust Resilience and Substantial Interest: A Survey of Pharmacological Cognitive Enhancement among University Students in the UK and Ireland

    PubMed Central

    Singh, Ilina; Bard, Imre; Jackson, Jonathan

    2014-01-01

    Use of ‘smart drugs’ among UK students is described in frequent media reports as a rapidly increasing phenomenon. This article reports findings from the first large-scale survey of pharmacological cognitive enhancement (PCE) among students in the UK and Ireland. Conducted from February to September 2012, a survey of a convenience sample of 877 students measured PCE prevalence, attitudes, sources, purposes and ethics. Descriptive and logistic regression statistical methods were used to analyse the data. Lifetime prevalence of PCE using modafinil, methylphenidate or Adderall was under 10%, while past regular and current PCE users of these substances made up between 0.3%–4% of the survey population. A substantial majority of students was unaware of and/or uninterested in PCE; however about one third of students were interested in PCE. PCE users were more likely to be male, British and older students; predictors of PCE use included awareness of other students using PCEs, ADHD symptomatology, ethical concerns, and alcohol and cannabis use. The survey addresses the need for better evidence about PCE prevalence and practices among university students in the UK. We recommend PCE-related strategies for universities based on the survey findings. PMID:25356917

  1. Catalyst design for enhanced sustainability through fundamental surface chemistry.

    PubMed

    Personick, Michelle L; Montemore, Matthew M; Kaxiras, Efthimios; Madix, Robert J; Biener, Juergen; Friend, Cynthia M

    2016-02-28

    Decreasing energy consumption in the production of platform chemicals is necessary to improve the sustainability of the chemical industry, which is the largest consumer of delivered energy. The majority of industrial chemical transformations rely on catalysts, and therefore designing new materials that catalyse the production of important chemicals via more selective and energy-efficient processes is a promising pathway to reducing energy use by the chemical industry. Efficiently designing new catalysts benefits from an integrated approach involving fundamental experimental studies and theoretical modelling in addition to evaluation of materials under working catalytic conditions. In this review, we outline this approach in the context of a particular catalyst-nanoporous gold (npAu)-which is an unsupported, dilute AgAu alloy catalyst that is highly active for the selective oxidative transformation of alcohols. Fundamental surface science studies on Au single crystals and AgAu thin-film alloys in combination with theoretical modelling were used to identify the principles which define the reactivity of npAu and subsequently enabled prediction of new reactive pathways on this material. Specifically, weak van der Waals interactions are key to the selectivity of Au materials, including npAu. We also briefly describe other systems in which this integrated approach was applied. PMID:26755756

  2. Controllably interfacing with metal: a strategy for enhancing CO oxidation on oxide catalysts by surface polarization.

    PubMed

    Bai, Yu; Zhang, Wenhua; Zhang, Zhenhua; Zhou, Jie; Wang, Xijun; Wang, Chengming; Huang, Weixin; Jiang, Jun; Xiong, Yujie

    2014-10-22

    Heterogeneous catalysis often involves charge transfer from catalyst surface to adsorbed molecules, whose activity thus depends on the surface charge density of catalysts. Here, we demonstrate a unique solution-phase approach to achieve controllable interfacial lengths in oxide-metal hybrid structures. Resulting from their different work functions, surface polarization is induced by the Ag-CuO interface and acts to tailor the surface charge state of CuO. As a result, the designed hybrid catalysts exhibit enhanced intrinsic activities in catalyzing CO oxidation in terms of apparent activation energy, as compared with their counterparts. Moreover, the CO conversion rate can be enhanced by maximizing the Ag-CuO interfacial length and thus the number of active sites on the CuO. This work provides a new strategy for tuning catalytic performance by controlling interface in hybrid catalysts. PMID:25296380

  3. Nano mineral fiber enhanced catalyst coated membranes for improving polymer electrolyte membrane fuel cell durability

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Xu, Ran; Mu, Shichun

    In order to protect the perfluorosulfonic acid (PFSA) ionomer from an attack of contaminant metal ions as well as to enhance the mechanical stability of catalyst layers, palygorskite (PGS) is introduced into the catalyst layer of polymer electrolyte membrane fuel cells. PGS is a widely used natural nano-sized silicate mineral fiber with unique nano-sized channel structure, has a strong absorption capacity for heavy metal ions. We identify a negative influence of Fe 2+ on PFSA membranes to make a comparative study. Subsequently catalyst coated membranes (CCMs) prepared with a PGS-Pt/C composite catalyst show a great effect in reducing Fe 2+ ion crossover. Results display that PGS absorbs Fe 2+ in nano-structure channels, and effectively protect PFSA ionomer in both the catalyst layer and membrane from hydroxyl radicals (OH rad) attack. Thus, the chemical stability of PFSA ionomer in both the catalyst layer and membrane is greatly improved. Furthermore, the enhancement of the mechanical performance of catalyst layers is discussed.

  4. Enhanced High Temperature Performance of NOx Reduction Catalyst Materials

    SciTech Connect

    Gao, Feng; Kim, Do Heui; Luo, Jinyong; Muntean, George G.; Peden, Charles HF; Howden, Ken; Currier, Neal; Kamasamudram, Krishna; Kumar, Ashok; Li, Junhui; Stafford, Randy; Yezerets, Aleksey; Castagnola, Mario; Chen, Hai Ying; Hess, Howard ..

    2012-12-31

    Two primary NOx after-treatment technologies have been recognized as the most promising approaches for meeting stringent NOx emission standards for diesel vehicles within the Environmental Protection Agency’s (EPA’s) 2007/2010 mandated limits, NOx Storage Reduction (NSR) and NH3 selective catalytic reduction (SCR); both are, in fact being commercialized for this application. However, in looking forward to 2015 and beyond with expected more stringent regulations, the continued viability of the NSR technology for controlling NOx emissions from lean-burn engines such as diesels will require at least two specific, significant and inter-related improvements. First, it is important to reduce system costs by, for example, minimizing the precious metal content while maintaining, even improving, performance and long-term stability. A second critical need for future NSR systems, as well as for NH3 SCR, will be significantly improved higher and lower temperature performance and stability. Furthermore, these critically needed improvements will contribute significantly to minimizing the impacts to fuel economy of incorporating these after-treatment technologies on lean-burn vehicles. To meet these objectives will require, at a minimum an improved scientific understanding of the following things: i) the various roles for the precious and coinage metals used in these catalysts; ii) the mechanisms for these various roles; iii) the effects of high temperatures on the active metal performance in their various roles; iv) mechanisms for higher temperature NOx storage performance for modified and/or alternative storage materials; v) the interactions between the precious metals and the storage materials in both optimum NOx storage performance and long term stability; vi) the sulfur adsorption and regeneration mechanisms for NOx reduction materials; vii) materials degradation mechanisms in CHA-based NH3 SCR catalysts. The objective of this CRADA project between PNNL and Cummins, Inc

  5. Photo-oxidation catalysts

    DOEpatents

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis

    2009-07-14

    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  6. Substantial enhancement of red emission intensity by embedding Eu-doped GaN into a microcavity

    NASA Astrophysics Data System (ADS)

    Inaba, Tomohiro; Lee, Dong-gun; Wakamatsu, Ryuta; Kojima, Takanori; Mitchell, Brandon; Capretti, Antonio; Gregorkiewicz, Tom; Koizumi, Atsushi; Fujiwara, Yasufumi

    2016-04-01

    We investigate resonantly excited photoluminescence from a Eu,O-codoped GaN layer embedded into a microcavity, consisting of an AlGaN/GaN distributed Bragg reflector and a Ag reflecting mirror. The microcavity is responsible for a 18.6-fold increase of the Eu emission intensity at ˜10K, and a 21-fold increase at room temperature. We systematically investigate the origin of this enhancement, and we conclude that it is due to the combination of several effects including, the lifetime shortening of the Eu emission, the strain-induced piezoelectric effect, and the increased extraction and excitation field efficiencies. This study paves the way for an alternative method to enhance the photoluminescence intensity in rare-earth doped semiconductor structures.

  7. A novel catalyst of warm-cloud seeding to enhance precipitation

    NASA Astrophysics Data System (ADS)

    Zhu, H. X.; Li, X. D.; Yang, R. J.

    2016-07-01

    Water is necessary for sustaining human life. In many regions of the world, traditional water sources cannot meet increasing water demands. Warm-cloud seeding is an efficient way to augment water supplies. In this paper, we explore two new hygroscopicity catalysts: Poly acrylamide (PAM) and Sodium polyacrylate (PAAS). We designed a series of experiments to investigate the effects of these catalysts together with common catalyst salt powder (NaCl). The experiment was held in a cloud chamber built in our laboratory. The results show that: 1) Catalysed by NaCl, a dose of 0.91g/m3 can obtain the best precipitation efficiency and enhancement rate at 70.8% and 142%, respectively; 2) A 1.36g/m3 dose catalysed by PAM and PAAS exhibits optimal performance at 76.7% and 70.4% precipitation efficiency, respectively; 3) Under the same conditions, PAM shows better catalytic effects than NaCl does.

  8. Alumina over-coating on Pd nanoparticle catalysts by atomic layer deposition : enhanced stability and reactivity.

    SciTech Connect

    Feng, H.; Lu, J.; Stair, P. C.; Elam, J. W.

    2011-04-01

    ALD Alumina was utilized as a protective layer to inhibit the sintering of supported nano-sized ALD Pd catalysts in the methanol decomposition reaction carried out at elevated temperatures. The protective ALD alumina layers were synthesized on Pd nanoparticles (1-2 nm) supported on high surface area alumina substrates. Up to a certain over-coat thickness, the alumina protective layers preserved or even slightly enhanced the catalytic activity and prevented sintering of the Pd nanoparticles up to 500 C.

  9. Enhancement of Pt/SnO2 Catalysts by Addition of H2O

    NASA Technical Reports Server (NTRS)

    Schryer, David R.; Sidney, Barry D.; Van Norman, John D.; Brown, Kenneth G.; Schryer, Jacqueline; Upchurch, Billy T.

    1990-01-01

    Water vapor in pretreatment gas restores essential hydroxyl groups. Platinum on tin oxide (Pt/SnO2) is good catalyst for oxidation of carbon monoxide (CO) at temperatures from about 25 degrees C to 100 degress C. Activity of Pt/SnO2 for CO oxidation significantly enhanced by pretreating it at approximately 225 degrees C with reducing gas such as CO. Technique useful in manufacture of high-power CO2 lasers for industrial and scientific uses.

  10. Enhanced formic acid electro-oxidation reaction on ternary Pd-Ir-Cu/C catalyst

    NASA Astrophysics Data System (ADS)

    Chen, Jinwei; Zhang, Jie; Jiang, Yiwu; Yang, Liu; Zhong, Jing; Wang, Gang; Wang, Ruilin

    2015-12-01

    Aim to further reduce the cost of Pd-Ir for formic acid electro-oxidation (FAEO), the Cu was used to construct a ternary metallic alloy catalyst. The prepared catalysts are characterized using XRD, TGA, EDX, TEM, XPS, CO-stripping, cyclic voltammetry and chronoamperometry. It is found that the Pd18Ir1Cu6 nanoparticles with a mean size of 3.3 nm are highly dispersed on carbon support. Componential distributions on catalyst are consistent with initial contents. Electrochemical measurements show that the PdIrCu/C catalyst exhibits the highest activity for FAEO. The mass activity of Pd in Pd18Ir1Cu6/C at 0.16 V (vs. SCE) is about 1.47, 1.62 and 2.08 times as high as that of Pd18Cu6/C, Pd18Ir1/C and Pd/C, respectively. The activity enhancement of PdIrCu/C should be attributed to the weakened CO adsorption strength and the removal of adsorbed intermediates at lower potential with the addition of Cu and Ir.

  11. Enhanced Photochemical Hydrogen Production by a Molecular Diiron Catalyst Incorporated into a Metal-Organic Framework

    SciTech Connect

    Pullen, Sonja; Fei, Honghan; Orthaber, Andreas; Cohen, Seth M.; Ott, Sascha

    2013-12-04

    A molecular proton reduction catalyst [FeFe](dcbdt)(CO)6 (1, dcbdt = 1,4-dicarboxylbenzene-2,3-dithiolate) with structural similarities to [FeFe]-hydrogenase active sites has been incorporated into a highly robust Zr(IV)-based metal–organic framework (MOF) by postsynthetic exchange (PSE). The PSE protocol is crucial as direct solvothermal synthesis fails to produce the functionalized MOF. The molecular integrity of the organometallic site within the MOF is demonstrated by a variety of techniques, including X-ray absorption spectroscopy. In conjunction with [Ru(bpy)3]2+ as a photosensitizer and ascorbate as an electron donor, MOF-[FeFe](dcbdt)(CO)6 catalyzes photochemical hydrogen evolution in water at pH 5. The immobilized catalyst shows substantially improved initial rates and overall hydrogen production when compared to a reference system of complex 1 in solution. Improved catalytic performance is ascribed to structural stabilization of the complex when incorporated in the MOF as well as the protection of reduced catalysts 1 and 12– from undesirable charge recombination with oxidized ascorbate.

  12. Performance enhancement of low temperature polymer electrolyte membrane fuel cells by catalyst and support layer modifications

    NASA Astrophysics Data System (ADS)

    Hall, Timothy David

    Possible enhancement of low temperature polymer electrolyte membrane fuel cells (PEMFC) or direct methanol fuel cells (DMFC) was investigated by modifying catalyst and support layers. Platinum (Pt) and platinum cobalt (Pt xCo1-x) alloys were prepared by pulsed electrodeposition onto Toray carbon paper. Composite supports composed of either commercial multi-walled nanofiber (MWNF) mats or MWNF layers on a commercial backing were also investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and energy dispersive x-ray (EDX) were used to characterize the surface structure, composition, and catalyst loading. Various electrochemical techniques with a wet electrochemical cell, a Nuvant multi-array system, and a Scribner fuel cell system were used to study and rank the effectiveness of the catalysts and supports toward both the methanol oxidation reaction and the oxygen reduction reaction. The activity toward methanol oxidation of the electrodeposited Pt catalyst was found to be dependent on the deposited mass. Further comparisons between commercial electrodes in the Nuvant system showed these deposits can yield activities comparable to those of commercially available electrodes. The structure of the Pt electrodeposits was highly non-uniform due to the H2 evolution during the deposition process blocking the cathodes surface. The activities of the planar structured PtxCo1-x deposits were insignificant for both oxygen reduction and methanol oxidation. The composition of the deposits ranged from 5 to 15 at% Pt. It was found by both the Nuvant and Scribner systems that the addition of a thin hydrophilic MWNF layer to a hydrophobic electrode would enhance the performance of a DMFC anode. In the Nuvant system, the addition of a thin hydrophilic MWNF layer to a hydrophobic electrode also enhanced the PEM cathode activity. This however was not corroborated by Scribner analysis, showing a

  13. Plasmon-enhanced reverse water gas shift reaction over oxide supported Au catalysts

    SciTech Connect

    Upadhye, AA; Ro, I; Zeng, X; Kim, HJ; Tejedor, I; Anderson, MA; Dumesic, JA; Huber, GW

    2015-01-01

    We show that localized surface plasmon resonance (LSPR) can enhance the catalytic activities of different oxide-supported Au catalysts for the reverse water gas shift (RWGS) reaction. Oxide-supported Au catalysts showed 30 to 1300% higher activity for RWGS under visible light compared to dark conditions. Au/TiO2 catalyst prepared by the deposition-precipitation (DP) method with 3.5 nm average Au particle size showed the highest activity for the RWGS reaction. Visible light is converted into chemical energy for this reaction with up to a 5% overall efficiency. A shift in the apparent activation energy (from 47 kJ mol(-1) in dark to 35 kJ mol(-1) in light) and apparent reaction order with respect to CO2 (from 0.5 in dark to 1.0 in light) occurs due to the LSPR. Our kinetic results indicate that the LSPR increases the rate of either the hydroxyl hydrogenation or carboxyl decomposition more than any other steps in the reaction network.

  14. CeO2-based catalysts with engineered morphologies for soot oxidation to enhance soot-catalyst contact

    PubMed Central

    2014-01-01

    As morphology plays a relevant role in solid/solid catalysis, where the number of contact points is a critical feature in this kind of reaction, three different ceria morphologies have been investigated in this work as soot oxidation catalysts: ceria nanofibers, which can become organized as a catalytic network inside diesel particulate filter channels and thus trap soot particles at several contact points but have a very low specific surface area (4 m2/g); solution combustion synthesis ceria, which has an uncontrolled morphology but a specific surface area of 31 m2/g; and three-dimensional self-assembled (SA) ceria stars, which have both high specific surface area (105 m2/g) and a high availability of contact points. A high microporous volume of 0.03 cm3/g and a finer crystallite size compared to the other morphologies suggested that self-assembled stars could improve their redox cycling capability and their soot oxidation properties. In this comparison, self-assembled stars have shown the best tendency towards soot oxidation, and the temperature of non-catalytic soot oxidation has dropped from 614°C to 403°C in tight and to 552°C in loose contact conditions, respectively. As far as the loose contact results are concerned, this condition being the most realistic and hence the most significant, self-assembled stars have exhibited the lowest T10% onset temperature of this trio (even after ageing), thus proving their higher intrinsic activity. Furthermore, the three-dimensional shape of self-assembled stars may involve more of the soot cake layer than the solution combustion synthesis or nanofibers of ceria and thus enhance the total number of contact points. The results obtained through this work have encouraged our efforts to understand soot oxidation and to transpose these results to real diesel particulate filters. PMID:24940178

  15. CeO2-based catalysts with engineered morphologies for soot oxidation to enhance soot-catalyst contact.

    PubMed

    Miceli, Paolo; Bensaid, Samir; Russo, Nunzio; Fino, Debora

    2014-01-01

    AS MORPHOLOGY PLAYS A RELEVANT ROLE IN SOLID/SOLID CATALYSIS, WHERE THE NUMBER OF CONTACT POINTS IS A CRITICAL FEATURE IN THIS KIND OF REACTION, THREE DIFFERENT CERIA MORPHOLOGIES HAVE BEEN INVESTIGATED IN THIS WORK AS SOOT OXIDATION CATALYSTS: ceria nanofibers, which can become organized as a catalytic network inside diesel particulate filter channels and thus trap soot particles at several contact points but have a very low specific surface area (4 m(2)/g); solution combustion synthesis ceria, which has an uncontrolled morphology but a specific surface area of 31 m(2)/g; and three-dimensional self-assembled (SA) ceria stars, which have both high specific surface area (105 m(2)/g) and a high availability of contact points. A high microporous volume of 0.03 cm(3)/g and a finer crystallite size compared to the other morphologies suggested that self-assembled stars could improve their redox cycling capability and their soot oxidation properties. In this comparison, self-assembled stars have shown the best tendency towards soot oxidation, and the temperature of non-catalytic soot oxidation has dropped from 614°C to 403°C in tight and to 552°C in loose contact conditions, respectively. As far as the loose contact results are concerned, this condition being the most realistic and hence the most significant, self-assembled stars have exhibited the lowest T 10% onset temperature of this trio (even after ageing), thus proving their higher intrinsic activity. Furthermore, the three-dimensional shape of self-assembled stars may involve more of the soot cake layer than the solution combustion synthesis or nanofibers of ceria and thus enhance the total number of contact points. The results obtained through this work have encouraged our efforts to understand soot oxidation and to transpose these results to real diesel particulate filters. PMID:24940178

  16. Enhanced stability of multilayer graphene-supported catalysts for polymer electrolyte membrane fuel cell cathodes

    NASA Astrophysics Data System (ADS)

    Marinkas, A.; Hempelmann, R.; Heinzel, A.; Peinecke, V.; Radev, I.; Natter, H.

    2015-11-01

    One of the biggest challenges in the field of polymer electrolyte membrane fuel cells (PEMFC) is to enhance the lifetime and the long-term stability of PEMFC electrodes, especially of cathodes, furthermore, to reduce their platinum loading, which could lead to a cost reduction for efficient PEMFCs. These demands could be achieved with a new catalyst support architecture consisting of a composite of carbon structures with significant different morphologies. A highly porous cathode catalyst support layer is prepared by addition of various carbon types (carbon black particles, multi-walled carbon nanotubes (MWCNT)) to multilayer graphene (MLG). The reported optimized cathodes shows extremely high durability and similar performance to commercial standard cathodes but with 89% lower Pt loading. The accelerated aging protocol (AAP) on the membrane electrode assemblies (MEA) shows that the presence of MLG increases drastically the durability and the Pt-extended electrochemical surface area (ECSA). In fact, after the AAP slightly enhanced performance can be observed for the MLG-containing cathodes instead of a performance loss, which is typical for the commercial carbon-based cathodes. Furthermore, the presence of MLG drastically decreases the ECSA loss rate. The MLG-containing cathodes show up to 6.8 times higher mass-normalized Pt-extended ECSA compared to the commercial standard systems.

  17. Enhancing the efficiency and regioselectivity of P450 oxidation catalysts by unnatural amino acid mutagenesis.

    PubMed

    Kolev, Joshua N; Zaengle, Jacqueline M; Ravikumar, Rajesh; Fasan, Rudi

    2014-05-01

    The development of effective strategies for modulating the reactivity and selectivity of cytochrome P450 enzymes represents a key step toward expediting the use of these biocatalysts for synthetic applications. We have investigated the potential of unnatural amino acid mutagenesis to aid efforts in this direction. Four unnatural amino acids with diverse aromatic side chains were incorporated at 11 active-site positions of a substrate-promiscuous CYP102A1 variant. The resulting "uP450s" were then tested for their catalytic activity and regioselectivity in the oxidation of two representative substrates: a small-molecule drug and a natural product. Large shifts in regioselectivity resulted from these single mutations, and in particular, for para-acetyl-Phe substitutions at positions close to the heme cofactor. Screening this mini library of uP450s enabled us to identify P450 catalysts for the selective hydroxylation of four aliphatic positions in the target substrates, including a C(sp(3))-H site not oxidized by the parent enzyme. Furthermore, we discovered a general activity-enhancing effect of active-site substitutions involving the unnatural amino acid para-amino-Phe, which resulted in P450 catalysts capable of supporting the highest total turnover number reported to date on a complex molecule (34,650). The functional changes induced by the unnatural amino acids could not be reproduced by any of the 20 natural amino acids. This study thus demonstrates that unnatural amino acid mutagenesis constitutes a promising new strategy for improving the catalytic activity and regioselectivity of P450 oxidation catalysts. PMID:24692265

  18. Enhancing the Efficiency and Regioselectivity of P450 Oxidation Catalysts via Unnatural Amino Acid Mutagenesis

    PubMed Central

    Kolev, Joshua N.; Zaengle, Jacqueline M.; Ravikumar, Rajesh

    2014-01-01

    The development of effective strategies for modulating the reactivity and selectivity of cytochrome P450 enzymes represents a key step toward expediting the use of these biocatalysts for synthetic applications. In this work, we investigated the potential of unnatural amino acid mutagenesis to aid efforts in this direction. To this end, four unnatural amino acids comprising a diverse set of aromatic side-chain groups were incorporated into eleven active site positions of a substrate-promiscuous CYP102A1 variant. The resulting ‘uP450s’ were then tested for their catalytic activity and regioselectivity in the oxidation of two representative substrates consisting of a small-molecule drug and a natural product. Large shifts in regioselectivity were obtained as a result of these single mutations and, in particular, via para-acetyl-Phe substitutions at positions in close proximity to the heme cofactor. Notably, screening of this mini library of uP450s enabled the rapid identification of P450 catalysts for the selective hydroxylation of four aliphatic positions in the target substrates, including a C(sp3)—H site not oxidized by the parent enzyme. Furthermore, our studies led to the discovery of a general activity-enhancing effect of active site substitutions involving the unnatural amino acid para-amino-Phe, resulting in P450 catalysts capable of supporting the highest total turnover number reported to date on a complex molecule (34,650 turnovers). The functional changes induced by the unnatural amino acids could not be recapitulated by any of the twenty natural amino acids. This study thus demonstrates that unnatural amino acid mutagenesis constitutes a promising, new strategy for improving the catalytic activity and regioselectivity of P450 oxidation catalysts. PMID:24692265

  19. Facile fabrication of palladium-ionic liquids-nitrogen-doped graphene nanocomposites as enhanced electro-catalyst for ethanol oxidation

    NASA Astrophysics Data System (ADS)

    Li, Shuwen; Yang, Honglei; Ren, Ren; Ma, Jianxin; Jin, Jun; Ma, Jiantai

    2015-10-01

    The palladium-ionic liquids-nitrogen-doped graphene nanocomposites are facile fabricated as enhanced electro-catalyst for ethanol oxidation. First, the ionic liquids functionalized nitrogen-doping graphene nanosheets (PDIL-NGS) with few layers is synthesized through a facile and effective one-pot hydrothermal method with graphene oxide as raw material, urea as reducing-doping agents and ionic liquids (ILs) derived from 3,4,9,10-perylene tetracarboxylic acid as functional molecules. The results of systematic characterization reveal that the PDIL molecules not only can functionalize NGS by π-π stacking with no affecting the nitrogen doping but also prevent the agglomeration of NGS. More importantly, the processing performance and the property of electron transfer are remarkably enhanced duo to introducing a large number of ILs groups. Then, the enhanced electrocatalytic Pd nanoparticles are successfully anchored on PDIL-NGS by a facile and surfactant-free synthetic technique. As an anode catalyst, the novel catalyst exhibits better kinetics, more superior electrocatalytic performance, higher tolerance and electrochemical stability than the other catalysts toward ethanol electrooxidation, owing to the role of PDIL molecules. Therefore, the new catalyst is believed to have the potential use for direct alcohol fuel cells in the future and the functionalized NGS is promising useful materials applied in other fields.

  20. Desulfurization of coal: enhanced selectivity using phase transfer catalysts. Quarterly report, March 1 - May 31, 1996

    SciTech Connect

    Palmer, S.R.; Hippo, E.J.

    1996-12-31

    Due to environmental problems related to the combustion of high sulfur Illinois coal, there continues to be interest in the development in viable pre-combustion desulfurization processes. Recent studies by the authors have obtained very good sulfur removals but the reagents that are used are too expensive. Use of cheaper reagents leads to a loss of desired coal properties. This study investigated the application phase transfer catalysts to the selective oxidation of sulfur in coal using air and oxygen as oxidants. The phase transfer catalyst is expected to function as a selectivity moderator by permitting the use of milder reaction conditions that otherwise necessary. This would enhance the sulfur selectivity and help retain the heating value of the coal. The use of certain coal combustion wastes for desulfurization, and the application of cerium (IV) catalyzed air oxidation for selective sulfur oxidation are also being studied. If successful, this project could lead to the rapid development of a commercially viable desulfurization process. This would significantly improve the marketability of Illinois coal.

  1. Iron-based cathode catalyst with enhanced power density in polymer electrolyte membrane fuel cells.

    PubMed

    Proietti, Eric; Jaouen, Frédéric; Lefèvre, Michel; Larouche, Nicholas; Tian, Juan; Herranz, Juan; Dodelet, Jean-Pol

    2011-01-01

    H(2)-air polymer-electrolyte-membrane fuel cells are electrochemical power generators with potential vehicle propulsion applications. To help reduce their cost and encourage widespread use, research has focused on replacing the expensive Pt-based electrocatalysts in polymer-electrolyte-membrane fuel cells with a lower-cost alternative. Fe-based cathode catalysts are promising contenders, but their power density has been low compared with Pt-based cathodes, largely due to poor mass-transport properties. Here we report an iron-acetate/phenanthroline/zeolitic-imidazolate-framework-derived electrocatalyst with increased volumetric activity and enhanced mass-transport properties. The zeolitic-imidazolate-framework serves as a microporous host for phenanthroline and ferrous acetate to form a catalyst precursor that is subsequently heat treated. A cathode made with the best electrocatalyst from this work, tested in H(2)-O(2,) has a power density of 0.75 W cm(-2) at 0.6 V, a meaningful voltage for polymer-electrolyte-membrane fuel cells operation, comparable with that of a commercial Pt-based cathode tested under identical conditions. PMID:21811245

  2. Criteria for substantiating claims.

    PubMed

    Aggett, Peter J

    2007-01-01

    Claims are used to support public health advocacy and marketing. Their evidence base is variable. Claims are made on (i) nutrient content, (ii) comparative merits, (iii) health benefits, and (iv) medical benefits. Experience with therapeutic agents has aided the development of recommendations for the substantiation of health claims for foods and food components, with which dietary supplements would be included. An EU Concerted Activity, Functional Food Science in Europe, suggested that such claims should be based on the general outcomes of 'enhanced function' and 'reduced risk of disease'. A further EU Concerted Activity, The Process for the Assessment of Scientific Support for Claims on Foods, proposed that the evidence base should provide: a characterization of the food or food component to which the claimed effect is attributed; human data, primarily from intervention studies that represent the target populations for the claim; a dose-response relationship: evidence of allowing for confounders including lifestyle, consumption patterns, background diet and food matrix; an appropriate duration for the study; a measure of compliance; and have adequate statistical power to test the hypothesis. When ideal endpoints are not easily accessible for measurement, validated and quality assured markers of the intermediate or final outcomes could be used, as long as their relationship is well characterized. Overall, the totality and coherence of published and unpublished evidence should be considered. Assessments for substantiation need expert judgement, weighting of the strength of the claim, and intelligent use of the criteria applied on an individual basis with respect both to gaps in knowledge and to any need for new knowledge and data. PMID:17913223

  3. Enhanced methanol electro-oxidation reaction on Pt-CoOx/MWCNTs hybrid electro-catalyst

    NASA Astrophysics Data System (ADS)

    Nouralishahi, Amideddin; Rashidi, Ali Morad; Mortazavi, Yadollah; Khodadadi, Abbas Ali; Choolaei, Mohammadmehdi

    2015-04-01

    The electro-catalytic behavior of Pt-CoOx/MWCNTs in methanol electro-oxidation reaction (MOR) is investigated and compared to that of Pt/MWCNTs. The electro-catalysts were synthesized by an impregnation method using NaBH4 as the reducing agent. The morphological and physical characteristics of samples are examined by XRD, TEM, ICP and EDS techniques. In the presence of CoOx, Pt nanoparticles were highly distributed on the support with an average particle size of 2 nm, an obvious decrease from 5.1 nm for Pt/MWCNTs. Cyclic voltammetry, CO-stripping, Chronoamperometry, and electrochemical impedance spectroscopy (EIS) measurements are used to study the electrochemical behavior of the electro-catalysts. The results revealed a considerable enhancement in the oxidation kinetics of COads on Pt active sites by the participation of CoOx. Compared to Pt/MWCNTs, Pt-CoOx/MWCNTs sample has a larger electrochemical active surface area (ECSA) and higher electro-catalytic activity and stability toward methanol electro-oxidation. According to the results of cyclic voltammetry, the forward anodic peak current density enhances more than 89% at the optimum atomic ratio of Pt:Co = 2:1. Furthermore, inclusion of cobalt oxide species causes the onset potential of methanol electro-oxidation reaction to shift 84 mV to negative values compared to that on Pt/MWCNTs. Based on EIS data, dehydrogenation of methanol is the rate-determining step of MOR on both Pt/MWCNTs and Pt-CoOx/MWCNTs, at small overpotentials. However, at higher overpotentials, the oxidation of adsorbed oxygen-containing groups controls the total rate of MOR process.

  4. Facile one-pot synthesis of Pt/graphene-TiO2 hybrid catalyst with enhanced methanol electrooxidation performance

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Wang, Zhen-Bo; Liu, Jing; Zhang, Jing-Jia; Sui, Xu-Lei; Zhang, Li-Mei; Gu, Da-Ming

    2015-04-01

    Pt/graphene-TiO2 hybrid catalysts have been synthesized by a facile one-pot solvothermal method. The Structural properties of obtained Pt/graphene-TiO2 catalysts are characterized by X-ray diffraction (XRD), Energy dispersive analysis of X-ray (EDAX) and transmission electron microscopy (TEM).Interesting, TEM presents Pt nanoparticles seem preferentially to locate between TiO2 and graphene, forming the unique triple junctions structure. The electrochemical experimental results indicate that Pt/graphene-TiO2 catalyst exhibits 1.46 times higher activity for methanol electrooxidation than that of Pt/graphene and its stability is improved by 15% as compared with Pt/graphene. Moreover, performance of Pt/graphene-TiO2 hybrid catalyst is evaluated by the Single Fuel Cell Tests for the first time. Single fuel cell tests show the maximum power density of the direct methanol fuel cell using Pt/graphene-TiO2 as the anode catalyst is increased by 55% compared with that using Pt/graphene catalyst at the same operating conditions. The significantly enhanced electrochemical performance can be ascribed to (1) the synergetic effect between Pt, graphene and TiO2; (2) strong metal-support interaction (SMSI) between Pt nanoparticles and TiO2. These findings suggest their great potential applications in fuel cells.

  5. Caseworker judgments and substantiation.

    PubMed

    Cross, Theodore P; Casanueva, Cecilia

    2009-02-01

    Substantiation can have an important effect on what interventions are pursued for children investigated for maltreatment, but researchers lack knowledge about how the decision to substantiate is made. Using information from 4,515 children from a national probability study of children investigated for maltreatment, this study examined how caseworker judgments of harm, risk, and evidence predicted substantiation. The substantiation rate was 29.9%, but the majority of cases were substantiated when caseworkers reported at least moderate harm, at least moderate risk, and/or probably to clearly sufficient evidence. Each judgment variable significantly predicted substantiation in a multivariable model, with evidence the strongest predictor. Child gender and age were significant predictors beyond harm, risk, and evidence, suggesting that other judgments also influence substantiation. In 9 of 100 cases, reports were not substantiated despite moderate to severe harm. Thus, substantiation is generally based on judgments of harm, risk, and evidence but not exclusively. The findings underline previous researchers' conclusions that substantiation is a flawed measure of child maltreatment and suggest that policy and practice related to substantiation are due for a fresh appraisal by state child welfare service agencies. PMID:18794302

  6. Pd@Pt core-shell concave decahedra: A class of catalysts for the oxygen reduction reaction with enhanced activity and durability

    DOE PAGESBeta

    Wang, Xue; Vera, Madeline; Chi, Miaofang; Xia, Younan; Luo, Ming; Huang, Hongwen; Ruditskiy, Aleksey; Park, Jinho; Bao, Shixiong; Liu, Jingyue; et al

    2015-11-13

    Here, we report a facile synthesis of multiply twinned Pd@Pt core shell concave decahedra by controlling the deposition of Pt on preformed Pd decahedral seeds. The Pt atoms are initially deposited on the vertices of a decahedral seed, followed by surface diffusion to other regions along the edges/ridges and then across the faces. Different from the coating of a Pd icosahedral seed, the Pt atoms prefer to stay at the vertices and edges/ridges of a decahedral seed even when the deposition is conducted at 200 degrees C, naturally generating a core shell structure covered by concave facets. The nonuniformity inmore » the Pt coating can be attributed to the presence of twin boundaries at the vertices, as well as the {100} facets and twin defects along the edges/ridges of a decahedron, effectively trapping the Pt adatoms at these high-energy sites. As compared to a commercial Pt/C catalyst, the Pd@Pt concave decahedra show substantial enhancement in both catalytic activity and durability toward the oxygen reduction reaction (ORR). For the concave decahedra with 29.6% Pt by weight, their specific (1.66 mA/cm2pt) and mass (1.60 A/mg/2pt) ORR activities are enhanced by 4.4 and 6.6 times relative to those of the Pt/C catalyst (0.36 mA/cm2pt and 0.32 A/mgpt, respectively). After 10 000 cycles of accelerated durability test, the concave decahedra still exhibit a mass activity of 0.69 A/mgpt, more than twice that of the pristine Pt/C catalyst.« less

  7. Pd@Pt core-shell concave decahedra: A class of catalysts for the oxygen reduction reaction with enhanced activity and durability

    SciTech Connect

    Wang, Xue; Vera, Madeline; Chi, Miaofang; Xia, Younan; Luo, Ming; Huang, Hongwen; Ruditskiy, Aleksey; Park, Jinho; Bao, Shixiong; Liu, Jingyue; Howe, Jane; Xie, Zhaoxiong

    2015-11-13

    Here, we report a facile synthesis of multiply twinned Pd@Pt core shell concave decahedra by controlling the deposition of Pt on preformed Pd decahedral seeds. The Pt atoms are initially deposited on the vertices of a decahedral seed, followed by surface diffusion to other regions along the edges/ridges and then across the faces. Different from the coating of a Pd icosahedral seed, the Pt atoms prefer to stay at the vertices and edges/ridges of a decahedral seed even when the deposition is conducted at 200 degrees C, naturally generating a core shell structure covered by concave facets. The nonuniformity in the Pt coating can be attributed to the presence of twin boundaries at the vertices, as well as the {100} facets and twin defects along the edges/ridges of a decahedron, effectively trapping the Pt adatoms at these high-energy sites. As compared to a commercial Pt/C catalyst, the Pd@Pt concave decahedra show substantial enhancement in both catalytic activity and durability toward the oxygen reduction reaction (ORR). For the concave decahedra with 29.6% Pt by weight, their specific (1.66 mA/cm2pt) and mass (1.60 A/mg/2pt) ORR activities are enhanced by 4.4 and 6.6 times relative to those of the Pt/C catalyst (0.36 mA/cm2pt and 0.32 A/mgpt, respectively). After 10 000 cycles of accelerated durability test, the concave decahedra still exhibit a mass activity of 0.69 A/mgpt, more than twice that of the pristine Pt/C catalyst.

  8. Quenching downstream of an external vapor catalyst separator

    SciTech Connect

    Forgac, J.M.; Hauschildt, F.W.; Quinn, G.P.; Rundell, D.N.; Schwartz, J.G.; Camp, M.S.

    1991-08-20

    This patent describes a catalytic cracking process. It comprises catalytically cracking feed oil in a catalytic cracking unit comprising a regenerator and at least one catalytic cracking reactor selected from the group consisting of a riser reactor and a fluidized bed reactor, in the presence of a cracking catalyst to produce a catalyst-laden stream comprising upgraded oil and coked catalyst; separating substantially all of the cracking catalyst from the catalyst laden stream in an external gross-cut separator downstream of the reactor into a catalyst rich stream comprising the coked catalyst and a product stream comprising the upgraded oil, and substantially immediately thereafter; quenching the product stream of upgraded oil discharged from the external gross-cut separator to substantially decrease thermal cracking of the upgraded oil to less valuable hydrocarbon products and light hydrocarbon gases and concurrently enhance the yield of naphtha to substantially increase the production of gasoline; regenerating the coked catalyst in a regenerator; and recycling the regenerated catalyst to the catalytic cracking reactor.

  9. Desulfurization of coal: Enhanced selectivity using phase transfer catalysts. Technical report, September 1--November 30, 1995

    SciTech Connect

    Palmer, S.R.; Hippo, E.J.

    1995-12-31

    Due to environmental problems related to the combustion of high sulfur Illinois coal, there continues to be interest in the development of viable pre-combustion desulfurization processes. Recent studies by the authors have obtained very good sulfur removals but the reagents that are used are too expensive. Use of cheaper reagents leads to a loss of desired coal properties. This study investigates the application of phase transfer catalysts to the selective oxidation of sulfur in coal using air and oxygen as oxidants. The phase transfer catalyst is expected to function as a selectivity moderator by permitting the use of milder reaction conditions than otherwise necessary. This would enhance the sulfur selectivity and help retain the heating value of the coal. The use of certain coal combustion wastes for desulfurization, and the application of cerium (IV) catalyzed air oxidations for selective sulfur oxidation are also being studied. If successful this project could lead to the rapid development of a commercially viable desulfurization process. This would significantly improve the marketability of Illinois coal. During this quarter aliquots of the IBC-101 coal have been ground to various particle sizes in an attempt to find the optimum physical pretreatment for mineral, especially pyrite, removal. Analysis of these various aliquots shows them to be representative of the original coal. In addition, preliminary desulfurization reactions using fly ash and scrubber sludges have been performed on an unoxidized IBC-101 sample. Results will be available next quarter. Also, SEM-EDAX analysis of the fly ash indicates that it contains oxides that have shown activity in base desulfurization reactions.

  10. Ultrasonic enhance acid hydrolysis selectivity of cellulose with HCl-FeCl3 as catalyst.

    PubMed

    Li, Jinbao; Zhang, Xiangrong; Zhang, Meiyun; Xiu, Huijuan; He, Hang

    2015-03-01

    The effect of ultrasonic pretreatment coupled with HCl-FeCl3 catalyst was evaluated to hydrolyze cellulose amorphous regions. The ultrasonic pretreatment leads to cavitation that affects the morphology and microstructure of fibers, enhancing the accessibility of chemical reagent to the loosened amorphous regions of cellulose. In this work, Fourier transform infrared spectroscopy (FTIR) was used to identify characteristic absorption bands of the constituents and the crystallinity was evaluated by the X-ray diffraction (XRD) technique. The results indicated that appropriate ultrasonic pretreatment assisted with FeCl3 can enhance the acid hydrolysis of amorphous regions of cellulose, thus improving the crystallinity of the remaining hydrocellulose. It was observed that sonication samples that were pretreated for 300 W and 20 min followed by acid hydrolysis had maximum of 78.9% crystallinity. The crystallinity was 9.2% higher than samples that were not subjected to ultrasound. In addition, the average fines length decreased from 49 μm to 37 μm. PMID:25498717

  11. Beneficial Role of Copper in the Enhancement of Durability of Ordered Intermetallic PtFeCu Catalyst for Electrocatalytic Oxygen Reduction.

    PubMed

    Arumugam, Balamurugan; Tamaki, Takanori; Yamaguchi, Takeo

    2015-08-01

    Design of Pt alloy catalysts with enhanced activity and durability is a key challenge for polymer electrolyte membrane fuel cells. In the present work, we compare the durability of the ordered intermetallic face-centered tetragonal (fct) PtFeCu catalyst for the oxygen reduction reaction (ORR) relative to its counterpart bimetallic catalysts, i.e., the ordered intermetallic fct-PtFe catalyst and the commercial catalyst from Tanaka Kikinzoku Kogyo, TKK-PtC. Although both fct catalysts initially exhibited an ordered structure and mass activity approximately 2.5 times higher than that of TKK-Pt/C, the presence of Cu at the ordered intermetallic fct-PtFeCu catalyst led to a significant enhancement in durability compared to that of the ordered intermetallic fct-PtFe catalyst. The ordered intermetallic fct-PtFeCu catalyst retained more than 70% of its mass activity and electrochemically active surface area (ECSA) over 10 000 durability cycles carried out at 60 °C. In contrast, the ordered intermetallic fct-PtFe catalyst maintained only about 40% of its activity. The temperature of the durability experiment is also shown to be important: the catalyst was more severely degraded at 60 °C than at room temperature. To obtain insight into the observed enhancement in durability of fct-PtFeCu catalyst, a postmortem analysis of the ordered intermetallic fct-PtFeCu catalyst was carried out using scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDX) line scan. The STEM-EDX line scans of the ordered intermetallic fct-PtFeCu catalyst over 10 000 durability cycles showed a smaller degree of Fe and Cu dissolution from the catalyst. Conversely, large dissolution of Fe was identified in the ordered intermetallic fct-PtFe catalyst, indicating a lesser retention of Fe that causes the destruction of ordered structure and gives rise to poor durability. The enhancement in the durability of the ordered intermetallic fct-PtFeCu catalyst is ascribed to

  12. Molecular co-catalyst accelerating hole transfer for enhanced photocatalytic H2 evolution

    PubMed Central

    Bi, Wentuan; Li, Xiaogang; Zhang, Lei; Jin, Tao; Zhang, Lidong; Zhang, Qun; Luo, Yi; Wu, Changzheng; Xie, Yi

    2015-01-01

    In artificial photocatalysis, sluggish kinetics of hole transfer and the resulting high-charge recombination rate have been the Achilles' heel of photocatalytic conversion efficiency. Here we demonstrate water-soluble molecules as co-catalysts to accelerate hole transfer for improved photocatalytic H2 evolution activity. Trifluoroacetic acid (TFA), by virtue of its reversible redox couple TFA·/TFA−, serves as a homogeneous co-catalyst that not only maximizes the contact areas between co-catalysts and reactants but also greatly promotes hole transfer. Thus K4Nb6O17 nanosheet catalysts achieve drastically increased photocatalytic H2 production rate in the presence of TFA, up to 32 times with respect to the blank experiment. The molecular co-catalyst represents a new, simple and highly effective approach to suppress recombination of photogenerated charges, and has provided fertile new ground for creating high-efficiency photosynthesis systems, avoiding use of noble-metal co-catalysts. PMID:26486863

  13. Molecular co-catalyst accelerating hole transfer for enhanced photocatalytic H2 evolution

    NASA Astrophysics Data System (ADS)

    Bi, Wentuan; Li, Xiaogang; Zhang, Lei; Jin, Tao; Zhang, Lidong; Zhang, Qun; Luo, Yi; Wu, Changzheng; Xie, Yi

    2015-10-01

    In artificial photocatalysis, sluggish kinetics of hole transfer and the resulting high-charge recombination rate have been the Achilles' heel of photocatalytic conversion efficiency. Here we demonstrate water-soluble molecules as co-catalysts to accelerate hole transfer for improved photocatalytic H2 evolution activity. Trifluoroacetic acid (TFA), by virtue of its reversible redox couple TFA./TFA-, serves as a homogeneous co-catalyst that not only maximizes the contact areas between co-catalysts and reactants but also greatly promotes hole transfer. Thus K4Nb6O17 nanosheet catalysts achieve drastically increased photocatalytic H2 production rate in the presence of TFA, up to 32 times with respect to the blank experiment. The molecular co-catalyst represents a new, simple and highly effective approach to suppress recombination of photogenerated charges, and has provided fertile new ground for creating high-efficiency photosynthesis systems, avoiding use of noble-metal co-catalysts.

  14. Radiofrequency treatment enhances the catalytic function of an immobilized nanobiohybrid catalyst

    NASA Astrophysics Data System (ADS)

    San, Boi Hoa; Ha, Eun-Ju; Paik, Hyun-Jong; Kim, Kyeong Kyu

    2014-05-01

    Biocatalysis, the use of enzymes in chemical transformation, has undergone intensive development for a wide range of applications. As such, maximizing the functionality of enzymes for biocatalysis is a major priority to enable industrial use. To date, many innovative technologies have been developed to address the future demand of enzymes for these purposes, but maximizing the catalytic activity of enzymes remains a challenge. In this study, we demonstrated that the functionality of a nanobiocatalyst could be enhanced by combining immobilization and radiofrequency (RF) treatment. Aminopeptidase PepA-encapsulating 2 nm platinum nanoparticles (PepA-PtNPs) with the catalytic activities of hydrolysis and hydrogenation were employed as multifunctional nanobiocatalysts. Immobilizing the nanobiocatalysts in a hydrogel using metal chelation significantly enhanced their functionalities, including catalytic power, thermal-stability, pH tolerance, organic solvent tolerance, and reusability. Most importantly, RF treatment of the hydrogel-immobilized PepA-PtNPs increased their catalytic power by 2.5 fold greater than the immobilized PepA. Our findings indicate that the catalytic activities and functionalities of PepA-PtNPs are greatly enhanced by the combination of hydrogel-immobilization and RF treatment. Based on our findings, we propose that RF treatment of nanobiohybrid catalysts immobilized on the bulk hydrogel represents a new strategy for achieving efficient biocatalysis.Biocatalysis, the use of enzymes in chemical transformation, has undergone intensive development for a wide range of applications. As such, maximizing the functionality of enzymes for biocatalysis is a major priority to enable industrial use. To date, many innovative technologies have been developed to address the future demand of enzymes for these purposes, but maximizing the catalytic activity of enzymes remains a challenge. In this study, we demonstrated that the functionality of a nanobiocatalyst

  15. QSAR-Assisted Design of an Environmental Catalyst for Enhanced Estrogen Remediation

    PubMed Central

    Colosi, Lisa M.; Huang, Qingguo; Weber, Walter J.

    2010-01-01

    A quantitative structure-activity relationship (QSAR) was used to streamline redesign of a model environmental catalyst, horseradish peroxidase (HRP), for enhanced reactivity towards a target pollutant, steroid hormone 17β-estradiol. This QSAR, embodying relationship between reaction rate and intermolecular binding distance, was used in silico to screen for mutations improving enzyme reactivity. Eight mutations mediating significant reductions in binding distances were expressed in Saccharomyces cerevisiae, and resulting recombinant HRP strains were analyzed to determine Michaelis-Menten parameters during reaction with the target substrate. Enzyme turnover rate, ln(kCAT), exhibited inverse relationship with model-predicted binding distances (R2 = 0.81), consistent with the QSAR. Additional analysis of native substrate degradation by selected mutants yielded unexpected increases in ln(kCAT) that were also inversely correlated (R2 = 1.00) with model-predicted binding distances. This suggests that the mechanism of improvement comprises a nonspecific “opening up” of the active site such that it better accommodates environmental estrogens of any size. The novel QSAR-assisted approach described herein offers specific advantages compared to conventional design strategies, most notably targeting an entire class of pollutants at one time and a flexible hybridization of benefits associated with rational design and directed evolution. Thus, this approach is a promising tool for improving enzyme-mediated environmental remediation. PMID:20797763

  16. Enhanced photocatalytic hydrogen production by introducing the carboxylic acid group into cobaloxime catalysts.

    PubMed

    Wang, Junfei; Li, Chao; Zhou, Qianxiong; Wang, Weibo; Hou, Yuanjun; Zhang, Baowen; Wang, Xuesong

    2015-10-28

    A series of cobaloxime complexes, [Co(iii)(dmgH)2(py-m-X)Cl] (dmgH = dimethylglyoxime, py-m-X = meta-substituted pyridine, X = COOH (2), COOCH3 (3), CH2CH2COOH (6), and CH2CH2COOCH3 (7)), and [Co(iii)(dmgH)2(py-p-X)Cl], (py-p-X = para-substituted pyridine, X = COOH (4) and COOCH3 (5)), were synthesized and their photocatalytic H2 production activities were compared in an artificial photosynthesis system containing a xanthene dye Eosin Y as the photosensitizer (PS) and triethanolamine (TEOA) as the sacrificial reductant (SR) in CH3CN/H2O (1 : 1, pH = 7.5). Irrespective of substitution by an electron-donating or electron withdrawing group, the photocatalytic H2 production activities of 2-7 are all higher than that of [Co(iii)(dmgH)2(py)Cl] (1). Importantly, meta-substitution is more efficient than para-substitution, and COOH is more efficient than COOCH3, in enhancing the photocatalytic activities. 6 showed the highest activity among the examined complexes. The -CH2CH2- chain linking COOH and pyridine might play a role in the promising performance of 6, which makes the proton relay via interaction between COOH and dmgH possible. This work may open new avenues for developing more efficient cobaloxime-based H2 evolution catalysts (HERs). PMID:26394744

  17. Establishing Substantial Equivalence: Transcriptomics

    NASA Astrophysics Data System (ADS)

    Baudo, María Marcela; Powers, Stephen J.; Mitchell, Rowan A. C.; Shewry, Peter R.

    Regulatory authorities in Western Europe require transgenic crops to be substantially equivalent to conventionally bred forms if they are to be approved for commercial production. One way to establish substantial equivalence is to compare the transcript profiles of developing grain and other tissues of transgenic and conventionally bred lines, in order to identify any unintended effects of the transformation process. We present detailed protocols for transcriptomic comparisons of developing wheat grain and leaf material, and illustrate their use by reference to our own studies of lines transformed to express additional gluten protein genes controlled by their own endosperm-specific promoters. The results show that the transgenes present in these lines (which included those encoding marker genes) did not have any significant unpredicted effects on the expression of endogenous genes and that the transgenic plants were therefore substantially equivalent to the corresponding parental lines.

  18. Purity-enhanced bulk synthesis of thin single-wall carbon nanotubes using iron-copper catalysts.

    PubMed

    Lim, H E; Miyata, Y; Nakayama, T; Chen, S; Kitaura, R; Shinohara, H

    2011-09-30

    We report high purity and high yield synthesis of single-wall carbon nanotubes (SWCNTs) of narrow diameter from iron-copper bimetal catalysts. The SWCNTs with diameter of 0.8-1.2 nm are synthesized using the zeolite-supported alcohol chemical vapour deposition method. Single metal and bimetal catalysts are systematically investigated to achieve both the enhancement of SWCNT yield and the suppression of the undesired formation of graphitic impurities. The relative yield and purity of SWCNTs are quantified using optical absorption spectroscopy with an ultracentrifuge-based purification technique. For the single metal catalyst, iron shows the highest catalytic activity compared with the other metals such as cobalt, nickel, molybdenum, copper, and platinum. It has been found that the addition of copper to iron results in the suppression of carbonaceous impurity formation without decreasing the SWCNT yield. The purity-enhanced SWCNT shows fairly low sheet resistance due to the improvement of inter-nanotube contacts. This scalable design of SWCNT synthesis with enhanced purity is therefore a promising tool for shaping future high performance devices. PMID:21891846

  19. Purity-enhanced bulk synthesis of thin single-wall carbon nanotubes using iron-copper catalysts

    NASA Astrophysics Data System (ADS)

    Lim, H. E.; Miyata, Y.; Nakayama, T.; Chen, S.; Kitaura, R.; Shinohara, H.

    2011-09-01

    We report high purity and high yield synthesis of single-wall carbon nanotubes (SWCNTs) of narrow diameter from iron-copper bimetal catalysts. The SWCNTs with diameter of 0.8-1.2 nm are synthesized using the zeolite-supported alcohol chemical vapour deposition method. Single metal and bimetal catalysts are systematically investigated to achieve both the enhancement of SWCNT yield and the suppression of the undesired formation of graphitic impurities. The relative yield and purity of SWCNTs are quantified using optical absorption spectroscopy with an ultracentrifuge-based purification technique. For the single metal catalyst, iron shows the highest catalytic activity compared with the other metals such as cobalt, nickel, molybdenum, copper, and platinum. It has been found that the addition of copper to iron results in the suppression of carbonaceous impurity formation without decreasing the SWCNT yield. The purity-enhanced SWCNT shows fairly low sheet resistance due to the improvement of inter-nanotube contacts. This scalable design of SWCNT synthesis with enhanced purity is therefore a promising tool for shaping future high performance devices.

  20. Enhancement of Nitrite Reduction Kinetics on Electrospun Pd-Carbon Nanomaterial Catalysts for Water Purification.

    PubMed

    Ye, Tao; Durkin, David P; Hu, Maocong; Wang, Xianqin; Banek, Nathan A; Wagner, Michael J; Shuai, Danmeng

    2016-07-20

    We report a facile synthesis method for carbon nanofiber (CNF) supported Pd catalysts via one-pot electrospinning and their application for nitrite hydrogenation. A mixture of Pd acetylacetonate (Pd(acac)2), polyacrylonitrile (PAN), and nonfunctionalized multiwalled carbon nanotubes (MWCNTs) was electrospun and thermally treated to produce Pd/CNF-MWCNT catalysts. The addition of MWCNTs with a mass loading of 1.0-2.5 wt % (to PAN) significantly improved nitrite reduction activity compared to the catalyst without MWCNT addition. The results of CO chemisorption confirmed that the addition of MWCNTs increased Pd exposure on CNFs and hence improved catalytic activity. PMID:27387354

  1. A novel iron (Ⅱ) polyphthalocyanine catalyst assembled on graphene with significantly enhanced performance for oxygen reduction reaction in alkaline medium

    NASA Astrophysics Data System (ADS)

    Lin, Lin; Li, Meng; Jiang, Liqing; Li, Yongfeng; Liu, Dajun; He, Xingquan; Cui, Lili

    2014-12-01

    To realize the large-scale commercial application of direct methanol fuel cells (DMFCs), the catalysts for oxygen reduction reaction (ORR) are the crucial obstacle. Here, an efficient non-noble-metal catalyst for ORR, denoted FePPc/PSS-Gr, has been obtained by anchoring p-phenyl-bis(3,4-dicyanophenyl) ether iron(Ⅱ) polyphthalocyanine (FePPc) on poly(sodium-p-styrenesulfonate) (PSS) modified graphene (PSS-Gr) through a solvothermally assisted π-π assembling approach. The Ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results reveal the π-π interaction between FePPc and PSS-Gr. The rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) measurements show that the proposed catalyst possesses an excellent catalytic performance towards ORR comparable with the commercial Pt/C catalyst in alkaline medium, such as high onset potential (-0.08 V vs. SCE), half-wave potential (-0.19 V vs. SCE), better tolerance to methanol crossover, excellent stability (81.1%, retention after 10,000 s) and an efficient four-electron pathway. The enhanced electrocatalytic performance could be chiefly attributed to its large electrochemically accessible surface area, fast electron transfer rate of PSS-Gr, in particular, the synergistic effect between the FePPc moieties and the PSS-Gr sheets.

  2. The surface sulfur doping induced enhanced performance of cobalt catalysts in oxygen evolution reactions.

    PubMed

    Al-Mamun, Mohammad; Zhu, Zhengju; Yin, Huajie; Su, Xintai; Zhang, Haimin; Liu, Porun; Yang, Huagui; Wang, Dan; Tang, Zhiyong; Wang, Yun; Zhao, Huijun

    2016-08-01

    A novel surface sulfur (S) doped cobalt (Co) catalyst for the oxygen evolution reaction (OER) is theoretically designed through the optimisation of the electronic structure of highly reactive surface atoms which is also validated by electrocatalytic OER experiments. PMID:27377872

  3. Bifunctional Ag/Fe/N/C Catalysts for Enhancing Oxygen Reduction via Cathodic Biofilm Inhibition in Microbial Fuel Cells.

    PubMed

    Dai, Ying; Chan, Yingzi; Jiang, Baojiang; Wang, Lei; Zou, Jinlong; Pan, Kai; Fu, Honggang

    2016-03-23

    Limitation of the oxygen reduction reaction (ORR) in single-chamber microbial fuel cells (SC-MFCs) is considered an important hurdle in achieving their practical application. The cathodic catalysts faced with a liquid phase are easily primed with the electrolyte, which provides more surface area for bacterial overgrowth, resulting in the difficulty in transporting protons to active sites. Ag/Fe/N/C composites prepared from Ag and Fe-chelated melamine are used as antibacterial ORR catalysts for SC-MFCs. The structure-activity correlations for Ag/Fe/N/C are investigated by tuning the carbonization temperature (600-900 °C) to clarify how the active-constituents of Ag/Fe and N-species influence the antibacterial and ORR activities. A maximum power density of 1791 mW m(-2) is obtained by Ag/Fe/N/C (630 °C), which is far higher than that of Pt/C (1192 mW m(-2)), only having a decline of 16.14% after 90 days of running. The Fe-bonded N and the cooperation of pyridinic N and pyrrolic N in Ag/Fe/N/C contribute equally to the highly catalytic activity toward ORR. The ·OH or O2(-) species originating from the catalysis of O2 can suppress the biofilm growth on Ag/Fe/N/C cathodes. The synergistic effects between the Ag/Fe heterojunction and N-species substantially contribute to the high power output and Coulombic efficiency of Ag/Fe/N/C catalysts. These new antibacterial ORR catalysts show promise for application in MFCs. PMID:26938657

  4. Establishing Substantial Equivalence: Metabolomics

    NASA Astrophysics Data System (ADS)

    Beale, Michael H.; Ward, Jane L.; Baker, John M.

    Modern ‘metabolomic’ methods allow us to compare levels of many structurally diverse compounds in an automated fashion across a large number of samples. This technology is ideally suited to screening of populations of plants, including trials where the aim is the determination of unintended effects introduced by GM. A number of metabolomic methods have been devised for the determination of substantial equivalence. We have developed a methodology, using [1H]-NMR fingerprinting, for metabolomic screening of plants and have applied it to the study of substantial equivalence of field-grown GM wheat. We describe here the principles and detail of that protocol as applied to the analysis of flour generated from field plots of wheat. Particular emphasis is given to the downstream data processing and comparison of spectra by multivariate analysis, from which conclusions regarding metabolome changes due to the GM can be assessed against the background of natural variation due to environment.

  5. Substantial evidence of effect.

    PubMed

    Gould, A Lawrence

    2002-02-01

    Pressures for rapid drug development, especially for treatments that may affect public health significantly, drive a need to reconsider what is necessary to establish the "substantial evidence" of efficacy and safety required for regulatory approval. The concept of substantial evidence of effect can be stated fairly simply in principle, but its application to the evaluation of findings from real clinical drug development programs can be quite complicated and depend on circumstances relating to the population studied and the condition being treated. This paper discusses a number of considerations that arise in attempting to address this issue. These include confirmation of efficacy/safety as opposed to replication of results, the use of surrogates for the clinical outcome, ethical considerations, the use of trials aimed at demonstrating equivalence or noninferiority instead of superiority of a new drug, and the balance between benefits and risks. Recent developments such as the International Conference on Harmonization (ICH) guidelines dealing with statistical principles and choice of control group, and Food and Drug Administration (FDA) guidances interpreting the 1998 Modernization Act identify useful alternative definitions of substantial evidence and also identify when a single study can be enough to demonstrate a clinically important effect. The primary difficulty with the use of noninferiority trials is the need to demonstrate assay sensitivity or validity, i.e., that the trial would have demonstrated the superiority of the active control treatment to placebo had the trial included a placebo group. Failure to demonstrate a significant difference between the presumed active treatments and an inactive control precludes a definitive conclusion of assay validity, but external evidence, e.g., from trials demonstrating the activity of the active control, may yet justify concluding that the trial was assay valid. Issues of interpretation of important unexpected

  6. Study of the catalyst evolution during annealing preceding the growth of carbon nanotubes by microwave plasma-enhanced chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Malesevic, Alexander; Chen, Hong; Hauffman, Tom; Vanhulsel, Annick; Terryn, Herman; Van Haesendonck, Chris

    2007-11-01

    A two-step catalyst annealing process is developed in order to control the diameter of nickel catalyst particles for the growth of carbon nanotubes (CNTs) by microwave plasma-enhanced chemical vapour deposition (MW PECVD). Thermal annealing of a continuous nickel film in a hydrogen (H2) environment in a first step is found to be insufficient for the formation of nanometre-size, high-density catalyst particles. In a second step, a H2 MW plasma treatment decreases the catalyst diameter by a factor of two and increases the particle density by a factor of five. An x-ray photoelectron spectroscopy study of the catalyst after each step in the annealing process is presented. It is found that the catalyst particles interact with the substrate during thermal annealing, thereby forming a silicate, even if a buffer layer in between the catalyst and the substrate is intended to prevent silicate formation. The silicate formation and reduction is shown to be directly related to the CNT growth mechanism, determining whether the catalyst particles reside at the base or the tip of the growing CNTs. The catalyst particles are used for the growth of a high-density CNT coating by MW PECVD. CNTs are analysed with electron microscopy and Raman spectroscopy.

  7. Enhanced photodegradation of pentachlorophenol by single and mixed nonionic and anionic surfactants using graphene-TiO₂ as catalyst.

    PubMed

    Zhang, Yaxin; He, Xin; Zeng, Guangming; Chen, Tan; Zhou, Zeyu; Wang, Hongtao; Lu, Wenjing

    2015-11-01

    The photodegradation of pentachlorophenol (PCP) in a surfactant-containing (single and mixed) complex system using graphene-TiO2 (GT) as catalyst was investigated. The objective was to better understand the behavior of surfactants in a GT catalysis system for its possible use in remediation technology of soil contaminated by hydrophobic organic compounds (HOCs). In a single-surfactant system, surfactant molecules aggregated on GT via hydrogen bonding and electrostatic force; nonideal mixing between nonionic and anionic surfactants rendered GT surface with mixed admicelles in a mixed surfactant system. Both effects helped incorporating PCP molecules into surfactant aggregates on catalyst surface. Hence, the targeted pollutants were rendered easily available to photo-yielded oxidative radicals, and photodegradation efficiency was significantly enhanced. Finally, real soil washing-photocatalysis trials proved that anionic-nonionic mixed surfactant soil washing coupled with graphene-TiO2 photocatalysis can be one promising technology for HOC-polluted soil remediation. PMID:26194233

  8. Kinetics of oxygen-enhanced water gas shift on bimetallic catalysts and the roles of metals and support

    NASA Astrophysics Data System (ADS)

    Kugai, Junichiro

    The post-processing of reformate is an important step in producing hydrogen (H2) with low carbon monoxide (CO) for low temperature fuel cells from syn-gas. However, the conventional process consists of three steps, i.e. two steps of water gas shift (WGS) and preferential oxidation (PROX) of CO, and it is not suitable for mobile applications due to the large volume of water gas shift (WGS) catalysts and conditioning and/or regeneration necessary for these catalysts. Aiming at replacing those three steps by a simple one-step process, small amount of oxygen was added to WGS (the reaction called oxygen-enhanced water gas shift or OWGS) to promote the reaction kinetics and low pyrophoric ceria-supported bimetallic catalysts were employed for stable performance in this reaction. Not only CO conversion, but also H2 yield was found to increase by the O2 addition on CeO2-supported catalysts. The characteristics of OWGS, high H2 production rate at 200 to 300°C at short contact time where unreacted O2 exists, evidenced the impact of O2 addition on surface species on the catalyst. Around 1.5 of reaction order in CO for various CeO2-supported metal catalysts for OWGS compared to reaction orders in CO ranging from -0.1 to 0.6 depending on metal species for WGS shows O2 addition decreases CO coverage to free up the active sites for co-reactant (H2O) adsorption and activation. Among the monometallic and bimetallic catalysts, Pt-Cu and Pd-Cu bimetallic catalysts were superior to monometallic catalysts in OWGS. These bimetallic components were found to form alloys where noble metal is surrounded mainly by Cu to have strong interaction between noble metal and copper resulting in high OWGS activity and low pyrophoric property. The metal loadings were optimized for CeO2-supported Pd-Cu bimetallic system and 2 wt% Pd with 5 -- 10 wt% Cu were found to be the optimum for the present OWGS condition. In the kinetic study, Pd in Pd-Cu was shown to increase the active sites for H2O

  9. Ultrasound enhanced heterogeneous activation of peroxydisulfate by bimetallic Fe-Co/GAC catalyst for the degradation of Acid Orange 7 in water.

    PubMed

    Cai, Chun; Wang, Liguo; Gao, Hong; Hou, Liwei; Zhang, Hui

    2014-06-01

    Bimetallic Fe-Co/GAC (granular activated carbon) was prepared and used as heterogeneous catalyst in the ultrasound enhanced heterogeneous activation of peroxydisulfate (PS, S2O(2-)8) process. The effect of initial pH, PS concentration, catalyst addition and stirring rate on the decolorization of Acid Orange 7 (AO7) was investigated. The results showed that the decolorization efficiency increased with an increase in PS concentration from 0.3 to 0.5 g/L and an increase in catalyst amount from 0.5 to 0.8 g/L. But further increase in PS concentration and catalyst addition would result in an unpronounced increase in decolorization efficiency. In the range of 300 to 900 r/min, stirring rate had little effect on AO7 decolorization. The catalyst stability was evaluated by measuring decolorization efficiency for four successive cycles. PMID:25079835

  10. Microwave enhanced alcoholysis of non-edible (algal, jatropha and pongamia) oils using chemically activated egg shell derived CaO as heterogeneous catalyst.

    PubMed

    Joshi, Girdhar; Rawat, Devendra S; Sharma, Amit Kumar; Pandey, Jitendra K

    2016-11-01

    Microwave enhanced fast and efficient alcoholysis (methanolysis and ethanolysis) of non-edible oils (algal, jatropha and pongamia) is achieved using chemically activated waste egg shell derived CaO (i.e. CaO(cesp)) as heterogeneous catalyst. CaO(cesp) was extracted from waste chicken egg shell and further activated chemically by supporting transition metal oxide. The maximum conversion was achieved using 3wt% catalysts under 700W microwave irradiation and 10:1 alcohol/oil ratio in 6min. Alcoholysis using ZnO activated CaO(cesp) catalyst has shown higher reaction yields in comparison to other modified catalysts. Methanolysis has shown better biodiesel conversion in comparison to ethanolysis. The catalyst has shown longer lifetime and sustained activity after being used for four cycles. Due to more saturated fatty acid content; algal biodiesel has shown improved fuel properties in comparison to other biodiesels. PMID:27521785

  11. Establishing Substantial Equivalence: Proteomics

    NASA Astrophysics Data System (ADS)

    Lovegrove, Alison; Salt, Louise; Shewry, Peter R.

    Wheat is a major crop in world agriculture and is consumed after processing into a range of food products. It is therefore of great importance to determine the consequences (intended and unintended) of transgenesis in wheat and whether genetically modified lines are substantially equivalent to those produced by conventional plant breeding. Proteomic analysis is one of several approaches which can be used to address these questions. Two-dimensional PAGE (2D PAGE) remains the most widely available method for proteomic analysis, but is notoriously difficult to reproduce between laboratories. We therefore describe methods which have been developed as standard operating procedures in our laboratory to ensure the reproducibility of proteomic analyses of wheat using 2D PAGE analysis of grain proteins.

  12. C-H functionalization: thoroughly tuning ligands at a metal ion, a chemist can greatly enhance catalyst's activity and selectivity.

    PubMed

    Shul'pin, Georgiy B

    2013-09-28

    This brief essay consists of a few "exciting stories" devoted to relations within a metal-complex catalyst between a metal ion and a coordinated ligand. When, as in the case of a human couple, the rapport of the partners is cordial and a love cements these relations, a chemist finds an ideal married couple, in other words he obtains a catalyst of choice which allows him to functionalize C-H bonds very efficiently and selectively. Examples of such lucky marriages in the catalytic world of ions and ligands are discussed here. Activity of the catalyst is characterized by turnover number (TON) or turnover frequency (TOF) as well as by yield of a target product. Introducing a chelating N,N- or N,O-ligand to the catalyst molecule (this can be an iron or manganese derivative) sharply enhances its activity. However, the activity of vanadium derivatives (with additionally added to the solution pyrazinecarboxylic acid, PCA) as well as of various osmium complexes does not dramatically depend on the nature of ligands surrounding metal ions. Complexes of these metals are very efficient catalysts in oxidations with H2O2. Osmium derivatives are record-holders exhibiting extremely high TONs whereas vanadium complexes are on the second position. Finally, elegant examples of alkane functionalization on the ions of non-transition metals (aluminium, gallium etc.) are described when one ligand within the metal complex (namely, hydroperoxyl ligand HOO(-)) helps other ligand of this complex (H2O2 molecule coordinated to the metal) to disintegrate into two species, generating very reactive hydroxyl radical. Hydrogen peroxide molecule, even ligated to the metal ion, is perfectly stable without the assistance of the neighboring HOO(-) ligand. This ligand can be easily oxidized donating an electron to its partner ligand (H2O2). In an analogous case, when the central ion in the catalyst is a transition metal, this ion changing its oxidation state can donate an electron to the coordinated H2O2

  13. Enhanced performance of gas diffusion electrode for electrochemical reduction of carbon dioxide to formate by adding polytetrafluoroethylene into catalyst layer

    NASA Astrophysics Data System (ADS)

    Wang, Qinian; Dong, Heng; Yu, Han; Yu, Hongbing

    2015-04-01

    Gas diffusion electrode (GDE) with Nafion bonded catalyst layer (CL) for electrochemical reduction of CO2 to formate (ERCF) suffers from CO2 mass transfer limitation. In this work, polytetrafluoroethylene (PTFE) with contents of 5.9 wt%, 7.7 wt%, 11.1 wt% and 20 wt% are added into the CL of the GDE with Sn catalyst (P-SGDE) for ERCF. The morphologies and porous structures of the P-SGDEs are examined by scanning electron microscope and mercury intrusion measurement, respectively. The electrochemical performances of the P-SGDEs are investigated by linear sweep voltammetry, electrochemical impedance spectroscopy and constant potential electrolysis. The results show that the Faraday efficiency (86.75 ± 2.89%) and current density (21.67 ± 1.29 mA cm-2) for ERCF were improved by 25.4% and 25.8% respectively when the content of PTFE is 11.1 wt%, probably owing to the enhancement in the catalyst active surface area and CO2 diffusion. This Faraday efficiency is the highest one found for ERCF with Sn GDE under similar conductions.

  14. Desulfurization of coal: Enhanced selectivity using phase transfer catalysts. Final technical report, September 1, 1995--August 31, 1996

    SciTech Connect

    Palmer, S.R.; Hippo, E.J.

    1997-05-01

    Due to environmental problems related to the combustion of high sulfur Illinois coal, there continues to be interest in the development of viable pre-combustion desulfurization processes. Recent studies by the authors have obtained very good sulfur removals but the reagents that are used are too expensive. Use of cheaper reagents leads to a loss of desired coal properties. This study investigated the application of phase transfer catalysts to the selective oxidation of sulfur in coal using air and oxygen as oxidants. The phase transfer catalyst was expected to function as a selectivity moderator by permitting the use of milder reaction conditions than otherwise necessary. This would enhance the sulfur selectivity and help retain the heating value of the coal. The use of certain coal combustion wastes for desulfurization, and the application of cerium (IV) catalyzed air oxidations for selective sulfur oxidation were also studied. If successful this project would have lead to the rapid development of a commercially viable desulfurization process. This would have significantly improved the marketability of Illinois coal. However, the phase transfer catalysts, the cerium and the scrubber sledge did not catalize the sulfur removal significantly.

  15. ENHANCING THE STABILITY OF POROUS CATALYSTS WITH SUPERCRITICAL REACTION MEDIA. (R826034)

    EPA Science Inventory

    Adsorption/desorption and pore-transport are key parameters influencing the activity and product selectivity in porous catalysts. With conventional reaction media (gas or liquid phase), one of these parameters is generally favorable while the other is not. For instance, while ...

  16. Enhanced High- and Low-Temperature Performance of NOx Reduction Catalyst Materials

    SciTech Connect

    Gao, Feng; Muntean, George G.; Peden, Charles HF; Howden, Ken; Currier, Neal; Kamasamudram, Krishna; Kumar, Ashok; Li, Junhui; Luo, Jinyong; Stafford, Randy; Yezerets, Aleksey; Castagnola, Mario; Chen, Hai-Ying; Hess, Howard ..

    2014-12-09

    In this annual CRADA program report, we will briefly highlight results from our recent studies of the stability of candidate K-based high temperature NSR materials, and comparative studies of low temperature performance of SSZ-13 and SAPO-34 CHA catalysts; in particular, recent results comparing Fe- and Cu-based CHA materials.

  17. Enhanced activity of urea electrooxidation on nickel catalysts supported on tungsten carbides/carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Du, Tingting; Cheng, Jin; Xie, Xing; Yang, Bolun; Li, Mingtao

    2015-04-01

    Nickel nanoparticles with tungsten carbides supported on the multi-walled carbon nanotubes, noted as Ni-WC/MWCNT catalyst, is prepared through an impregnation method and used for the electrooxidation of urea in alkaline conditions. The micro-morphology and composition of the Ni-WC/MWCNT particles are determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The electrooxidation activity and conductivity of the catalyst are investigated by cyclic voltammetry and electrochemical impedance spectroscopy, respectively. Characterization results indicate that the Ni nanoparticles are uniformly distributed on the WC/MWCNT framework, and the Ni-WC/MWCNT catalyst shows an improved activity for the urea electrooxidation. The current densities of Ni-WC/MWCNT are over 3 times and 15 times higher than those of the Ni-WC/C and Ni/C catalysts, respectively, and the electrochemical impedance also decreases markedly. The higher activity on Ni-WC/MWCNT is attributed to the support effect of MWCNT as well as the synergistic effect between Ni and WC.

  18. Use of metal hydrous titanium oxide catalysts to enhance coal tar yield via hydropyrolysis

    SciTech Connect

    Klavetter, E.A.; Stephens, H.P.; Dosch, R.G.

    1990-01-01

    Catalytic hydropyrolysis experiments performed in this project on several US and UK coals have established that tar yields in excess of 70% (daf basis) and conversions (100%-char) in excess of 80% can be achieved from bituminous coals containing 80--84% dmmf carbon using hydrous titanium oxide (HTO) catalysts with low concentrations of active metals. Total conversion approaches the reactive maceral contents for these coals. Previously performed two-stage catalytic hydropyrolysis experiments have demonstrated that high yields of liquid products with high H/C ratios, low heteroatom contents, and a significant concentration of light naphtha can be achieved. The objectives of this research are to determine suitable methods for catalyzing the hydropyrolysis process and to investigate the reactions and mechanisms responsible for the high conversion of coal materials to distillable liquids via direct catalytic hydropyrolysis. Recently developed hydrous titanium oxide (HTO)-supported catalysts have received encouraging results in direct coal liquefaction applications. Results of hydropyrolysis experiment using Mo and Pd HTO catalysts coated directly onto the coal are presented here and compared with results from experiments using uncatalyzed coal samples and using a dispersed MoS{sub 2} catalyst. The effect of coal rank, active metals concentration, dispersion method, and metal type are discussed. 9 refs., 6 figs., 2 tabs.

  19. Immobilization of a Metal-Nitrogen-Carbon Catalyst on Activated Carbon with Enhanced Cathode Performance in Microbial Fuel Cells.

    PubMed

    Yang, Wulin; Logan, Bruce E

    2016-08-23

    Applications of microbial fuel cells (MFCs) are limited in part by low power densities mainly due to cathode performance. Successful immobilization of an Fe-N-C co-catalyst on activated carbon (Fe-N-C/AC) improved the oxygen reduction reaction to nearly a four-electron transfer, compared to a twoelectron transfer achieved using AC. With acetate as the fuel, the maximum power density was 4.7±0.2 W m(-2) , which is higher than any previous report for an air-cathode MFC. With domestic wastewater as a fuel, MFCs with the Fe-N-C/AC cathode produced up to 0.8±0.03 W m(-2) , which was twice that obtained with a Pt-catalyzed cathode. The use of this Fe-N-C/AC catalyst can therefore substantially increase power production, and enable broader applications of MFCs for renewable electricity generation using waste materials. PMID:27416965

  20. Optimized Blanching Reduces the Host Cell Protein Content and Substantially Enhances the Recovery and Stability of Two Plant-Derived Malaria Vaccine Candidates

    PubMed Central

    Menzel, Stephan; Holland, Tanja; Boes, Alexander; Spiegel, Holger; Bolzenius, Johanna; Fischer, Rainer; Buyel, Johannes F.

    2016-01-01

    Plants provide an advantageous expression platform for biopharmaceutical proteins because of their low pathogen burden and potential for inexpensive, large-scale production. However, the purification of target proteins can be challenging due to issues with extraction, the removal of host cell proteins (HCPs), and low expression levels. The heat treatment of crude extracts can reduce the quantity of HCPs by precipitation thus increasing the purity of the target protein and streamlining downstream purification. In the overall context of downstream process (DSP) development for plant-derived malaria vaccine candidates, we applied a design-of-experiments approach to enhance HCP precipitation from Nicotiana benthamiana extracts generated after transient expression, using temperatures in the 20–80°C range, pH values of 3.0–8.0 and incubation times of 0–60 min. We also investigated the recovery of two protein-based malaria vaccine candidates under these conditions and determined their stability in the heat-treated extract while it was maintained at room temperature for 24 h. The heat precipitation of HCPs was also carried out by blanching intact plants in water or buffer prior to extraction in a blender. Our data show that all the heat precipitation methods reduced the amount of HCP in the crude plant extracts by more than 80%, simplifying the subsequent DSP steps. Furthermore, when the heat treatment was performed at 80°C rather than 65°C, both malaria vaccine candidates were more stable after extraction and the recovery of both proteins increased by more than 30%. PMID:26925077

  1. Optimized Blanching Reduces the Host Cell Protein Content and Substantially Enhances the Recovery and Stability of Two Plant-Derived Malaria Vaccine Candidates.

    PubMed

    Menzel, Stephan; Holland, Tanja; Boes, Alexander; Spiegel, Holger; Bolzenius, Johanna; Fischer, Rainer; Buyel, Johannes F

    2016-01-01

    Plants provide an advantageous expression platform for biopharmaceutical proteins because of their low pathogen burden and potential for inexpensive, large-scale production. However, the purification of target proteins can be challenging due to issues with extraction, the removal of host cell proteins (HCPs), and low expression levels. The heat treatment of crude extracts can reduce the quantity of HCPs by precipitation thus increasing the purity of the target protein and streamlining downstream purification. In the overall context of downstream process (DSP) development for plant-derived malaria vaccine candidates, we applied a design-of-experiments approach to enhance HCP precipitation from Nicotiana benthamiana extracts generated after transient expression, using temperatures in the 20-80°C range, pH values of 3.0-8.0 and incubation times of 0-60 min. We also investigated the recovery of two protein-based malaria vaccine candidates under these conditions and determined their stability in the heat-treated extract while it was maintained at room temperature for 24 h. The heat precipitation of HCPs was also carried out by blanching intact plants in water or buffer prior to extraction in a blender. Our data show that all the heat precipitation methods reduced the amount of HCP in the crude plant extracts by more than 80%, simplifying the subsequent DSP steps. Furthermore, when the heat treatment was performed at 80°C rather than 65°C, both malaria vaccine candidates were more stable after extraction and the recovery of both proteins increased by more than 30%. PMID:26925077

  2. CATALYSIS SCIENCE INITIATIVE: From First Principles Design to Realization of Bimetallic Catalysts for Enhanced Selectivity

    SciTech Connect

    MAVRIKAKIS, MANOS DUMESIC, JAMES A.

    2007-05-03

    In this project, we have integrated state-of-the-art Density Functional Theory (DFT) models of heterogeneous catalytic processes with high-throughput screening of bimetallic catalytic candidates for important industrial problems. We have studied a new class of alloys characterized by a surface composition different from the bulk composition, and investigated their stability and activity for the water-gas shift reaction and the oxygen reduction reaction. The former reaction is an essential part of hydrogen production; the latter is the rate-limiting step in low temperature H2 fuel cells. We have identified alloys that have remarkable stability and activity, while having a much lower material cost for both of these reactions. Using this knowledge of bimetallic interactions, we have also made progress in the industrially relevant areas of carbohydrate reforming and conversion of biomass to liquid alkanes. One aspect of this work is the conversion of glycerol (a byproduct of biodiesel production) to synthesis gas. We have developed a bifunctional supported Pt catalyst that can cleave the carbon-carbon bond while also performing the water-gas shift reaction, which allows us to better control the H2:CO ratio. Knowledge gained from the theoretical metal-metal interactions was used to develop bimetallic catalysts that perform this reaction at low temperature, allowing for an efficient coupling of this endothermic reaction with other reactions, such as Fischer-Tropsch or methanol synthesis. In our work on liquid alkane production from biomass, we have studied deactivation and selectivity in these areas as a function of metal-support interactions and reaction conditions, with an emphasis on the bifunctionality of the catalysts studied. We have identified a stable, active catalyst for this process, where the selectivity and yield can be controlled by the reaction conditions. While complete rational design of catalysts is still elusive, this work demonstrates the power of

  3. AgI/TiO2 nanobelts monolithic catalyst with enhanced visible light photocatalytic activity.

    PubMed

    Yi, Junhui; Huang, Lingling; Wang, Hongjuan; Yu, Hao; Peng, Feng

    2015-03-01

    AgI nanoparticles (NPs) have been decorated on the TiO2 nanobelts (NBs) immobilized on a metal Ti substrate by a simple impregnating-precipitation method. The as-achieved AgI/TiO2 monolithic catalyst exhibits a high and stable visible photocatalytic activity toward acid orange II (AO-II) degradation, which is attributed to the suitable energy band match of AgI NPs and TiO2 NBs, leading to the efficient transfer of photo-generated electrons. In addition, it was found that ·O2(-) radicals and h(+) are the main reactive species for the degradation of AO-II under visible light irradiation. A reasonable photocatalytic mechanism of AgI/TiO2 photocatalyst toward AO-II degradation was discussed. This monolithic catalyst provides an advantage over the drawback encountered with powder suspension. PMID:25463235

  4. Using ammonium bicarbonate as pore former in activated carbon catalyst layer to enhance performance of air cathode microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Li, Da; Qu, Youpeng; Liu, Jia; He, Weihua; Wang, Haiman; Feng, Yujie

    2014-12-01

    The rolling catalyst layers in air cathode microbial fuel cells (MFCs) are prepared by introducing NH4HCO3 as pore former (PF) with four PF/activated carbon mass ratios of 0.1, 0.2, 0.3 and 1.0. The maximum power density of 892 ± 8 mW m-2 is obtained by cathodes with the mass ratio of 0.2, which is 33% higher than that of the control reactor (without PF, 671 ± 22 mW m-2). Pore analysis indicates the porosity increases by 38% and the major pore range concentrates between 0.5 μm-0.8 μm which likely facilitates to enrich the active reaction sites compared to 0.8 μm-3.0 μm in the control and other PF-cathodes. In addition, pore structure endows the cathode improved exchange current density by 2.4 times and decreased charge transfer resistance by 44%, which are the essential reasons to enhance the oxygen reduction. These results show that addition of NH4HCO3 proves an effective way to change the porosity and pore distribution of catalyst layers and then enhance the MFC performance.

  5. Nickel phosphide nanoparticles-nitrogen-doped graphene hybrid as an efficient catalyst for enhanced hydrogen evolution activity

    NASA Astrophysics Data System (ADS)

    Pan, Yuan; Yang, Na; Chen, Yinjuan; Lin, Yan; Li, Yanpeng; Liu, Yunqi; Liu, Chenguang

    2015-11-01

    Development of hybrid catalysts with high activity, good stability and low cost is extremely desirable for hydrogen production by electrolysis of water. In this work, a hybrid composed of Ni2P nanoparticles (NPs) on N-doped reduced graphene oxide (NRGO) is synthesized via an in situ thermal decomposition approach for the first time and investigated as a catalyst for the hydrogen evolution reaction (HER). The as-synthesized Ni2P/NRGO hybrid exhibits an enhanced catalytic activity with low onset overpotential (37 mV), a small Tafel slope (59 mV dec-1), a much larger exchange current density (4.9 × 10-5 A cm-2), and lower HER activation energy (46.9 kJ mol-1) than Ni2P/RGO hybrid. In addition, the Ni2P/NRGO hybrid maintains its catalytic activity for at least 60‧000 s in acidic media. The enhanced catalytic activity is attributed to the synergistic effect of N-doped RGO and Ni2P NPs, the charged natures of Ni and P, as well as the high electrical conductivity of Ni2P/NRGO hybrid. This study may offer a new strategy for improving the electrocatalytic activity for hydrogen production.

  6. Enhanced catalytic performance of Pd catalyst for formic acid electrooxidation in ionic liquid aqueous solution

    NASA Astrophysics Data System (ADS)

    Feng, Yuan-Yuan; Yin, Qian-Ying; Lu, Guo-Ping; Yang, Hai-Fang; Zhu, Xiao; Kong, De-Sheng; You, Jin-Mao

    2014-12-01

    A protic ionic liquid (IL), n-butylammonium nitrate (N4NO3), is prepared and employed as the electrolyte for formic acid electrooxidation reaction (FAOR) on Pd catalysts. The oxidation peak potential of FAOR in the IL solution shows about a 200 mV negative shift as compared with those in traditional H2SO4/HClO4 electrolytes, suggesting that FAOR can be more easily carried out on Pd catalysts in IL media. The catalytic properties of Pd toward FAOR are not only dependent on the concentration of IL, as a consequence of the varied electronic conductivity of the IL solution, but also on the high potential limit of the cyclic voltammograms. When the Pd catalyst is cycled up to 1.0 V (vs. SCE), which induces a significant oxidation of Pd, it shows ca. 4.0 times higher activity than that not subjected to the Pd oxidation (up to 0.6 V). The Pd oxides, which are more easily formed in IL solution than in traditional H2SO4/HClO4 electrolytes, may play a crucial role in increasing the catalytic activities of Pd toward FAOR. Our work would shed new light on the mechanism of FAOR and highlight the potential applications of IL as green and environment-friendly electrolytes in fuel cells and other technologies.

  7. Graphene nanoribbons hybridized carbon nanofibers: remarkably enhanced graphitization and conductivity, and excellent performance as support material for fuel cell catalysts

    NASA Astrophysics Data System (ADS)

    Wang, Chaonan; Gao, Hongrong; Li, Hong; Zhang, Yiren; Huang, Bowen; Zhao, Junhong; Zhu, Yan; Yuan, Wang Zhang; Zhang, Yongming

    2014-01-01

    High electronic conductivity of the support material and uniform distribution of the catalyst nanoparticles (NPs) are extremely desirable for electrocatalysts. In this paper, we present our recent progress on electrocatalysts for fuel cells with simultaneously improved conductivity of the supporting carbon nanofibers (CNFs) and distribution of platinum (Pt) NPs through facile incorporation of graphene nanoribbons (GNRs). Briefly, GNRs were obtained by the cutting and unzipping of multiwalled carbon nanotubes (MWCNTs) and subsequent thermal reduction and were first used as novel nanofillers in CNFs towards high performance support material for electrocatalysis. Through electrospinning and carbonization processes, GNR embedded carbon nanofibers (G-CNFs) with greatly enhanced graphitization and electronic conductivity were synthesized. Chemical deposition of Pt NPs onto G-CNFs generated a new Pt-G-CNF hybrid catalyst, with homogeneously distributed Pt NPs of ~3 nm. Compared to Pt-CNF (Pt on pristine CNFs) and Pt-M-CNF (Pt on MWCNT embedded CNFs), Pt-G-CNF hybrids exhibit significantly improved electrochemically active surface area (ECSA), better CO tolerance for electro-oxidation of methanol and higher electrochemical stability, testifying G-CNFs are promising support materials for high performance electrocatalysts for fuel cells.High electronic conductivity of the support material and uniform distribution of the catalyst nanoparticles (NPs) are extremely desirable for electrocatalysts. In this paper, we present our recent progress on electrocatalysts for fuel cells with simultaneously improved conductivity of the supporting carbon nanofibers (CNFs) and distribution of platinum (Pt) NPs through facile incorporation of graphene nanoribbons (GNRs). Briefly, GNRs were obtained by the cutting and unzipping of multiwalled carbon nanotubes (MWCNTs) and subsequent thermal reduction and were first used as novel nanofillers in CNFs towards high performance support material for

  8. Iron- and nitrogen-functionalized graphene as a non-precious metal catalyst for enhanced oxygen reduction in an air-cathode microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Li, Sizhe; Hu, Yongyou; Xu, Qian; Sun, Jian; Hou, Bin; Zhang, Yaping

    2012-09-01

    In this work, iron- and nitrogen-functionalized graphene (Fe-N-G) as a non-precious metal catalyst is synthesized via a facile method of thermal treatment of a mixture of Fe salt, graphitic carbon nitride (g-C3N4) and chemically reduced graphene. The electrocatalytic activity of the prepared catalysts toward oxygen reduction reaction (ORR) evaluated by using linear sweep voltammetry tests shows that the Fe-N-G catalyst has more positive onset potential and increased reduction current densities as compared to the pristine graphene (P-G) catalyst, indicating an enhanced ORR activity of the Fe-N-G catalyst. More importantly, the Fe-N-G-MFC achieves the highest power density of 1149.8 mW m-2, which is ∼2.1 times of that generated with the Pt/C-MFC (561.1 mW m-2) and much higher than that of the P-G-MFC (109 mW m-2). These results demonstrate that the Fe-N-G catalyst can hold the promise of being an excellent alternative to the costly Pt catalyst for practical MFC applications.

  9. Reducible oxide based catalysts

    DOEpatents

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  10. Enhanced hydrothermal stability of Cu-ZSM-5 catalyst via surface modification in the selective catalytic reduction of NO with NH3

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Shi, Juan; Liu, Jian; Wang, Daxi; Zhao, Zhen; Cheng, Kai; Li, Jianmei

    2016-07-01

    The surface of Cu-ZSM-5 catalyst was modified by chemical liquid deposition (CLD) of tetraethoxysilane (TEOS) for enhancing its hydrothermal stability in the selective catalytic reduction of NO with NH3. After hydrothermal aging at 750 °C for 13 h, the catalytic performance of Cu-ZSM-5-Aged catalyst was significantly reduced for NO reduction in the entire temperature range, while that of Cu-ZSM-5-CLD-Aged catalyst was affected very little. The characterization results indicated that an inert silica layer was deposited on the surface of Cu-ZSM-5 and formed a protective layer, which prevents the detachment of Cu2+ from ZSM-5 ion-exchange positions and the dealumination of zeolite during the hydrothermal aging process. Based on the data it is hypothesized to be the primary reason for the high hydrothermal stability of Cu-ZSM-5-CLD catalyst.

  11. Silver/iron oxide/graphitic carbon composites as bacteriostatic catalysts for enhancing oxygen reduction in microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Ma, Ming; You, Shijie; Gong, Xiaobo; Dai, Ying; Zou, Jinlong; Fu, Honggang

    2015-06-01

    Biofilms from anode heterotrophic bacteria are inevitably formed over cathodic catalytic sites, limiting the performances of single-chamber microbial fuel cells (MFCs). Graphitic carbon (GC) - based nano silver/iron oxide (AgNPs/Fe3O4/GC) composites are prepared from waste pomelo skin and used as antibacterial oxygen reduction catalysts for MFCs. AgNPs and Fe3O4 are introduced in situ into the composites by one-step carbothermal reduction, enhancing their conductivity and catalytic activity. To investigate the effects of Fe species on the antibacterial and catalytic properties, AgNPs/Fe3O4/GC is washed with sulfuric acid (1 mol L-1) for 0.5 h, 1 h, and 5 h and marked as AgNPs/Fe3O4/GC-x (x = 0.5 h, 1 h and 5 h, respectively). A maximum power density of 1712 ± 35 mW m-2 is obtained by AgNPs/Fe3O4/GC-1 h, which declines by 4.12% after 17 cycles. Under catalysis of all AgNP-containing catalysts, oxygen reduction reaction (ORR) proceeds via the 4e- pathway, and no toxic effects to anode microorganisms result from inhibiting the cathodic biofilm overgrowth. With the exception of AgNPs/Fe3O4/GC-5 h, the AgNPs-containing composites exhibit remarkable power output and coulombic efficiency through lowering proton transfer resistance and air-cathode biofouling. This study provides a perspective for the practical application of MFCs using these efficient antibacterial ORR catalysts.

  12. Catalyst-Free Plasma Enhanced Growth of Graphene from Sustainable Sources.

    PubMed

    Jacob, Mohan V; Rawat, Rajdeep S; Ouyang, Bo; Bazaka, Kateryna; Kumar, D Sakthi; Taguchi, Dai; Iwamoto, Mitsumasa; Neupane, Ram; Varghese, Oomman K

    2015-09-01

    Details of a fast and sustainable bottom-up process to grow large area high quality graphene films without the aid of any catalyst are reported in this paper. We used Melaleuca alternifolia, a volatile natural extract from tea tree plant as the precursor. The as-fabricated graphene films yielded a stable contact angle of 135°, indicating their potential application in very high hydrophobic coatings. The electronic devices formed by sandwiching pentacene between graphene and aluminum films demonstrated memristive behavior, and hence, these graphene films could find use in nonvolatile memory devices also. PMID:26263025

  13. From First Principles Design to Realization of Bimetallic Catalysts for Enhanced Selectivity

    SciTech Connect

    Lobo, Raul F.; Crooks, Richard M.; Mavrikakis, Manos

    2014-04-08

    “Catalysis by design” has been a dream for decades. To specify the composition and structure of matter to effect a desired catalytic transformation with desired and predicted rate and selectivity remains a monumental challenge, especially in heterogeneous catalysis. Our research thrusts have been chosen not only for their practical and scientific relevance, e.g. for more efficient and sustainable chemicals and fuels production, but also because they provide a foundation for developing and exploring broadly applicable principles and strategies for catalyst design.

  14. Enhancement of Treatment Efficiency of Recalcitrant Wastewater Containing Textile Dyes Using a Newly Developed Iron Zeolite Socony Mobil-5 Heterogeneous Catalyst

    PubMed Central

    Ahmad, Mushtaq; Asghar, Anam; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

    2015-01-01

    Fenton oxidation, an advanced oxidation process, is an efficient method for the treatment of recalcitrant wastewaters. Unfortunately, it utilizes H2O2 and iron-based homogeneous catalysts, which lead to the formation of high volumes of sludge and secondary pollutants. To overcome these problems, an alternate option is the usage of heterogeneous catalyst. In this study, a heterogeneous catalyst was developed to provide an alternative solution for homogeneous Fenton oxidation. Iron Zeolite Socony Mobile-5 (Fe-ZSM-5) was synthesized using a new two-step process. Next, the catalyst was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis and tested against a model wastewater containing the azo dye Acid Blue 113. Results showed that the loading of iron particles reduced the surface area of the catalyst from 293.59 to 243.93 m2/g; meanwhile, the average particle size of the loaded material was 12.29 nm. Furthermore, efficiency of the developed catalyst was evaluated by performing heterogeneous Fenton oxidation. Taguchi method was coupled with principal component analysis in order to assess and optimize mineralization efficiency. Experimental results showed that under optimized conditions, over 99.7% degradation and 77% mineralization was obtained, with a 90% reduction in the consumption of the developed catalyst. Furthermore, the developed catalyst was stable and reusable, with less than 2% leaching observed under optimized conditions. Thus, the present study proved that newly developed catalyst has enhanced the oxidation process and reduced the chemicals consumption. PMID:26517827

  15. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, R.G.; Dosch, R.G.

    1993-01-05

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  16. Crystalline titanate catalyst supports

    SciTech Connect

    Anthony, R.G.; Dosch, R.G.

    1991-12-31

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  17. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, Rayford G.; Dosch, Robert G.

    1993-01-01

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  18. Photo-enhanced activity of Pt and Pt-Ru catalysts towards the electro-oxidation of methanol

    NASA Astrophysics Data System (ADS)

    Arulmani, Dheevesh V.; Eastcott, Jennie I.; Mavilla, Stephanie G.; Easton, E. Bradley

    2014-02-01

    Electrocatalyst materials, consisting of Pt or Pt-Ru supported on carbon with and without TiO2, are evaluated for their activity towards the methanol oxidation reaction (MOR) in 1.0 M H2SO4 at 25 °C in the presence and absence of visible light irradiation. Electrochemical studies showed that enhanced MOR activity is achieved upon irradiation with visible light for each catalyst, in both the presence and absence of TiO2. Irradiation leads to no improvement in activity towards the formic acid oxidation reaction (FAOR) indicating that irradiation aids in the removal of adsorbed intermediate species, such as CO, during MOR. While the presence of a TiO2 support does lead to an increase in activity upon irradiation, about 50% of the improvements arise solely from the irradiation of the metal-containing electrocatalysts themselves.

  19. Three-dimensional mesoporous titanosilicates prepared by modified sol-gel method: Ideal gold catalyst supports for enhanced propene epoxidation.

    PubMed

    Sinha, A K; Seelan, S; Okumura, M; Akita, T; Tsubota, S; Haruta, M

    2005-03-10

    Mesoporous titanosilicates with 1-12 mol % Ti content and with three-dimensional wormhole-like mesoporosity are prepared by a modified sol-gel technique. Sorption analysis shows that there is little change in the surface properties with increasing Ti concentration in the samples, implying that Ti atoms either are well-dispersed on the walls of the silica matrix or are present inside the framework with no pore blocking effect. Spectroscopic analysis shows that the Ti atoms are atomically dispersed in the silica matrix even at very high Ti concentration and there is no observable Ti aggregate (anatase) present in the samples. These titanosilicate samples after Au deposition followed by trimethylsilylation (for enhanced hydrophobicity) are highly efficient catalysts for vapor-phase propene epoxidation using O2 and H2. It was possible to achieve commercially desirable performance with about 7% propene conversion, >90% propene oxide selectivity, and about 40% hydrogen efficiency. PMID:16851450

  20. The enhanced catalytic performance of cobalt catalysts towards butadiene polymerization by introducing a labile donor in a salen ligand.

    PubMed

    Gong, Dirong; Wang, Baolin; Jia, Xiaoyu; Zhang, Xuequan

    2014-03-14

    A family of cobalt complexes supported by a tridentate Schiff base ligand with a labile donor (O, S, N) as a pendant arm (Co1-Co12, formulated as CoL2) were synthesized by the treatment of the corresponding ligands with cobalt acetate tetrahydrate. The resultant complexes were well characterized by elemental analysis, FT-IR, magnetic moment as well as EI-MS. The solid-state structures of Co7 and Co12 were determined by X-ray diffraction and both established a distorted octahedron geometry around the cobalt center. The butadiene polymerization capabilities of the 12 complexes were evaluated and compared in representative cases. Diethylaluminum chloride (AlEt2Cl) was found to be the compatible activator resulting in highly active catalysts for producing polybutadiene of 93.8-98.2% cis-1,4 enchainment with negligible 1,2-structure and trans-1,4 units. It appears that a certain degree of lability of the donor is beneficial for high catalytic activity, generally following the order of O > S > N, and the high cis-1,4 selectivity. Moreover, the remarkable thermal stability of these systems has been achieved: the catalytic systems have the ability of conducting a high level of active and selective polymerization, reaching an upper limit of polymerization temperature of about 70 °C. The enhanced catalytic performances were further rationalized by the established diene polymerization mechanism, which could shed light on developing highly selective and reactive industrially applicable catalysts with an enhanced thermal stability. PMID:24468706

  1. Enhanced electrochemical methanation of carbon dioxide with a dispersible nanoscale copper catalyst.

    PubMed

    Manthiram, Karthish; Beberwyck, Brandon J; Alivisatos, A Paul

    2014-09-24

    Although the vast majority of hydrocarbon fuels and products are presently derived from petroleum, there is much interest in the development of routes for synthesizing these same products by hydrogenating CO2. The simplest hydrocarbon target is methane, which can utilize existing infrastructure for natural gas storage, distribution, and consumption. Electrochemical methods for methanizing CO2 currently suffer from a combination of low activities and poor selectivities. We demonstrate that copper nanoparticles supported on glassy carbon (n-Cu/C) achieve up to 4 times greater methanation current densities compared to high-purity copper foil electrodes. The n-Cu/C electrocatalyst also exhibits an average Faradaic efficiency for methanation of 80% during extended electrolysis, the highest Faradaic efficiency for room-temperature methanation reported to date. We find that the level of copper catalyst loading on the glassy carbon support has an enormous impact on the morphology of the copper under catalytic conditions and the resulting Faradaic efficiency for methane. The improved activity and Faradaic efficiency for methanation involves a mechanism that is distinct from what is generally thought to occur on copper foils. Electrochemical data indicate that the early steps of methanation on n-Cu/C involve a pre-equilibrium one-electron transfer to CO2 to form an adsorbed radical, followed by a rate-limiting non-electrochemical step in which the adsorbed CO2 radical reacts with a second CO2 molecule from solution. These nanoscale copper electrocatalysts represent a first step toward the preparation of practical methanation catalysts that can be incorporated into membrane-electrode assemblies in electrolyzers. PMID:25137433

  2. Use of polyoxometalate catalysts in ionic liquids to enhance the dissolution and delignification of woody biomass.

    PubMed

    Sun, Ning; Jiang, Xinyu; Maxim, Mirela L; Metlen, Andreas; Rogers, Robin D

    2011-01-17

    A well-known polyoxometalate, [PV₂Mo₁₀O₄₀]⁵⁻, in both acidic (acidic POM, H₅[PV₂Mo₁₀O₄₀]) and ionic liquid-compatible form ([C₂mim]POM, [1-ethyl-3-methylimidazolium]₄H[PV₂Mo₁₀O₄₀]), has been studied as a catalyst for the dissolution and delignification of wood in the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C(2) mim]OAc). Differences were observed with variables such as the form of POM, POM loading, and reaction conditions. Generally, the addition of POM leads to a faster dissolution, a lower lignin content in the recovered cellulose-rich materials (isolated pulp), and a lower isolated yield of lignin due to its oxidation. Acidic POM decreases the lignin content of the pulp without compromising the yield of the pulp. [C₂mim]POM in the IL facilitates greater delignification (lower lignin content in pulp) than the IL with acidic POM; however, the overall pulp yield is also lower indicating some degradation of the carbohydrates. The POM can be recovered with [C₂mim]OAc after evaporation of the reconstitution solvent (e.g., acetone/water) and can be reused, albeit with some loss of POM and loss of POM activity under the current conditions. PMID:21226213

  3. [Enhanced electro-catalytic oxidation of dye wastewater with FePMo12 adopted catalyst].

    PubMed

    Wang, Li; Yue, Lin; Guo, Jian-Bo; Yang, Jing-Liang; Lian, Jing; Luo, Xiao; Wang, Kai-Hong

    2014-05-01

    Electrochemical oxidation degradation of azo dyes has become a widely used method in recent years. Iron phosphomolybdate (FePMo12) was synthesized with molybdophosphoric acid and ferric salt. Morphology and microstructure of catalyst were chararerized by IR spectrometry and X-ray diffraction. The heteropolyanion showed a Keggin structure. Electrochemical oxidation of acid red 3R was investigated in the presence of FePMo12 supported on modified 4A molecular sieve (4A) as packing materials in the reactor. The results showed that the optimal technological conditions for decolorization of acid red 3R simulated wastewater were as follows: active component load 3% , electrolytic voltage 22 V, initial pH 4, air-flow 0.08 m3 h- ', electrode span 3.0 cm. Under the opñrrizd conditions, the decolorization efficiency, COD and TOC removal efficiencies reached 75.3% , 65.4% and 46.0% after 90 min, respectively. With the addition of NaCI to the dyes solution during electrolysis, the decolorization efficiency increased, while the effect of Na2SO4 on the degradation was negative. The efficiency of degradation and mineralization of the acid red 3R were estimated based on the absorbance measurements by UV-vis. It shows that the conjugated structure of dye was destroyed primarily. PMID:25055676

  4. FePt nanoparticles assembled on graphene as enhanced catalyst for oxygen reduction reaction.

    PubMed

    Guo, Shaojun; Sun, Shouheng

    2012-02-01

    Seven-nanometer FePt nanoparticles (NPs) were synthesized and assembled on graphene (G) by a solution-phase self-assembly method. These G/FePt NPs were a more active and durable catalyst for oxygen reduction reaction (ORR) in 0.1 M HClO(4) than the same NPs or commercial Pt NPs deposited on conventional carbon support. The G/FePt NPs annealed at 100 °C for 1 h under Ar + 5% H(2) exhibited specific ORR activities of 1.6 mA/cm(2) at 0.512 V and 0.616 mA/cm(2) at 0.557 V (vs Ag/AgCl). As a comparison, the commercial Pt NPs (2-3 nm) had specific activities of 0.271 and 0.07 mA/cm(2) at the same potentials. The G/FePt NPs were also much more stable in the ORR condition and showed nearly no activity change after 10 000 potential sweeps. The work demonstrates that G is indeed a promising support to improve NP activity and durability for practical catalytic applications. PMID:22279956

  5. Amperometric S-Nitrosothiol Sensor with Enhanced Sensitivity Based on Organoselenium Catalysts

    PubMed Central

    Cha, Wansik; Anderson, Meredith R.; Zhang, Fenghua; Meyerhoff, Mark E.

    2008-01-01

    A new S-nitrosothiol (RSNO) detection strategy based on an electrochemical sensor is described for rapidly estimating levels of total RSNOs in blood and other biological samples. The sensor employs a cellulose dialysis membrane covalently modified with an organoselenium catalyst that converts RSNOs to NO at the distal tip of an amperometric NO sensor. The sensor is characterized by very low detection limits (< 20 nM), good long-term stability and can be employed for the rapid detection of total low molecular weight (LMW) RSNO levels in whole blood samples using a simple standard addition method. A strategy for detecting macromolecular RSNOs is also demonstrated via use of a transnitrosation reaction with added LMW thiols allowing the estimation of total RSNO levels in blood. The sensor is shown to exhibit high selectivity over nitrosamines and nitrite. Such RSNO detection is potentially useful to reveal correlation between blood RSNO levels and endothelial cell dysfunction, which often is associated with cardiovascular diseases. PMID:19168347

  6. Substantial enhancement in intrinsic coercivity on M-type strontium hexaferrite through the increase in magneto-crystalline anisotropy by co-doping of group-V and alkali elements

    SciTech Connect

    Ahn, Kyunghan Ryu, Byungki; Korolev, Dmitry; Jae Kang, Young

    2013-12-09

    The effect of d{sup 1} impurity doping in Sr-hexaferrite (SrM) on the magnetic anisotropy is investigated. First-principles calculations revealed that group-V elements (V, Nb) are stabilized with co-doping of alkali elements. Na{sup 1+}/K{sup 1+} doping at Sr{sup 2+}-site is found to be critical to form the d{sup 1} impurities at Fe-site. Experimentally, Na–V doped SrM shows the intrinsic coercivity of ∼5.4 kOe, which is ∼300% enhancement compared to undoped SrM and comparable value to La–Co co-doped SrM. Finally, the spin-orbit coupling from non-vanishing angular momentum of d{sup 1} impurity in SrM should be a main factor for such a substantial improvement of intrinsic coercivity.

  7. Stabilization of Hydrogen Production via Methanol Steam Reforming in Microreactor by Al2O3 Nano-Film Enhanced Catalyst Adhesion.

    PubMed

    Jeong, Heondo; Na, Jeong-Geol; Jang, Min Su; Ko, Chang Hyun

    2016-05-01

    In hydrogen production by methanol steam reforming reaction with microchannel reactor, Al2O3 thin film formed by atomic layer deposition (ALD) was introduced on the surface of microchannel reactor prior to the coating of catalyst particles. Methanol conversion rate and hydrogen production rate, increased in the presence of Al2O3 thin film. Over-view and cross-sectional scanning electron microscopy study showed that the adhesion between catalyst particles and the surface of microchannel reactor enhanced due to the presence of Al2O3 thin film. The improvement of hydrogen production rate inside the channels of microreactor mainly came from the stable fixation of catalyst particles on the surface of microchannels. PMID:27483762

  8. A New Bioinspired Perchlorate Reduction Catalyst with Significantly Enhanced Stability via Rational Tuning of Rhenium Coordination Chemistry and Heterogeneous Reaction Pathway.

    PubMed

    Liu, Jinyong; Han, Mengwei; Wu, Dimao; Chen, Xi; Choe, Jong Kwon; Werth, Charles J; Strathmann, Timothy J

    2016-06-01

    Rapid reduction of aqueous ClO4(-) to Cl(-) by H2 has been realized by a heterogeneous Re(hoz)2-Pd/C catalyst integrating Re(O)(hoz)2Cl complex (hoz = oxazolinyl-phenolato bidentate ligand) and Pd nanoparticles on carbon support, but ClOx(-) intermediates formed during reactions with concentrated ClO4(-) promote irreversible Re complex decomposition and catalyst deactivation. The original catalyst design mimics the microbial ClO4(-) reductase, which integrates Mo(MGD)2 complex (MGD = molybdopterin guanine dinucleotide) for oxygen atom transfer (OAT). Perchlorate-reducing microorganisms employ a separate enzyme, chlorite dismutase, to prevent accumulation of the destructive ClO2(-) intermediate. The structural intricacy of MGD ligand and the two-enzyme mechanism for microbial ClO4(-) reduction inspired us to improve catalyst stability by rationally tuning Re ligand structure and adding a ClOx(-) scavenger. Two new Re complexes, Re(O)(htz)2Cl and Re(O)(hoz)(htz)Cl (htz = thiazolinyl-phenolato bidentate ligand), significantly mitigate Re complex decomposition by slightly lowering the OAT activity when immobilized in Pd/C. Further stability enhancement is then obtained by switching the nanoparticles from Pd to Rh, which exhibits high reactivity with ClOx(-) intermediates and thus prevents their deactivating reaction with the Re complex. Compared to Re(hoz)2-Pd/C, the new Re(hoz)(htz)-Rh/C catalyst exhibits similar ClO4(-) reduction activity but superior stability, evidenced by a decrease of Re leaching from 37% to 0.25% and stability of surface Re speciation following the treatment of a concentrated "challenge" solution containing 1000 ppm of ClO4(-). This work demonstrates the pivotal roles of coordination chemistry control and tuning of individual catalyst components for achieving both high activity and stability in environmental catalyst applications. PMID:27182602

  9. Enhanced Dry Reforming of Methane on Ni and Ni-Pt Catalysts Synthesized by Atomic Layer Deposition

    SciTech Connect

    Gould, Troy D.; Montemore, Matthew M.; Lubers, Alia M.; Ellis, Lucas D.; Weimer, Alan; Falconer, John L.; Medlin, James W.

    2015-02-25

    Atomic layer deposition (ALD) was used to deposit Ni and Pt on alumina supports to form monometallic and bimetallic catalysts with initial particle sizes of 1–2.4 nm. The ALD catalysts were more active (per mass of metal) than catalysts prepared by incipient wetness (IW) for dry reforming of methane (DRM), and they did not form carbon whiskers during reaction due to their sufficiently small size. Catalysts modified by Pt ALD had higher rates of reaction per mass of metal and inhibited coking, whereas NiPt catalysts synthesized by IW still formed carbon whiskers. Temperature-programmed reduction of Ni catalysts modified by Pt ALD indicated the presence of bimetallic interaction. Density functional theory calculations suggested that under reaction conditions, the NiPt surfaces form Ni-terminated surfaces that are associated with higher DRM rates (due to their C and O adsorption energies, as well as the CO formation and CH4 dissociation energies).

  10. Nanofiltration of rhodium tris(triphenylphosphine) catalyst in ethyl acetate solution

    NASA Astrophysics Data System (ADS)

    Shaharun, Maizatul S.; Mustafa, Ahmad K.; Taha, Mohd F.

    2012-09-01

    Solvent resistant nanofiltration (SRNF) using polymer membranes has recently received enhanced attention due to the search for cleaner and more energy-efficient technologies. The large size of the rhodium tris(triphenylphosphine) [HRh(CO)(PPh3)3] catalyst (>400 Da) - relative to other components of the hydroformylation reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (DuraMem{trade mark, serif} 200 and DuraMem{trade mark, serif} 500) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. Good HRh(CO)(PPh3)3 rejection (>0.95) and solvent fluxes of 9.9 L/m2ṡh1 at 2.0 MPa were obtained in the catalyst-ethyl acetate-DuraMem 500 system. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted on the catalyst-ethyl acetate-membrane systems. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting solvent flux.

  11. Enhancing the available specific surface area of carbon supports to boost the electroactivity of nanostructured Pt catalysts.

    PubMed

    Holade, Yaovi; Morais, Claudia; Servat, Karine; Napporn, Teko W; Kokoh, K Boniface

    2014-12-14

    We report increasing improvements in the available specific surface area of the commonly used Vulcan XC 72R and Ketjenblack EC-600JD carbons by simple thermal pre-treatment. The treated Vulcan and Ketjenblack substrates have a specific surface area of 322 and 1631 m(2) g(-1), respectively, instead of 262 and 1102 m(2) g(-1) for the as-received materials, which is a 23 and 48% improvement. Subsequently, when used as platinum nanoparticle (3 nm) supports, the electrochemical active surface area is enhanced by factors of 2.2 and 1.2 for treated Vulcan and Ketjenblack carbons, respectively. Furthermore, electrochemical investigations have highlighted a surprisingly improved catalytic activity for the pre-treated Vulcan XC 72R and Ketjenblack EC-600JD supported Pt nanoparticles. In fact, the synthesized nanostructures from the so-called "Bromide Anion Exchange" method exhibit good catalytic activity toward glucose electrooxidation, both in the alkaline medium and the phosphate buffered solution at pH 7.4. More importantly, the present catalysts are four times more active than those in the literature prepared under similar conditions for glucose dehydrogenation at low potential (0.27 V vs. Reversible Hydrogen Electrode). Consequently, these remarkable trends uncovered herein provide ample new strategic routes for the pre-treatment of Vulcan XC 72R and Ketjenblack carbons for widespread uses. PMID:25351933

  12. Effects of feed gas composition and catalyst thickness on carbon nanotube and nanofiber synthesis by plasma enhanced chemical vapor deposition.

    PubMed

    Garg, R K; Kim, S S; Hash, D B; Gore, J P; Fisher, T S

    2008-06-01

    Many engineering applications require carbon nanotubes with specific characteristics such as wall structure, chirality and alignment. However, precise control of nanotube properties grown to application specifications remains a significant challenge. Plasma-enhanced chemical vapor deposition (PECVD) offers a variety of advantages in the synthesis of carbon nanotubes in that several important synthesis parameters can be controlled independently. This paper reports an experimental study of the effects of reacting gas composition (percentage methane in hydrogen) and catalyst film thickness on carbon nanotube (CNT) growth and a computational study of gas-phase composition for the inlet conditions of experimentally observed carbon nanotube growth using different chemical reaction mechanisms. The simulations seek to explain the observed effects of reacting gas composition and to identify the precursors for CNT formation. The experimental results indicate that gas-phase composition significantly affects the synthesized material, which is shown to be randomly aligned nanotube and nanofiber mats for relatively methane-rich inlet gas mixtures and non-tubular carbon for methane-lean incoming mixtures. The simulation results suggest that inlet methane-hydrogen mixture coverts to an acetylene-methane-hydrogen mixture with minor amounts of ethylene, hydrogen atom, and methyl radical. Acetylene appears to be the indicator species for solid carbon formation. The simulations also show that inlet methane-hydrogen mixture does not produce enough gas-phase precursors needed to form quality CNTs below 5% CH4 concentrations in the inlet stream. PMID:18681048

  13. Enhancement of Biodiesel Production from Marine Alga, Scenedesmus sp. through In Situ Transesterification Process Associated with Acidic Catalyst

    PubMed Central

    Kim, Ga Vin; Choi, WoonYong; Kang, DoHyung; Lee, ShinYoung; Lee, HyeonYong

    2014-01-01

    The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp. PMID:24689039

  14. Atomic layer-by-layer deposition of platinum on palladium octahedra for enhanced catalysts toward the oxygen reduction reaction.

    PubMed

    Park, Jinho; Zhang, Lei; Choi, Sang-Il; Roling, Luke T; Lu, Ning; Herron, Jeffrey A; Xie, Shuifen; Wang, Jinguo; Kim, Moon J; Mavrikakis, Manos; Xia, Younan

    2015-03-24

    We systematically evaluated two different approaches to the syntheses of Pd@PtnL (n = 2-5) core-shell octahedra. We initially prepared the core-shell octahedra using a polyol-based route by titrating a Pt(IV) precursor into the growth solution containing Pd octahedral seeds at 200 °C through the use of a syringe pump. The number of Pt atomic layers could be precisely controlled from two to five by increasing the volume of the precursor solution while fixing the amount of seeds. We then demonstrated the synthesis of Pd@PtnL octahedra using a water-based route at 95 °C through the one-shot injection of a Pt(II) precursor. Due to the large difference in reaction temperature, the Pd@PtnL octahedra obtained via the water-based route showed sharper corners than their counterparts obtained through the polyol-based route. When compared to a commercial Pt/C catalyst based upon 3.2 nm Pt particles, the Pd@PtnL octahedra prepared using both methods showed similar remarkable enhancement in terms of activity (both specific and mass) and durability toward the oxygen reduction reaction. Calculations based upon periodic, self-consistent density functional theory suggested that the enhancement in specific activity for the Pd@PtnL octahedra could be attributed to the destabilization of OH on their PtnL*/Pd(111) surface relative to the {111} and {100} facets exposed on the surface of Pt/C. The destabilization of OH facilitates its hydrogenation, which was found to be the rate-limiting step of the oxygen reduction reaction on all these surfaces. PMID:25661922

  15. Post-Treatments for Multifunctional Property Enhancement of Carbon Nanotube Fibers from the Floating Catalyst Method.

    PubMed

    Tran, Thang Q; Fan, Zeng; Mikhalchan, Anastasiia; Liu, Peng; Duong, Hai M

    2016-03-30

    We investigated the effects of the synthesis conditions and condensation processes on the chemical compositions and multifunctional performance of the directly spun carbon nanotube (CNT) fibers. On the basis of the optimized synthesis conditions, a two-step post-treatment technique which involved acidification and epoxy infiltration was also developed to further enhance their mechanical and electrical properties. As a result, their tensile strength and Young's modulus increased remarkably by 177% and 325%, respectively, while their electrical conductivity also reached 8235 S/cm. This work may provide a general strategy for the postprocessing optimization of the directly spun CNT fibers. The treated CNT fibers with superior properties are promising for a wide range of applications, such as structural reinforcements and lightweight electric cables. PMID:26966936

  16. Atomic Layer-by-Layer Deposition of Pt on Pd Nanocubes for Catalysts with Enhanced Activity and Durability toward Oxygen Reduction

    SciTech Connect

    Xie, Shuifen; Choi, Sang; Lu, Ning; Roling, Luke T.; Herron, Jeffrey A.; Zhang, Lei; Park, Jinho; Wang, Jinguo; Kim, Moon J.; Xie, Zhaoxiong; Mavrikakis, Manos; Xia, Younan

    2014-06-11

    An effective strategy for reducing the Pt content while retaining the activity of a Pt-based catalyst is to deposit the Pt atoms as ultrathin skins of only a few atomic layers thick on nanoscale substrates made of another metal. During deposition, however, the Pt atoms often take an island growth mode because of a strong bonding between Pt atoms. Here we report a versatile route to the conformal deposition of Pt as uniform, ultrathin shells on Pd nanocubes in a solution phase. The introduction of the Pt precursor at a relatively slow rate and high temperature allowed the deposited Pt atoms to spread across the entire surface of a Pd nanocube to generate a uniform shell. The thickness of the Pt shell could be controlled from one to six atomic layers by varying the amount of Pt precursor added into the system. Compared to a commercial Pt/C catalyst, the Pd@PnL (n = 1-6) core-shell nanocubes showed enhancements in specific activity and durability toward the oxygen reduction reaction (ORR). Density functional theory (DFT) calculations on model (100) surfaces suggest that the enhancement in specific activity can be attributed to the weakening of OH binding through ligand and strain effects, which, in turn, increases the rate of OH hydrogenation. A volcano-type relationship between the ORR specific activity and the number of Pt atomic layers was derived, in good agreement with the experimental results. Both theoretical and experimental studies indicate that the ORR specific activity was maximized for the catalysts based on Pd@Pt2-3L nanocubes. Because of the reduction in Pt content used and the enhancement in specific activity, the Pd@Pt1L nanocubes showed a Pt mass activity with almost three-fold enhancement relative to the Pt/C catalyst.

  17. Enhanced effect of water vapor on complete oxidation of formaldehyde in air with ozone over MnOx catalysts at room temperature.

    PubMed

    Zhao, De-Zhi; Shi, Chuan; Li, Xiao-Song; Zhu, Ai-Min; Jang, Ben W-L

    2012-11-15

    At room temperature, the enhanced effect of water vapor on ozone catalytic oxidation (OZCO) of formaldehyde to CO2 over MnOx catalysts and the reaction stability was reported. In a dry air stream, only below 20% of formaldehyde could be oxidized into CO2 by O3. In humid air streams (RH≥55%), ∼100% of formaldehyde were oxidized into CO2 by O3 and the reaction stability was significantly enhanced. Meanwhile, in situ Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectra of OZCO of HCHO demonstrate that the amount of both monodentate and bidentate carbonate species on MnOx, in the dry stream, increased gradually with time on stream (TOS). However, in the humid stream, almost no accumulation of carbonate species on the catalysts was observed. To clarify the enhanced mechanism, formaldehyde surface reactions and CO2 adsorption/desorption on the fresh, O3 and O3+H2O treated MnOx catalysts were examined comparatively. PMID:23021101

  18. Enhanced catalytic activity over MIL-100(Fe) loaded ceria catalysts for the selective catalytic reduction of NOx with NH₃ at low temperature.

    PubMed

    Wang, Peng; Sun, Hong; Quan, Xie; Chen, Shuo

    2016-01-15

    The development of catalysts for selective catalytic reduction (SCR) reactions that are highly active at low temperatures and show good resistance to SO2 and H2O is still a challenge. In this study, we have designed and developed a high-performance SCR catalyst based on nano-sized ceria encapsulated inside the pores of MIL-100(Fe) that combines excellent catalytic power with a metal organic framework architecture synthesized by the impregnation method (IM). Transmission electron microscopy (TEM) revealed the encapsulation of ceria in the cavities of MIL-100(Fe). The prepared IM-CeO2/MIL-100(Fe) catalyst shows improved catalytic activity both at low temperatures and throughout a wide temperature window. The temperature window for 90% NOx conversion ranges from 196 to 300°C. X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) analysis indicated that the nano-sized ceria encapsulated inside MIL-100(Fe) promotes the production of chemisorbed oxygen on the catalyst surface, which greatly enhances the formation of the NO2 species responsible for fast SCR reactions. PMID:26414927

  19. Process of making supported catalyst

    SciTech Connect

    Schwarz, James A.; Subramanian, Somasundaram

    1992-01-01

    Oxide supported metal catalysts have an additional metal present in intimate association with the metal catalyst to enhance catalytic activity. In a preferred mode, iridium or another Group VIII metal catalyst is supported on a titania, alumina, tungsten oxide, silica, or composite oxide support. Aluminum ions are readsorbed onto the support and catalyst, and reduced during calcination. The aluminum can be added as aluminum nitrate to the iridium impregnate solution, e.g. chloroiridic acid.

  20. Production of substantially pure fructose

    SciTech Connect

    Hatcher, H.J.; Gallian, J.J.; Leeper, S.A.

    1990-05-22

    This patent describes a process for the production of a substantially pure product containing greater than 60% fructose. It comprises: combining a sucrose-containing substrate with effective amounts of a levansucrase enzyme preparation to form levan and glucose; purifying the levan by at least one of the following purification methods: ultrafiltration, diafiltration, hyperfiltration, reverse osmosis, liquid--liquid partition, solvent extraction, chromatography, and precipitation; hydrolyzing the levan to form fructose substantially free of glucose and sucrose; and recovering the fructose by at least one of the following recovery methods: hyperfiltration, reverse osmosis, evaporation, drying, crystallization, and chromatography.

  1. Oxygen-reducing catalyst layer

    DOEpatents

    O'Brien, Dennis P.; Schmoeckel, Alison K.; Vernstrom, George D.; Atanasoski, Radoslav; Wood, Thomas E.; Yang, Ruizhi; Easton, E. Bradley; Dahn, Jeffrey R.; O'Neill, David G.

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  2. Production of substantially pure fructose

    DOEpatents

    Hatcher, Herbert J.; Gallian, John J.; Leeper, Stephen A.

    1990-01-01

    A process is disclosed for the production of substantially pure fructose from sucrose-containing substrates. The process comprises converting the sucrose to levan and glucose, purifying the levan by membrane technology, hydrolyzing the levan to form fructose monomers, and recovering the fructose.

  3. Enhancing low-temperature activity and durability of Pd-based diesel oxidation catalysts using ZrO2 supports

    DOE PAGESBeta

    Kim, Mi -Young; Kyriakidou, Eleni A.; Choi, Jae -Soon; Toops, Todd J.; Binder, Andrew J.; Thomas, Cyril; Schwartz, Viviane; Chen, Jihua; Hensley, Dale K.; Parks, II, James E.

    2016-01-18

    In this study, we investigated the impact of ZrO2 on the performance of palladium-based oxidation catalysts with respect to low-temperature activity, hydrothermal stability, and sulfur tolerance. Pd supported on ZrO2 and SiO2 were synthesized for a comparative study. Additionally, in an attempt to maximize the ZrO2 surface area and improve sulfur tolerance, a Pd support with ZrO2-dispersed onto SiO2 was studied. The physicochemical properties of the catalysts were examined using ICP, N2 sorption, XRD, SEM, TEM, and NH3-, CO2-, and NOx-TPD. The activity of the Pd catalysts were measured from 60 to 600 °C in a flow of 4000 ppmmore » CO, 500 ppm NO, 1000 ppm C3H6, 4% O2, 5% H2O, and Ar balance. The Pd catalysts were evaluated in fresh, sulfated, and hydrothermally aged states. Overall, the ZrO2-containing catalysts showed considerably higher CO and C3H6 oxidation activity than Pd/SiO2 under the reaction conditions studied.« less

  4. Use of multi-transition-metal-ion-exchanged zeolite 13X catalysts in methane emissions abatement

    SciTech Connect

    Hui, K.S.; Chao, C.Y.H.; Kwong, C.W.; Wan, M.P.

    2008-04-15

    Methane is a potent greenhouse gas. It has a global warming potential (GWP) 23 times greater than carbon dioxide. Reducing methane emissions would lead to substantial economic and environmental benefits. This study investigated the performance of multi-transition-metal-(Cu, Cr, Ni, and Co)-ion-exchanged zeolite 13X catalysts in methane emissions abatement. The catalytic activity in methane combustion using multi-ion-exchanged catalysts was studied with different parameters including the molar percentage of metal loading, the space velocity, and the inlet methane concentration under atmospheric pressure and at a relatively low reaction temperature of 500 C. The performance of the catalysts was determined in terms of the apparent activation energy, the number of active sites of the catalyst, and the BET surface area of the catalyst. This study showed that multi-ion-exchanged catalysts outperformed single-ion-exchanged and acidified 13X catalysts and that lengthening the residence time led to a higher methane conversion percentage. The enhanced catalytic activity in the multi-ion-exchanged catalysts was attributed to the presence of exchanged transition ions instead of acid sites in the catalyst. The catalytic activity of the catalysts was influenced by the metal loading amount, which played an important role in affecting the apparent activation energy for methane combustion, the active sites, and the BET surface area of the catalyst. Increasing the amount of metal loading in the catalyst decreased the apparent activation energy for methane combustion and also the BET surface area of the catalyst. An optimized metal loading amount at which the highest catalytic activity was observed due to the combined effects of the various factors was determined. (author)

  5. Enhanced Fischer-Tropsch synthesis performance of iron-based catalysts supported on nitric acid treated N-doped CNTs

    NASA Astrophysics Data System (ADS)

    Li, Zhenhua; Liu, Renjie; Xu, Yan; Ma, Xinbin

    2015-08-01

    Iron-based catalysts supported on N-doped CNTs (NCNTs) treated by various concentrations of nitric acid for Fischer-Tropsch synthesis (FTS) were investigated. An improved catalytic performance for the iron catalyst supported on acid treated NCNTs was obtained and the suitable nitric acid concentration was 10 M. The physiochemical properties of the NCNTs and the corresponding catalysts were characterized by BET, TEM, XRD, XPS, TGA and H2-TPR. The acid treatment removed the impurity and amorphous carbon, damaged the bamboo-like structure and increased the number of oxygen-containing functional groups and graphitization degree on the NCNTs. The more iron particles located inside the channels of NCNTs, the better catalytic FTS performance due to high dispersion and reducibility.

  6. Epoxidation catalyst and process

    DOEpatents

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  7. Effect of nitrogen post-doping on a commercial platinum-ruthenium/carbon anode catalyst

    NASA Astrophysics Data System (ADS)

    Corpuz, April R.; Wood, Kevin N.; Pylypenko, Svitlana; Dameron, Arrelaine A.; Joghee, Prabhuram; Olson, Tim S.; Bender, Guido; Dinh, Huyen N.; Gennett, Thomas; Richards, Ryan M.; O'Hayre, Ryan

    2014-02-01

    This work investigates the effects of after-the-fact chemical modification of a state-of-the-art commercial carbon-supported PtRu catalyst for direct methanol fuel cells (DMFCs). A commercial PtRu/C (JM HiSPEC-10000) catalyst is post-doped with nitrogen by ion-implantation, where "post-doped" denotes nitrogen doping after metal is carbon-supported. Composition and performance of the PtRu/C catalyst post-modified with nitrogen at several dosages are evaluated using X-ray photoelectron spectroscopy (XPS), rotating disk electrode (RDE), and membrane electrode assemblies (MEAs) for DMFC. Overall, implantation at high dosage results in 16% higher electrochemical surface area and enhances performance, specifically in the mass transfer region. Rotating disk electrode (RDE) results show that after 5000 cycles of accelerated durability testing to high potential, the modified catalyst retains 34% more electrochemical surface area (ECSA) than the unmodified catalyst. The benefits of nitrogen post-doping are further substantiated by DMFC durability studies (carried out for 425 h), where the MEA with the modified catalyst exhibits higher surface area and performance stability in comparison to the MEA with unmodified catalyst. These results demonstrate that post-doping of nitrogen in a commercial PtRu/C catalyst is an effective approach, capable of improving the performance of available best-in-class commercial catalysts.

  8. Application of meta- and para- phenylenediamine as enhanced oxime ligation catalysts for protein labeling, PEGylation, immobilization and release

    PubMed Central

    Mahmoodi, Mohammad M.; Rashidian, Mohammad; Zhang, Yi; Distefano, Mark D.

    2015-01-01

    Meta- and para- phenylenediamines have recently been shown to catalyze oxime and hydrazone ligation reactions at rates much faster than aniline, a commonly used catalyst. Here, it is demonstrated how these new catalysts can be used in a generally applicable procedure for fluorescent labeling, PEGylation, immobilization and release of aldehyde and ketone functionalized proteins. The chemical orthogonality of phenylenediamine-catalyzed oxime ligation versus copper catalyzed click reaction has also been harnessed for simultaneous dual labeling of bifunctional proteins containing both aldehyde and alkyne groups in high yield. PMID:25640893

  9. When Magnetic Catalyst Meets Magnetic Reactor: Etherification of FCC Light Gasoline as an Example

    NASA Astrophysics Data System (ADS)

    Cheng, Meng; Xie, Wenhua; Zong, Baoning; Sun, Bo; Qiao, Minghua

    2013-06-01

    The application of elaborately designed magnetic catalysts has long been limited to ease their separation from the products only. In this paper, we for the first time employed a magnetic sulphonated poly(styrene-divinylbenzene) resin catalyst on a magnetically stabilized-bed (MSB) reactor to enhance the etherification of fluidized catalytic cracking (FCC) light gasoline, one of the most important reactions in petroleum refining industry. We demonstrated that the catalytic performance of the magnetic acid resin catalyst on the magnetic reactor is substantially enhanced as compared to its performance on a conventional fixed-bed reactor under otherwise identical operation conditions. The magnetic catalyst has the potential to be loaded and unloaded continuously on the magnetic reactor, which will greatly simplify the current complex industrial etherification processes.

  10. When Magnetic Catalyst Meets Magnetic Reactor: Etherification of FCC Light Gasoline as an Example

    PubMed Central

    Cheng, Meng; Xie, Wenhua; Zong, Baoning; Sun, Bo; Qiao, Minghua

    2013-01-01

    The application of elaborately designed magnetic catalysts has long been limited to ease their separation from the products only. In this paper, we for the first time employed a magnetic sulphonated poly(styrene-divinylbenzene) resin catalyst on a magnetically stabilized-bed (MSB) reactor to enhance the etherification of fluidized catalytic cracking (FCC) light gasoline, one of the most important reactions in petroleum refining industry. We demonstrated that the catalytic performance of the magnetic acid resin catalyst on the magnetic reactor is substantially enhanced as compared to its performance on a conventional fixed-bed reactor under otherwise identical operation conditions. The magnetic catalyst has the potential to be loaded and unloaded continuously on the magnetic reactor, which will greatly simplify the current complex industrial etherification processes. PMID:23756855

  11. Electrochemical enhanced heterogeneous activation of peroxydisulfate by Fe-Co/SBA-15 catalyst for the degradation of Orange II in water.

    PubMed

    Cai, Chun; Zhang, Hui; Zhong, Xin; Hou, Liwei

    2014-12-01

    Mesoporous silica SBA-15 supported iron and cobalt catalysts (Fe-Co/SBA-15) were prepared and used in the electrochemical (EC) enhanced heterogeneous activation of peroxydisulfate (PDS, S2O8(2-)) process for the removal of Orange II. The effects of some important reaction parameters such as initial pH, current density, PDS concentration and dosage of Fe-Co/SBA-15 catalysts were investigated. The results showed that the decolorization efficiency was not significantly affected by the initial pH value, and it did increase with the higher PDS concentration, current density and Fe-Co/SBA-15 dosage. Both the sulfate radical (SO4(·-)) and the hydroxyl radical (OH) are considered as the primary reactive oxidants for the Orange II decolorization. The Fe-Co/SBA-15 catalyst maintained its high activity during repeated batch experiments. The intermediate products were identified by GC-MS analysis and a plausible degradation pathway is proposed accordingly. The removal efficiencies of chemical oxygen demand (COD) and total organic carbon (TOC) were 52.1% and 31.9%, respectively after 60 min of reaction time but reached 82.9% and 51.5%, respectively when the reaction time was extended to 24 h. Toxicity tests with activated sludge indicated that the toxicity of the solution increased during the first 30 min and then decreased as the oxidation proceeded. PMID:25259475

  12. Homogeneously dispersed multimetal oxygen-evolving catalysts.

    PubMed

    Zhang, Bo; Zheng, Xueli; Voznyy, Oleksandr; Comin, Riccardo; Bajdich, Michal; García-Melchor, Max; Han, Lili; Xu, Jixian; Liu, Min; Zheng, Lirong; García de Arquer, F Pelayo; Dinh, Cao Thang; Fan, Fengjia; Yuan, Mingjian; Yassitepe, Emre; Chen, Ning; Regier, Tom; Liu, Pengfei; Li, Yuhang; De Luna, Phil; Janmohamed, Alyf; Xin, Huolin L; Yang, Huagui; Vojvodic, Aleksandra; Sargent, Edward H

    2016-04-15

    Earth-abundant first-row (3d) transition metal-based catalysts have been developed for the oxygen-evolution reaction (OER); however, they operate at overpotentials substantially above thermodynamic requirements. Density functional theory suggested that non-3d high-valency metals such as tungsten can modulate 3d metal oxides, providing near-optimal adsorption energies for OER intermediates. We developed a room-temperature synthesis to produce gelled oxyhydroxides materials with an atomically homogeneous metal distribution. These gelled FeCoW oxyhydroxides exhibit the lowest overpotential (191 millivolts) reported at 10 milliamperes per square centimeter in alkaline electrolyte. The catalyst shows no evidence of degradation after more than 500 hours of operation. X-ray absorption and computational studies reveal a synergistic interplay between tungsten, iron, and cobalt in producing a favorable local coordination environment and electronic structure that enhance the energetics for OER. PMID:27013427

  13. Bifunctional enhancement of oxygen reduction reaction activity on Ag catalysts due to water activation on LaMnO3 supports in alkaline media

    NASA Astrophysics Data System (ADS)

    Park, Shin-Ae; Lee, Eun-Kyung; Song, Hannah; Kim, Yong-Tae

    2015-08-01

    Ag is considered to be one of the best candidates for oxygen reduction reaction electrocatalysts in alkaline media for application in various electrochemical energy devices. In this study, we demonstrate that water activation is a key factor in enhancing the ORR activity in alkaline media, unlike in acid environments. Ag supported on LaMnO3 having a high oxophilicity showed a markedly higher ORR activity than that on carbon with inert surfaces. Through various electrochemical tests, it was revealed that the origin of the enhanced ORR activity of Ag/LaMnO3 is the bifunctional effect mainly due to the water activation at the interface between Ag and LaMnO3. Furthermore, the ligand effect due to the charge transfer from Mn to Ag leads to the enhancement of both oxygen activation on Ag and water activation on Mn sites, and hence, an improvement in the ORR activity of Ag/LaMnO3. On the other hand, the strain effect based on the fine structure variation in the lattice was negligible. We therefore suggest that the employment of a co-catalyst or support with highly oxophilic nature and the maximization of the interface between catalyst and support should be considered in the design of electrocatalysts for the ORR in alkaline media.

  14. Bifunctional enhancement of oxygen reduction reaction activity on Ag catalysts due to water activation on LaMnO3 supports in alkaline media.

    PubMed

    Park, Shin-Ae; Lee, Eun-Kyung; Song, Hannah; Kim, Yong-Tae

    2015-01-01

    Ag is considered to be one of the best candidates for oxygen reduction reaction electrocatalysts in alkaline media for application in various electrochemical energy devices. In this study, we demonstrate that water activation is a key factor in enhancing the ORR activity in alkaline media, unlike in acid environments. Ag supported on LaMnO3 having a high oxophilicity showed a markedly higher ORR activity than that on carbon with inert surfaces. Through various electrochemical tests, it was revealed that the origin of the enhanced ORR activity of Ag/LaMnO3 is the bifunctional effect mainly due to the water activation at the interface between Ag and LaMnO3. Furthermore, the ligand effect due to the charge transfer from Mn to Ag leads to the enhancement of both oxygen activation on Ag and water activation on Mn sites, and hence, an improvement in the ORR activity of Ag/LaMnO3. On the other hand, the strain effect based on the fine structure variation in the lattice was negligible. We therefore suggest that the employment of a co-catalyst or support with highly oxophilic nature and the maximization of the interface between catalyst and support should be considered in the design of electrocatalysts for the ORR in alkaline media. PMID:26310526

  15. Bifunctional enhancement of oxygen reduction reaction activity on Ag catalysts due to water activation on LaMnO3 supports in alkaline media

    PubMed Central

    Park, Shin-Ae; Lee, Eun-Kyung; Song, Hannah; Kim, Yong-Tae

    2015-01-01

    Ag is considered to be one of the best candidates for oxygen reduction reaction electrocatalysts in alkaline media for application in various electrochemical energy devices. In this study, we demonstrate that water activation is a key factor in enhancing the ORR activity in alkaline media, unlike in acid environments. Ag supported on LaMnO3 having a high oxophilicity showed a markedly higher ORR activity than that on carbon with inert surfaces. Through various electrochemical tests, it was revealed that the origin of the enhanced ORR activity of Ag/LaMnO3 is the bifunctional effect mainly due to the water activation at the interface between Ag and LaMnO3. Furthermore, the ligand effect due to the charge transfer from Mn to Ag leads to the enhancement of both oxygen activation on Ag and water activation on Mn sites, and hence, an improvement in the ORR activity of Ag/LaMnO3. On the other hand, the strain effect based on the fine structure variation in the lattice was negligible. We therefore suggest that the employment of a co-catalyst or support with highly oxophilic nature and the maximization of the interface between catalyst and support should be considered in the design of electrocatalysts for the ORR in alkaline media. PMID:26310526

  16. SR-135, a Peroxynitrite Decomposing Catalyst, Enhances β-cell Function and Survival in B6D2F1 Mice Fed a High Fat Diet

    PubMed Central

    Johns, Michael; Fyalka, Robert; Shea, Jennifer A.; Neumann, William L.; Rausaria, Smita; Msengi, Eliwaza Naomi; Imani-Nejad, Maryam; Zollars, Harry; McPherson, Timothy; Schober, Joseph; Wooten, Joshua; Kwon, Guim

    2015-01-01

    Peroxynitrite has been implicated in β-cell dysfunction and insulin resistance in obesity. Chemical catalysts that destroy peroxynitrite, therefore, may have therapeutic value for treating type 2 diabetes. To this end, we have recently demonstrated that Mn(III) bis(hydroxyphenyl)-dipyrromethene complexes, SR-135 and its analogues, can effectively catalyze the decomposition of peroxynitrite in vitro and in vivo through a 2-electron mechanism (Rausaria et al. 2011). To study the effects of SR-135 on glucose homeostasis in obesity, B6D2F1 mice were fed with a high fat-diet (HFD) for 12 weeks and treated with vehicle, SR-135 (5 mg/kg), or a control drug SRB for 2 weeks. SR-135 significantly reduced fasting blood glucose and insulin levels, and enhanced glucose tolerance as compared to HFD control, vehicle or SRB. SR-135 also enhanced glucose-stimulated insulin secretion based on ex vivo studies. Moreover, SR-135 increased insulin content, restored islet architecture, decreased islet size, and reduced tyrosine nitration and apoptosis. These results suggest that a peroxynitrite decomposing catalyst enhances β-cell function and survival under nutrient overload. PMID:25935364

  17. Pt-free carbon-based fuel cell catalyst prepared from spherical polyimide for enhanced oxygen diffusion

    PubMed Central

    Nabae, Yuta; Nagata, Shinsuke; Hayakawa, Teruaki; Niwa, Hideharu; Harada, Yoshihisa; Oshima, Masaharu; Isoda, Ayano; Matsunaga, Atsushi; Tanaka, Kazuhisa; Aoki, Tsutomu

    2016-01-01

    The development of a non-precious metal (NPM) fuel cell catalyst is extremely important to achieve globalization of polymer electrolyte fuel cells due to the cost and scarcity of platinum. Here, we report on a NPM cathode catalyst prepared by the pyrolysis of spherical polyimide nanoparticles that contain small amounts of Fe additive. 60 nm diameter Fe-containing polyimide nanoparticles were successfully synthesized by the precipitation polymerization of pyromellitic acid dianhydride and 1,3,5-tris(4-aminophenyl)benzene with Fe(acac)3 (acac = acetylacetonate) as an additive. The particles were subsequently carbonized by multistep pyrolysis to obtain the NPM catalyst while retaining the small particle size. The catalyst has good performance and promising durability for fuel cell applications. The fuel cell performance under a 0.2 MPa air atmosphere at 80 °C of 1.0 A cm−2 at 0.46 V is especially remarkable and better than that previously reported. PMID:26987682

  18. Enhancement of alpha-oxygen formation and N2O decomposition on Fe/ZSM-5 catalysts by extraframework Al.

    PubMed

    Sun, Keqiang; Zhang, Haidong; Xia, Haian; Lian, Yuxiang; Li, Ying; Feng, Zhaochi; Ying, Pinliang; Li, Can

    2004-11-01

    The concentration of alpha-oxygen which can oxidize methane to methanol and benzene to phenol at RT, increases linearly with the amount of introduced extraframework Al on Fe/ZSM-5 catalysts prepared by solid-state exchange of FeCl3 and AlCl3 with H-ZSM-5. PMID:15514825

  19. Pt-free carbon-based fuel cell catalyst prepared from spherical polyimide for enhanced oxygen diffusion

    NASA Astrophysics Data System (ADS)

    Nabae, Yuta; Nagata, Shinsuke; Hayakawa, Teruaki; Niwa, Hideharu; Harada, Yoshihisa; Oshima, Masaharu; Isoda, Ayano; Matsunaga, Atsushi; Tanaka, Kazuhisa; Aoki, Tsutomu

    2016-03-01

    The development of a non-precious metal (NPM) fuel cell catalyst is extremely important to achieve globalization of polymer electrolyte fuel cells due to the cost and scarcity of platinum. Here, we report on a NPM cathode catalyst prepared by the pyrolysis of spherical polyimide nanoparticles that contain small amounts of Fe additive. 60 nm diameter Fe-containing polyimide nanoparticles were successfully synthesized by the precipitation polymerization of pyromellitic acid dianhydride and 1,3,5-tris(4-aminophenyl)benzene with Fe(acac)3 (acac = acetylacetonate) as an additive. The particles were subsequently carbonized by multistep pyrolysis to obtain the NPM catalyst while retaining the small particle size. The catalyst has good performance and promising durability for fuel cell applications. The fuel cell performance under a 0.2 MPa air atmosphere at 80 °C of 1.0 A cm‑2 at 0.46 V is especially remarkable and better than that previously reported.

  20. Pt-free carbon-based fuel cell catalyst prepared from spherical polyimide for enhanced oxygen diffusion.

    PubMed

    Nabae, Yuta; Nagata, Shinsuke; Hayakawa, Teruaki; Niwa, Hideharu; Harada, Yoshihisa; Oshima, Masaharu; Isoda, Ayano; Matsunaga, Atsushi; Tanaka, Kazuhisa; Aoki, Tsutomu

    2016-01-01

    The development of a non-precious metal (NPM) fuel cell catalyst is extremely important to achieve globalization of polymer electrolyte fuel cells due to the cost and scarcity of platinum. Here, we report on a NPM cathode catalyst prepared by the pyrolysis of spherical polyimide nanoparticles that contain small amounts of Fe additive. 60 nm diameter Fe-containing polyimide nanoparticles were successfully synthesized by the precipitation polymerization of pyromellitic acid dianhydride and 1,3,5-tris(4-aminophenyl)benzene with Fe(acac)3 (acac = acetylacetonate) as an additive. The particles were subsequently carbonized by multistep pyrolysis to obtain the NPM catalyst while retaining the small particle size. The catalyst has good performance and promising durability for fuel cell applications. The fuel cell performance under a 0.2 MPa air atmosphere at 80 °C of 1.0 A cm(-2) at 0.46 V is especially remarkable and better than that previously reported. PMID:26987682

  1. Modeling Geometric Arrangements of TiO2-Based Catalyst Substrates and Isotropic Light Sources to Enhance the Efficiency of a Photocatalystic Oxidation (PCO) Reactor

    NASA Technical Reports Server (NTRS)

    Richards, Jeffrey T.; Levine, Lanfang H.; Husk, Geoffrey K.

    2011-01-01

    The closed confined environments of the ISS, as well as in future spacecraft for exploration beyond LEO, provide many challenges to crew health. One such challenge is the availability of a robust, energy efficient, and re-generable air revitalization system that controls trace volatile organic contaminants (VOCs) to levels below a specified spacecraft maximum allowable concentration (SMAC). Photocatalytic oxidation (PCO), which is capable of mineralizing VOCs at room temperature and of accommodating a high volumetric flow, is being evaluated as an alternative trace contaminant control technology. In an architecture of a combined air and water management system, placing a PCO unit before a condensing heat exchanger for humidity control will greatly reduce the organic load into the humidity condensate loop ofthe water processing assembly (WPA) thereby enhancing the life cycle economics ofthe WPA. This targeted application dictates a single pass efficiency of greater than 90% for polar VOCs. Although this target was met in laboratory bench-scaled reactors, no commercial or SBIR-developed prototype PCO units examined to date have achieved this goal. Furthermore, the formation of partial oxidation products (e.g., acetaldehyde) was not eliminated. It is known that single pass efficiency and partial oxidation are strongly dependent upon the contact time and catalyst illumination, hence the requirement for an efficient reactor design. The objective of this study is to maximize the apparent contact time and illuminated catalyst surface area at a given reactor volume and volumetric flow. In this study, a Ti02-based photocatalyst is assumed to be immobilized on porous substrate panels and illumination derived from linear isotropic light sources. Mathematical modeling using computational fluid dynamics (CFD) analyses were performed to investigate the effect of: 1) the geometry and configuration of catalyst-coated substrate panels, 2) porosity of the supporting substrate, and 3

  2. Catalyst dispersion and activity under conditions of temperature- staged liquefaction. [Catalyst precursors for molybdenum-based catalyst and iron-based catalyst

    SciTech Connect

    Davis, A.; Schobert, H.H.; Mitchell, G.D.; Artok, L.

    1992-07-01

    Two coals, a Texas subbituminous C and a Utah high volatile A bituminous, were used to examine the effects of solvent swelling and catalyst impregnation on liquefaction conversion behavior in temperature staged reactions for 30 minutes each at 275{degree} and 425{degree}C in H{sub 2} and 95:5 H{sub 2}:H{sub 2}S atmospheres. Methanol, pyridine, tetrahydrofuran, and tetrabutylammonium hydroxide were used as swelling agents. Molybdenum-based catalyst precursors were ammonium tetrathiomolybdate, molybdenum trisulfide, molybdenum hexacarbonyl, and bis(tricarbonylcyclopentadienyl-molybdenum). Ferrous sulfate and bis(dicarbonylcyclo-pentadienyliron) served as iron-based catalyst precursors. In addition, ion exchange was used for loading iron onto the subbituminous coal. For most experiments, liquefaction in H{sub 2}:H{sub 2}S was superior to that in H{sub 2}, regardless of the catalyst precursor. The benefit of the H{sub 2}S was greater for the subbituminous, presumably because of its higher iron content relative to the hvab coal. Tetrabutylammonium hydroxide was the only swelling agent to enhance conversion of the hvab coal significantly; it also caused a remarkable increase in conversion of the subbituminous coal. The combined application of solvent swelling and catalyst impregnation also improves liquefaction, mainly through increased oil yields from the hvab coal and increased asphaltenes from the subbituminous. A remarkable effect from use of ammonium tetrathiomolybdate as a catalyst precursor is substantial increase in pristane and phytane yields. Our findings suggest that these compounds are, at least in part, bound to the coal matrix.

  3. Investigation of Mixed Oxide Catalysts for NO Oxidation

    SciTech Connect

    Szanyi, Janos; Karim, Ayman M.; Pederson, Larry R.; Kwak, Ja Hun; Mei, Donghai; Tran, Diana N.; Herling, Darrell R.; Muntean, George G.; Peden, Charles HF; Howden, Ken; Qi, Gongshin; Li, Wei

    2014-12-09

    The oxidation of engine-generated NO to NO2 is an important step in the reduction of NOx in lean engine exhaust because NO2 is required for the performance of the LNT technology [2], and it enhances the activities of ammonia selective catalytic reduction (SCR) catalysts [1]. In particular, for SCR catalysts an NO:NO2 ratio of 1:1 is most effective for NOx reduction, whereas for LNT catalysts, NO must be oxidized to NO2 before adsorption on the storage components. However, NO2 typically constitutes less than 10% of NOx in lean exhaust, so catalytic oxidation of NO is essential. Platinum has been found to be especially active for NO oxidation, and is widely used in DOC and LNT catalysts. However, because of the high cost and poor thermal durability of Pt-based catalysts, there is substantial interest in the development of alternatives. The objective of this project, in collaboration with partner General Motors, is to develop mixed metal oxide catalysts for NO oxidation, enabling lower precious metal usage in emission control systems. [1] M. Koebel, G. Madia, and M. Elsener, Catalysis Today 73, 239 (2002). [2] C. H. Kim, G. S. Qi, K. Dahlberg, and W. Li, Science 327, 1624 (2010).

  4. Catalysts for emerging energy applications

    SciTech Connect

    Bruce C. Gates; George W. Huber; Christopher L. Marshall; Phillip N. Ross; Jeffrey Siirola; Yong Wang

    2008-04-15

    Catalysis is the essential technology for chemical transformation, including production of fuels from the fossil resources petroleum, natural gas, and coal. Typical catalysts for these conversions are robust porous solids incorporating metals, metal oxides, and/or metal sulfides. As efforts are stepping up to replace fossil fuels with biomass, new catalysts for the conversion of the components of biomass will be needed. Although the catalysts for biomass conversion might be substantially different from those used in the conversion of fossil feedstocks, the latter catalysts are a starting point in today's research. Major challenges lie ahead in the discovery of efficient biomass conversion catalysts, as well as in the discovery of catalysts for conversion of CO{sub 2} and possibly water into liquid fuels. 16 refs., 6 figs., 1 tab.

  5. MO-E-18C-05: Global Health Catalyst: A Novel Platform for Enhancing Access to Medical Physics Education and Research Excellence (AMPERE)

    SciTech Connect

    Ngwa, W; Moreau, M; Asana, L

    2014-06-15

    Purpose: To develop a platform for catalyzing collaborative global Cancer Care Education and Research (CaRE), with a prime focus on enhancing Access to Medical Physics Education and Research Excellence (AMPERE) Methods: An analysis of over 50 global health collaborations between partners in the U.S. and low and middle income countries (LMIC) in Africa was carried out to assess the models of collaborations in Education and Research and relative success. A survey was carried out with questions including: the nature of the collaboration, how it was initiated, impact of culture and other factors, and recommendations for catalyzing/enhancing such collaborations. An online platform called Global Health Catalyst was developed for enhancing AMPERE. Results: The analysis yielded three main models for global health collaborations with survey providing key recommendations on how to enhance such collaborations. Based on this, the platform was developed, and customized to allow Medical Physicists and other Radiation oncology (RadOnc) professionals interested in participating in Global health to readily do so e.g. teach an online course module, participate in training Medical Physicists or other RadOnc health professionals in LMIC, co-mentor students, residents or postdocs, etc. The growing list of features on the platform also include: a feature to enable people to easily find each other, form teams, operate more effectively as partners from different disciplines, institutions, nations and cultural backgrounds, share tools and technologies, obtain seed funding to develop curricula and/or embark upon new areas of investigation, and participate in humanitarian outreach: remote treatment planning assistance, and participation in virtual Chart Rounds, etc. Conclusion: The developed Global Health Catalyst platform could enable any Medical Physicist or RadoOnc professional interested in global health to readily participate in the Education/training of next generation Rad

  6. Clean Donor Oxidation Enhances the H2 Evolution Activity of a Carbon Quantum Dot-Molecular Catalyst Photosystem.

    PubMed

    Martindale, Benjamin C M; Joliat, Evelyne; Bachmann, Cyril; Alberto, Roger; Reisner, Erwin

    2016-08-01

    Carbon quantum dots (CQDs) are new-generation light absorbers for photocatalytic H2 evolution in aqueous solution, but the performance of CQD-molecular catalyst systems is currently limited by the decomposition of the molecular component. Clean oxidation of the electron donor by donor recycling prevents the formation of destructive radical species and non-innocent oxidation products. This approach allowed a CQD-molecular nickel bis(diphosphine) photocatalyst system to reach a benchmark lifetime of more than 5 days and a record turnover number of 1094±61 molH2  (molNi )(-1) for a defined synthetic molecular nickel catalyst in purely aqueous solution under AM1.5G solar irradiation. PMID:27355200

  7. Enhanced performance of the catalytic conversion of allyl alcohol to 3-hydroxypropionic acid using bimetallic gold catalysts.

    PubMed

    Falletta, Ermelinda; Della Pina, Cristina; Rossi, Michele; He, Qian; Kiely, Christopher J; Hutchings, Graham J

    2011-01-01

    One of the strategic building blocks in organic synthesis is 3-hydroxypropionic acid, which is particularly important for the manufacture of high performance polymers. However, to date, despite many attempts using both biological and chemical routes, no large scale effective process for manufacturing 3-hydroxypropionic acid has been developed. One potentially useful starting point is from allyl alcohol, as this can be obtained in principle from the dehydration of glycerol, thereby presenting a bio-renewable green pathway to this important building block. The catalytic transformation of allyl alcohol to 3-hydroxypropionic acid presents interesting challenges in catalyst design, particularly with respect to the control of selectivity among the products that can be expected, as acrylic acid, acrolein and glyceric acid can also be formed. In this paper, we present a novel eco-sustainable catalytic pathway leading to 3-hydroxypropionic acid, which highlights the outstanding potential of gold-based and bimetallic catalysts in the aerobic oxidation of allyl alcohol. PMID:22455056

  8. On the design of Pt based catalysts. Combining porous architecture with surface modification by Sn for electrocatalytic activity enhancement

    NASA Astrophysics Data System (ADS)

    Flórez-Montaño, Jonathan; García, Gonzalo; Rodríguez, José L.; Pastor, Elena; Cappellari, Paula; Planes, Gabriel A.

    2015-05-01

    Metallic mesoporous (MP) catalysts with large surface area can be obtained in-situ, in a single step, by electrochemical reduction. In this work, the electrochemical behavior of MPPt and Sn modified mesoporous Pt (MPPt/Sn) was studied and compared with commercial carbon supported PtSn alloy (3:1). The electrochemical activity toward carbon monoxide and methanol oxidation reactions were evaluated by cyclic voltammetry and chronoamperometry, whereas X-ray photoelectron spectroscopy was used to determine the surface composition and oxidation state of the atoms in the top layers of the catalysts. The analysis of methanol conversion to CO2 was performed with aid of differential electrochemical mass spectrometry (DEMS). Results reveal a better performance of the MPPt/Sn, which shows higher current density and energy conversion efficiency of fuel to CO2 than conventional carbon supported PtSn alloy (3:1).

  9. Enhanced high temperature performance of MgAl2O4-supported Pt-BaO lean NOx trap catalysts

    SciTech Connect

    Kwak, Ja Hun; Kim, Do Heui; Szanyi, Janos; Cho, Sung June; Peden, Charles HF

    2012-03-05

    The structural and chemical characteristics of Pt/BaO lean-NO{sub x} trap (LNT) catalysts supported on {gamma}-Al{sub 2}O{sub 3} and MgAl{sub 2}O{sub 4} are compared in this study. The Pt-BaO/MgAl{sub 2}O{sub 4} sample shows relatively low NO{sub x} uptake at temperatures below 300 C, and the temperature of maximum NO{sub x} uptake (T{sub max}) is shifted to 350 C in comparison to that of Pt-BaO/Al{sub 2}O{sub 3} (T{sub max} {approx}250 C). More importantly, the NO{sub x} uptake over the MgAl{sub 2}O{sub 4}-supported catalyst at 350 C is twice that of the alumina-based one. The shift toward the higher temperature NO{sub x} uptake is explained by the larger interfacial area between Pt and BaO, due to smaller Pt clusters as evidenced by TEM and Pt L3 EXAFS. In situ TR-XRD results demonstrate that the formation of a BaAl{sub 2}O{sub 4} phase in the BaO/MgAl{sub 2}O{sub 4} LNT catalyst occurs at a temperature about 100 C higher than on BaO/Al{sub 2}O{sub 3}, which may also represent a beneficial attribute of the BaO/MgAl{sub 2}O{sub 4} LNT with respect to catalyst stability.

  10. Synthesis of substantially monodispersed colloids

    NASA Technical Reports Server (NTRS)

    Klabunde, Kenneth J. (Inventor); Stoeva, Savka (Inventor); Sorensen, Christopher (Inventor)

    2003-01-01

    A method of forming ligated nanoparticles of the formula Y(Z).sub.x where Y is a nanoparticle selected from the group consisting of elemental metals having atomic numbers ranging from 21-34, 39-52, 57-83 and 89-102, all inclusive, the halides, oxides and sulfides of such metals, and the alkali metal and alkaline earth metal halides, and Z represents ligand moieties such as the alkyl thiols. In the method, a first colloidal dispersion is formed made up of nanoparticles solvated in a molar excess of a first solvent (preferably a ketone such as acetone), a second solvent different than the first solvent (preferably an organic aryl solvent such as toluene) and a quantity of ligand moieties; the first solvent is then removed under vacuum and the ligand moieties ligate to the nanoparticles to give a second colloidal dispersion of the ligated nanoparticles solvated in the second solvent. If substantially monodispersed nanoparticles are desired, the second dispersion is subjected to a digestive ripening process. Upon drying, the ligated nanoparticles may form a three-dimensional superlattice structure.

  11. Enhanced photocatalytic efficiency of NiS/TiO{sub 2} composite catalysts using sunset yellow, an azo dye under day light illumination

    SciTech Connect

    Rajamanickam, D.; Dhatshanamurthi, P.; Shanthi, M.

    2015-01-15

    Highlights: • NiS/TiO{sub 2} was successfully synthesized by sol–gel method. • This new method of preparation gives a homogeneous dispersion of NiS on TiO{sub 2}. • Degradation activity of NiS/TiO{sub 2} is found to be more efficient than other catalysts. • Addition of oxidants enhances the degradation efficiency significantly. • COD measurements reveal the complete mineralization of dye molecules. • The catalyst is found to be reusable. - Abstract: To improve the solar light induced photocatalytic application performances of TiO{sub 2}, in this study, the NiS modified TiO{sub 2} composite photocatalysts with various ratios of NiS to TiO{sub 2} were prepared by sol–gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (B–E–T) surface area measurement methods. The photocatalytic activity of NiS/TiO{sub 2} was investigated for the degradation of sunset yellow (SY) in aqueous solution using solar light. The NiS/TiO{sub 2} is found to be more efficient than prepared TiO{sub 2} and TiO{sub 2}–P25 at pH 7 for the mineralization of SY. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The degradation was strongly enhanced in the presence of oxidants such as H{sub 3}K{sub 5}O{sub 18}S{sub 4} (Oxone), KIO{sub 4}, and KBrO{sub 3}. The mineralization of SY has been identified by COD measurements. The catalyst is found to be reusable.

  12. The Benzyl Ester Group of Amino Acid Monomers Enhances Substrate Affinity and Broadens the Substrate Specificity of the Enzyme Catalyst in Chemoenzymatic Copolymerization.

    PubMed

    Ageitos, Jose Manuel; Yazawa, Kenjiro; Tateishi, Ayaka; Tsuchiya, Kousuke; Numata, Keiji

    2016-01-11

    The chemoenzymatic polymerization of amino acid monomers by proteases involves a two-step reaction: the formation of a covalent acyl-intermediate complex between the protease and the carboxyl ester group of the monomer and the subsequent deacylation of the complex by aminolysis to form a peptide bond. Although the initiation with the ester group of the monomer is an important step, the influence of the ester group on the polymerization has not been studied in detail. Herein, we studied the effect of the ester groups (methyl, ethyl, benzyl, and tert-butyl esters) of alanine and glycine on the synthesis of peptides using papain as the catalyst. Alanine and glycine were selected as monomers because of their substantially different affinities toward papain. The efficiency of the polymerization of alanine and glycine benzyl esters was much greater than that of the other esters. The benzyl ester group therefore allowed papain to equally polymerize alanine and glycine, even though the affinity of alanine toward papain is substantially higher. The characterization of the copolymers of alanine and glycine in terms of the secondary structure and thermal properties revealed that the thermal stability of the peptides depends on the amino acid composition and resultant secondary structure. The current results indicate that the nature of the ester group drastically affects the polymerization efficiency and broadens the substrate specificity of the protease. PMID:26620763

  13. Generating power from cellulose in an alkaline fuel cell enhanced by methyl viologen as an electron-transfer catalyst

    NASA Astrophysics Data System (ADS)

    Hao, Miaoqing; Liu, Xianhua; Feng, Mengnan; Zhang, Pingping; Wang, Guangyi

    2014-04-01

    In this work, we developed a single-compartment direct cellulose alkaline fuel cell by using nickel foam as the anode and methyl viologen as an electron transfer catalyst. The maximum power density of the fuel cell at optimal conditions is 450 mW m-2. High-performance liquid chromatography detected short-chain aliphatic carboxylic acids in the oxidation products. Using common reed and red algae as fuels, the fuel cell achieved maximum power densities of 295 mW m-2 and 154 mW m-2, respectively.

  14. Preparation and application of zirconium sulfate supported on SAPO-34 molecular sieve as solid acid catalyst for esterification

    SciTech Connect

    Xu, Dongyan Ma, Hong; Cheng, Fei

    2014-05-01

    Graphical abstract: - Highlights: • SAPO-34 supported zirconium sulfate solid acid catalyst was prepared. • Esterification of acetic acid with ethanol can be catalyzed by ZS/SAPO-34. • The hydration of ZS is vital to the acidic property and catalytic performance. • The ZS/SAPO-34 catalyst treated at 200 °C shows good reusability. - Abstract: Zirconium sulfate (ZS) was supported on SAPO-34 molecular sieve by using an incipient wetness impregnation method with zirconium sulfate as the precursor. The as-prepared catalysts were used as solid acid catalyst for esterification reaction of acetic acid with ethanol. The influence of calcination temperature on the acidic property, catalytic activity, and reusability of ZS/SAPO-34 catalysts were mainly investigated. FT-IR, SEM, EDS and TG analysis have been carried out to demonstrate the characteristics of ZS/SAPO-34 catalysts. It was found that the 30 wt%ZS/SAPO-34 catalysts display the property of superacid irrespective of calcination temperature. The ZS/SAPO-34 catalyst treated at 200 °C can enhance the interaction between the supported ZS and SAPO-34 and keep the catalyst remaining substantially active after several reaction cycles. However, further increasing calcination temperature will cause the transfer of ZS from hydrate to anhydrous phase, and thus the decrease of activity.

  15. Ultrasound enhanced heterogeneous activation of peroxymonosulfate by a bimetallic Fe-Co/SBA-15 catalyst for the degradation of Orange II in water.

    PubMed

    Cai, Chun; Zhang, Hui; Zhong, Xing; Hou, Liwei

    2015-01-01

    Mesoporous silica SBA-15 supported iron and cobalt (Fe-Co/SBA-15) was prepared and used as catalyst in the ultrasound (US) enhanced heterogeneous activation of peroxymonosulfate (PMS, HSO5(-)) process. The effects of some important reaction parameters on the removal of Orange II by US/Fe-Co/SBA-15/PMS process were investigated. The results indicated that the removal rate of Orange II was not significantly affected by the initial pH, and it increased with the higher PMS concentration, reaction temperature, Fe-Co/SBA-15 dosage and ultrasonic power. Furthermore, sulfate radicals (SO4(-)) were assumed to be the dominating reactive species for the Orange II decolorization. Moreover, the Fe-Co/SBA-15 catalyst showed high activity during the repeated experiments. The intermediate products were identified by GC-MS, thereby a plausible degradation pathway is proposed. In addition, the chemical oxygen demand (COD) removal efficiencies at 2 and 24h were 56.8% and 80.1%, respectively and the corresponding total organic carbon (TOC) removal efficiencies were 33.8 and 53.3%. Finally, toxicity tests with activated sludge showed that the toxicity of the solution increased during the first stage and then decreased significantly with the progress of the oxidation. PMID:25262480

  16. Highly Stable and Active Catalyst for Sabatier Reactions

    NASA Technical Reports Server (NTRS)

    Hu, Jianli; Brooks, Kriston P.

    2012-01-01

    Highly active Ru/TiO2 catalysts for Sabatier reaction have been developed. The catalysts have shown to be stable under repeated shutting down/startup conditions. When the Ru/TiO2 catalyst is coated on the engineered substrate Fe-CrAlY felt, activity enhancement is more than doubled when compared with an identically prepared engineered catalyst made from commercial Degussa catalyst. Also, bimetallic Ru-Rh/TiO2 catalysts show high activity at high throughput.

  17. Synthesis of graphene-supported one-dimensional nanoporous Pt based catalysts, and their enhanced performance on methanol electro-oxidation

    NASA Astrophysics Data System (ADS)

    Hong, Liji; Hao, Yanfei; Yang, Yunyun; Yuan, Junhua; Niu, Li

    2015-01-01

    A novel approach is developed to synthesize PtIr or Pt nanowires (NWs) supported on the reduced graphene oxide (RGO) using Te NWs as template based on the replacement reaction. The resulting RGO-supported PtIr and Pt electrocatalysts are characterized by transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy and electrochemical techniques. TEM images show that these Pt based catalysts are uniformly distributed in the matrix of graphene with a characteristic of one-dimensional (1D) nanoporous structure. As one of promising anode materials used in the direct methanol fuel cells, these 1D nanoporous PtIr/RGO (or Pt/RGO) hybrids exhibit an enlarged electroactive surface and enhanced catalytic activity toward the methanol reaction relative to those PtIr or Pt NWs without graphene support.

  18. Simultaneous Oxidization of NOx and SO2 by a New Non-thermal Plasma Reactor Enhanced by Catalyst and Additive

    NASA Astrophysics Data System (ADS)

    Kim, Heejoon; Jun, Han; Sakaguchi, Yuhei; Minami, Wataru

    2008-02-01

    The non-thermal plasma as one of the most promising technologies for removing NOx and SO2 has attracted much attention. In this study, a new plasma reactor combined with catalyst and additive was developed to effectively oxidize and remove NOx and SO2 in the flue gas. The experimental results showed that TiO2 could improve the oxidation efficiency of SO2 in the case of applying plasma while having a negative effect on the oxidation process of NO and NOx. With the addition of NH3, the oxidation rates of NOx, NO and SO2 were slightly increased. However, the effect of adding NH3 on NOx oxidation was negative when the temperature was above 200°C.

  19. Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol

    SciTech Connect

    Sun, Junming; Karim, Ayman M.; Zhang, He; Kovarik, Libor; Li, Xiaohong S.; Hensley, Alyssa; McEwen, Jean-Sabin; Wang, Yong

    2013-10-01

    Abstract Carbon supported metal catalysts (Cu/C, Fe/C, Pd/C, Pt/C, PdFe/C and Ru/C) have been prepared, characterized and tested for vapor-phase hydrodeoxygenation (HDO) of guaiacol (GUA) at atmospheric pressure. Phenol was the major intermediate on all catalysts. Over the noble metal catalysts saturation of the aromatic ring was the major pathway observed at low temperature (250 °C), forming predominantly cyclohexanone and cyclohexanol. Substantial ring opening reaction was observed on Pt/C and Ru/C at higher reaction temperatures (e.g., 350 °C). Base metal catalysts, especially Fe/C, were found to exhibit high HDO activity without ring-saturation or ring-opening with the main products being benzene, phenol along with small amounts of cresol, toluene and trimethylbenzene (TMB). A substantial enhancement in HDO activity was observed on the PdFe/C catalysts. Compared with Fe/C, the yield to oxygen-free aromatic products (i.e., benzene/toluene/TMB) on PdFe/C increased by a factor of four at 350 °C, and by approximately a factor of two (83.2% versus 43.3%) at 450 °C. The enhanced activity of PdFe/C is attributed to the formation of PdFe alloy as evidenced by STEM, EDS and TPR.

  20. 29 CFR 1990.145 - Consideration of substantial new issues or substantial new evidence.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... substance any substantial new issues upon which the Secretary did not reach a conclusion in the rulemaking... 29 Labor 9 2010-07-01 2010-07-01 false Consideration of substantial new issues or substantial new... of substantial new issues or substantial new evidence. (a) Substantial new issues....

  1. 29 CFR 1990.145 - Consideration of substantial new issues or substantial new evidence.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... substance any substantial new issues upon which the Secretary did not reach a conclusion in the rulemaking... 29 Labor 9 2011-07-01 2011-07-01 false Consideration of substantial new issues or substantial new... of substantial new issues or substantial new evidence. (a) Substantial new issues....

  2. Bimetallic Catalysts.

    ERIC Educational Resources Information Center

    Sinfelt, John H.

    1985-01-01

    Chemical reaction rates can be controlled by varying composition of miniscule clusters of metal atoms. These bimetallic catalysts have had major impact on petroleum refining, where work has involved heterogeneous catalysis (reacting molecules in a phase separate from catalyst.) Experimentation involving hydrocarbon reactions, catalytic…

  3. Fabrication of Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) catalysts with enhanced electrochemical performance by removing an inherent heterogeneous surface film layer.

    PubMed

    Jung, Jae-Il; Jeong, Hu Young; Kim, Min Gyu; Nam, Gyutae; Park, Joohyuk; Cho, Jaephil

    2015-01-14

    A heat-treatment approach for Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) (BSCF5582) is introduced as a way of enhancing the electrocatalytic performance of perovskite catalysts. The perovskite made by heat-treatment in oxygen atmosphere loses around 30 nm of spinel layer on the surface relative to the untreated version, and demonstrates enhanced oxygen reduction reaction and oxygen evolution reaction catalytic activities. PMID:25413252

  4. Oxyhydrochlorination catalyst

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1992-01-01

    An improved catalyst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HCl and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  5. Catalysts for Dehydrogenation of ammonia boranes

    SciTech Connect

    Heinekey, Dennis M.

    2014-12-19

    Several effective homogeneous catalysts for the dehydrogenation of amine boranes have been developed. The best catalyst uses an iridium complex, and is capable of dehydrogenating H3NBH3 (AB) and CH3NH2BH3 (MeAB) at comparable rates. Thermodynamic measurements using this catalyst demonstrate that the dehydrogenation of AB and MeAB is substantially exothermic, which has important implications for regeneration.

  6. Dual function cracking catalyst (DFCC) composition

    SciTech Connect

    Occelli, M.L.

    1986-10-07

    The patent describes a novel catalytic cracking composition comprising a cracking catalyst having high activity and, as a separate and distinct entity, a diluent comprising a substantially catalytically inactive crystalline aluminosilicte having a fresh MAT Activity below about 1. The diluent is clinoptilolite and the cracking catalyst contains a rare earth-exchanged crystalline aluminium silicate. The cracking catalyst comprises from about ten to about 60 weight percent of a zeolite having cracking characteristics dispersed in a refractory metal oxide matrix.

  7. Fabrication of hollow platinum-ruthenium core-shell catalysts with nanochannels and enhanced performance for methanol oxidation

    NASA Astrophysics Data System (ADS)

    Hu, Yuming; Zhu, Aimei; Zhang, Qiugen; Liu, Qinglin

    2015-12-01

    This work reports the preparation of hollow PtRu core-shell catalysts with TiO2 as template, in which the Pt nanoparticles (NPs) grow on the exterior surface of Ru layer. The quantity of Pt NPs is easily tailored to control the integrity of Pt shell through varying the concentration of H2PtCl6 solution. Scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and selected-area electron diffraction (SAED) are used to characterize the structure and morphology of H-PtRu. The core-shell structure is confirmed by the high-angle annular dark-field scanning TEM (HAADF-STEM) with energy-disperse X-ray spectroscopy (EDX). The electrochemical performance of H-PtRu is investigated by cyclic voltammetry and chronoamperometry. Results show that the catalytic activity of H-PtRu toward methanol oxidation reaction (MOR) is ∼2.5 times higher than that of Pt/C (JM), and the electrocatalytic stability improves with the increase of Ru content. Furthermore, H-PtRu exhibits better stability for methanol oxidation compared to Pt/C (JM) and PtRu/C (JM).

  8. Enhanced performance and stability of high temperature proton exchange membrane fuel cell by incorporating zirconium hydrogen phosphate in catalyst layer

    NASA Astrophysics Data System (ADS)

    Barron, Olivia; Su, Huaneng; Linkov, Vladimir; Pollet, Bruno G.; Pasupathi, Sivakumar

    2015-03-01

    Zirconium hydrogen phosphate (ZHP) together with polytetrafluoroethylene (PTFE) polymer binder is incorporated into the catalyst layers (CLs) of ABPBI (poly(2,5-benzimidazole))-based high temperature polymer electrolyte membrane fuel cell (HT-PEMFCs) to improve its performance and durability. The influence of ZHP content (normalised with respect to dry PTFE) on the CL properties are structurally characterised by scanning electron microscopy (SEM) and mercury intrusion porosimetry. Electrochemical analyses of the resultant membrane electrode assemblies (MEAs) are performed by recording polarisation curves and impedance spectra at 160 °C, ambient pressure and humidity. The result show that a 30 wt.% ZHP/PTFE content in the CL is optimum for improving fuel cell performance, the resultant MEA delivers a peak power of 592 mW cm-2 at a cell voltage of 380 mV. Electrochemical impedance spectra (EIS) indicate that 30% ZHP in the CL can increase the proton conductivity compared to the pristine PTFE-gas diffusion electrode (GDE). A short term stability test (∼500 h) on the 30 wt.% ZHP/PTFE-GDE shows a remarkable high durability with a degradation rate as low as ∼19 μV h-1 at 0.2 A cm-2, while 195 μV h-1 was obtained for the pristine GDE.

  9. One-step synthesis of Fe–N–S-tri-doped TiO{sub 2} catalyst and its enhanced visible light photocatalytic activity

    SciTech Connect

    Cheng, Xiuwen; Yu, Xiujuan; Xing, Zipeng

    2012-11-15

    Graphical abstract: FeNS-TiO{sub 2} exhibits stronger SPS response than that of pure TiO{sub 2}, indicating that the FeNS-TiO{sub 2} should have a higher separation rates of photoinduced charge carriers. Further, for the sample FeNS-TiO{sub 2} a broad shoulder SPS response can be seen at the wavelength range from 390 to 550 nm, suggesting that the light absorption in visible region of FeNS-TiO{sub 2} was greatly improved, which is beneficial to the enhancement of photocatalytic activity. Display Omitted Highlights: ► FeNS-TiO{sub 2} catalyst has been synthesized in the presence of ammonium ferrous sulfate. ► The light absorption edge of FeNS-TiO{sub 2} catalyst was red-shifted to visible region. ► The separation efficiency of photoinduced charge carriers of FeNS-TiO{sub 2} was improved. ► The activity enhanced mechanism of FeNS-TiO{sub 2} was discussed in detail. -- Abstract: Fe–N–S-tridoped TiO{sub 2} was synthesized through simple one step sol–gel reactions in the presence of ammonium ferrous sulfate. The resulting materials were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance spectrum and surface photovoltage spectroscopy. Results revealed that Fe and S were incorporated into the lattice of TiO{sub 2} by substituting for some Ti atoms and N for O atoms in the lattice of TiO{sub 2}. Tri-doping with Fe, N and S could inhibit the phase transformation of TiO{sub 2} from anatase to rutile, restrain the growth of crystallite sizes, extended the light absorption into the visible region and separate photoinduced charge carriers. The visible photocatalytic activity of Fe–N–S-tridoped TiO{sub 2} was higher than that of N-TiO{sub 2} and P25 TiO{sub 2}. The enhanced photocatalytic activity was attributed to the small crystallite size, high crystallinity, the intense light absorption in visible region, narrow band gap and high separation efficiency of photoinduced charge carriers.

  10. Polymerization catalyst

    SciTech Connect

    Graves, V.

    1987-05-12

    A process is described for polymerizing at least one alpha olefin under conditions characteristic of Ziegler polymerization wherein the polymerization is conducted in the presence of a catalyst system which comprises: a supported catalyst prepared under anhydrous conditions by the sequential steps of: preparing a slurry of inert particulate support material; adding to the slurry a solution of an organomagnesium compound; adding to the slurry and reacting a solution of a zirconium halide compound, hafnium compound or mixtures thereof; adding to the slurry and reacting a halogenator; adding to the slurry and reacting a tetravalent titanium halide compound; and recovering solid catalyst.

  11. Polymerization catalyst

    SciTech Connect

    Graves, V.

    1986-10-21

    A process is described for polymerizing at least one alpha-olefin under conditions characteristic of Ziegler polymerization wherein the polymerization is conducted in the presence of a catalyst comprising: a supported catalyst prepared under anhydrous conditions by the steps of: (1) sequentially; (a) preparing a slurry of inert particulate support material; (b) adding to the slurry a solution of an organomagnesium compound; (c) adding to the slurry and reacting a solution of zirconium compound; and (2) thereafter; (d) adding to the slurry and reacting a halogenator; (e) adding to the slurry and reacting a tetravalent titanium compound; (f) recovering solid catalyst; and an organoaluminum compound.

  12. Synergetic effects of Sr-doped CuBi2O4 catalyst with enhanced photoactivity under UVA- light irradiation.

    PubMed

    Elaziouti, A; Laouedj, N; Bekka, A

    2016-08-01

    Sr-doped CuBi2O4 micro-particles were successively synthesized via a solid-state technique and were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and UV-vis diffuse reflectance spectroscopy (UV-vis-DRS) techniques. Results show that Sr-doped CuBi2O4 was crystallized with a spinel-type structure and tetragonal crystal system, and the band gap energy was about 1.35 eV. The as-prepared Sr-doped CuBi2O4 treated at 573 °C for 12 h exhibited the highest efficiency, as a result of 97.22 % of CR degradation within 220 min, which is approximately 31 times greater than CR photodegradation when catalyzed by CuBi2O4 (3.13 %) and about 2.3 times superior than that catalyzed by the untreated Sr-doped CuBi2O4 sample (42.08 %). Pseudo-first-order kinetic model gave the best fit, with highest correlation coefficients (R (2) = 0.94-0.97). The Sr-doping and extending reaction time up to 12 h could be effective in producing Sr-doped CuBi2O4 materials that delay electron-hole recombination, thereby increasing the lifetime of the electron electron-hole separation and support the charge carrier transfer to the catalyst surface. On the basis of the calculated energy band positions, superoxide radical anions (O2 (•-)) were the main oxidative species responsible for the photocatalytic degradation of CR dye solution. PMID:26150294

  13. Strengthening leadership as a catalyst for enhanced patient safety culture: a repeated cross-sectional experimental study

    PubMed Central

    Kristensen, Solvejg; Christensen, Karl Bang; Jaquet, Annette; Møller Beck, Carsten; Sabroe, Svend; Bartels, Paul; Mainz, Jan

    2016-01-01

    Objectives Current literature emphasises that clinical leaders are in a position to enable a culture of safety, and that the safety culture is a performance mediator with the potential to influence patient outcomes. This paper aims to investigate staff's perceptions of patient safety culture in a Danish psychiatric department before and after a leadership intervention. Methods A repeated cross-sectional experimental study by design was applied. In 2 surveys, healthcare staff were asked about their perceptions of the patient safety culture using the 7 patient safety culture dimensions in the Safety Attitudes Questionnaire. To broaden knowledge and strengthen leadership skills, a multicomponent programme consisting of academic input, exercises, reflections and discussions, networking, and action learning was implemented among the clinical area level leaders. Results In total, 358 and 325 staff members participated before and after the intervention, respectively. 19 of the staff members were clinical area level leaders. In both surveys, the response rate was >75%. The proportion of frontline staff with positive attitudes improved by ≥5% for 5 of the 7 patient safety culture dimensions over time. 6 patient safety culture dimensions became more positive (increase in mean) (p<0.05). Frontline staff became more positive on all dimensions except stress recognition (p<0.05). For the leaders, the opposite was the case (p<0.05). Staff leaving the department after the first measurement had rated job satisfaction lower than the staff staying on (p<0.05). Conclusions The improvements documented in the patient safety culture are remarkable, and imply that strengthening the leadership can act as a significant catalyst for patient safety culture improvement. Further studies using a longitudinal study design are recommended to investigate the mechanism behind leadership's influence on patient safety culture, sustainability of improvements over time, and the association of change

  14. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, Gerald P.; Zhao, Jianmin; Feng, Zhen

    1996-01-01

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered.

  15. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, G.P.; Zhao, J.; Feng, Z.

    1996-12-03

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered. 3 figs.

  16. Tethered catalysts for the hydration of carbon dioxide

    SciTech Connect

    Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

    2014-11-04

    A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

  17. Enhancing the power generation in microbial fuel cells with effective utilization of goethite recovered from mining mud as anodic catalyst.

    PubMed

    Jadhav, Dipak A; Ghadge, Anil N; Ghangrekar, Makarand M

    2015-09-01

    Catalytic effect of goethite recovered from iron-ore mining mud was studied in microbial fuel cells (MFCs). Characterization of material recovered from mining mud confirms the recovery of iron oxide as goethite. Heat treated goethite (550 °C) and untreated raw goethite were coated on stainless-steel anode of MFC-1 and MFC-2, respectively; whereas, unmodified stainless-steel anode was used in MFC-3 (control). Fivefold increment in power was obtained in MFC-1 (17.1 W/m(3) at 20 Ω) than MFC-3 (3.5 W/m(3)). MFC with raw goethite coated anode also showed enhanced power (11 W/m(3)). Higher Coulombic efficiency (34%) was achieved in MFC-1 than control MFC-3 (13%). Decrease in mass-transport losses and higher redox current during electrochemical analyses support improved electron transfer with the use of goethite on anode. Cheaper goethite coating kinetically accelerates the electron transfer between bacteria and anode, proving to be a novel approach for enhancing the electricity generation along with organic matter removal in MFC. PMID:25983229

  18. 46 CFR 28.501 - Substantial alterations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Substantial alterations. 28.501 Section 28.501 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.501 Substantial alterations. (a) Except as provided in paragraph (b) of this section, a vessel that is...

  19. 40 CFR 725.94 - Substantiation requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT REPORTING REQUIREMENTS AND REVIEW PROCESSES FOR MICROORGANISMS Confidentiality and Public... Inventory, the claim must be reasserted and substantiated at the time the Notice of Commencement (NOC) is... Inventory. (2) The submitter must substantiate the claim for confidentiality of the microorganism...

  20. 77 FR 39452 - Substantial Business Activities; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-03

    ..., June 12, 2012 (77 FR 34887) regarding whether a foreign corporation has substantial business activities...- 107889-12), which was the subject of FR. Doc. 2012-14238, is corrected as follows: On page 34887, column... Internal Revenue Service 26 CFR Part 1 RIN 1545-BK85 Substantial Business Activities; Correction...

  1. Fluorination process using catalyst

    DOEpatents

    Hochel, Robert C.; Saturday, Kathy A.

    1985-01-01

    A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

  2. Significant enhancement of photoreactivity of graphitic carbon nitride catalysts under acidic conditions and the underlying H(+)-mediated mechanism.

    PubMed

    Zhang, Xue-Song; Tian, Ke; Hu, Jian-Yang; Jiang, Hong

    2015-12-01

    Graphitic carbon nitride (g-C3N4) is an emerging photocatalyst for organic pollutants degradation owing to its excellent stability and metal-free property. In this study, the photocatalytic activity of acidified g-C3N4 (ag-C3N4) was systematically investigated using rhodamine B (rhB) as a model organic pollutant. The results showed the photoreactivity of ag-C3N4 is significantly enhanced with the decrease of pH values. The apparent rate constant (kapp) of rhB degradation over ag-C3N4 is 11.59×10(-3)min(-1) at pH7.0 and it increases to 103.50×10(-3)min(-1) at pH3.0 under visible light. A series of analyses demonstrate that the photodegradation mechanism is a combination of a H(+)-promoted generation of OH and elevation of the redox potential of conduct band of C3N4. The change of surface properties of C3N4 caused by pH variation also affects the degradation of some zwitterionic compounds by changing the adsorption orientation of pollutants. The revealed mechanism of visible light-C3N4-rhB system is meaningful to broaden the usage of C3N4 to the photodegradation of other organic pollutants. PMID:26172516

  3. A Non-sulfided flower-like Ni-PTA Catalyst that Enhances the Hydrotreatment Efficiency of Plant Oil to Produce Green Diesel

    PubMed Central

    Liu, Jing; Chen, Pan; Deng, Lihong; He, Jing; Wang, Luying; Rong, Long; Lei, Jiandu

    2015-01-01

    The development of a novel non-sulfided catalyst with high activity for the hydrotreatment processing of plant oils, is of high interest as a way to improve the efficient production of renewable diesel. To attempt to develop such a catalyst, we first synthesized a high activity flower-like Ni-PTA catalyst used in the hydrotreatment processes of plant oils. The obtained catalyst was characterized with SEM, EDX, HRTEM, BET, XRD, H2-TPR, XPS and TGA. A probable formation mechanism of flower-like Ni(OH)2 is proposed on the basis of a range of contrasting experiments. The results of GC showed that the conversion yield of Jatropha oil was 98.95%, and the selectivity of C11-C18 alkanes was 70.93% at 360 °C, 3 MPa, and 15 h−1. The activity of this flower-like Ni-PTA catalyst was more than 15 times higher than those of the conventional Ni-PTA/Al2O3 catalysts. Additionally, the flower-like Ni-PTA catalyst exhibited good stability during the process of plant oil hydrotreatment. PMID:26503896

  4. A Non-sulfided flower-like Ni-PTA Catalyst that Enhances the Hydrotreatment Efficiency of Plant Oil to Produce Green Diesel

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Chen, Pan; Deng, Lihong; He, Jing; Wang, Luying; Rong, Long; Lei, Jiandu

    2015-10-01

    The development of a novel non-sulfided catalyst with high activity for the hydrotreatment processing of plant oils, is of high interest as a way to improve the efficient production of renewable diesel. To attempt to develop such a catalyst, we first synthesized a high activity flower-like Ni-PTA catalyst used in the hydrotreatment processes of plant oils. The obtained catalyst was characterized with SEM, EDX, HRTEM, BET, XRD, H2-TPR, XPS and TGA. A probable formation mechanism of flower-like Ni(OH)2 is proposed on the basis of a range of contrasting experiments. The results of GC showed that the conversion yield of Jatropha oil was 98.95%, and the selectivity of C11-C18 alkanes was 70.93% at 360 °C, 3 MPa, and 15 h-1. The activity of this flower-like Ni-PTA catalyst was more than 15 times higher than those of the conventional Ni-PTA/Al2O3 catalysts. Additionally, the flower-like Ni-PTA catalyst exhibited good stability during the process of plant oil hydrotreatment.

  5. Enhancement of Glycerol Steam Reforming Activity and Thermal Stability by Incorporating CeO2 and TiO2 in Ni- and Co-MCM-41 Catalysts

    NASA Astrophysics Data System (ADS)

    Dade, William N.

    Hydrogen (H2) has many applications in industry with current focus shifted to production of hydrocarbon fuels and valuable oxygenates using the Fischer-Tropsch technology and direct use in proton exchange membrane fuel cell (PEMFC). Hydrogen is generally produced via steam reforming of natural gas or alcohols like methanol and ethanol. Glycerol, a by-product of biodiesel production process, is currently considered to be one of the most attractive sources of sustainable H2 due to its high H/C ratio and bio-based origin. Ni and Co based catalysts have been reported to be active in glycerol steam reforming (GSR); however, deactivation of the catalysts by carbon deposition and sintering under GSR operating conditions is a major challenge. In this study, a series of catalysts containing Ni and Co nanoparticles incorporated in CeO2 and TiO2 modified high surface area MCM-41 have been synthesized using one-pot method. The catalysts are tested for GSR (at H2O/Glycerol mole ratio of 12 and GHSV of 2200 h-1) to study the effect of support modification and reaction temperature (450 - 700 °C) on the product selectivity and long term stability. GSR results revealed that all the catalysts performed significantly well exhibiting over 85% glycerol conversion at 650 °C except Ni catalysts that showed better low temperature activities. Deactivation studies of the catalysts conducted at 650 °C indicated that the Ni-TiO2-MCM-41 and Ni-CeO 2-MCM-41 were resistant to deactivation with ˜100% glycerol conversion for 40 h. In contrast, Co-TiO2-MCM-41 perform poorly as the catalyst rapidly deactivated after 12 h to yield ˜20% glycerol conversion after 40 h. The WAXRD and TGA-DSC analyses of spent catalysts showed a significant amount of coke deposition that might explain catalysts deactivation. The flattening shape of the original BET type IV isotherm with drastic reduction of catalyst surface area can also be responsible for observed drop in catalysts activities.

  6. Autothermal reforming catalyst having perovskite structure

    DOEpatents

    Krumpel, Michael; Liu, Di-Jia

    2009-03-24

    The invention addressed two critical issues in fuel processing for fuel cell application, i.e. catalyst cost and operating stability. The existing state-of-the-art fuel reforming catalyst uses Rh and platinum supported over refractory oxide which add significant cost to the fuel cell system. Supported metals agglomerate under elevated temperature during reforming and decrease the catalyst activity. The catalyst is a perovskite oxide or a Ruddlesden-Popper type oxide containing rare-earth elements, catalytically active firs row transition metal elements, and stabilizing elements, such that the catalyst is a single phase in high temperature oxidizing conditions and maintains a primarily perovskite or Ruddlesden-Popper structure under high temperature reducing conditions. The catalyst can also contain alkaline earth dopants, which enhance the catalytic activity of the catalyst, but do not compromise the stability of the perovskite structure.

  7. Sabatier Catalyst Poisoning Investigation

    NASA Technical Reports Server (NTRS)

    Nallette, Tim; Perry, Jay; Abney, Morgan; Knox, Jim; Goldblatt, Loel

    2013-01-01

    The Carbon Dioxide Reduction Assembly (CRA) on the International Space Station (ISS) has been operational since 2010. The CRA uses a Sabatier reactor to produce water and methane by reaction of the metabolic CO2 scrubbed from the cabin air and the hydrogen byproduct from the water electrolysis system used for metabolic oxygen generation. Incorporating the CRA into the overall air revitalization system has facilitated life support system loop closure on the ISS reducing resupply logistics and thereby enhancing longer term missions. The CRA utilizes CO2 which has been adsorbed in a 5A molecular sieve within the Carbon Dioxide Removal Assembly, CDRA. There is a potential of compounds with molecular dimensions similar to, or less than CO2 to also be adsorbed. In this fashion trace contaminants may be concentrated within the CDRA and subsequently desorbed with the CO2 to the CRA. Currently, there is no provision to remove contaminants prior to entering the Sabatier catalyst bed. The risk associated with this is potential catalyst degradation due to trace organic contaminants in the CRA carbon dioxide feed acting as catalyst poisons. To better understand this risk, United Technologies Aerospace System (UTAS) has teamed with MSFC to investigate the impact of various trace contaminants on the CRA catalyst performance at relative ISS cabin air concentrations and at about 200/400 times of ISS concentrations, representative of the potential concentrating effect of the CDRA molecular sieve. This paper summarizes our initial assessment results.

  8. Catalyst activator

    DOEpatents

    McAdon, Mark H.; Nickias, Peter N.; Marks, Tobin J.; Schwartz, David J.

    2001-01-01

    A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

  9. Dichloromethane photodegradation using titanium catalysts

    SciTech Connect

    Tanguay, J.F.; Suib, S.L.; Coughlin, R.W. )

    1989-06-01

    The use of titanium dioxide and titanium aluminosilicates in the photocatalytic destruction of chlorinated hydrocarbons is investigated. Titanium-exchanged clays, titanium-pillared clays, and titanium dioxide in the amorphous, anatase, and rutile forms are used to photocatalytically degrade dichloromethane to hydrochloric acid and carbon dioxide. Bentonite clays pillared by titanium dioxide are observed to be more catalytically active than titanium-exchanged clays. Clays pillared by titanium aluminum polymeric cations display about the same catalytic activity as that of titanium-exchanged clays. The rutile form of titanium dioxide is the most active catalyst studied for the dichloromethane degradation reaction. The anatase form of titanium dioxide supported on carbon felt was also used as a catalyst. This material is about five times more active than titanium dioxide-pillared clays. Degradation of dichloromethane using any of these catalysts can be enhanced by oxygen enrichment of the reaction solution or by preirradiating the catalyst with light.

  10. Catalyst suppliers consolidate further, offer more catalysts

    SciTech Connect

    Rhodes, A.K.

    1995-10-02

    The list of suppliers of catalysts to the petroleum refining industry has decreased by five since Oil and Gas Journal`s survey of refining catalysts and catalytic additives was last published. Despite the consolidation, the list of catalyst designations has grown to about 950 in this latest survey, compared to 820 listed in 1993. The table divides the catalysts by use and gives data on their primary differentiating characteristics, feedstock, products, form, bulk density,catalyst support, active agents, availability, and manufactures.

  11. Activity and stability enhancement of copper-alumina catalysts using cerium and zinc promoters for the selective production of hydrogen via steam reforming of methanol

    NASA Astrophysics Data System (ADS)

    Patel, Sanjay; Pant, K. K.

    The catalytic activity and hydrogen selectivity of cerium and zinc promoted copper-alumina catalysts have been investigated for the selective production of hydrogen via steam reforming of methanol (SRM). The SRM was carried out in a fixed bed tubular reactor at atmospheric pressure over a temperature range 200-300 °C. The major reaction products were hydrogen and carbon dioxide with traces of carbon monoxide. Catalysts of varying compositions were prepared by the wet impregnation method and characterized by atomic absorption spectroscopy (AAS), BET surface area, pore volume, pore size, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and thermogravimetry analysis (TGA). Results revealed that the methanol conversion, hydrogen selectivity and carbon monoxide formation varied with the type of promoter and content of copper in the catalyst. Cerium promoted Cu-Zn-Ce-Al-oxide catalysts improved the activity and hydrogen selectivity greatly and also kept the CO formation very low. Using cerium the SRM could be carried out at lower temperature with high methanol conversion, results in suppression of methanol decomposition and reverse water gas shift reactions eventually end-up with the low carbon monoxide and hydrogen rich product stream. Cerium also stabilizes the copper-alumina catalysts effectively that was confirmed by deactivation studies in which cerium promoted Cu-Zn-Ce-Al-oxide catalysts gave the consistent performance for a long run-time compared to catalysts containing only zinc promoter. The optimum operating conditions for SRM have been investigated by detailed study of effects of reaction temperature, contact time and steam to methanol molar ratio on methanol conversion, hydrogen selectivity and CO formation. Reaction pathway has been proposed for the SRM based on results obtained.

  12. Enhanced visible-light H2 evolution of g-C3N4 photocatalysts via the synergetic effect of amorphous NiS and cheap metal-free carbon black nanoparticles as co-catalysts

    NASA Astrophysics Data System (ADS)

    Wen, Jiuqing; Li, Xin; Li, Haiqiong; Ma, Song; He, Kelin; Xu, Yuehua; Fang, Yueping; Liu, Wei; Gao, Qiongzhi

    2015-12-01

    In this report, g-C3N4-based photocatalysts with dual co-catalysts of amorphous NiS and carbon black were firstly synthesized through a facile two-step process. The g-C3N4/carbon black/NiS composite photocatalyst were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), N2 adsorption, photoluminescence (PL) spectra and transient photocurrent responses. The photocatalytic activities for photocatalytic hydrogen evolution under visible light irradiation (λ ≥ 420 nm) were measured using an aqueous solution containing triethanolamine as an electron donor. Moreover, the results showed that the ternary g-C3N4 photocatalyst loaded by 0.5 wt% carbon black and 1.5 wt% NiS could achieve the highest H2-production rate of 992 μmol g-1 h-1 under visible-light irradiation (>420 nm), which is about 2.51 times higher than that of the corresponding binary g-C3N4/1.5% NiS photocatalyst. It is believed that the enhanced photocatalytic H2-evolution activities could be attributed to the excellent synergetic effect between the carbon black and NiS as co-catalysts on the surface of g-C3N4, leading to the improved visible light absorption, promoted charge separation and enhanced the following H2-evolution kinetics. This work would not only demonstrate the promising potentials of carbon black as co-catalyst for applications in visible-light H2 generation, but also offer a new insight into the construction of highly efficient and stable g-C3N4-based hybrid semiconductor nanocomposites with dual co-catalysts for diverse photocatalytic applications.

  13. Hydrocracking catalyst

    SciTech Connect

    Hilfman, L.; O'Hara, M.

    1980-07-01

    A description is given of a process for the conversion of heavy hydrocarbon oil boiling above about 650/sup 0/F into lower boiling hydrocarbons, which comprises hydrocracking the heavy oil in admixture with hydrogen and in contact with a catalyst with comprising a ra re earth exchange metal component and a platinum group metal component supported on a mixture of ziegler alumina and a zeolite.

  14. Catalyst regeneration process including metal contaminants removal

    DOEpatents

    Ganguli, Partha S.

    1984-01-01

    Spent catalysts removed from a catalytic hydrogenation process for hydrocarbon feedstocks, and containing undesired metals contaminants deposits, are regenerated. Following solvent washing to remove process oils, the catalyst is treated either with chemicals which form sulfate or oxysulfate compounds with the metals contaminants, or with acids which remove the metal contaminants, such as 5-50 W % sulfuric acid in aqueous solution and 0-10 W % ammonium ion solutions to substantially remove the metals deposits. The acid treating occurs within the temperature range of 60.degree.-250.degree. F. for 5-120 minutes at substantially atmospheric pressure. Carbon deposits are removed from the treated catalyst by carbon burnoff at 800.degree.-900.degree. F. temperature, using 1-6 V % oxygen in an inert gas mixture, after which the regenerated catalyst can be effectively reused in the catalytic process.

  15. 40 CFR 725.94 - Substantiation requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... microorganism identity confidential in the MCAN and wants the identity to be listed on the confidential... submitted under § 725.190. Otherwise, EPA will list the specific microorganism identity on the public Inventory. (2) The submitter must substantiate the claim for confidentiality of the microorganism...

  16. 40 CFR 725.94 - Substantiation requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substantiation requirements. 725.94 Section 725.94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT REPORTING REQUIREMENTS AND REVIEW PROCESSES FOR MICROORGANISMS Confidentiality and Public Access to Information § 725.94...

  17. 40 CFR 725.94 - Substantiation requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... microorganism identity confidential in the MCAN and wants the identity to be listed on the confidential... submitted under § 725.190. Otherwise, EPA will list the specific microorganism identity on the public Inventory. (2) The submitter must substantiate the claim for confidentiality of the microorganism...

  18. 24 CFR 902.79 - Substantial default.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Notification of substantial default and response. If information from an annual assessment or audit, or any... substantively accurate; and (v) Notification to the PHA that, absent a satisfactory response in accordance with... determined to be an emergency, or in any case where the events or conditions precipitating the...

  19. Substantially oxygen-free contact tube

    NASA Technical Reports Server (NTRS)

    Pike, James F. (Inventor)

    1993-01-01

    A device for arc welding is provided in which a continuously-fed electrode wire is in electrical contact with a contact tube. The contact tube is improved by using a substantially oxygen-free conductive alloy in order to reduce the amount of electrical erosion.

  20. 21 CFR 514.4 - Substantial evidence.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... adequate and well-controlled studies, such as a study in a target species, study in laboratory animals... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUG APPLICATIONS General Provisions § 514.4 Substantial...

  1. 21 CFR 514.4 - Substantial evidence.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... effectiveness of the new animal drug involved that the new animal drug will have the effect it purports or is... have its intended effect. (b) Characteristics of substantial evidence—(1) Qualifications of experts... for use other than in animal feed or drinking water. (iii) Antibacterial with respect to a...

  2. 21 CFR 514.4 - Substantial evidence.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... effectiveness of the new animal drug involved that the new animal drug will have the effect it purports or is... have its intended effect. (b) Characteristics of substantial evidence—(1) Qualifications of experts... for use other than in animal feed or drinking water. (iii) Antibacterial with respect to a...

  3. Substantially Oxygen-Free Contact Tube

    NASA Technical Reports Server (NTRS)

    Pike, James F. (Inventor)

    1991-01-01

    A device for arc welding is provided in which a continuously-fed electrode wire is in electrical contact with a contact tube. The contact tube is improved by using a substantially oxygen-free conductive alloy in order to reduce the amount of electrical erosion.

  4. Catalyst and method for aqueous phase reactions

    DOEpatents

    Elliott, Douglas C.; Hart, Todd R.

    1999-01-01

    The present invention is a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional metal deposited onto the support in a second dispersed phase. The additional metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase without substantially affecting the catalytic activity, thereby increasing the life time of the catalyst.

  5. The enhancement effect of nitrogen, fluorine-codoped titanium dioxide on the carbon supported platinum nano-catalyst for methanol electrooxidation reaction

    NASA Astrophysics Data System (ADS)

    Li, Guoqiang; Yao, Shikui; Zhu, Jianbing; Liu, Changpeng; Xing, Wei

    2015-03-01

    TiO2 (anatase) codoped with nitrogen and fluorine is synthesized by a simple solid state route, using urea and ammonium fluoride as sources of nitrogen and fluorine, respectively. N,F-TiO2 and carbon are mixed up physically as hybrid support of Pt nanoparticles for methanol electrooxidation. TEM shows that the utilization of the hybrid support leads to the uniform distribution and small particles size of Pt nanoparticles (Pt NPs) in Pt-N,F-TiO2/C catalyst. COad stripping experiment results indicate that the addition of N,F-TiO2 facilitates the oxidative removal of CO on Pt surface. Furthermore, cyclic voltammetric and chronoamperometric experiments show that the prepared Pt-N,F-TiO2/C catalyst exhibits much better catalytic activity and stability compared to Pt-TiO2/C, Pt/C (JM) and Pt/C (hm) catalysts. For instance, the peak current and the stable current at 7200 s of the Pt-N,F-TiO2/C catalyst are about 1.85 and 2.66 times of the Pt/C (JM) catalyst. The catalytic performance of the Pt-N,F-TiO2/C is also evaluated in a direct methanol fuel cell (DMFC), which exhibits a maximum power density of 51.6 mW cm-2, 1.65 times of an analogs fuel cell using Pt/C (JM) as an anode catalyst. Therefore, the N,F-TiO2 has great application prospect as a high-performance electrocatalyst support for methanol electrooxidation in DMFC.

  6. FCCU operating changes optimize octane catalyst use

    SciTech Connect

    Desai, P.H.

    1986-09-01

    The use of octane-enhancing catalysts in a fluid catalytic cracking unit (FCCU) requires changes in the operation of the unit to derive maximum benefits from the octane catalyst. In addition to the impressive octane gain achieved by the octane catalyst, the catalyst also affects the yield structure, the unit heat balance, and the product slate by reducing hydrogen transfer reactions. Catalyst manufacturers have introduced new product lines based upon ultrastable Y type (USY) zeolites which can result in 2 to 3 research octane number (RON) gains over the more traditional rare earth exchanged Y type (REY) zeolites. Here are some operating techniques for the FCCU and associated processes that will allow maximum benefits from octane catalyst use.

  7. [Catalyst research]. Final Report

    SciTech Connect

    Ian P Rothwell; David R McMillin

    2005-03-14

    Research results are the areas of catalyst precursor synthesis, catalyst fluxionality, catalyst stability, polymerization of {alpha}-olefins as well as the chemistry of Group IV and Group V metal centers with aryloxide and arylsulfide ligands.

  8. Mo2 C as Non-Noble Metal Co-Catalyst in Mo2 C/CdS Composite for Enhanced Photocatalytic H2 Evolution under Visible Light Irradiation.

    PubMed

    Ma, Baojun; Xu, Haojie; Lin, Keying; Li, Jie; Zhan, Haijuan; Liu, Wanyi; Li, Can

    2016-04-21

    Co-catalysts are a major factor to enhance photocatalytic H2 activity; they are mainly composed of expensive noble metals. Here, we reported a new non-noble-metal co-catalyst Mo2 C that efficiently improves the photocatalytic H2 evolution of CdS under visible light irradiation. Mo2 C is prepared by temperature-programmed reaction with molybdenum oxide as precursor, and the Mo2 C/CdS composite is prepared by deposition of CdS on Mo2 C. The optimum composite 2.0 % Mo2 C/CdS shows a high H2 evolution rate of 161 μmol h(-1) , which is ten times higher than that of CdS alone and 2.3 times higher than the optimum for 1.0 % Pt/CdS. Moreover, the Mo2 C/CdS is stable for 50 h. This study presents a new low-cost non-noble-metal co-catalyst as a photocatalyst to achieve highly efficient H2 evolution. PMID:26934039

  9. Accreditation as a Catalyst for Institutional Effectiveness

    ERIC Educational Resources Information Center

    Dodd, Ann H.

    2004-01-01

    Accreditation bodies increasingly force institutions to merge their accountability reporting, institutional research, outcomes assessment, and decision-making activities, thus serving as catalysts for enhancing institutional effectiveness. (Contains 3 figures.)

  10. A La-doped Mg-Al mixed metal oxide supported copper catalyst with enhanced catalytic performance in transfer dehydrogenation of 1-decanol.

    PubMed

    Zhang, Ming; Zhao, Yajie; Liu, Qian; Yang, Lan; Fan, Guoli; Li, Feng

    2016-01-21

    In the present work, a La-doped Mg-Al mixed metal oxide supported copper catalyst (Cu/La-MgAlO) was synthesized through a layered double hydroxide precursor route. The materials were characterized by powder X-ray diffraction, transmission electron microscopy, CO2-temperature programmed desorption, Fourier transform infrared spectra of CO2 absorption, and X-ray photoelectron spectroscopy. The results revealed that the introduction of a trace amount of La could significantly improve the surface basicity of the Cu/La-MgAlO catalyst, especially strong Lewis basicity. Compared with the undoped supported Cu catalyst, Cu/La-MgAlO exhibited much higher activity and selectivity in the liquid-phase transfer dehydrogenation of 1-decanol with a 1-decanal yield up to 89%. The excellent catalytic efficiency was mainly ascribed to the surface cooperation between the Lewis basic sites and the adjacent Cu(0)/Cu(+) species. That is, basic sites, especially strong-strength basic sites, held the key to the abstraction of protons from the hydroxyl group in 1-decanol, while the adjacent Cu(0) and Cu(+) species were responsible for the hydrogen transfer and the adsorption of styrene in the transfer dehydrogenation and hydrogenation reactions, respectively. This study provides a new method for designing cost-effective supported copper-based catalysts highly efficient for the transfer dehydrogenation of primary aliphatic alcohols by modifying the surface basicity of metal oxide supports. PMID:26659760

  11. Oil removal of spent hydrotreating catalyst CoMo/Al2O3 via a facile method with enhanced metal recovery.

    PubMed

    Yang, Yue; Xu, Shengming; Li, Zhen; Wang, Jianlong; Zhao, Zhongwei; Xu, Zhenghe

    2016-11-15

    Deoiling process is a key issue for recovering metal values from spent hydrotreating catalysts. The oils can be removed with organic solvents, but the industrialized application of this method is greatly hampered by the high cost and complex processes. Despite the roasting method is simple and low-cost, it generates hardest-to-recycle impurities (CoMoO4 or NiMoO4) and enormous toxic gases. In this study, a novel and facile approach to remove oils from the spent hydrotreating catalysts is developed. Firstly, surface properties of spent catalysts are characterized to reveal the possibility of oil removal. And then, oils are removed with water solution under the conditions of 90°C, 0.1wt% SDS, 2.0wt% NaOH and 10ml/gL/S ratio for 4h. Finally, thermal treatment and leaching tests are carried out to further explore the advantages of oil removal. The results show that no hardest-to-recycle impurity CoMoO4 is found in XPS spectra of thermally treated samples after deoiling and molybdenum is leached completely with sodium carbonate solution. It means that the proposed deoiling method can not only remove oils simply and without enormous harmful gases generating, but also avoid the generation of detrimental impurity and promote recycling of valuable metals from spent hydrotreating catalysts. PMID:27484947

  12. Does Pluto have a substantial atmosphere

    SciTech Connect

    Trafton, L.

    1980-01-01

    The presence of CH4 ice on Pluto implies that Pluto may have a substantial atmosphere consisting of heavy gases. Without such an atmosphere, sublimation of the CH4 ice would be so rapid on a cosmogonic time scale that either such an atmosphere would soon develop through the exposure of gases trapped in the CH4 ice or else the surface CH4 ice would soon be all sublimated away as other, more stable, ices became exposed. If such stable ices were present from the beginning, the existence of CH4 frosts would also imply that Pluto's present atmosphere contains a remnant of its primordial atmosphere.

  13. New Claus catalyst tests accurately reflect process conditions

    SciTech Connect

    Maglio, A.; Schubert, P.F.

    1988-09-12

    Methods for testing Claus catalysts are developed that more accurately represent the actual operating conditions in commercial sulfur recovery units. For measuring catalyst activity, an aging method has been developed that results in more meaningful activity data after the catalyst has been aged, because all catalysts undergo rapid initial deactivation in commercial units. An activity test method has been developed where catalysts can be compared at less than equilibrium conversion. A test has also been developed to characterize abrasion loss of Claus catalysts, in contrast to the traditional method of determining physical properties by measuring crush strengths. Test results from a wide range of materials correlated well with actual pneumatic conveyance attrition. Substantial differences in Claus catalyst properties were observed as a result of using these tests.

  14. Low-Temperature CO-Oxidation Catalysts for Long-Life CO2 Lasers

    NASA Technical Reports Server (NTRS)

    Schryer, David R. (Editor); Hoflund, Gar B. (Editor)

    1990-01-01

    Low-temperature CO-oxidation catalysts are necessary for closed-cycle pulsed CO2 lasers as well as for other applications, including air purification. The papers presented in this volume discuss several such catalysts, including information on catalyst preparation, techniques for enhancing catalyst performance, laboratory and laser test results, and mechanistic considerations.

  15. Theoretical modeling of temperature dependent catalyst-assisted growth of conical carbon nanotube tip by plasma enhanced chemical vapor deposition process

    NASA Astrophysics Data System (ADS)

    Tewari, Aarti; Sharma, Suresh C.

    2015-02-01

    A theoretical model has been developed to examine the effect of substrate temperature on the growth of the conical carbon nanotube (CNT) tip assisted by the catalyst in a reactive plasma. The growth rate of the CNT with conical tip because of diffusion and accretion of ions on catalyst nanoparticle including the charging rate of the CNT, kinetics of plasma species, and the evolution of the substrate temperature in reactive plasma has been taken into account. The effect of substrate temperature for different ion densities and temperatures on the growth of the conical CNT tip has been investigated for typical glow discharge plasma parameters. The results of the present model can serve as a major tool in better understanding of plasma heating effects on the growth of CNTs.

  16. Theoretical modeling of temperature dependent catalyst-assisted growth of conical carbon nanotube tip by plasma enhanced chemical vapor deposition process

    SciTech Connect

    Tewari, Aarti; Sharma, Suresh C.

    2015-02-15

    A theoretical model has been developed to examine the effect of substrate temperature on the growth of the conical carbon nanotube (CNT) tip assisted by the catalyst in a reactive plasma. The growth rate of the CNT with conical tip because of diffusion and accretion of ions on catalyst nanoparticle including the charging rate of the CNT, kinetics of plasma species, and the evolution of the substrate temperature in reactive plasma has been taken into account. The effect of substrate temperature for different ion densities and temperatures on the growth of the conical CNT tip has been investigated for typical glow discharge plasma parameters. The results of the present model can serve as a major tool in better understanding of plasma heating effects on the growth of CNTs.

  17. Penultimate effect in ethylene-styrene copolymerization and the discovery of highly active ethylene-styrene catalysts with increased styrene reactivity.

    PubMed

    Arriola, Daniel J; Bokota, Marilyn; Campbell, Richard E; Klosin, Jerzy; LaPointe, Robert E; Redwine, O David; Shankar, Ravi B; Timmers, Francis J; Abboud, Khalil A

    2007-06-01

    For the first time commercially relevant catalysts for the copolymerization of ethylene and styrene have been identified. The catalysts maintain very high copolymer efficiencies at relatively high reactor temperatures without sacrificing styrene comonomer reactivity. The observations which led to this discovery are based upon the kinetic analysis of ethylene-styrene copolymerization using constrained geometry catalyst (eta5-C5Me4)(SiMe2-N-t-Bu)TiMe2 (1). This analysis revealed a substantial styrene penultimate monomer effect. Inherent reactivity of 1 toward styrene is greatly improved when the penultimate monomer on the growing polymer chain is styrene rather than ethylene. The presence of a penultimate styrene effect led to the hypothesis that catalysts bearing aromatic moieties in close proximity to the active site could lead to enhancement of styrene reactivity for this catalyst family. This hypothesis was born out by two new constrained geometry catalysts, one having two phenyl substituents placed in the 3 and 3' positions of the Cp ring (2) and the other with a 2,2'-biphenyl fragment attached to the Cp ring (3). Both catalysts exhibit higher activity than that of 1 and, more importantly, much higher styrene reactivity leading to copolymers with substantially increased styrene content (21.5% for 2, 30.6% for 3) as compared to 1 (11%) under the same polymerization conditions. Analysis of the X-ray crystal structures of 2 and 3 shows no overriding structural arguments for the increased performance. Outstanding polymerization characteristics achieved with 3 make this catalyst a candidate for commercial production of ethylene-styrene resins in a solution process. PMID:17489593

  18. Novel catalyst widens octane opportunities

    SciTech Connect

    Pritchard, G.

    1987-01-01

    Of the octane upgrading options available, refiners are focusing on those which offer a low upgrading cost, a low capital cost and a short implementation time. The BP ETHEROL Process with the novel trifunctional catalyst satisfies all of these requirements and, with the added ability to produce heavier ethers than just MTBE, provides a new opportunity for octane enhancement. The trifunctional catalyst combines the benefits of etherification, diolefin hydrogenation and olefin isomerisation in one single catalyst and for essentially no incremental investment relative to a conventional MTBE unit. The economics demonstrate that at an upgrading cost of 15 cents per octane barrel, the BP ETHEROL Process is highly competitive with other octane upgrading options.

  19. Pretreatment of CO oxidation catalysts

    NASA Technical Reports Server (NTRS)

    Vannorman, John D.

    1988-01-01

    CO oxidation catalysts with high activity in the range of 25 C to 100 C are important for long-life, closed-cycle operation of pulsed carbon dioxide 2 lasers. A reductive pretreatment with either CO or H sub 2 was shown to significantly enhance the activity of a commerically-available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above caused an initial dip in observed CO or O sub 2 loss or CO sub 2 formation in a test gas mixture of 1 percent CO and 0.5 percent O sub 2 in a He gas matrix before a steady-state yield was obtained. This dip was found to be caused by dehydration of the surface of the catalyst and was readily eliminated by humidifying the catalyst or the test gas mixture. It was also found that too much moisture resulted in a lower overall yield of CO sub 2. Under similar conditions, it is hypothesized that the effect of the humidification is to increase the concentration of OH groups on the surface of the catalyst. The effect of having high concentration of CO sub 2 in the test gas mixture upon the loss of CO and O sub 2 as well as the effect of periods of relaxation of the catalyst under non-test gas conditions was studied. The purpose of these studies was to gain an insight into the mechanism of CO oxidation on this type of catalyst.

  20. Electrochemical catalyst recovery method

    DOEpatents

    Silva, L.J.; Bray, L.A.

    1995-05-30

    A method of recovering catalyst material from latent catalyst material solids includes: (a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; (b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; (c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and (d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications. 3 figs.

  1. Electrochemical catalyst recovery method

    DOEpatents

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

    A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.

  2. New catalyst improves sulfur recovery at Canadian plant

    SciTech Connect

    Nasato, E. ); MacDougall, R.S. ); Lagas, J.A. )

    1994-02-28

    Installation at Mobil Oil Canada Ltd.'s Lone Pine Creek, Alta., gas plant of a second-generation Superclaus catalyst has, combined with the first-generation catalyst, resulted in higher overall sulfur recovery at lower reactor temperatures. Superclaus reactor inlet temperatures have been reduced from 255 to 200 C. and as a result have saved on utility costs and reduced tail-gas flow and CO[sub 2] emissions. Initial results indicate overall plant sulfur recovery has improved to the 98.7--98.9% range, up from the 98.0--98.3% first-generation catalyst performance level. The enhanced second-generation catalyst has also proven more operationally flexible than the first-generation catalyst. The paper describes the improved catalyst, the Superclaus process, catalyst performance, catalyst loading, equipment modifications, and performance of the plant.

  3. Long-Life Catalyst

    NASA Technical Reports Server (NTRS)

    1999-01-01

    STC Catalysts, Inc. (SCi) manufactures a noble metal reducible oxide catalyst consisting primarily of platinum and tin dioxide deposited on a ceramic substrate. It is an ambient temperature oxidation catalyst that was developed primarily for Carbon Dioxide Lasers.The catalyst was developed by the NASA Langley Research Center for the Laser Atmospheric Wind Sounder Program (LAWS) which was intended to measure wind velocity on a global basis. There are a number of NASA owned patents covering various aspects of the catalyst.

  4. Communication: Enhanced oxygen reduction reaction and its underlying mechanism in Pd-Ir-Co trimetallic alloys

    SciTech Connect

    Ham, Hyung Chul; Hwang, Gyeong S.; Manogaran, Dhivya; Lee, Kang Hee; Jin, Seon-ah; You, Dae Jong; Pak, Chanho; Kwon, Kyungjung

    2013-11-28

    Based on a combined density functional theory and experimental study, we present that the electrochemical activity of Pd{sub 3}Co alloy catalysts toward oxygen reduction reaction (ORR) can be enhanced by adding a small amount of Ir. While Ir tends to favorably exist in the subsurface layers, the underlying Ir atoms are found to cause a substantial modification in the surface electronic structure. As a consequence, we find that the activation barriers of O/OH hydrogenation reactions are noticeably lowered, which would be mainly responsible for the enhanced ORR activity. Furthermore, our study suggests that the presence of Ir in the near-surface region can suppress Co out-diffusion from the Pd{sub 3}Co substrate, thereby improving the durability of Pd-Ir-Co catalysts. We also discuss the relative roles played by Ir and Co in enhancing the ORR activity relative to monometallic Pd catalysts.

  5. Substantial nitrogen pollution embedded in international trade

    NASA Astrophysics Data System (ADS)

    Oita, Azusa; Malik, Arunima; Kanemoto, Keiichiro; Geschke, Arne; Nishijima, Shota; Lenzen, Manfred

    2016-02-01

    Anthropogenic emissions of reactive nitrogen to the atmosphere and water bodies can damage human health and ecosystems. As a measure of a nation’s contribution to this potential damage, a country’s nitrogen footprint has been defined as the quantity of reactive nitrogen emitted during the production, consumption and transportation of commodities consumed within that country, whether those commodities are produced domestically or internationally. Here we use global emissions databases, a global nitrogen cycle model, and a global input-output database of domestic and international trade to calculate the nitrogen footprints for 188 countries as the sum of emissions of ammonia, nitrogen oxides and nitrous oxide to the atmosphere, and of nitrogen potentially exportable to water bodies. Per-capita footprints range from under 7 kg N yr-1 in some developing countries to over 100 kg N yr-1 in some wealthy nations. Consumption in China, India, the United States and Brazil is responsible for 46% of global emissions. Roughly a quarter of the global nitrogen footprint is from commodities that were traded across country borders. The main net exporters have significant agricultural, food and textile exports, and are often developing countries, whereas important net importers are almost exclusively developed economies. We conclude that substantial local nitrogen pollution is driven by demand from consumers in other countries.

  6. EARLY CHILDHOOD INVESTMENTS SUBSTANTIALLY BOOST ADULT HEALTH

    PubMed Central

    Campbell, Frances; Conti, Gabriella; Heckman, James J.; Moon, Seong Hyeok; Pinto, Rodrigo; Pungello, Elizabeth; Pan, Yi

    2014-01-01

    High-quality early childhood programs have been shown to have substantial benefits in reducing crime, raising earnings, and promoting education. Much less is known about their benefits for adult health. We report the long-term health impacts of one of the oldest and most heavily cited early childhood interventions with long-term follow-up evaluated by the method of randomization: the Carolina Abecedarian Project (ABC). Using recently collected biomedical data, we find that disadvantaged children randomly assigned to treatment have significantly lower prevalence of risk factors for cardiovascular and metabolic diseases in their mid-30s. The evidence is especially strong for males. The mean systolic blood pressure among the control males is 143, while only 126 among the treated. One in four males in the control group is affected by metabolic syndrome, while none in the treatment group is. To reach these conclusions, we address several statistical challenges. We use exact permutation tests to account for small sample sizes and conduct a parallel bootstrap confidence interval analysis to confirm the permutation analysis. We adjust inference to account for the multiple hypotheses tested and for nonrandom attrition. Our evidence shows the potential of early life interventions for preventing disease and promoting health. PMID:24675955

  7. Gasdynamic substantiation of physical theory of meteors

    NASA Astrophysics Data System (ADS)

    Egorova, Lidia A.; Tirskiy, Grigoriy A.

    2014-12-01

    Physical theory of meteors developing since 30s of the last century, based on two ordinary differential equations: the equation of motion for the center of mass of meteoroid and equation of meteoroid ablation. These equations contain drag and heat transfer coefficients, which are share of momentum and energy transferred from gas to meteoroid and effective enthalpy of mass loss. Accounting for different values of these coefficients substantially changes meteoroid ballistics compared with the results of simple physical theory of meteors. For the drag coefficient a simple interpolation formula is valid for all flow regimes and depends on the Reynolds number. The heat transfer coefficient represented in the form of the approximation depending on density and meteoroid radius. Based on the law of conservation of mass and energy at the front of meteoroid melting and evaporation the explicit expression for the effective enthalpy of mass loss Q was obtained, depending on the speed of the meteoroid and heterogeneous reactions on the surface. Classical solution gives a significant deviation from the exact one obtained in present study for small bodies (1 mm) at high altitudes and high speeds.

  8. Sulphur condensation influence in Claus catalyst performance.

    PubMed

    Mora, R L

    2000-12-01

    The Claus process is an efficient way of removing H(2)S from acid gas streams and this is widely practised in industries such as natural gas processing, oil refining and metal smelting. Increasingly strict pollution control regulations require maximum sulphur recovery from the Claus unit in order to minimise sulphur-containing effluent. The most widely used Claus catalyst in sulphur recovery units is non-promoted spherical activated alumina. Properties associated with optimum non-promoted Claus catalyst performance include high surface area, appropriate pore size distribution and enhanced physical properties. The objective of this paper is to outline a procedure in order to estimate Claus catalyst effectiveness after pore plugging due to sulphur condensation. Catalyst deactivation due to pore plugging by sulphur is modelled employing a Bethe lattice and its corresponding performance is described by means of a modified effectiveness factor. Model results show an improvement in the modified effectiveness factor due to modifications in catalyst porous structure. PMID:11040389

  9. Manganese dioxide as a new cathode catalyst in microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Hu, Boxun; Suib, Steven; Lei, Yu; Li, Baikun

    This study focused on manganese oxides with a cryptomelane-type octahedral molecular sieve (OMS-2) structure to replace platinum as a cathode catalyst in microbial fuel cells (MFCs). Undoped (ud-OSM-2) and three catalysts doped with cobalt (Co-OMS-2), copper (Cu-OMS-2), and cerium (Ce-OMS-2) to enhance their catalytic performances were investigated. The novel OMS-2 cathodes were examined in granular activated carbon MFC (GACMFC) with sodium acetate as the anode reagent and oxygen in air as the cathode reagent. The results showed that after 400 h of operation, the Co-OMS-2 and Cu-OMS-2 exhibited good catalytic performance in an oxygen reduction reaction (ORR). The voltage of the Co-OMS-2 GACMFC was 217 mV, and the power density was 180 mW m -2. The voltage of the Cu-OMS-2 GACMFC was 214 mV and the power density was 165 mW m -2. The internal resistance (R in) of the OMS-2 GACMFCs (18 ± 1 Ω) was similar to that of the platinum GACMFCs (17 Ω). Furthermore, the degradation rates of organic substrates in the OMS-2 GACMFCs were twice those in the platinum GACMFCs, which enhance their wastewater treatment efficiencies. This study indicated that using OMS-2 manganese oxides to replace platinum as a cathodic catalyst enhances power generation, increases contaminant removal, and substantially reduces the cost of MFCs.

  10. Hydrocarbon reforming catalyst material and configuration of the same

    DOEpatents

    Singh, Prabhakar; Shockling, Larry A.; George, Raymond A.; Basel, Richard A.

    1996-01-01

    A hydrocarbon reforming catalyst material comprising a catalyst support impregnated with catalyst is provided for reforming hydrocarbon fuel gases in an electrochemical generator. Elongated electrochemical cells convert the fuel to electrical power in the presence of an oxidant, after which the spent fuel is recirculated and combined with a fresh hydrocarbon feed fuel forming the reformable gas mixture which is fed to a reforming chamber containing a reforming catalyst material, where the reforming catalyst material includes discrete passageways integrally formed along the length of the catalyst support in the direction of reformable gas flow. The spent fuel and/or combusted exhaust gases discharged from the generator chamber transfer heat to the catalyst support, which in turn transfers heat to the reformable gas and to the catalyst, preferably via a number of discrete passageways disposed adjacent one another in the reforming catalyst support. The passageways can be slots extending inwardly from an outer surface of the support body, which slots are partly defined by an exterior confining wall. According to a preferred embodiment, the catalyst support is non-rigid, porous, fibrous alumina, wherein the fibers are substantially unsintered and compressible, and the reforming catalyst support is impregnated, at least in the discrete passageways with Ni and MgO, and has a number of internal slot passageways for reformable gas, the slot passageways being partly closed by a containing outer wall.

  11. Hydrocarbon reforming catalyst material and configuration of the same

    DOEpatents

    Singh, P.; Shockling, L.A.; George, R.A.; Basel, R.A.

    1996-06-18

    A hydrocarbon reforming catalyst material comprising a catalyst support impregnated with catalyst is provided for reforming hydrocarbon fuel gases in an electrochemical generator. Elongated electrochemical cells convert the fuel to electrical power in the presence of an oxidant, after which the spent fuel is recirculated and combined with a fresh hydrocarbon feed fuel forming the reformable gas mixture which is fed to a reforming chamber containing a reforming catalyst material, where the reforming catalyst material includes discrete passageways integrally formed along the length of the catalyst support in the direction of reformable gas flow. The spent fuel and/or combusted exhaust gases discharged from the generator chamber transfer heat to the catalyst support, which in turn transfers heat to the reformable gas and to the catalyst, preferably via a number of discrete passageways disposed adjacent one another in the reforming catalyst support. The passageways can be slots extending inwardly from an outer surface of the support body, which slots are partly defined by an exterior confining wall. According to a preferred embodiment, the catalyst support is non-rigid, porous, fibrous alumina, wherein the fibers are substantially unsintered and compressible, and the reforming catalyst support is impregnated, at least in the discrete passageways with Ni and MgO, and has a number of internal slot passageways for reformable gas, the slot passageways being partly closed by a containing outer wall. 5 figs.

  12. ''KN'' series cracking catalysts

    SciTech Connect

    Klapstov, V.F.; Khlebrikova, M.A.; Maslova, A.A.; Nefedov, B.K.

    1986-09-01

    The basic directions in improving high-activity zeolitic cracking catalysts at the present stage are improvements in the resistance to attrition and increases in the bulk density of the catalysts, along with a changeover to relatively waste-free catalyst manufacturing technology. Catalysts of the ''KN'' series have been synthesized recently with improved quality characteristics. Low-waste technology is used in manufacturing them. Data are presented which show that the KN catalysts are better than the other Soviet catalysts. The starting materials and reagents in preparing the KN catalysts are technical alumina, rare-earth element nitrates, a natural component (such as clay conforming to specification TU-21-25-146-75), sodium hydroxide, and granulated sodium silicate. The preparation of the KN catalysts is described and no silica gel is used in manufacturing the KN series catalyst, in contrast to the RSG-6Ts catalyst. The use of KN series catalysts in place of KMTsR in catalytic cracking units will result in an increase in the naphtha yield by at least 20% by weight, as well as a reduction of the catalyst consumption by a factor of 2-3. A changeover to the commerical production of this catalyst will make it possible to reduce saline waste by a factor of 8-10 and reduce the catalyst cost by a factor of 1.5-2.

  13. Integrated current collector and catalyst support

    DOEpatents

    Bregoli, Lawrence J.

    1985-10-22

    An integrated current collecting electrode for a molten carbonate fuel cell includes a corrugated metal conductive strip positioned in contact with a catalyst layer. The corrugations of the metal strip form a plurality of gas channels immediately adjacent the surface of the catalyst through which a reactant gas flows. Each channel is filled with a particulate material to maintain separation between the metal strip and the catalyst in ensuring gas channel integrity. The catalyst may be in the form of a compacted, particulate material provided the particle size of the material within the gas channels is larger than that of the catalyst particles to prevent catalyst migration to the metal conductor and provide reactant gas access to the catalyst layer. The gas channels formed by the corrugations of the metal strip are arranged in an offset pattern along the direction of gas flow for improved reactant gas distribution to the catalyst layer. The particulate material positioned within the gas flow channels may be a ceramic conductor such as a perovskite or a spinel for enhanced current collection.

  14. Integrated current collector and catalyst support

    DOEpatents

    Bregoli, L.J.

    1984-10-17

    An integrated current collecting electrode for a molten carbonate fuel cell includes a corrugated metal conductive strip positioned in contact with a catalyst layer. The corrugations of the metal strip form a plurality of gas channels immediately adjacent the surface of the catalyst through which a reactant gas flows. Each channel is filled with a particulate material to maintain separation between the metal strip and the catalyst in ensuring gas channel integrity. The catalyst may be in the form of a compacted, particulate material provided the particle size of the material within the gas channels is larger than that of the catalyst particles to prevent catalyst migration to the metal conductor and provide reactant gas access to the catalyst layer. The gas channels formed by the corrugations of the metal strip are arranged in an offset pattern along the direction of gas flow for improved reactant gas distribution to the catalyst layer. The particulate material positioned within the gas flow channels may be a ceramic conductor such as a perovskite or a spinel for enhanced current collection.

  15. Hierarchical Mesoporous/Macroporous Perovskite La0.5Sr0.5CoO3-x Nanotubes: A Bifunctional Catalyst with Enhanced Activity and Cycle Stability for Rechargeable Lithium Oxygen Batteries.

    PubMed

    Liu, Guoxue; Chen, Hongbin; Xia, Lu; Wang, Suqing; Ding, Liang-Xin; Li, Dongdong; Xiao, Kang; Dai, Sheng; Wang, Haihui

    2015-10-14

    Perovskites show excellent specific catalytic activity toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solutions; however, small surface areas of the perovskites synthesized by traditional sol-gel methods lead to low utilization of catalytic sites, which gives rise to poor Li-O2 batteries performance and restricts their application. Herein, a hierarchical mesporous/macroporous perovskite La0.5Sr0.5CoO3-x (HPN-LSC) nanotube is developed to promote its application in Li-O2 batteries. The HPN-LSC nanotubes were synthesized via electrospinning technique followed by postannealing. The as-prepared HPN-LSC catalyst exhibits outstanding intrinsic ORR and OER catalytic activity. The HPN-LSC/KB electrode displays excellent performance toward both discharge and charge processes for Li-O2 batteries, which enhances the reversibility, the round-trip efficiency, and the capacity of resultant batteries. The synergy of high catalytic activity and hierarchical mesoporous/macroporous nanotubular structure results in the Li-O2 batteries with good rate capability and excellent cycle stability of sustaining 50 cycles at a current density of 0.1 mA cm(-2) with an upper-limit capacity of 500 mAh g(-1). The results will benefit for the future development of high-performance Li-O2 batteries using hierarchical mesoporous/macroporous nanostructured perovskite-type catalysts. PMID:26418118

  16. Radiation-induced reactions of COH 2 gas mixtures over various solid catalysts

    NASA Astrophysics Data System (ADS)

    Nagai, S.; Arai, H.; Hatada, M.

    Studies have been carried out of radiation-induced reactions of COH 2 gas mixtures in the presence of various solid catalysts in order to find possibilities of synthesizing organic raw materials from COH 2 by radiation for the future. The solid catalysts studied include Fischer-Tropsch catalyst (FeCu supported by diatomaceous earth), titania(TiO 2), and silica gel. Analysis of the reaction products over Fischer-Tropsch catalyst or semiconductors such as TiO 2 and ZnOCr 2O 3 reveals that these solid catalysts do not sensitize the radiation chemical reaction of COH 2 but show the secondary effects on the reaction so as to induce the hydrogenation of olefins produced by the catalytic reaction and of aldehydes produced in gas phase by radiation. On the other hand, silica gel and other insulators such as alumina have been found to exhibit high catalytic activity in the formation of hydrocarbons from COH 2 under electron beam irradiation at 300°C. It has been shown experimentally that secondary reactions between H 2 and carbonaceous solid produced from CO make a substantial contribution to the formation of hydrocarbons from COH 2 over silica gel. In an attempt to find the role of silica gel in the reaction to produce hydrocarbons, radiation-induced reactions have been studied of H 2 with the carbonaceous solid that had been produced by irradiation of CO in the absence of solid catalyst, over TiO 2, or over silica gel. The results indicate that silica gel not only enhances the yields of CO 2 and carbonaceous solid from CO but also promotes hydrogenation reactions of the carbonaceous solid under electron beam irradiation.

  17. Ceramic catalyst materials

    SciTech Connect

    Sault, A.G.; Gardner, T.J.; Hanprasopwattanna, A.; Reardon, J.; Datye, A.K.

    1995-08-01

    Hydrous titanium oxide (HTO) ion-exchange materials show great potential as ceramic catalyst supports due to an inherently high ion-exchange capacity which allows facile loading of catalytically active transition metal ions, and an ability to be cast as thin films on virtually any substrate. By coating titania and HTO materials onto inexpensive, high surface area substrates such as silica and alumina, the economics of using these materials is greatly improved, particularly for the HTO materials, which are substantially more expensive in the bulk form than other oxide supports. In addition, the development of thin film forms of these materials allows the catalytic and mechanical properties of the final catalyst formulation to be separately engineered. In order to fully realize the potential of thin film forms of titania and HTO, improved methods for the deposition and characterization of titania and HTO films on high surface area substrates are being developed. By varying deposition procedures, titania film thickness and substrate coverage can be varied from the submonolayer range to multilayer thicknesses on both silica and alumina. HTO films can also be formed, but the quality and reproducibility of these films is not nearly as good as for pure titania films. The films are characterized using a combination of isopropanol dehydration rate measurements, point of zero charge (PZC) measurements, BET surface area, transmission electron microscopy (TEM), and elemental analysis. In order to assess the effects of changes in film morphology on catalytic activity, the films are being loaded with MoO{sub 3} using either incipient wetness impregnation or ion-exchange of heptamolybdate anions followed by calcining. The MoO{sub 3} is then sulfided to form MOS{sub 2}, and tested for catalytic activity using pyrene hydrogenation and dibenzothiophene (DBT) desulfurization, model reactions that simulate reactions occurring during coal liquefaction.

  18. Substantial improvement of nanotube processability by freeze-drying.

    PubMed

    Maugey, M; Neri, W; Zakri, C; Derré, A; Pénicaud, A; Noé, L; Chorro, M; Launois, P; Monthioux, M; Poulin, P

    2007-08-01

    As-produced carbon nanotubes often contain a fraction of impurities such as metal catalysts, inorganic supports, and carbon by-products. These impurities can be partially removed by using acidic dissolution. The resulting nanotube materials have to be dried to form a powder. The processability of nanotubes subjected to regular (thermal vaporisation) drying is particularly difficult because capillary forces pack and stick the nanotubes irreversibly, which limits their dispersability in polymeric matrices or solvents. We show that this dramatic limitation can be circumvented by using freeze-drying instead of regular-drying during nanotube purification process. In this case, the nanotubes are trapped in frozen water which is then sublimated. As a result the final powder is significantly less compact and, more important, the nanotubes can be easily dispersed with no apparent aggregates, thereby greatly enhancing their processability, e.g., they can be used to make homogeneous composites and fibers. Results from coagulation spinning from water-based dispersions of regularly-dried and freeze-dried nanotubes are compared. We also show that freeze-dried materials, in contrast to regularly-dried materials, can be dissolved in organic polar solvents using alkali-doped nanotubes. High resolution TEM and XRD analysis demonstrate that the nanotube structure and quality are not affected at the nanoscale by freeze-drying treatments. PMID:17685277

  19. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... activities like taking care of one's self, household tasks, hobbies, therapy, school attendance, club...) Substantial work activity. Substantial work activity is work activity that involves doing significant...

  20. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... activities like taking care of one's self, household tasks, hobbies, therapy, school attendance, club...) Substantial work activity. Substantial work activity is work activity that involves doing significant...

  1. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... activities like taking care of one's self, household tasks, hobbies, therapy, school attendance, club...) Substantial work activity. Substantial work activity is work activity that involves doing significant...

  2. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... activities like taking care of one's self, household tasks, hobbies, therapy, school attendance, club...) Substantial work activity. Substantial work activity is work activity that involves doing significant...

  3. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... activities like taking care of one's self, household tasks, hobbies, therapy, school attendance, club...) Substantial work activity. Substantial work activity is work activity that involves doing significant...

  4. Ruthenium-based olefin metathesis catalysts bearing pH-responsive ligands: External control of catalyst solubility and activity

    NASA Astrophysics Data System (ADS)

    Balof, Shawna Lynn

    2011-12-01

    Sixteen novel, Ru-based olefin metathesis catalysts bearing pH responsive ligands were synthesized. The pH-responsive groups employed with these catalysts included dimethylamino (NMe2) modified NHC ligands as well as N-donor dimethylaminopyridine (DMAP) and 3-(o-pyridyl)propylidene ligands. These pH-responsive ligands provided the means by which the solubility and/or activity profiles of the catalysts produced could be controlled via acid addition. The main goal of this dissertation was to design catalyst systems capable of performing ring opening metathesis (ROMP) and ring closing metathesis (RCM) reactions in both organic and aqueous media. In an effort to quickly gain access to new catalyst structures, a template synthesis for functionalized NHC ligand precursors was designed, in addition to other strategies, to obtain ligand precursors with ancillary NMe2 groups. Kinetic studies for the catalysts produced from these precursors showed external control of catalyst solubility was afforded via protonation of the NMe2 groups of their NHC ligands. Additionally, this protonation afforded external control of catalyst propagation rates for several catalysts. This is the first known independent external control for the propagation rates of ROMP catalysts. The incorporation of pH-responsive N-donor ligands into catalyst structures also provided the means for the external control of metathesis activity, as the protonation of these ligands resulted in an increased initiation rate based on their fast and irreversible dissociation from the metal center. The enhanced external control makes these catalysts applicable to a wide range of applications, some of which have been explored by us and/or through collaboration. Three of the catalysts designed showed remarkable metathesis activity in aqueous media. These catalysts displayed comparable RCM activity in aqueous media to a class of water-soluble catalysts reported by Grubbs et al., considered to be the most active catalyst for

  5. Enhancement of photocatalytic activity in reducing CO2 over CdS/g-C3N4 composite catalysts under UV light irradiation

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoxiao; Xin, Weiyue; Yin, Xiaohong; Shao, Xiao

    2016-05-01

    The polymeric graphite-like carbon nitride (g-C3N4) and CdS/g-C3N4 composites of different mass fractions were synthesized via polycondensation and hydrothermal methods, respectively. XRD, SEM-EDS, TEM, UV-vis and PL were applied to characterize the structure, morphology and optical properties of the as-prepared CdS/g-C3N4 composites. The photocatalytic activities of the catalysts were evaluated by the reduction of CO2 in methanol solution to form methyl formate. The results indicated that the photocatalytic activities of the CdS/g-C3N4 composites were improved significantly compared with that of the pure CdS and g-C3N4. The highest activity appeared at mass ratio 1:2 of CdS:g-C3N4.

  6. Membrane electrode assembly with enhanced platinum utilization for high temperature proton exchange membrane fuel cell prepared by catalyst coating membrane method

    NASA Astrophysics Data System (ADS)

    Liang, Huagen; Su, Huaneng; Pollet, Bruno G.; Linkov, Vladimir; Pasupathi, Sivakumar

    2014-11-01

    In this work, membrane electrode assemblies (MEAs) prepared by catalyst coating membrane (CCM) method are investigated for reduced platinum (Pt) loading and improved Pt utilization of high temperature proton exchange membrane fuel cell (PEMFC) based on phosphoric acid (PA)-doped poly(2,5-benzimidazole) (AB-PBI) membrane. The results show that CCM method exhibits significantly higher cell performance and Pt-specific power density than that of MEAs prepared with conventional gas diffusion electrode (GDE) under a low Pt loading level. In-suit cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) show that the MEAs prepared by the CCM method have a higher electrochemical surface area (ECSA), low cell ohmic resistance and low charge transfer resistance as compared to those prepared with GDEs at the same Pt loading.

  7. Lewis Base Catalysts 6: Carbene Catalysts

    PubMed Central

    Moore, Jennifer L.

    2013-01-01

    The use of N-heterocyclic carbenes as catalysts for organic transformations has received increased attention in the past 10 years. A discussion of catalyst development and nucleophilic characteristics precedes a description of recent advancements and new reactions using N-heterocyclic carbenes in catalysis. PMID:21494949

  8. 20 CFR 404.1675 - Finding of substantial failure.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Finding of substantial failure. 404.1675... DISABILITY INSURANCE (1950- ) Determinations of Disability Substantial Failure § 404.1675 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  9. 20 CFR 416.1075 - Finding of substantial failure.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Finding of substantial failure. 416.1075... AGED, BLIND, AND DISABLED Determinations of Disability Substantial Failure § 416.1075 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  10. 20 CFR 404.1675 - Finding of substantial failure.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Finding of substantial failure. 404.1675... DISABILITY INSURANCE (1950- ) Determinations of Disability Substantial Failure § 404.1675 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  11. 20 CFR 416.1075 - Finding of substantial failure.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Finding of substantial failure. 416.1075... AGED, BLIND, AND DISABLED Determinations of Disability Substantial Failure § 416.1075 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  12. 20 CFR 404.1675 - Finding of substantial failure.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Finding of substantial failure. 404.1675... DISABILITY INSURANCE (1950- ) Determinations of Disability Substantial Failure § 404.1675 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  13. 20 CFR 416.1075 - Finding of substantial failure.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Finding of substantial failure. 416.1075... AGED, BLIND, AND DISABLED Determinations of Disability Substantial Failure § 416.1075 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  14. 20 CFR 404.1675 - Finding of substantial failure.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Finding of substantial failure. 404.1675... DISABILITY INSURANCE (1950- ) Determinations of Disability Substantial Failure § 404.1675 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  15. 20 CFR 416.1075 - Finding of substantial failure.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Finding of substantial failure. 416.1075... AGED, BLIND, AND DISABLED Determinations of Disability Substantial Failure § 416.1075 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  16. 20 CFR 404.1675 - Finding of substantial failure.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Finding of substantial failure. 404.1675... DISABILITY INSURANCE (1950- ) Determinations of Disability Substantial Failure § 404.1675 Finding of substantial failure. A finding of substantial failure with respect to a State may not be made unless and...

  17. Dehydration of glycerol over niobia-supported silicotungstic acid catalysts.

    PubMed

    Lee, Young Yi; Ok, Hye Jeong; Moon, Dong Ju; Kim, Jong Ho; Park, Nam Cook; Kim, Young Chul

    2013-01-01

    Liquid-phase dehydration of glycerol to acrolein over nanosized niobia-supported silicotungstic acid catalysts was performed to investigate the effect of the silicotungstic acid loading on the catalytic performance of the catalysts. The catalysts were prepared by following an impregnation method with different HSiW loadings in the range of 10-50 wt%. The prepared catalysts were characterized by N2 physisorption, XRD, FT-IR, TPD of ammonia, and TGA. Dehydration of glycerol was conducted in an autoclave reactor under the conditions of controlled reaction temperatures under corresponding pressure. Increasing HSiW loading rapidly increased the acidity of HSiW/Nb205 catalyst and rate of glycerol conversion, but acrolein selectivity decreased due to enhanced deactivation of the catalyst by carbon deposit. Consequently, it was confirmed that catalytic activity for the dehydration of glycerol to acrolein was dependant on the acidity of catalyst and can be controlled by HSiW loading. PMID:23646735

  18. Environmentally benign production of biodiesel using heterogeneous catalysts.

    PubMed

    Hara, Michikazu

    2009-01-01

    Fuelling the future: The production of esters of higher fatty acids from plant materials is of great interest for the manufacture of biodiesel. Heterogeneous catalysts can provide new routes for the environmentally benign production of biodiesel. Particulate heterogeneous catalysts can be readily separated from products following reaction allowing the catalyst to be reused, generating less waste, and consuming less energy. Diesel engines are simple and powerful, and exhibit many advantages in energy efficiency and cost. Therefore, the production of higher fatty acid esters from plant materials has become of interest in recent years for the manufacture of biodiesel, a clean-burning alternative fuel. The industrial production of biodiesel mostly proceeds in the presence of "soluble" catalysts such as alkali hydroxides and liquid acids. A considerable amount of energy is required for the purification of products and catalyst separation, and furthermore these catalysts are not reusable. This process results in substantial energy wastage and the production of large amounts of chemical waste. Particulate heterogeneous catalysts can be readily separated from products following reaction, allowing the catalyst to be reused and consuming less energy. This Minireview describes the environmentally benign production of biodiesel using heterogeneous catalysts such as solid bases, acid catalysts, and immobilized enzymes. PMID:19180600

  19. System for reactivating catalysts

    SciTech Connect

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  20. Development of a stable cobalt-ruthenium Fisher-Tropsch catalyst. Final report

    SciTech Connect

    Frame, R.R.; Gala, H.B.

    1995-02-01

    The reverse micelle catalyst preparation method has been used to prepare catalysts on four supports: magnesium oxide, carbon, alumina- titania and steamed Y zeolite. These catalysts were not as active as a reference catalyst prepared during previous contracts to Union Carbide Corp. This catalyst was supported on steamed Y zerolite support and was impregnated by a pore-filling method using a nonaqueous solvent. Additional catalysts were prepared via pore- filling impregnation of steamed Y zeolites. These catalysts had levels of cobalt two to three and a half times as high as the original Union Carbide catalyst. On a catalyst volume basis they were much more active than the previous catalyst; on an atom by atom basis the cobalt was about of the same activity, i.e., the high cobalt catalysts` cobalt atoms were not extensively covered over and deactivated by other cobalt atoms. The new, high activity, Y zerolite catalysts were not as stable as the earlier Union Carbide catalyst. However, stability enhancement of these catalysts should be possible, for instance, through adjustment of the quantity and/or type of trace metals present. A primary objective of this work was determination whether small amounts of ruthenium could enhance the activity of the cobalt F-T catalyst. The reverse micelle catalysts were not activated by ruthenium, indeed scanning transmission electronic microscopy (STEM) analysis provided some evidence that ruthenium was not present in the cobalt crystallites. Ruthenium did not seem to activate the high cobalt Y zeolite catalyst either, but additional experiments with Y zeolite-supported catalysts are required. Should ruthenium prove not to be an effective promoter under the simple catalyst activation procedure used in this work, more complex activation procedures have been reported which are claimed to enhance the cobalt/ruthenium interaction and result in activity promotion by ruthenium.

  1. STUDY OF SOLVENT AND CATALYST INTERACTIONS IN DIRECT COAL LIQUEFACTION

    SciTech Connect

    Michael T. Klein

    1998-10-01

    Major objectives of the present project are to develop a better understanding of the roles of the catalyst and the liquefaction solvent in the coal liquefaction process. An open question concerning the role of the catalyst is whether intimate contact between the catalyst and the coal particles is important or required. To answer this question, it had been planned to coat an active catalyst with a porous silica coating which was found to retain catalyst activity while preventing actual contact between catalyst and coal. Consultation with people in DuPont who coat catalysts for increasing abrasion resistance have indicated that only portions of the catalyst are coated by their process (spray drying) and that sections of uncoated catalyst remain. For that reason, it was decided to suspend the catalyst in a basket separated from the coal in the reactor. The basket walls were to be permeable to the liquefaction solvent but not to the coal particles. Several such baskets were constructed of stainless steel with holes which would not permit passage of coal particles larger than 30 mesh. Liquefactions run with the coal of greater than 30 mesh size gave normal conversion of coal to liquid in the absence of catalyst in the basket, but substantially increased conversion when Ni/Mo on alumina catalyst was in the basket. While this result is interesting and suggestive of some kind of mass transfer of soluble material occurring between the catalyst and the coal, it does not eliminate the possibility of breakdown of the coal particle into particle sizes permeable to the basket. Indeed, a small amount of fine coal has been found inside the basket. To determine whether fine coal from breakdown of the coal particles is responsible for the conversion, a new basket is being prepared with 0.5{micro}m pore size.

  2. Enhanced oxidation of Si using low-temperature oxidation catalyst SrTi1‑ x Mg x O3‑δ

    NASA Astrophysics Data System (ADS)

    Li, Li; Ikeda, Akihiro; Asano, Tanemasa

    2016-06-01

    We newly propose the use of functional oxide to produce O* radicals in an oxidation furnace for the application to oxidation of semiconductor at low temperatures. SrTi1‑ x Mg x O3‑δ is prepared and placed together with a Si wafer in an electric furnace to perform oxidation of Si in flowing O2 under the atmospheric pressure. X-ray diffraction and gas desorption analyses show that SrTi1‑ x Mg x O3‑δ contains oxygen vacancies and emits atomic oxygen at temperatures above 400 °C. Growth rate of SiO2 at the Si surface is shown to be increased by placing SrTi1‑ x Mg x O3‑δ with Si and the rate increases with increasing the composition x of the oxide. It is also shown that the activation energies of the linear and parabolic rate constants in the Deal–Grove oxidation model is reduced by using SrTi1‑ x Mg x O3‑δ oxidation catalyst.

  3. Three-dimensional N,B-doped graphene aerogel as a synergistically enhanced metal-free catalyst for the oxygen reduction reaction.

    PubMed

    Xu, Congcong; Su, Yan; Liu, Dajun; He, Xingquan

    2015-10-14

    Here, a novel N,B-doped graphene aerogel, abbreviated as N,B-GA, was obtained via a two-step approach and served as a metal-free catalyst for the oxygen reduction reaction (ORR). This two-step method involved a hydrothermal reaction and a pyrolysis procedure, guaranteeing the efficient insertion of the heteroatoms. The resulting three-dimensional (3D) N,B-GA obtained at pyrolysis temperature of 1000 °C exhibited outstanding catalytic activity for the oxygen reduction reaction (ORR), comparable to that of Pt/C. In addition, the catalytic activity of this 3D N,B-GA was obviously better than that of the nitrogen-doped graphene aerogel (N-GA) and boron-doped graphene aerogel (B-GA) in terms of the onset potential, half-wave potential and diffusion limiting current density. The superior catalytic reactivity arises from the synergistic coupling of the B and N dopants within the graphene domains. PMID:26364585

  4. Enhanced photocatalytic activity of hydrothermally grown BiFeO3 nanostructures and role of catalyst recyclability in photocatalysis based on magnetic framework

    NASA Astrophysics Data System (ADS)

    Dhanalakshmi, Radhalayam; Muneeswaran, M.; Vanga, Pradeep Reddy; Ashok, M.; Giridharan, N. V.

    2016-01-01

    The photocatalytic activity of bismuth ferrite (BiFeO3: BFO) nanostructures on the degradation of methyl violet 2B (MV) is demonstrated for the first time under sunlight irradiation with the efficiency of 97.6 %. The photocatalytic BFO nanostructures have been successfully synthesized through hydrothermal method. Initial characterization of BFO nanostructures such as structural, functional, morphological, optical, and magnetic properties has been performed. From the X-ray diffraction analysis, the synthesized nanostructures are found to have rhombohedral structure with R3c space group confirmed by Rietveld analysis. The formation of perovskite structure is confirmed through FTIR analysis. Nanostructures were found to have rod-like morphology with the length between 15 and 20 nm and diameter of about 2-3 nm measured through HR-TEM. The surface area and N2 adsorption-desorption isotherms have been preformed through BET analysis. The optical band gap investigation shows that the E g value of BFO is about 2.1 eV. The magnetization measurements revealed a weak ferromagnetic behavior at room temperature, and the same has been confirmed through ABK plot. The photocatalytic activity of BFO is tested on the degradation of harmful MV dye under the irradiation of direct sunlight, influences of oxygen, and hydrogen peroxide. The photodecomposition kinetics of MV has been described through Langmuir-Hinshelwood model. The stability and recyclability of catalyst have also been studied.

  5. Catalyst patterning for nanowire devices

    NASA Technical Reports Server (NTRS)

    Li, Jun (Inventor); Cassell, Alan M. (Inventor); Han, Jie (Inventor)

    2004-01-01

    Nanowire devices may be provided that are based on carbon nanotubes or single-crystal semiconductor nanowires. The nanowire devices may be formed on a substrate. Catalyst sites may be formed on the substrate. The catalyst sites may be formed using lithography, thin metal layers that form individual catalyst sites when heated, collapsible porous catalyst-filled microscopic spheres, microscopic spheres that serve as masks for catalyst deposition, electrochemical deposition techniques, and catalyst inks. Nanowires may be grown from the catalyst sites.

  6. Oral administration of SR-110, a peroxynitrite decomposing catalyst, enhances glucose homeostasis, insulin signaling, and islet architecture in B6D2F1 mice fed a high fat diet.

    PubMed

    Johns, Michael; Esmaeili Mohsen Abadi, Sakineh; Malik, Nehal; Lee, Joshua; Neumann, William L; Rausaria, Smita; Imani-Nejad, Maryam; McPherson, Timothy; Schober, Joseph; Kwon, Guim

    2016-04-15

    Peroxynitrite has been implicated in type 2 diabetes and diabetic complications. As a follow-up study to our previous work on SR-135 (Arch Biochem Biophys 577-578: 49-59, 2015), we provide evidence that this series of compounds are effective when administered orally, and their mechanisms of actions extend to the peripheral tissues. A more soluble analogue of SR-135, SR-110 (from a new class of Mn(III) bis(hydroxyphenyl)-dipyrromethene complexes) was orally administered for 2 weeks to B6D2F1 mice fed a high fat-diet (HFD). Mice fed a HFD for 4 months gained significantly higher body weights compared to lean diet-fed mice (52 ± 1.5 g vs 34 ± 1.3 g). SR-110 (10 mg/kg daily) treatment significantly reduced fasting blood glucose and insulin levels, and enhanced glucose tolerance as compared to HFD control or vehicle (peanut butter) group. SR-110 treatment enhanced insulin signaling in the peripheral organs, liver, heart, and skeletal muscle, and reduced lipid accumulation in the liver. Furthermore, SR-110 increased insulin content, restored islet architecture, decreased islet size, and reduced tyrosine nitration. These results suggest that a peroxynitrite decomposing catalyst is effective in improving glucose homeostasis and restoring islet morphology and β-cell insulin content under nutrient overload. PMID:26970045

  7. Process for the regeneration of metallic catalysts

    DOEpatents

    Katzer, James R.; Windawi, Hassan

    1981-01-01

    A method for the regeneration of metallic hydrogenation catalysts from the class consisting of Ni, Rh, Pd, Ir, Pt and Ru poisoned with sulfur, with or without accompanying carbon deposition, comprising subjecting the catalyst to exposure to oxygen gas in a concentration of about 1-10 ppm. intermixed with an inert gas of the group consisting of He, A, Xe, Kr, N.sub.2 and air substantially free of oxygen to an extent such that the total oxygen molecule throughout is in the range of about 10 to 20 times that of the hydrogen sulfide molecular exposure producing the catalyst poisoning while maintaining the temperature in the range of about 300.degree. to 500.degree. C.

  8. Recombination Catalysts for Hypersonic Fuels

    NASA Technical Reports Server (NTRS)

    Chinitz, W.

    1998-01-01

    The goal of commercially-viable access to space will require technologies that reduce propulsion system weight and complexity, while extracting maximum energy from the products of combustion. This work is directed toward developing effective nozzle recombination catalysts for the supersonic and hypersonic aeropropulsion engines used to provide such access to space. Effective nozzle recombination will significantly reduce rk=le length (hence, propulsion system weight) and reduce fuel requirements, further decreasing the vehicle's gross lift-off weight. Two such catalysts have been identified in this work, barium and antimony compounds, by developing chemical kinetic reaction mechanisms for these materials and determining the engine performance enhancement for a typical flight trajectory. Significant performance improvements are indicated, using only 2% (mole or mass) of these compounds in the combustor product gas.

  9. Textured catalysts and methods of making textured catalysts

    DOEpatents

    Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.

    2007-03-06

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  10. Enhanced catalytic performance in hydrogen generation from NaBH4 hydrolysis by super porous cryogel supported Co and Ni catalysts

    NASA Astrophysics Data System (ADS)

    Seven, Fahriye; Sahiner, Nurettin

    2014-12-01

    The neutral 3-D superporous cryogel is prepared from a poly(acrylamide) (p(AAm)) hydrogel network modified with an amidoximation reaction to induce chemical changes to produce superporous amidoximated-p(AAm) (amid-p(AAm)) cryogel. The newly-formed strongly ionizable matrices can readily absorb metal ions such as Co(II) and Ni(II) enabling in situ preparation of corresponding metal nanoparticles by NaBH4 treatments. It is found that the superporous amid-p(AAm)-Co cryogel composite is very effective as a catalyst for H2 generation from hydrolysis of NaBH4 in alkaline medium. Furthermore, it is demonstrated that the metal ion loading capacity and catalytic activity of superporous amid-p(AAm)-Co cryogel composites increased with 2nd and 3rd Co(II) ion loading and reduction cycles. The hydrogen generation rate of p(AAm)-Co metal composites is increased to 1926.3 ± 1.1 from 1130.2 ± 1.5 (mL H2) (min)-1 (g of M)-1. The effect of various parameters such as porosity, metal type, the number of reloading and reduction cycles of the metal ion, and temperature are investigated for the hydrolysis of NaBH4. The kinetic parameters such as energy, enthalpy and entropy are determined as Ea = 39.7 ± 0.2 kJ mol-1, ΔH = 37.2 ± 0.1 kJ mol-1 and ΔS = -171.9 ± 0.5 J mol-1 K-1, respectively.

  11. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.

    1990-06-17

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  12. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.; Patel, S.A.; Dalai, A.K.; Jayanthi, G.; Ledakowicz, S.

    1990-04-30

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  13. Methanol Oxidation Using Ozone on Titania-Supported Vanadium Catalyst

    EPA Science Inventory

    Ozone-enhanced catalytic oxidation of methanol has been conducted at mild temperatures of 100 to 250NC using V2O5/TiO2 catalyst prepared by the sol-gel method. The catalyst was characterized using XRD, surface area measurements, and temperature-programmed desorption of methanol. ...

  14. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.

    1992-01-10

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  15. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.; Patel, S.A.

    1990-01-15

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  16. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.

    1991-10-28

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  17. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.

    1990-10-29

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  18. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.

    1991-07-19

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  19. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.

    1991-04-24

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  20. Development of improved iron Fischer-Tropsch catalysts

    SciTech Connect

    Bukur, D.B.

    1991-01-25

    The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.

  1. The Nature and Substantiation of Official Sexual Abuse Reports.

    ERIC Educational Resources Information Center

    Eckenrode, John; And Others

    1988-01-01

    A sample of 796 New York sexual abuse reports was studied to explore factors associated with substantiation of the reports following an investigation. Substantiation rates increased with the child's age, and reports were more likely to be substantiated when they involved female children or came from a mandated source. (Author/JDD)

  2. 24 CFR 907.3 - Bases for substantial default.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Bases for substantial default. 907.3 Section 907.3 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT... DEVELOPMENT SUBSTANTIAL DEFAULT BY A PUBLIC HOUSING AGENCY § 907.3 Bases for substantial default....

  3. 19 CFR 10.7 - Substantial containers or holders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Substantial containers or holders. 10.7 Section 10... Exported and Returned § 10.7 Substantial containers or holders. (a) Substantial containers or holders... domestic products exported and returned. When such containers or holders are imported not containing...

  4. 29 CFR 825.218 - Substantial and grievous economic injury.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Substantial and grievous economic injury. 825.218 Section... Medical Leave Act § 825.218 Substantial and grievous economic injury. (a) In order to deny restoration to... cause “substantial and grievous economic injury” to the operations of the employer, not whether...

  5. 29 CFR 825.218 - Substantial and grievous economic injury.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Substantial and grievous economic injury. 825.218 Section... Medical Leave Act § 825.218 Substantial and grievous economic injury. (a) In order to deny restoration to... cause “substantial and grievous economic injury” to the operations of the employer, not whether...

  6. 29 CFR 825.218 - Substantial and grievous economic injury.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Substantial and grievous economic injury. 825.218 Section... Medical Leave Act § 825.218 Substantial and grievous economic injury. (a) In order to deny restoration to... cause “substantial and grievous economic injury” to the operations of the employer, not whether...

  7. 29 CFR 825.218 - Substantial and grievous economic injury.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Substantial and grievous economic injury. 825.218 Section... Medical Leave Act § 825.218 Substantial and grievous economic injury. (a) In order to deny restoration to... cause substantial and grievous economic injury to the operations of the employer, not whether...

  8. 29 CFR 825.218 - Substantial and grievous economic injury.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Substantial and grievous economic injury. 825.218 Section... Medical Leave Act § 825.218 Substantial and grievous economic injury. (a) In order to deny restoration to... cause substantial and grievous economic injury to the operations of the employer, not whether...

  9. Catalyst for Carbon Monoxide Oxidation

    NASA Technical Reports Server (NTRS)

    Davis, Patricia; Brown, Kenneth; VanNorman, John; Brown, David; Upchurch, Billy; Schryer, David; Miller, Irvin

    2010-01-01

    catalyst composition in an amount of about 5 to 25 (especially 7) percent by weight, SnO2 is present in an amount of about 30 to 40 (especially 40) percent by weight, and silica gel is present in an amount of 45 to 55 (especially 50) percent by weight. The composition of this catalyst was suggested by preliminary experiments in which a Pt/SnO2 catalyst was needed for bound water to enhance its activity. These experimental results suggested that if the water were bound to the surface, this water would enhance and prolong catalyst activity for long time periods. Because the catalyst is to be exposed to a laser gas mixture, and because a CO2 laser can tolerate only a very small amount of moisture, a hygroscopic support for the catalyst would provide the needed H2O into the gas. Silica gel is considered to be superior because of its property to chemisorb water on its surface over a wide range of moisture content.

  10. Synthesis and characterization of g-C{sub 3}N{sub 4}/Cu{sub 2}O composite catalyst with enhanced photocatalytic activity under visible light irradiation

    SciTech Connect

    Peng, Biyu; Zhang, Shengsen; Yang, Siyuan; Wang, Hongjuan; Yu, Hao; Zhang, Shanqing; Peng, Feng

    2014-08-15

    The prepared g-C{sub 3}N{sub 4}/Cu{sub 2}O composite exhibited the enhanced photocatalytic activity under visible-light irradiation due to the stronger ability in separation of electron–hole pairs, which was proven by the transient photocurrent measurement. - Highlights: • The coupled Cu{sub 2}O with g-C{sub 3}N{sub 4} of narrow-band-gap semiconductor has been designed. • g-C{sub 3}N{sub 4}/Cu{sub 2}O is prepared via an alcohol-aqueous based on chemical precipitation method. • g-C{sub 3}N{sub 4}/Cu{sub 2}O exhibits the enhanced photocatalytic activity under visible-light. • The enhanced photocatalytic activity is proven by the transient photocurrent test. • A mechanism for the visible-light-driven photocatalysis of g-C{sub 3}N{sub 4}/Cu{sub 2}O is revealed. - Abstract: To overcome the drawback of low photocatalytic efficiency brought by electron–hole pairs recombination and narrow photo-response range, a novel g-C{sub 3}N{sub 4}/Cu{sub 2}O composite photocatalyst was designed and prepared successfully. Compared with bare Cu{sub 2}O and g-C{sub 3}N{sub 4}, the g-C{sub 3}N{sub 4}/Cu{sub 2}O composite exhibited significantly enhanced photocatalytic activity for acid orange-II (AO-II) degradation under visible light irradiation. Based on energy band positions, the mechanism of enhanced visible-light photocatalytic activity was proposed.

  11. Methods of making textured catalysts

    DOEpatents

    Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.

    2010-08-17

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  12. Catalyst Alloys Processing

    NASA Astrophysics Data System (ADS)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  13. Enhanced Activity of CuCeO Catalysts for CO Oxidation: Influence of Cu2O and the Dispersion of Cu2O, CuO, and CeO2.

    PubMed

    Wang, Zhenhua; Li, Ren; Chen, Qianwang

    2015-08-01

    CuCeO catalysts prepared by a hydrothermal method with subsequent calcination are tested for the catalytic oxidation of CO. This synthesis method leads to a homogeneous dispersion of Cu2 O, CuO, and CeO2 in the catalysts. The composition of the catalysts is determined by the molar ratio of the metals, the hydrothermal process, and calcination temperature and influences the catalytic performance. The catalyst containing Cu2 O exhibits high catalytic activity with almost 100 % CO conversion at 105 °C and shows excellent stability with the conversion ratio not decreasing after four months of storage. PMID:26017784

  14. DEVELOPMENT OF TRANSITION METAL OXIDE-ZEOLITE CATALYSTS TO CONTROL CHLORINATED VOC AIR EMISSIONS

    EPA Science Inventory

    The paper discusses the development of transition metal oxide (TMO)-zeolite oxidation catalysts to control chlorinated volatile organic compound (CVOC) air emissions. esearch has been initiated to enhance the utility of these catalysts by the development of a sorption-catalyst sy...

  15. METHOD OF PURIFYING CATALYSTS

    DOEpatents

    Joris, G.G.

    1958-09-01

    It has been fuund that the presence of chlorine as an impurity adversely affects the performance of finely divided platinum catalysts such as are used in the isotopic exchange process for the production of beavy water. This chlorine impurity may be removed from these catalysts by treating the catalyst at an elevated temperature with dry hydrogen and then with wet hydrogen, having a hydrogen-water vapor volume of about 8: 1. This alternate treatment by dry hydrogen and wet hydrogen is continued until the chlorine is largely removed from the catalyst.

  16. Polyolefin catalyst manufacturing

    SciTech Connect

    Inkrott, K.E.; Scinta, J.; Smith, P.D. )

    1989-10-16

    Statistical process control (SPC) procedures are absolutely essential for making new-generation polyolefin catalysts with the consistent high quality required by modern polyolefin processes. Stringent quality assurance is critical to the production of today's high-performance catalysts. Research and development efforts during the last 20 years have led to major technological improvements in the polyolefin industry. New generation catalysts, which once were laboratory curiosities, must now be produced commercially on a regular and consistent basis to meet the increasing requirements of the plastics manufacturing industry. To illustrate the more stringent requirements for producing the new generation polyolefin catalysts, the authors compare the relatively simple, first-generation polypropylene catalyst production requirements with some of the basic requirements of manufacturing a more complex new-generation catalyst, such as Catalyst Resources Inc.'s LYNX 900. The principles which hold true for the new-generation catalysts such as LYNX 900 are shown to apply equally to the scale-up of other advanced technology polyolefin catalysts.

  17. Liquefaction with microencapsulated catalysts

    DOEpatents

    Weller, Sol W.

    1985-01-01

    A method of dispersing a liquefaction catalyst within coal or other carbonaceous solids involves providing a suspension in oil of microcapsules containing the catalyst. An aqueous solution of a catalytic metal salt is emulsified in the water-immiscible oil and the resulting minute droplets microencapsulated in polymeric shells by interfacial polycondensation. The catalyst is subsequently blended and dispersed throughout the powdered carbonaceous material to be liquefied. At liquefaction temperatures the polymeric microcapsules are destroyed and the catalyst converted to minute crystallites in intimate contact with the carbonaceous material.

  18. Catalyst dispersion and activity under conditions of temperature- staged liquefaction. Technical progress report, January--March 1992

    SciTech Connect

    Davis, A.; Schobert, H.H.; Mitchell, G.D.; Artok, L.

    1992-07-01

    Two coals, a Texas subbituminous C and a Utah high volatile A bituminous, were used to examine the effects of solvent swelling and catalyst impregnation on liquefaction conversion behavior in temperature staged reactions for 30 minutes each at 275{degree} and 425{degree}C in H{sub 2} and 95:5 H{sub 2}:H{sub 2}S atmospheres. Methanol, pyridine, tetrahydrofuran, and tetrabutylammonium hydroxide were used as swelling agents. Molybdenum-based catalyst precursors were ammonium tetrathiomolybdate, molybdenum trisulfide, molybdenum hexacarbonyl, and bis(tricarbonylcyclopentadienyl-molybdenum). Ferrous sulfate and bis(dicarbonylcyclo-pentadienyliron) served as iron-based catalyst precursors. In addition, ion exchange was used for loading iron onto the subbituminous coal. For most experiments, liquefaction in H{sub 2}:H{sub 2}S was superior to that in H{sub 2}, regardless of the catalyst precursor. The benefit of the H{sub 2}S was greater for the subbituminous, presumably because of its higher iron content relative to the hvab coal. Tetrabutylammonium hydroxide was the only swelling agent to enhance conversion of the hvab coal significantly; it also caused a remarkable increase in conversion of the subbituminous coal. The combined application of solvent swelling and catalyst impregnation also improves liquefaction, mainly through increased oil yields from the hvab coal and increased asphaltenes from the subbituminous. A remarkable effect from use of ammonium tetrathiomolybdate as a catalyst precursor is substantial increase in pristane and phytane yields. Our findings suggest that these compounds are, at least in part, bound to the coal matrix.

  19. Power generation using spinel manganese-cobalt oxide as a cathode catalyst for microbial fuel cell applications.

    PubMed

    Mahmoud, Mohamed; Gad-Allah, Tarek A; El-Khatib, K M; El-Gohary, Fatma

    2011-11-01

    This study focused on the use of spinel manganese-cobalt (Mn-Co) oxide, prepared by a solid state reaction, as a cathode catalyst to replace platinum in microbial fuel cells (MFCs) applications. Spinel Mn-Co oxides, with an Mn/Co atomic ratios of 0.5, 1, and 2, were prepared and examined in an air cathode MFCs which was fed with a molasses-laden synthetic wastewater and operated in batch mode. Among the three Mn-Co oxide cathodes and after 300 h of operation, the Mn-Co oxide catalyst with Mn/Co atomic ratio of 2 (MnCo-2) exhibited the highest power generation 113 mW/m2 at cell potential of 279 mV, which were lower than those for the Pt catalyst (148 mW/m2 and 325 mV, respectively). This study indicated that using spinel Mn-Co oxide to replace platinum as a cathodic catalyst enhances power generation, increases contaminant removal, and substantially reduces the cost of MFCs. PMID:21944282

  20. Efficient sulfur-tolerant bimetallic catalysts for hydrogen generation from diesel fuel

    NASA Astrophysics Data System (ADS)

    Cheekatamarla, Praveen K.; Lane, Alan M.

    Catalytic autothermal reforming (ATR) of synthetic diesel and JP8 over supported metal catalysts has been investigated in the present study. Bimetallic catalysts exhibited superior performance compared to the commercial catalyst and the monometallic counterparts. BET, temperature-programmed desorption (TPD), temperature-programmed reduction (TPR) and XPS were utilized for characterizing these formulations, which showed that the enhanced stability is due to a strong metal-metal and metal-support interaction in the catalyst.

  1. Core-shell nanostructured catalysts.

    PubMed

    Zhang, Qiao; Lee, Ilkeun; Joo, Ji Bong; Zaera, Francisco; Yin, Yadong

    2013-08-20

    excellent catalytic activity for the oxidation of organic compounds under UV, visible, and direct sunlight. The enhanced photocatalytic efficiency of this nanostructure resulted from an added interfacial nonmetal doping, which improved visible light absorption, and from plasmonic metal decoration that enhanced light harvesting and charge separation. In addition to our synthetic efforts, we have developed ways to evaluate the accessibility of reactants to the metal cores and to characterize the catalytic properties of the core-shell samples we have synthesized. We have adapted infrared absorption spectroscopy and titration experiments using carbon monoxide and other molecules as probes to study adsorption on the surface of metal cores in metal oxide-shell structures in situ in both gas and liquid phases. In particular, the experiments in solution have provided insights into the ease of diffusion of molecules of different sizes in and out of the shells in these catalysts. PMID:23268644

  2. Combinatorial synthesis and screening of fuel cell catalysts

    NASA Astrophysics Data System (ADS)

    Jayaraman, Shrisudersan

    Polymer electrolyte membrane fuel cells (PEMFCs) are compact power sources that can operate with high efficiencies and low emission of environmentally harmful gases. One of the major barriers impeding the development of PEMFCs as a competitive energy source is the inability of existing anode catalysts to oxidize fuels other than hydrogen at sufficient levels due to catalyst deactivation by carbon monoxide (CO) and other partial oxidation products. The focus of this research is the development and application of combinatorial strategies to construct and interrogate electrooxidation (anode) catalysts pertaining to PEMFCs to discover catalysts with enhanced performance in catalyst deactivating environments. A novel method (known as the "gel-transfer" method) for synthesizing catalyst composition gradient libraries for combinatorial catalyst discovery was developed. This method involved transferring a spatial concentration gradient of precursor metal salts created within a polymer gel on to a solid conducting substrate by electrochemical reduction. Chemically sensitive surface-imaging techniques, namely, scanning electrochemical microscopy (SECM) and optical screening with a pH-dependent fluorescence probe were used to characterize the combinatorial catalyst samples. The utility of SECM as a screening tool to measure the activity of multicomponent catalyst libraries towards fuel cell electrooxidation reactions was established with simple catalyst libraries including a platinum coverage gradient and platinum-ruthenium and platinum-ruthenium-molybdenum arrays. A platinum-ruthenium surface composition gradient was constructed through the gel-transfer method and its reactivity towards hydrogen oxidation in the presence of a catalyst poison (CO) was mapped using the SECM. Ruthenium composition between 20 and 30% exhibited superior performance than the rest of the binary. The gel-transfer method was extended to construct a ternary platinum-ruthenium-rhodium catalyst library

  3. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2015-09-29

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  4. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2012-10-02

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  5. Fischer-Tropsch Catalysts

    NASA Technical Reports Server (NTRS)

    White, James H. (Inventor); Taylor, Jesse W. (Inventor)

    2008-01-01

    Catalyst compositions and methods for F-T synthesis which exhibit high CO conversion with minor levels (preferably less than 35% and more preferably less than 5%) or no measurable carbon dioxide generation. F-T active catalysts are prepared by reduction of certain oxygen deficient mixed metal oxides.

  6. Improved zeolitic isocracking catalysts

    SciTech Connect

    Dahlberg, A.J.; Habib, M.M.; Moore, R.O.; Law, D.V.; Convery, L.J.

    1995-09-01

    Chevron Research Company introduced the first low pressure, low temperature catalytic hydrocracking process--ISOCRACKING--in 1959. Within the last four years, Chevron has developed and commercialized three new zeolitic ISOCRACKING catalysts. ICR 209 is Chevron`s latest noble metal ISOCRACKING catalyst. It offers improved liquid yield stability, longer life, and superior polynuclear aromatics control compared to its predecessor. ICR 209`s high hydrogenation activity generates the highest yields of superior quality jet fuel of any zeolitic ISOCRACKING catalyst. The second new ISOCRACKING catalyst, ICR 208, is a base metal catalyst which combines high liquid selectivity and high light naphtha octane in hydrocrackers operating for maximum naphtha production. ICR 210 is another new base metal catalyst which offers higher liquid yields and longer life than ICR 208 by virtue of a higher hydrogenation-to-acidity ratio. Both ICR 208 and ICR 210 have been formulated to provide higher liquid yield throughout the cycle and longer cycle length than conventional base metal/zeolite catalysts. This paper will discuss the pilot plant and commercial performances of these new ISOCRACKING catalysts.

  7. Enhanced stability of CaO and/or La2O3 promoted Pd/Al2O3 egg-shell catalysts in partial oxidation of methane to syngas.

    PubMed

    Wang, Jinlong; Yu, Hongbo; Ma, Zhen; Zhou, Shenghu

    2013-01-01

    An egg-shell Pd/Al2O3 catalyst showed higher activity than a regular Pd/Al2O3 catalyst in the partial oxidation of methane to syngas, but a common problem of this reaction is the catalyst deactivation on stream. We attempted to modify the egg-shell catalyst via impregnation with some metal oxide additives. Although the addition of MgO did not show any beneficial effect, the addition of CaO and/or La2O3 significantly improved the stability due to the suppression of carbon deposition and phase transformation of the Al2O3 support. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and thermogravimetric analysis (TGA). PMID:23860276

  8. Improved catalysts and method

    SciTech Connect

    Taylor, C.E.; Noceti, R.P.

    1990-12-31

    An improved catalyst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HCl and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride. 8 figs., 3 tabs.

  9. 49 CFR 384.301 - Substantial compliance-general requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 CFR 383.123 not later than September 30, 2006. (c) A State must come into substantial compliance... statutes, regulations, administrative procedures and practices, organizational structures, internal...

  10. 49 CFR 384.301 - Substantial compliance-general requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., organizational structures, internal control mechanisms, resource assignments (facilities, equipment, and... come into substantial compliance with 49 CFR 383.123 not later than September 30, 2006. (c) A...

  11. 49 CFR 384.301 - Substantial compliance-general requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., organizational structures, internal control mechanisms, resource assignments (facilities, equipment, and... come into substantial compliance with 49 CFR 383.123 not later than September 30, 2006. (c) A...

  12. 49 CFR 384.301 - Substantial compliance-general requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., organizational structures, internal control mechanisms, resource assignments (facilities, equipment, and... come into substantial compliance with 49 CFR 383.123 not later than September 30, 2006. (c) A...

  13. 49 CFR 384.301 - Substantial compliance-general requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., organizational structures, internal control mechanisms, resource assignments (facilities, equipment, and... come into substantial compliance with 49 CFR 383.123 not later than September 30, 2006. (c) A...

  14. The Constitution of the Human Embryo as Substantial Change.

    PubMed

    Alvargonzález, David

    2016-04-01

    This paper analyzes the transformation from the human zygote to the implanted embryo under the prism of substantial change. After a brief introduction, it vindicates the Aristotelian ideas of substance and accident, and those of substantial and accidental change. It then claims that the transformation from the multicelled zygote to the implanted embryo amounts to a substantial change. Pushing further, it contends that this substantial change cannot be explained following patterns of genetic reductionism, emergence, and self-organization, and proposes Gustavo Bueno's idea of anamorphosis as a means to encapsulate criticism against such positions. PMID:26850033

  15. Enhanced catalyst-free nucleation of GaN nanowires on amorphous Al{sub 2}O{sub 3} by plasma-assisted molecular beam epitaxy

    SciTech Connect

    Sobanska, Marta Klosek, Kamil; Borysiuk, Jolanta; Kret, Slawomir; Tchutchulasvili, Giorgi; Gieraltowska, Sylwia; Zytkiewicz, Zbigniew R.

    2014-01-28

    We report on plasma-assisted molecular beam epitaxial growth of GaN nanowires (NWs) on Si(111) substrates with a thin amorphous Al{sub 2}O{sub 3} buffer layer deposited by atomic layer deposition. Comparison of nucleation kinetics shows that presence of amorphous Al{sub 2}O{sub 3} buffer significantly enhances spontaneous nucleation of GaN NWs. Slower nucleation was observed on partially amorphous silicon nitride films. No growth of NWs was found on sapphire substrate under the same growth conditions which we explain by a low density of defects on monocrystalline substrate surface where NWs may nucleate. Our finding shows that tuning of substrate microstructure is an efficient tool to control rate of self-induced nucleation of GaN NWs.

  16. Towards the Rational Design of Nanoparticle Catalysts

    NASA Astrophysics Data System (ADS)

    Dash, Priyabrat

    This research is focused on development of routes towards the rational design of nanoparticle catalysts. Primarily, it is focused on two main projects; (1) the use of imidazolium-based ionic liquids (ILs) as greener media for the design of quasi-homogeneous nanoparticle catalysts and (2) the rational design of heterogeneous-supported nanoparticle catalysts from structured nanoparticle precursors. Each project has different studies associated with the main objective of the design of nanoparticle catalysts. In the first project, imidazolium-based ionic liquids have been used for the synthesis of nanoparticle catalysts. In particular, studies on recyclability, reuse, mode-of-stability, and long-term stability of these ionic-liquid supported nanoparticle catalysts have been done; all of which are important factors in determining the overall "greenness" of such synthetic routes. Three papers have been published/submitted for this project. In the first publication, highly stable polymer-stabilized Au, Pd and bimetallic Au-Pd nanoparticle catalysts have been synthesized in imidazolium-based 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) ionic liquid (Journal of Molecular Catalysis A: Chemical, 2008, 286, 114). The resulting nanoparticles were found to be effective and selective quasi-homogeneous catalysts towards a wide-range of hydrogenation reactions and the catalyst solution was reused for further catalytic reactions with minimal loss in activity. The synthesis of very pure and clean ILs has allowed a platform to study the effects of impurities in the imidazolium ILs on nanoparticle stability. In a later study, a new mode of stabilization was postulated where the presence of low amounts of 1-methylimidazole has substantial effects on the resulting stability of Au and Pd-Au nanoparticles in these ILs (Chemical Communications, 2009, 812). In further continuation of this study, a comparative study involving four stabilization protocols for nanoparticle

  17. 19 CFR 134.35 - Articles substantially changed by manufacture.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Articles substantially changed by manufacture. 134...; DEPARTMENT OF THE TREASURY COUNTRY OF ORIGIN MARKING Exceptions to Marking Requirements § 134.35 Articles substantially changed by manufacture. (a) Articles other than goods of a NAFTA country. An article used in...

  18. 40 CFR Appendix C to Part 112 - Substantial Harm Criteria

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 22 2014-07-01 2013-07-01 true Substantial Harm Criteria C Appendix C to Part 112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS OIL POLLUTION PREVENTION Pt. 112, App. C Appendix C to Part 112—Substantial Harm Criteria 1.0Introduction The flowchart provided in Attachment C-I...

  19. 40 CFR Appendix C to Part 112 - Substantial Harm Criteria

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Substantial Harm Criteria C Appendix C to Part 112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS OIL POLLUTION PREVENTION Pt. 112, App. C Appendix C to Part 112—Substantial Harm Criteria 1.0Introduction The flowchart provided in Attachment C-I...

  20. 40 CFR Appendix C to Part 112 - Substantial Harm Criteria

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 23 2012-07-01 2012-07-01 false Substantial Harm Criteria C Appendix C to Part 112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS OIL POLLUTION PREVENTION Pt. 112, App. C Appendix C to Part 112—Substantial Harm Criteria 1.0Introduction The flowchart provided in Attachment C-I...

  1. 40 CFR Appendix C to Part 112 - Substantial Harm Criteria

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 22 2011-07-01 2011-07-01 false Substantial Harm Criteria C Appendix C to Part 112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS OIL POLLUTION PREVENTION Pt. 112, App. C Appendix C to Part 112—Substantial Harm Criteria 1.0Introduction The flowchart provided in Attachment C-I...

  2. 40 CFR Appendix C to Part 112 - Substantial Harm Criteria

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 23 2013-07-01 2013-07-01 false Substantial Harm Criteria C Appendix C to Part 112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS OIL POLLUTION PREVENTION Pt. 112, App. C Appendix C to Part 112—Substantial Harm Criteria 1.0Introduction The flowchart provided in Attachment C-I...

  3. 26 CFR 1.528-4 - Substantiality test.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 7 2014-04-01 2013-04-01 true Substantiality test. 1.528-4 Section 1.528-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Homeowners Associations § 1.528-4 Substantiality test. (a) In general. In...

  4. 19 CFR 134.35 - Articles substantially changed by manufacture.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Articles substantially changed by manufacture. 134...; DEPARTMENT OF THE TREASURY COUNTRY OF ORIGIN MARKING Exceptions to Marking Requirements § 134.35 Articles substantially changed by manufacture. (a) Articles other than goods of a NAFTA country. An article used in...

  5. 19 CFR 134.35 - Articles substantially changed by manufacture.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Articles substantially changed by manufacture. 134... substantially changed by manufacture. (a) Articles other than goods of a NAFTA country. An article used in the United States in manufacture which results in an article having a name, character, or use differing...

  6. 19 CFR 134.35 - Articles substantially changed by manufacture.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Articles substantially changed by manufacture. 134... substantially changed by manufacture. (a) Articles other than goods of a NAFTA country. An article used in the United States in manufacture which results in an article having a name, character, or use differing...

  7. 19 CFR 134.35 - Articles substantially changed by manufacture.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Articles substantially changed by manufacture. 134... substantially changed by manufacture. (a) Articles other than goods of a NAFTA country. An article used in the United States in manufacture which results in an article having a name, character, or use differing...

  8. 20 CFR 627.477 - Governor's determination of substantial violation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Governor's determination of substantial... Standards § 627.477 Governor's determination of substantial violation. (a) Except as provided at paragraph (d) of this section, if, as a result of financial and compliance audits or otherwise, the...

  9. Differentiating between substantiated, suspected, and unsubstantiated maltreatment in Canada.

    PubMed

    Trocmé, Nico; Knoke, Della; Fallon, Barbara; MacLaurin, Bruce

    2009-02-01

    The decision to substantiate is a key factor in determining eligibility for services and decisions to press criminal charges or to remove a child, and it is frequently the basis for selecting samples of maltreated children or to measure recidivism or intervention effectiveness. Although there is a growing body of research on case substantiation in the United States, few studies have examined this decision in other jurisdictions. Using data from the 2003 Canadian Incidence Study of Reported Child Abuse and Neglect, this study examines the profiles of a national sample of 10,010 investigations. Multivariate analyses reveal that substantiation decisions are generally made in a fashion that is relatively consistent with the clinical characteristics of cases. Along with severity of harm, parent risk factors, and housing risk factors, police referrals are among the most important predictors of case substantiation. Cases involving multiple forms of maltreatment are also more likely to be substantiated. PMID:18710956

  10. MicroChannel Reactors for ISRU Applications Using Nanofabricated Catalysts

    NASA Astrophysics Data System (ADS)

    Carranza, Susana; Makel, Darby B.; Vander Wal, Randall L.; Berger, Gordon M.; Pushkarev, Vladimir V.

    2006-01-01

    With the new direction of NASA to emphasize the exploration of the Moon, Mars and beyond, quick development and demonstration of efficient systems for In-Situ Resources Utilization (ISRU) is more critical and timely than ever before. Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. This paper presents current development of miniaturized chemical processing systems that combine microchannel reactor design with nanofabricated catalysts. Carbon nanotubes (CNT) are used to produce a nanostructure within microchannel reactors, as support for catalysts. By virtue of their nanoscale dimensions, nanotubes geometrically restrict the catalyst particle size that can be supported upon the tube walls. By confining catalyst particles to sizes smaller than the CNT diameter, a more uniform catalyst particle size distribution may be maintained. The high dispersion permitted by the vast surface area of the nanoscale material serves to retain the integrity of the catalyst by reducing sintering or coalescence. Additionally, catalytic efficiency increases with decreasing catalyst particle size (reflecting higher surface area per unit mass) while chemical reactivity frequently is enhanced at the nanoscale. Particularly significant is the catalyst exposure. Rather than being confined within a porous material or deposited upon a 2-d surface, the catalyst is fully exposed to the reactant gases by virtue of the nanofabricated support structure. The combination of microchannel technology with nanofabricated catalysts provides a synergistic effect, enhancing both technologies with the potential to produce much more efficient systems than either technology alone. The development of highly efficient microchannel reactors will be applicable to multiple ISRU programs. By selection of proper nanofabricated catalysts, the microchannel reactors can be

  11. Autothermal reforming of propane over Ni-based hydrotalcite catalysts.

    PubMed

    Park, Sun-Young; Kim, Jong-Ho; Moon, Dong-Ju; Park, Nam-Cook; Kim, Young-Chul

    2010-05-01

    Ni-based hydrotalcite catalysts were investigated for ATR of propane in a fixed-bed flow reactor. The reactions were carried out with a H2O/C/O2 stream ratio of 3/1/0.73 at temperatures ranging from 300 to 700 degrees C. The solvents used in the manufacture of Ni-based catalysts noble metal/Ni/MgAl catalysts or substituted active material were changed in order to decrease the level of catalyst deactivation. The use of a mixture of ethanol and water during the formation of the Pd-Ni/MgAl catalyst produced a higher hydrogen yield than that using water only. In addition, the use of acetone in the synthesis of Ru-Ni/MgAl catalyst produced a higher hydrogen yield than using water only. This shows that the solvents used for the noble metals affect the degree of dispersion and particle size of the nickel and prevented carbon deposition resulting in the enhanced hydrogen selectivity and catalyst activity. Active metals were substituted during the preparation of hydrotalcite catalysts. Among the catalysts prepared with various ratio (Ni:Fe) tested at high temperature, the ratio, Ni:Fe = 75:25, showed best performance. There was less sintering of Ni particles due to substitution of the active metal at the optimal ratio. PMID:20358916

  12. Increasing FCC regenerator catalyst level

    SciTech Connect

    Wong, R.F. )

    1993-11-01

    A Peruvian FCC unit's operations were improved by increasing the regenerator's catalyst level. This increase resulted in lower stack losses, an improved temperature profile, increased catalyst activity and a lower catalyst consumption rate. A more stable operation saved this Peruvian refiner over $131,000 per year in catalyst alone. These concepts and data may be suitable for your FCC unit as well.

  13. Protein Scaffolding for Small Molecule Catalysts

    SciTech Connect

    Baker, David

    2014-09-14

    We aim to design hybrid catalysts for energy production and storage that combine the high specificity, affinity, and tunability of proteins with the potent chemical reactivities of small organometallic molecules. The widely used Rosetta and RosettaDesign methodologies will be extended to model novel protein / small molecule catalysts in which one or many small molecule active centers are supported and coordinated by protein scaffolding. The promise of such hybrid molecular systems will be demonstrated with the nickel-phosphine hydrogenase of DuBois et. al.We will enhance the hydrogenase activity of the catalyst by designing protein scaffolds that incorporate proton relays and systematically modulate the local environment of the catalyticcenter. In collaboration with DuBois and Shaw, the designs will be experimentally synthesized and characterized.

  14. Pyrochlore catalysts for hydrocarbon fuel reforming

    DOEpatents

    Berry, David A.; Shekhawat, Dushyant; Haynes, Daniel; Smith, Mark; Spivey, James J.

    2012-08-14

    A method of catalytically reforming a reactant gas mixture using a pyrochlore catalyst material comprised of one or more pyrochlores having the composition A2B2-y-zB'yB"zO7-.DELTA., where y>0 and z.gtoreq.0. Distribution of catalytically active metals throughout the structure at the B site creates an active and well dispersed metal locked into place in the crystal structure. This greatly reduces the metal sintering that typically occurs on supported catalysts used in reforming reactions, and reduces deactivation by sulfur and carbon. Further, oxygen mobility may also be enhanced by elemental exchange of promoters at sites in the pyrochlore. The pyrochlore catalyst material may be utilized in catalytic reforming reactions for the conversion of hydrocarbon fuels into synthesis gas (H2+CO) for fuel cells, among other uses.

  15. Fuel cell development for transportation: Catalyst development

    SciTech Connect

    Doddapaneni, N.; Ingersoll, D.

    1996-12-31

    Fuel cells are being considered as alternative power sources for transportation and stationary applications. The degradation of commonly used electrode catalysts (e.g. Pt, Ag, and others) and corrosion of carbon substrates are making commercialization of fuel cells incorporating present day technologies economically problematic. Furthermore, due to the instability of the Pt catalyst, the performance of fuel cells declines on long-term operation. When methanol is used as the fuel, a voltage drop, as well as significant thermal management problems can be encountered, the later being due to chemical oxidation of methanol at the platinized carbon at the cathode. Though extensive work was conducted on platinized electrodes for both the oxidation and reduction reactions, due to the problems mentioned above, fuel cells have not been fully developed for widespread commercial use. Several investigators have previously evaluated metal macrocyclic complexes as alternative catalysts to Pt and Pt/Ru in fuel cells. Unfortunately, though they have demonstrated catalytic activity, these materials were found to be unstable on long term use in the fuel cell environment. In order to improve the long-term stability of metal macrocyclic complexes, we have chemically bonded these complexes to the carbon substrate, thereby enhancing their catalytic activity as well as their chemical stability in the fuel cell environment. We have designed, synthesized, and evaluated these catalysts for O{sub 2} reduction, H{sub 2} oxidation, and direct methanol oxidation in Proton Exchange Membrane (PEM) and aqueous carbonate fuel cells. These catalysts exhibited good catalytic activity and long-term stability. In this paper we confine our discussion to the initial performance results of some of these catalysts in H{sub 2}/O{sub 2} PEM fuel cells, including their long-term performance characteristics as well as CO poisoning effects on these catalysts.

  16. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2011-11-15

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  17. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2010-06-29

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  18. Catalysts and method

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1991-01-01

    An improved catlayst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HC1 and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  19. Polymerization catalyst system

    SciTech Connect

    Graves, V.

    1986-03-25

    This patent describes a catalyst system for polymerizing at least one alpha-olefin under conditions characteristic of Ziegler polymerization. This system consists of: 1. a supported polymerization catalyst or mixture of polymerization catalysts prepared under anhydrous conditions by the sequential steps of: (a) preparing a slurry of inert particulate porous support material; (b) adding to the slurry a solution of an organomagnesium compound; (c) adding to the slurry and reacting a solution of a zirconium halide compound, hafnium compound or mixtures thereof; (d) adding to the slurry and reacting a halogenator; (e) adding to the slurry and reacting a tetravalent titanium halide compound; and (f) recovering solid catalyst component; 2. an organoaluminum compound; and 3. a promotor of chlorinated hydrocarbons having one to 20 carbon atoms.

  20. Hydrocracking catalysts and processes

    SciTech Connect

    Dolbear, G.E.

    1995-12-31

    Hydrocracking processes convert aromatic gas oils into high quality gasoline, diesel, and turbine stocks. They operate at high hydrogen pressures, typically greater than 1500 psig. Operating temperatures range from 600-700{degrees}F (315-382{degrees}C). Commercial catalysts vary in activity and selectivity, allowing process designers to emphasize middle distillates, naphtha, or both. Catalysts are quite stable in use, with two year unit run lengths typical. A pretreatment step to remove nitrogen compounds is usually part of the same process unit. These HDN units operate integrally with the hydrocracking. The hydrogenation reactions are strongly exothermic, while the cracking is roughly thermal neutral. This combination can lead to temperature runaways. To avoid this, cold hydrogen is injected at several points in hydrocracking reactors. The mechanics of mixing this hydrogen with the oil and redistributing the mixture over the catalyst bed are very important in controlling process operation and ensuring long catalyst life.

  1. Plasmatron-catalyst system

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander; Alexeev, Nikolai

    2007-10-09

    A plasmatron-catalyst system. The system generates hydrogen-rich gas and comprises a plasmatron and at least one catalyst for receiving an output from the plasmatron to produce hydrogen-rich gas. In a preferred embodiment, the plasmatron receives as an input air, fuel and water/steam for use in the reforming process. The system increases the hydrogen yield and decreases the amount of carbon monoxide.

  2. Catalytic reforming catalyst

    SciTech Connect

    Buss, W.C.; Kluksdahl, H.E.

    1980-12-09

    An improved catalyst, having a reduced fouling rate when used in a catalytic reforming process, said catalyst comprising platinum disposed on an alumina support wherein the alumina support is obtained by removing water from aluminum hydroxide produced as a by-product from a ziegler higher alcohol synthesis reaction, and wherein the alumina is calcined at a temperature of 1100-1400/sup 0/F so as to have a surface area of 165 to 215 square meters per gram.

  3. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, Robert J.; Gao, Hanrong

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilation, olefin oxidation, isomerization, hydrocyanation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical.

  4. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, R.J.; Gao, H.

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilication, olefin oxidation, isomerization, hydrocyanidation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical. 2 figs.

  5. 26 CFR 1.507-6 - Substantial contributor defined.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... taxable years. Status as a substantial contributor, however, will date from the time when the donor first... October 9, 1969, H (W's spouse at the time of the 1941 gift) is considered to have made such...

  6. Oxidation-reduction catalyst and its process of use

    NASA Technical Reports Server (NTRS)

    Jordan, Jeffrey D. (Inventor); Watkins, Anthony Neal (Inventor); Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor)

    2008-01-01

    This invention relates generally to a ruthenium stabilized oxidation-reduction catalyst useful for oxidizing carbon monoxide, and volatile organic compounds, and reducing nitrogen oxide species in oxidizing environments, substantially without the formation of toxic and volatile ruthenium oxide species upon said oxidizing environment being at high temperatures.

  7. Comprehensive catalyst management

    SciTech Connect

    Pritchard, S.

    2007-05-15

    From January 2009, as SCR season expands from five months to year-round to meet new US Clean Air Interstate Rule standards, new catalyst strategies are increasingly important. Power plants will need a comprehensive management strategy that accounts for a wide range of old and new issues to achieve peak performance. An optimum plan is necessary for catalyst replacement or addition. SCR systems should be inspected and evaluated at least once a year. Levels of deactivation agents, most often arsenic and calcium oxide, need to match the particular coals used. Tools such as Cormetech's FIELD Guide are available to quantify the effect on catalyst life under various fuel-firing scenarios. Tests should be conducted to evaluate the NH{sub 3}/NOx distribution over time to maximise catalyst performance. The article gives a case study of catalyst management at the Tennessee Valley Authority Allen plant. Recent changes have created new variables to be considered in a catalyst management process, notably the expansion of the operating temperature range, mercury oxidation and SO{sub 3} emission limits. Cormetech has researched these areas. 5 figs., 2 photos.

  8. 26 CFR 1.274-5 - Substantiation requirements.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 3 2011-04-01 2011-04-01 false Substantiation requirements. 1.274-5 Section 1.274-5 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.274-5 Substantiation requirements. (a)-(b) . For further guidance, see § 1.274-5T(a) and...

  9. Novel ebullated bed catalyst regeneration technology improves regenerated catalyst quality

    SciTech Connect

    Neuman, D.J.

    1995-09-01

    Regeneration of spent hydroprocessing catalysts has long been practiced by the refining industry. With increased pressures on refiners to reduce catalyst expenditures and waste generation, refiners are more frequently reusing spent hydroprocessing catalysts after ex-situ regeneration to restore catalytic activity. By reusing regenerated catalyst for at least two cycles, the refiner reduces catalyst waste by at least one-half. As environmental laws become more restrictive, spent hydroprocessing catalyst is more likely to be classified as hazardous waste. Disposal of spent catalyst, which was previously accomplished by landfilling, now requires more expensive reclamation techniques. TRICAT has introduced the TRICAT Regeneration Process (TRP), a novel ebullated bed regeneration plant, to improve the catalyst regeneration process. The ebullated bed design allows for better control of heat release during the regeneration process. As a result, the regeneration can be accomplished in a single-pass, with improved catalyst activity retention. Catalyst losses are also minimized due to reduced catalyst handling. Commercial results from the TRP have demonstrated successful scale-up of the technology from pilot scale. The plant has achieved complete recovery of the available catalyst activity with little or no losses in catalyst yield or extrudate length. The flexibility of the TRP to process a variety of catalysts is also discussed.

  10. Supported Molten Metal Catalysis. A New Class of Catalysts

    SciTech Connect

    Ravindra Datta; Ajeet Singh; Manuela Serban; Istvan Halasz

    2006-06-02

    We describe a new class of heterogeneous catalysts called supported molten metal catalysis (SMMC), in which molten metal catalysts are dispersed as nanodroplets on the surface of porous supports, allowing much larger active surface area than is possible in conventional contacting techniques for catalytic metals that are molten under reaction conditions, thus greatly enhancing their activity and potential utility. Specific examples of different types of reactions are provided to demonstrate the broad applicability of the technique in designing active, selective, and stable new catalysts. It is shown that dispersing the molten metal on a support in the suggested manner can enhance the rate of a reaction by three to four orders of magnitude as a result of the concomitant increase in the active surface area. New reaction examples include {gamma}-Al{sub 2}O{sub 3} supported molten Te (melting point 450 C) and Ga (MP 30 C) catalysts for bifunctional methylcyclohexane dehydrogenation. These catalysts provide activity similar to conventional Pt-based catalysts for this with better resistance to coking. In addition, results are described for a controlled pore glass supported molten In (MP 157 C) catalyst for the selective catalytic reduction of NO with ethanol in the presence of water, demonstrating activities superior to conventional catalysts for this reaction. A discussion is also provided on the characterization of the active surface area and dispersion of these novel supported catalysts. It is clear based on the results described that the development of new active and selective supported molten metal catalysts for practical applications is entirely plausible.

  11. Enhanced conversion of syngas to liquid motor fuels

    DOEpatents

    Coughlin, Peter K.; Rabo, Jule A.

    1986-01-01

    Synthesis gas comprising carbon monoxide and hydrogen is converted to C.sub.5.sup.+ hydrocarbons suitable for use as liquid motor fuels by contact with a dual catalyst system capable of enhancing the selectivity of said conversion to motor fuel range hydrocarbons and the quality of the resulting motor fuel product. The catalyst composition employs a Fischer-Tropsch catalyst, together with a co-catalyst/support component comprising SAPO silicoaluminophosphate, non-zeolitic molecular sieve catalyst.

  12. Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, January 1, 1993--March 31, 1993

    SciTech Connect

    Bukur, D.B.

    1993-04-20

    The objective of proposed research is the development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance. Studies of both supported and unsupported iron/copper/potassium catalysts are presented.

  13. Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, April 1, 1993--June 31, 1993

    SciTech Connect

    Bukur, D.B.

    1993-07-15

    The objective of proposed research is the development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance. Studies of both supported and unsupported iron/copper/potassium catalysts are presented.

  14. Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, October 1, 1992--December 31, 1992

    SciTech Connect

    Bukur, D.B.

    1993-01-29

    The objective of proposed research is the development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance. Studies of both supported and unsupported iron/copper/potassium catalysts are presented.

  15. Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, April 1, 1992--June 30, 1992

    SciTech Connect

    Bukur, D.B.

    1992-07-15

    The objective of proposed research is the development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance. Studies of both supported and unsupported iron/copper/potassium catalysts are presented.

  16. Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, July 1, 1992--September 30, 1992

    SciTech Connect

    Bukur, D.B.

    1992-10-23

    The objective of proposed research is the development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance. Studies of both supported and unsupported iron/copper/potassium catalysts are presented.

  17. Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, July 1, 1993--September 30, 1993

    SciTech Connect

    Bukur, D.B.

    1993-10-21

    The objective of proposed research is the development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance. Studies of both supported and unsupported iron/copper/potassium catalysts are presented.

  18. Measuring Substantial Reduction in Functioning in Patients with CFS

    PubMed Central

    Jason, Leonard A.; Brown, Molly; Evans, Meredyth; Anderson, Valerie; Lerch, Athena; Brown, Abigail; Hunnell, Jessica; Porter, Nicole

    2011-01-01

    Purpose All of the major current case definitions for chronic fatigue syndrome (CFS) specify substantial reductions in previous levels of occupational, educational, social, or personal activities to meet criteria. Difficulties have been encountered in operationalizing “substantial reductions.” For example, the Medical Outcomes Study Short Form-36 Health Survey (SF-36) has been used to determine whether individuals met the CFS disability criterion. However, previous methods of using the SF-36 have been prone to including people without substantial reductions in key areas of physical functioning when diagnosing CFS. This study sought to empirically identify the most appropriate SF-36 subscales for measuring substantial reductions in patients with CFS. Method The SF-36 was administered to two samples of patients with CFS: one recruited from tertiary care and the other a community-based sample; as well as a non-fatigued control group. Receiver operating characteristics were used to determine optimal cutoff scores for identifying patients with CFS. Results The SF-36 Role-Emotional subscale had the worst sensitivity and specificity, whereas the Vitality, Role-Physical, and Social Functioning subscales had the best sensitivity and specificity. Conclusion Based on evidence from this study, potential criteria for defining substantial reductions in functioning and diagnosing CFS is provided. PMID:20617920

  19. Deactivator for olefin polymerization catalyst

    SciTech Connect

    Rekers, L.J.; Speca, A.N.; Mayhew, H.W.

    1987-03-10

    A method is described comprising deactivating an olefin polymerization catalyst selected from the group consisting of Ziegler-Natta transition element catalysts and catalysts based on transition metal oxides by contacting the catalyst with a copolymer. The copolymer consists of an alpha-olefin having from 2 to about 12 carbon atoms and an unsaturated ester of a carboxylic acid. The deactivating copolymer is present in an amount such that the molar ratio of the unsaturated ester thereof to the sum of the transition element component of the polymerization catalyst and a cocatalyst for the transition element catalyst is in the range of between about 0.1 and about 6.

  20. Multimetallic nanoparticle catalysts with enhanced electrooxidation

    DOEpatents

    Sun, Shouheng; Zhang, Sen; Zhu, Huiyuan; Guo, Shaojun

    2015-07-28

    A new structure-control strategy to optimize nanoparticle catalysis is provided. The presence of Au in FePtAu facilitates FePt structure transformation from chemically disordered face centered cubic (fcc) structure to chemically ordered face centered tetragonal (fct) structure, and further promotes formic acid oxidation reaction (FAOR). The fct-FePtAu nanoparticles show high CO poisoning resistance, achieve mass activity as high as about 2810 mA/mg Pt, and retain greater than 90% activity after a 13 hour stability test.

  1. Metal salt catalysts for enhancing hydrogen spillover

    DOEpatents

    Yang, Ralph T; Wang, Yuhe

    2013-04-23

    A composition for hydrogen storage includes a receptor, a hydrogen dissociating metal doped on the receptor, and a metal salt doped on the receptor. The hydrogen dissociating metal is configured to spill over hydrogen to the receptor, and the metal salt is configured to increase a rate of the spill over of the hydrogen to the receptor.

  2. Method of sealing an ultracapacitor substantially free of water

    DOEpatents

    Chapman-Irwin, Patricia; Feist, Thomas Paul

    2002-04-02

    A method of sealing an ultracapacitor substantially free of water is disclosed. The method includes providing a multilayer cell comprising two solid, non porous current collectors, separated by two porous electrodes with a separator between the two electrodes, sealing the cell with a reclosable hermetic closure. Water inside the closure is dissociated by an applied voltage to the cell and escapes in the form of hydrogen and oxygen when the closure is unmated, the closure is then mated to hermetically seal the cell which is substantially free of water.

  3. Quality assurance for purchased catalysts

    SciTech Connect

    Puls, F.H. )

    1988-09-01

    Petrochemical industries require many different types of catalysts in process operations. A significantly portion of these requirements is being met through purchases from merchant catalyst suppliers. The importance of catalysts and of catalyst quality to these industries cannot be overstated. It is not surprising that in the quest for quality which has affected much of US industry in the last few years, catalysts were among the first products which were singled out for development of quality assurance. Currently, catalyst supplier auditing and certification procedures are being implemented. Primary emphasis is on the implementation of statistical process control procedures in the manufacture of commercially available catalyst. Thus, a trend exists to move from quality assurance (QA) and quality control (QC) for purchased catalysts to statistical process control (SPC). This development is being supported by audits of the suppliers' manufacturing quality control systems. The keystone of quality management is the concept of customer and supplier working together for their mutual advantage. The focus in this presentation will be on two topics. (1) Fixed bed catalysts: The recognition of lot-to-lot variations led to purchase specifications which then led to quality control procedures for purchased catalysts. (2) Catalyst suppliers: the limitations of quality control for catalysts will be discussed, and the efforts of catalyst suppliers to apply SPC will be mentioned.

  4. DEVELOPMENT OF PRECIPITATED IRON FISCHER-TROPSCH CATALYSTS

    SciTech Connect

    Dr. Dragomir B. Bukur; Dr. X. Lang; Dr. S. Chokkaram; Dr. L. Nowicki; G. Wei; Dr. Y. Ding; Dr. B. Reddy; Dr. S. Xiao

    1999-07-22

    Despite the current worldwide oil glut, the US will ultimately require large-scale production of liquid (transportation) fuels from coal. Slurry phase Fischer-Tropsch (F-T) technology, with its versatile product slate, may be expected to play a major role in production of transportation fuels via indirect coal liquefaction. Some of the F-T catalysts synthesized and tested at Texas A and M University under DOE Contract No. DE-AC22-89PC89868 were more active than any other known catalysts developed for maximizing production of high molecular weight hydrocarbons (waxes). The objectives of the present contract were to demonstrate repeatability of catalyst performance and reproducibility of preparation procedures of two of these catalysts on a laboratory scale. Improvements in the catalyst performance were attempted through the use of: (a) higher reaction pressure and gas space velocity to maximize the reactor productivity; (b) modifications in catalyst preparation steps; and (c) different pretreatment procedures. Repeatability of catalyst performance and reproducibility of catalyst synthesis procedure have been successfully demonstrated in stirred tank slurry reactor tests. Reactor space-time-yield was increased up to 48% by increasing reaction pressure from 1.48 MPa to 2.17 MPa, while maintaining the gas contact time and synthesis gas conversion at a constant value. Use of calcination temperatures above 300 C, additional CaO promoter, and/or potassium silicate as the source of potassium promoter, instead of potassium bicarbonate, did not result in improved catalyst performance. By using different catalyst activation procedures they were able to increase substantially the catalyst activity, while maintaining low methane and gaseous hydrocarbon selectivities. Catalyst productivity in runs SA-0946 and SA-2186 was 0.71 and 0.86 gHC/g-Fe/h, respectively, and this represents 45-75% improvement in productivity relative to that achieved in Rheinpreussen's demonstration plant

  5. Supported organoiridium catalysts for alkane dehydrogenation

    DOEpatents

    Baker, R. Thomas; Sattelberger, Alfred P.; Li, Hongbo

    2013-09-03

    Solid supported organoiridium catalysts, a process for preparing such solid supported organoiridium catalysts, and the use of such solid supported organoiridium catalysts in dehydrogenation reactions of alkanes is provided. The catalysts can be easily recovered and recycled.

  6. Contributors to Enhanced CO2 Electroreduction Activity and Stability in a Nanostructured Au Electrocatalyst.

    PubMed

    Kim, Haeri; Jeon, Hyo Sang; Jee, Michael Shincheon; Nursanto, Eduardus Budi; Singh, Jitendra Pal; Chae, Keunhwa; Hwang, Yun Jeong; Min, Byoung Koun

    2016-08-23

    The formation of a nanostructure is a popular strategy for catalyst applications because it can generate new surfaces that can significantly improve the catalytic activity and durability of the catalysts. However, the increase in the surface area resulting from nanostructuring does not fully explain the substantial improvement in the catalytic properties of the CO2 electroreduction reaction, and the underlying mechanisms have not yet been fully understood. Here, based on a combination of extended X-ray absorption fine structure analysis, X-ray photoelectron spectroscopy, and Kelvin probe force microscopy, we observed a contracted Au-Au bond length and low work function with the nanostructured Au surface that had enhanced catalytic activity for electrochemical CO2 reduction. The results may improve the understanding of the enhanced stability of the nanostructured Au electrode based on the resistance of cation adhesion during the CO2 reduction reaction. PMID:27466025

  7. TOPICAL REVIEW: Nanoparticle catalysts

    NASA Astrophysics Data System (ADS)

    Moshfegh, A. Z.

    2009-12-01

    In this review, the importance of nanoparticles (NPs), with emphasis on their general and specific properties, especially the high surface-to-volume ratio (A/V), in many technological and industrial applications is studied. Some physical and chemical preparation methods for growing several metallic and binary alloy NP catalysts are reviewed. The growth and mechanism of catalytic reactions for synthesis of 1D nanostructures such as ZnO nanowires and multiwall carbon nanotubes (MWCNTs) are discussed. Gas-phase production with emphasis on dependence of catalytic activity and selectivity on size, shape and structure of NPs is also investigated. Application of NP catalysts in several technological processes including H2 production and storage as well as antibacterial effect, gas sensors and fuel cells is discussed. The mechanism of H2 production from catalytic photoelectrochemical and photocatalytic degradation reactions of some organic dyes is discussed. Finally, the future outlook of NP catalysts in various disciplines is presented.

  8. Partial oxidation catalyst

    DOEpatents

    Krumpelt, Michael; Ahmed, Shabbir; Kumar, Romesh; Doshi, Rajiv

    2000-01-01

    A two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion. The dehydrogenation portion is a group VIII metal and the oxide-ion conducting portion is selected from a ceramic oxide crystallizing in the fluorite or perovskite structure. There is also disclosed a method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

  9. Catalyst, method of making, and reactions using the catalyst

    DOEpatents

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Gao, Yufei [Kennewick, WA

    2009-03-03

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  10. Catalyst, Method Of Making, And Reactions Using The Catalyst

    DOEpatents

    Tonkovich, Anna Lee Y.; Wang, Yong; Gao, Yufei

    2004-07-13

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  11. Secret Lives of Catalysts Revealed

    SciTech Connect

    Salmeron, Miquel; Somorjai, Gabor

    2008-01-01

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-releases/2008/10/21/catalysts/

  12. Engelhard expands oxidation catalysts portfolio

    SciTech Connect

    Rotman, D.

    1997-02-26

    Engelhard says its agreement earlier this month to market Amoco Chemical`s proprietary maleic anhydride catalyst reflects an effort to expand its speciality catalysts business (CW, Feb. 19, p.5). In particular, the company says it is looking for additional alliances to bolster its oxidation catalysts portfolio. {open_quotes}There are some areas of oxidation catalysis that are reasonably attractive,{close_quotes} says Paul Lamb, marketing director/chemical catalysts. He says that while Engelhard is not interested in commodity oxidation catalysts, such as those used to make sulfuric acid, it does want to boost offerings for higher-value oxidation catalysts. Engelhard is collaborating with Geon to offer oxychlorination catalysts for making ethylene dichloride. It also markets oxidation catalysts for vinyl acetate production.

  13. 76 FR 38961 - Tobacco Products, Exemptions From Substantial Equivalence Requirements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-05

    ... / Tuesday, July 5, 2011 / Rules and Regulations#0;#0; ] DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and... Substantial Equivalence Requirements AGENCY: Food and Drug Administration, HHS. ACTION: Final rule. SUMMARY: The Food and Drug Administration (FDA) is issuing this final rule to establish procedures...

  14. 29 CFR 4043.27 - Distribution to a substantial owner.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... TERMINATIONS REPORTABLE EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.27 Distribution to a substantial owner. (a) Reportable event. A reportable event occurs for... does not exceed the limitation (as of the date the reportable event occurs) under section...

  15. 29 CFR 4043.27 - Distribution to a substantial owner.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 9 2014-07-01 2014-07-01 false Distribution to a substantial owner. 4043.27 Section 4043.27 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION PLAN TERMINATIONS REPORTABLE EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.27 Distribution to a...

  16. 29 CFR 4043.27 - Distribution to a substantial owner.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... TERMINATIONS REPORTABLE EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.27 Distribution to a substantial owner. (a) Reportable event. A reportable event occurs for... does not exceed the limitation (as of the date the reportable event occurs) under section...

  17. 29 CFR 4043.27 - Distribution to a substantial owner.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Distribution to a substantial owner. 4043.27 Section 4043.27 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION PLAN TERMINATIONS REPORTABLE EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.27 Distribution to a...

  18. 29 CFR 4043.27 - Distribution to a substantial owner.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... TERMINATIONS REPORTABLE EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.27 Distribution to a substantial owner. (a) Reportable event. A reportable event occurs for... does not exceed the limitation (as of the date the reportable event occurs) under section...

  19. 77 FR 35245 - Substantially Underserved Trust Areas (SUTA)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... entitled ``Department Programs and Activities Excluded from Executive Order 12372,'' (50 FR 47034). However... October 14, 2011, (76 FR 63846), the agency requested comments regarding implementing the Substantially... Guarantees. The Catalog is available on the Internet at http://www.cfda.gov . Executive Order 12372...

  20. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  1. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  2. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  3. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  4. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  5. 15 CFR 970.209 - Substantial compliance with application requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Substantial compliance with application requirements. 970.209 Section 970.209 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE GENERAL REGULATIONS OF THE ENVIRONMENTAL...

  6. 76 FR 737 - Tobacco Products, Exemptions From Substantial Equivalence Requirements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-06

    ...The Food and Drug Administration (FDA) is issuing this proposed rule to establish procedures for requesting an exemption from the substantial equivalence requirements of the Family Smoking Prevention and Tobacco Control Act (Tobacco Control Act). The proposed rule would describe the process and statutory criteria for requesting an exemption and explain how FDA would review requests for......

  7. 15 CFR 970.209 - Substantial compliance with application requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Substantial compliance with application requirements. 970.209 Section 970.209 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE GENERAL REGULATIONS OF THE ENVIRONMENTAL...

  8. 15 CFR 970.209 - Substantial compliance with application requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Substantial compliance with application requirements. 970.209 Section 970.209 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE GENERAL REGULATIONS OF THE ENVIRONMENTAL...

  9. 26 CFR 7.105-2 - Substantial gainful activity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 14 2012-04-01 2012-04-01 false Substantial gainful activity. 7.105-2 Section 7.105-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX... because of a physical or mental impairment accepts sheltered employment in a protected environment...

  10. 26 CFR 7.105-2 - Substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Substantial gainful activity. 7.105-2 Section 7.105-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX... because of a physical or mental impairment accepts sheltered employment in a protected environment...

  11. Mistreatment in Assisted Living Facilities: Complaints, Substantiations, and Risk Factors

    ERIC Educational Resources Information Center

    Phillips, Linda R.; Guo, Guifang

    2011-01-01

    Purpose of the Study: Use archived public data from Arizona to explore relationships among selected institutional and resident risk and situation-specific factors and complaints and substantiated allegations of various types of mistreatment in assisted living facilities (ALFs). Design and Methods: An exploratory/descriptive 2-group design was…

  12. 29 CFR 4.12 - Substantial interest proceedings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... procedures set forth at 29 CFR part 6. (f) Referral to the Administrative Review Board. When the person or... accordance with the procedures set forth at 29 CFR part 8. ... 29 Labor 1 2010-07-01 2010-07-01 true Substantial interest proceedings. 4.12 Section 4.12...

  13. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Meaning of substantial gainful activity. 416.910 Section 416.910 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Definition of Disability §...

  14. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Meaning of substantial gainful activity. 416.910 Section 416.910 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Definition of Disability §...

  15. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Meaning of substantial gainful activity. 416.910 Section 416.910 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Definition of Disability §...

  16. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Meaning of substantial gainful activity. 416.910 Section 416.910 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Definition of Disability §...

  17. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Meaning of substantial gainful activity. 416.910 Section 416.910 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Definition of Disability §...

  18. 15 CFR 970.209 - Substantial compliance with application requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Substantial compliance with application requirements. 970.209 Section 970.209 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE GENERAL REGULATIONS OF THE ENVIRONMENTAL...

  19. Iridium-catalyst-based autonomous bubble-propelled graphene micromotors with ultralow catalyst loading.

    PubMed

    Wang, Hong; Sofer, Zdeněk; Eng, Alex Yong Sheng; Pumera, Martin

    2014-11-10

    A novel concept of an iridium-based bubble-propelled Janus-particle-type graphene micromotor with very high surface area and with very low catalyst loading is described. The low loading of Ir catalyst (0.54 at %) allows for fast motion of graphene microparticles with high surface area of 316.2 m(2)  g(-1). The micromotor was prepared with a simple and scalable method by thermal exfoliation of iridium-doped graphite oxide precursor composite in hydrogen atmosphere. Oxygen bubbles generated from the decomposition of hydrogen peroxide at the iridium catalytic sites provide robust propulsion thrust for the graphene micromotor. The high surface area and low iridium catalyst loading of the bubble-propelled graphene motors offer great possibilities for dramatically enhanced cargo delivery. PMID:25293511

  20. Alumina-supported Pd-Ag catalysts for low-temperature CO and methanol oxidation

    NASA Technical Reports Server (NTRS)

    Mccabe, R. W.

    1987-01-01

    Pd-Ag bimetallic catalysts, supported on gamma-Al2O3, have been evaluated as exhaust catalysts for methanol-fueled vehicles. Laboratory studies have shown that a 0.01% Pd-5% Ag catalyst has greater CO and CH3OH oxidation activity than either 0.01% Pd or 5% Ag catalysts alone. Moreover, Pd and Ag interact synergistically in the bimetallic catalyst to produce greater CO and CH3OH oxidation rates and lower yields of methanol partial oxidation products than expected from a mixture of the single-component catalysts. The Pd-Ag synergism results from Pd promoting the rate of O2 adsorption and reaction with CO and CH3OH on Ag. Rate enhancement by the bimetallic catalyst is greatest at short reactor residence times where the oxygen adsorption rate limits the overall reaction rate.

  1. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    SciTech Connect

    Andrew W. Wang

    2002-05-15

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is: 2H{sub 2} + CO = CH{sub 3}OH 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a scaleup project

  2. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    SciTech Connect

    Andrew W. Wang

    2002-01-01

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is shown below: 2H{sub 2} + CO = CH{sub 3}OH; 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O; H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a

  3. Preparation of arrays of long carbon nanotubes using catalyst structure

    DOEpatents

    Zhu, Yuntian T.; Arendt, Paul; Li, Qingwen; Zhang, Xiefie

    2016-03-22

    A structure for preparing an substantially aligned array of carbon nanotubes include a substrate having a first side and a second side, a buffer layer on the first side of the substrate, a catalyst on the buffer layer, and a plurality of channels through the structure for allowing a gaseous carbon source to enter the substrate at the second side and flow through the structure to the catalyst. After preparing the array, a fiber of carbon nanotubes may be spun from the array. Prior to spinning, the array can be immersed in a polymer solution. After spinning, the polymer can be cured.

  4. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction

    SciTech Connect

    Chunshan, Song; Kirby, S.; Schmidt, E.

    1995-12-31

    The objective of this project is to explore bimetallic dispersed catalysts for more efficient coal liquefaction. Coal liquefaction involves cleavage of methylene, dimethylene and ether bridges connecting various aromatic units and the reactions of various oxygen functional groups. This paper describes recent results on (1) hydrodeoxygenation of O-containing polycyclic model compounds using novel organometallic catalyst precursors; and (2) activity and selectivity of dispersed Fe catalysts from organometallic and inorganic precursors for hydrocracking of 4-(1-naphthylmethyl) bibenzyl. The results showed that some iron containing catalysts have higher activity in the sulfur-free form, contrary to conventional wisdom. Adding sulfur to Fe precursors with Cp-ligands decreased the activity of the resulting catalyst. This is in distinct contrast to the cases with iron pentacarbonyl and superfine Fe{sub 2}O{sub 3}, where S addition increased their catalytic activity substantially. A positive correlation between sulfur addition and increased activity can be seen, but a reversed trend between Fe cluster size and hydrocracking conversion could be observed, for carbonyl-type Fe precursors. It is apparent that the activity and selectivity of Fe catalysts for NMBB conversion depends strongly on both the type of ligand environment, the oxidation state and the number of intermetal bonds in the molecular precursor.

  5. Separation of catalyst from Fischer-Tropsch slurry

    DOEpatents

    White, Curt M.; Quiring, Michael S.; Jensen, Karen L.; Hickey, Richard F.; Gillham, Larry D.

    1998-10-27

    In a catalytic process for converting synthesis gas including hydrogen and carbon monoxide to hydrocarbons and oxygenates by a slurry Fischer-Tropsch synthesis, the wax product along with dispersed catalyst is removed from the slurry and purified by removing substantially all of the catalyst prior to upgrading the wax and returning a portion to the Fischer-Tropsch reaction. Separation of the catalyst particles from the wax product is accomplished by dense gas and/or liquid extraction in which the organic compounds in the wax are dissolved and carried away from the insoluble inorganic catalyst particles that are primarily inorganic in nature. The purified catalyst free wax product can be subsequently upgraded by various methods such as hydrogenation, isomerization, hydrocracking, conversion to gasoline and other products over ZSM-5 aluminosilicate zeolite, etc. The catalyst particles are returned to the Fischer-Tropsch Reactor by slurring them with a wax fraction of appropriate molecular weight, boiling point and viscosity to avoid reactor gelation.

  6. Separation of catalyst from Fischer-Tropsch slurry

    DOEpatents

    White, C.M.; Quiring, M.S.; Jensen, K.L.; Hickey, R.F.; Gillham, L.D.

    1998-10-27

    In a catalytic process for converting synthesis gas including hydrogen and carbon monoxide to hydrocarbons and oxygenates by a slurry Fischer-Tropsch synthesis, the wax product along with dispersed catalyst is removed from the slurry and purified by removing substantially all of the catalyst prior to upgrading the wax and returning a portion to the Fischer-Tropsch reaction. Separation of the catalyst particles from the wax product is accomplished by dense gas and/or liquid extraction in which the organic compounds in the wax are dissolved and carried away from the insoluble inorganic catalyst particles that are primarily inorganic in nature. The purified catalyst-free wax product can be subsequently upgraded by various methods such as hydrogenation, isomerization, hydrocracking, conversion to gasoline and other products over ZSM-5 aluminosilicate zeolite, etc. The catalyst particles are returned to the Fischer-Tropsch Reactor by mixing them with a wax fraction of appropriate molecular weight, boiling point and viscosity to avoid reactor gelation. 2 figs.

  7. Covalent heterogenization of discrete bis(8-quinolinolato)dioxomolybdenum(VI) and dioxotungsten(VI) complexes by a metal-template/metal-exchange method: Cyclooctene epoxidation catalysts with enhanced performances

    SciTech Connect

    Yang, Ying; Chattopadhyay, Soma; Shibata, Tomohiro; Ren, Yang; Lee, Sungsik; Kan, Qiubin

    2014-10-01

    A metal-template/metal-exchange method was used to imprint covalently attached bis(8- quinolinolato)dioxomolybdenum(VI) and dioxotungsten(VI) complexes onto large surface-area, mesoporous SBA-15 silica to obtain discrete MoO2 VIT and WO2 VIT catalysts bearing different metal loadings, respectively. Homogeneous counterparts, MoO2 VIN and WO2 VIN, as well as randomly ligandgrafted heterogeneous analogues, MoO2 VIG and WO2 VIG, were also prepared for comparison. X-ray absorption fine structure (XAFS), pair distribution function (PDF) and UV–vis data demonstrate that MoO2 VIT and WO2 VIT adopt a more solution-like bis(8-quinolinol) coordination environment than MoO2 VIG and WO2 VIG, respectively. Correspondingly, the templated MoVI and WVI catalysts show superior performances to their randomly grafted counterparts and neat analogues in the epoxidation of cyclooctene. It is found that the representative MoO2 VIT-10% catalyst can be recycled up to five times without significant loss of reactivity, and heterogeneity test confirms the high stability of MoO2 VIT-10% catalyst against leaching of active species into solution. The homogeneity of the discrete bis(8-quinolinol) metal spheres templated on SBA-15 should be responsible for the superior performances.

  8. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  9. Catalyst increases COS conversion

    SciTech Connect

    Goodboy, K.P.

    1985-02-18

    Increasingly stringent air quality legislation is placing greater emphasis on conversion of COS and CS/sub 2/ in Claus plants for the maximum sulfur recovery. Overall sulfur recovery goals are dependent upon outstanding service from the Claus catalyst in each reactor because catalyst activity is a major factor influencing plant performance. Today's catalyst are much improved over those used 10 years ago for the Claus (H/sub 2/S/SO/sub 2/) reaction. Recent technical efforts have focused on the conversion of COS and CS/sub 2/. These carbon-sulfur compounds can account for as much as 50% of the sulfur going to the incinerator, which essentially converts all remaining sulfur species to SO/sub 2/ for atmospheric dispersion. Previously, the mechanism of Claus COS conversion, i.e., hydrolysis or oxidation by SO/sub 2/, was studied and the conclusion was that oxidation by SO/sub 2/ appears to be the predominate mode of COS conversion on sulfated alumina catalysts.

  10. Zinc sulfide liquefaction catalyst

    DOEpatents

    Garg, Diwakar

    1984-01-01

    A process for the liquefaction of carbonaceous material, such as coal, is set forth wherein coal is liquefied in a catalytic solvent refining reaction wherein an activated zinc sulfide catalyst is utilized which is activated by hydrogenation in a coal derived process solvent in the absence of coal.

  11. Catalyst, 2000-01.

    ERIC Educational Resources Information Center

    Ryan, Barbara E., Ed.

    2001-01-01

    "Catalyst" is a publication designed to assist higher education in developing alcohol and other drug prevention polices and programs that will foster students' academic and social development and promote campus and community safety. Issue 1 of volume 6 introduces a series of "Presidential Profiles" in which university presidents describe their…

  12. Tight bifunctional hierarchical catalyst.

    PubMed

    Højholt, Karen T; Vennestrøm, Peter N R; Tiruvalam, Ramchandra; Beato, Pablo

    2011-12-28

    A new concept to prepare tight bifunctional catalysts has been developed, by anchoring CoMo(6) clusters on hierarchical ZSM-5 zeolites for simultaneous use in HDS and hydrocracking catalysis. The prepared material displays a significant improved activity in HDS catalysis compared to the impregnated counterpart. PMID:22048337

  13. Salesperson, Catalyst, Manager, Leader.

    ERIC Educational Resources Information Center

    Worth, Michael J.; Asp, James W., II

    1996-01-01

    This article examines four roles of the college or university development officer: salesperson (when direct solicitation is seen as the officer's primary role); catalyst (or sales manager, adviser, expert, facilitator); manager (stressing the importance of the overall office functioning); and leader (who exerts a leadership role in the…

  14. Noble metal ionic catalysts.

    PubMed

    Hegde, M S; Madras, Giridhar; Patil, K C

    2009-06-16

    Because of growing environmental concerns and increasingly stringent regulations governing auto emissions, new more efficient exhaust catalysts are needed to reduce the amount of pollutants released from internal combustion engines. To accomplish this goal, the major pollutants in exhaust-CO, NO(x), and unburned hydrocarbons-need to be fully converted to CO(2), N(2), and H(2)O. Most exhaust catalysts contain nanocrystalline noble metals (Pt, Pd, Rh) dispersed on oxide supports such as Al(2)O(3) or SiO(2) promoted by CeO(2). However, in conventional catalysts, only the surface atoms of the noble metal particles serve as adsorption sites, and even in 4-6 nm metal particles, only 1/4 to 1/5 of the total noble metal atoms are utilized for catalytic conversion. The complete dispersion of noble metals can be achieved only as ions within an oxide support. In this Account, we describe a novel solution to this dispersion problem: a new solution combustion method for synthesizing dispersed noble metal ionic catalysts. We have synthesized nanocrystalline, single-phase Ce(1-x)M(x)O(2-delta) and Ce(1-x-y)Ti(y)M(x)O(2-delta) (M = Pt, Pd, Rh; x = 0.01-0.02, delta approximately x, y = 0.15-0.25) oxides in fluorite structure. In these oxide catalysts, Pt(2+), Pd(2+), or Rh(3+) ions are substituted only to the extent of 1-2% of Ce(4+) ion. Lower-valent noble metal ion substitution in CeO(2) creates oxygen vacancies. Reducing molecules (CO, H(2), NH(3)) are adsorbed onto electron-deficient noble metal ions, while oxidizing (O(2), NO) molecules are absorbed onto electron-rich oxide ion vacancy sites. The rates of CO and hydrocarbon oxidation and NO(x) reduction (with >80% N(2) selectivity) are 15-30 times higher in the presence of these ionic catalysts than when the same amount of noble metal loaded on an oxide support is used. Catalysts with palladium ion dispersed in CeO(2) or Ce(1-x)Ti(x)O(2) were far superior to Pt or Rh ionic catalysts. Therefore, we have demonstrated that the

  15. Substantial Life Extension and the Fair Distribution of Healthspans.

    PubMed

    Wareham, Christopher S

    2016-10-01

    One of the strongest objections to the development and use of substantially life-extending interventions is that they would exacerbate existing unjust disparities of healthy lifespans between rich and poor members of society. In both popular opinion and ethical theory, this consequence is sometimes thought to justify a ban on life-prolonging technologies. However, the practical and ethical drawbacks of banning receive little attention, and the viability of alternative policies is seldom considered. Moreover, where ethicists do propose alternatives, there is scant effort to consider their merits in light of developing world priorities. In response to these shortcomings, I distinguish four policy options and, on the basis of a plausible intuition about fairness, evaluate their implications for a fair distribution of healthy lifespans. I claim that even in developing nations it would be fairest to favor policies that promote equal access to at least one promising category of substantially life-extending intervention: calorie restriction mimetics. PMID:27465775

  16. Patients' substantialization of disease, the hybrid symptom and metaphysical care.

    PubMed

    Pârvan, Alexandra

    2015-06-01

    In the context of current scholarship concerned with facilitating integration between the biomedical and the patient-centred models of care, the article suggests that disease brings about an ontological disruption in patients, which is not directly addressed in either model, and may interfere with treatment and therapy outcomes if not met with a type of care termed here as 'metaphysical'. The receipt of diagnosis and medical care can give patients the sense that they are ontologically diminished, or less of a human, and along with physicians' approaches to and discourses about disease, may prompt them to seek ontological restoration or security in the same way as psychologically traumatized patients sometimes do: by treating the disease and/or the experience of harm associated with it as a thing that exists per se. I call this 'substantialization' of disease (or harm) and draw on Augustine's theory of non-substantial deficiencies (physiological and moral) and on Plato's and Plotinus's different takes on such defects in order to discuss what substantialization can do for patients. Based on literature that examines patients' ways of talking about and living with their disease, I speculate that substantialization can generate a 'hybrid symptom', consisting in patterns of exercising agency which may predispose to non-adherence. Ways in which physicians could provide metaphysical care are proposed, along with an understanding of chronic patients as hybrid ontological and agentic units, which draws on theories of enactive cognition. I opine that metaphysical care may facilitate integration between the depersonalized and personalized models of care. PMID:25312387

  17. Sulfur condensation in Claus catalyst

    SciTech Connect

    Schoffs, G.R.

    1985-02-01

    The heterogeneous reactions in which catalyst deactivation by pore plugging occur are listed and include: coke formation in petroleum processing, especially hydrocracking and hydrodesulfurization catalysts; steam reforming and methnation catalysts; ammonia synthesis catalyst; and automobile exhause catalysts. The authors explain how the Claus process converts hydrogen sulfide produced by petroleum desulfurization units and gas treatment processes into elemental sulfur and water. More than 15 million tons of sulfur are recovered annually by this process. Commercial Claus plants appear to operate at thermodynamic equilibrium. Depending on the H2S content of the feed and the number of reactors, total H2S conversion to elemental sulfur can exceed 95%.

  18. Molybdenum sulfide/carbide catalysts

    DOEpatents

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  19. Automatic Filtering and Substantiation of Drug Safety Signals

    PubMed Central

    Bauer-Mehren, Anna; van Mullingen, Erik M.; Avillach, Paul; Carrascosa, María del Carmen; Garcia-Serna, Ricard; Piñero, Janet; Singh, Bharat; Lopes, Pedro; Oliveira, José L.; Diallo, Gayo; Ahlberg Helgee, Ernst; Boyer, Scott; Mestres, Jordi; Sanz, Ferran; Kors, Jan A.; Furlong, Laura I.

    2012-01-01

    Drug safety issues pose serious health threats to the population and constitute a major cause of mortality worldwide. Due to the prominent implications to both public health and the pharmaceutical industry, it is of great importance to unravel the molecular mechanisms by which an adverse drug reaction can be potentially elicited. These mechanisms can be investigated by placing the pharmaco-epidemiologically detected adverse drug reaction in an information-rich context and by exploiting all currently available biomedical knowledge to substantiate it. We present a computational framework for the biological annotation of potential adverse drug reactions. First, the proposed framework investigates previous evidences on the drug-event association in the context of biomedical literature (signal filtering). Then, it seeks to provide a biological explanation (signal substantiation) by exploring mechanistic connections that might explain why a drug produces a specific adverse reaction. The mechanistic connections include the activity of the drug, related compounds and drug metabolites on protein targets, the association of protein targets to clinical events, and the annotation of proteins (both protein targets and proteins associated with clinical events) to biological pathways. Hence, the workflows for signal filtering and substantiation integrate modules for literature and database mining, in silico drug-target profiling, and analyses based on gene-disease networks and biological pathways. Application examples of these workflows carried out on selected cases of drug safety signals are discussed. The methodology and workflows presented offer a novel approach to explore the molecular mechanisms underlying adverse drug reactions. PMID:22496632

  20. New catalysts for coal processing: Metal carbides and nitrides

    SciTech Connect

    S. Ted Oyama; David F. Cox

    1999-12-03

    The subject of this research project was to investigate the catalytic properties of a new class of materials, transition metal carbides and nitrides, for treatment of coal liquid and petroleum feedstocks. The main objectives were: (1) preparation of catalysts in unsupported and supported form; (2) characterization of the materials; (3) evaluation of their catalytic properties in HDS and HDN; (4) measurement of the surface properties; and (5) observation of adsorbed species. All of the objectives were substantially carried out and the results will be described in detail below. The catalysts were transition metal carbides and nitrides spanning Groups 4--6 in the Periodic Table. They were chosen for study because initial work had shown they were promising materials for hydrotreating. The basic strategy was first to prepare the materials in unsupported form to identify the most promising catalyst, and then to synthesize a supported form of the material. Already work had been carried out on the synthesis of the Group VI compounds Mo{sub 2}C, Mo{sub 2}N, and WC, and new methods were developed for the Group V compounds VC and NbC. All the catalysts were then evaluated in a hydrotreating test at realistic conditions. It was found that the most active catalyst was Mo{sub 2}C, and further investigations of the material were carried out in supported form. A new technique was employed for the study of the bulk and surface properties of the catalysts, near edge x-ray absorption spectroscopy (NEXAFS), that fingerprinted the electronic structure of the materials. Finally, two new research direction were explored. Bimetallic alloys formed between two transition metals were prepared, resulting in catalysts having even higher activity than Mo{sub 2}C. The performance of the catalysts in hydrodechloration was also investigated.

  1. The remarkable enhancement of CO-pretreated CuO-Mn2O3/γ-Al2O3 supported catalyst for the reduction of NO with CO: the formation of surface synergetic oxygen vacancy.

    PubMed

    Li, Dan; Yu, Qiang; Li, Shan-Shan; Wan, Hai-Qin; Liu, Lian-Jun; Qi, Lei; Liu, Bin; Gao, Fei; Dong, Lin; Chen, Yi

    2011-05-01

    NO reduction by CO was investigated over CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuOMn2O3/γ-Al2O3 model catalysts before and after CO pretreatment at 300 °C. The CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst exhibited higher catalytic activity than did the other catalysts. Based on X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflectance spectroscopy (DRS), Raman, and H2-temperature-programmed reduction (TPR) results, as well as our previous studies, the possible interaction model between dispersed copper and manganese oxide species as well as γ-Al2O3 surface has been proposed. In this model, Cu and Mn ions occupied the octahedral vacant sites of γ-Al2O3, with the capping oxygen on top of the metal ions to keep the charge conservation. For the fresh CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, the -Cu-O-Cu- and -Mn-O-Mn- species were formed on the surface of γ-Al2O3, respectively; but for the fresh CuO-Mn2O3/γ-Al2O3 catalyst, -Cu-O-Mn- species existed on the surface of -Al2O3. After CO pretreatment, -Cu-□-Cu- and -Mn-□-Mn- (□ represents surface oxygen vacancy (SOV)) species would be formed in CO-pretreated CuO/γ-Al2O3 and CO-pretreated Mn2O3/γ-Al2O3 catalysts, respectively; whereas -Cu-□-Mn- species existed in CO-pretreated CuO-Mn2O3/γ-Al2O3. Herein, a new concept, surface synergetic oxygen vacancy (SSOV), which describes the oxygen vacancy formed between the individual Mn and Cu ions, is proposed for CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst. In addition, the role of SSOV has also been approached by NO temperature-programmed desorption (TPD) and in situ FTIR experiments. The FTIR results of competitive adsorption between NO and CO on all the CO-pretreated CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuO-Mn2O3/γ-Al2O3 samples demonstrated that NO molecules mainly were adsorbed on Mn2+ and CO mainly on Cu+ sites. The current study suggests that the properties of the SSOVs in CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst were significantly

  2. Factors affecting activated carbon-based catalysts for selective hydrogen sulfide oxidation

    SciTech Connect

    Li, Huixing; Monnell, J.D.; Alvin, M.A.; Vidic, R.D.

    2008-09-01

    The primary product of coal gasification processes is synthesis gas (syngas), a mixture of CO, H2, CO2, H2O and a number of minor components. Among the most significant minor components in syngas is hydrogen sulfide (H2S). In addition to its adverse environmental impact, H2S poisons the catalysts and hydrogen purification membranes, and causes severe corrosion in gas turbines. Technologies that can remove H2S from syngas and related process streams are, therefore, of considerable practical interest. To meet this need, we work towards understanding the mechanism by which prospective H2S catalysts perform in simulated fuel gas conditions. Specifically, we show that for low-temperature gas clean-up (~1408C) using activated carbon fibers and water plays a significant role in H2S binding and helps to prolong the lifetime of the material. Basic surface functional groups were found to be imperative for significant conversion of H2S to daughter compounds, whereas metal oxides (La and Ce) did little to enhance this catalysis. We show that although thermal regeneration of the material is possible, the regenerated material has a substantially lower catalytic and sorption capacity.

  3. Nano Catalysts for Diesel Engine Emission Remediation

    SciTech Connect

    Narula, Chaitanya Kumar; Yang, Xiaofan; Debusk, Melanie Moses; Mullins, David R; Mahurin, Shannon Mark; Wu, Zili

    2012-06-01

    The objective of this project was to develop durable zeolite nanocatalysts with broader operating temperature windows to treat diesel engine emissions to enable diesel engine based equipment and vehicles to meet future regulatory requirements. A second objective was to improve hydrothermal durability of zeolite catalysts to at least 675 C. The results presented in this report show that we have successfully achieved both objectives. Since it is accepted that the first step in NO{sub x} conversion under SCR (selective catalytic reduction) conditions involves NO oxidation to NO{sub 2}, we reasoned that catalyst modification that can enhance NO oxidation at low-temperatures should facilitate NO{sub x} reduction at low temperatures. Considering that Cu-ZSM-5 is a more efficient catalyst than Fe-ZSM-5 at low-temperature, we chose to modify Cu-ZSM-5. It is important to point out that the poor low-temperature efficiency of Fe-ZSM-5 has been shown to be due to selective absorption of NH{sub 3} at low-temperatures rather than poor NO oxidation activity. In view of this, we also reasoned that an increased electron density on copper in Cu-ZSM-5 would inhibit any bonding with NH{sub 3} at low-temperatures. In addition to modified Cu-ZSM-5, we synthesized a series of new heterobimetallic zeolites, by incorporating a secondary metal cation M (Sc{sup 3+}, Fe{sup 3+}, In{sup 3+}, and La{sup 3+}) in Cu exchanged ZSM-5, zeolite-beta, and SSZ-13 zeolites under carefully controlled experimental conditions. Characterization by diffuse-reflectance ultra-violet-visible spectroscopy (UV-Vis), X-ray powder diffraction (XRD), extended X-ray absorption fine structure spectroscopy (EXAFS) and electron paramagnetic resonance spectroscopy (EPR) does not permit conclusive structural determination but supports the proposal that M{sup 3+} has been incorporated in the vicinity of Cu(II). The protocols for degreening catalysts, testing under various operating conditions, and accelerated aging

  4. Intermediate Ethanol Blends Catalyst Durability Program

    SciTech Connect

    West, Brian H; Sluder, Scott; Knoll, Keith; Orban, John; Feng, Jingyu

    2012-02-01

    In the summer of 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the test program was to develop information important to assessing the viability of using intermediate blends as a contributor to meeting national goals for the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20 - gasoline blended with 15% and 20% ethanol - on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This report provides the results of the catalyst durability study, a substantial part of the overall test program. Results from additional projects will be reported separately. The principal purpose of the catalyst durability study was to investigate the effects of adding up to 20% ethanol to gasoline on the durability of catalysts and other aspects of the emissions control systems of vehicles. Section 1 provides further information about the purpose and context of the study. Section 2 describes the experimental approach for the test program, including vehicle selection, aging and emissions test cycle, fuel selection, and data handling and analysis. Section 3 summarizes the effects of the ethanol blends on emissions and fuel economy of the test vehicles. Section 4 summarizes notable unscheduled maintenance and testing issues experienced during the program. The appendixes provide additional detail about the statistical models used in the analysis, detailed statistical analyses, and detailed vehicle specifications.

  5. Site-Selective Acylations with Tailor-Made Catalysts.

    PubMed

    Huber, Florian; Kirsch, Stefan F

    2016-04-18

    The acylation of alcohols catalyzed by N,N-dimethylamino pyridine (DMAP) is, despite its widespread use, sometimes confronted with substrate-specific problems: For example, target compounds with multiple hydroxy groups may show insufficient selectivity for one hydroxyl, and the resulting product mixtures are hardly separable. Here we describe a concept that aims at tailor-made catalysts for the site-specific acylation. To this end, we introduce a catalyst library where each entry is constructed by connecting a variable and readily tuned peptide scaffold with a catalytically active unit based on DMAP. For selected examples, we demonstrate how library screening leads to the identification of optimized catalysts, and the substrates of interest can be converted with a markedly enhanced site-selectivity compared with only DMAP. Furthermore, substrate-optimized catalysts of this type can be used to selectively convert "their" substrate in the presence of structurally similar compounds, an important requisite for reactions with mixtures of substances. PMID:26970553

  6. Ru/FTO: Heterogeneous catalyst for glycerol hydrogenolysis

    NASA Astrophysics Data System (ADS)

    Samad, Wan Zurina; Isahak, Wan Nor Roslam Wan; Liew, Kin Hong; Nordin, Norazzizi; Yarmo, Mohd Ambar; Yusop, Muhammad Rahimi

    2014-09-01

    An introduction of Fluorine-doped tin oxide (FTO) as new catalyst support with Ru metal had enhanced the conversion and selectivity for glycerol hydrogenolysis. A small cluster of Ru were highly dispersed and intercalated over FTO via simple chemical mixture and reduction method. In comparison with various metal (Pd, Os, Cu), Ru/FTO catalyst showed the highest conversion (100%) and highly selectivity of 1,2-propanediol (94%) in the hydrogenolysis of glycerol. The reaction was optimally conducted at 150 °C, 20 bar of H2 pressure and at 8 hours. Ru/FTO catalyst was ascribed as active catalyst due to the amphoteric sites of FTO and small size of Ru metal. This provides high surface concentration of reduction process that involves the chemical bond dissociation in the glycerol hydrogenolysis.

  7. Carbon nanotube patterning with capillary micromolding of catalyst.

    PubMed

    Lee, Jaewon; Ryu, Choonghan; Lee, Sungwoo; Jung, Donggeun; Kim, Hyoungsub; Chae, Heeyeop

    2007-11-01

    Patterning of multi-walled carbon nanotube (MWNT) in a plasma enhanced chemical vapor deposition (PECVD) chamber has been achieved by catalyst patterning using capillary micromolding process. Iron acetate catalyst nanoparticles were dissolved in ethanol and mold was fabricated with polydimethylsiloxane (PDMS). The ethanol solution containing catalyst nanoparticles was filled into the microchannel formed between PDMS mold and Si-wafer by capillary force. The capillary action of different solvents was simulated by commercial CFD-ACE+ simulation code to determine optimal solvents. Simulated result shows that the choice of solvent was critical in this capillary filling process. After the catalyst patterning, MWNT was grown at 700 approximately 800 degrees C by PECVD process using CH4 and Ar gas in a scale of approximately 10 micro-meters in a tubular inductively coupled plasma reactor. Grown CNTs were analyzed by FE-SEM and Raman Spectroscopy. PMID:18047145

  8. Photochemical route for synthesizing atomically dispersed palladium catalysts.

    PubMed

    Liu, Pengxin; Zhao, Yun; Qin, Ruixuan; Mo, Shiguang; Chen, Guangxu; Gu, Lin; Chevrier, Daniel M; Zhang, Peng; Guo, Qing; Zang, Dandan; Wu, Binghui; Fu, Gang; Zheng, Nanfeng

    2016-05-13

    Atomically dispersed noble metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low (usually below 0.5%) to avoid the formation of metal nanoparticles through sintering. We report a photochemical strategy to fabricate a stable atomically dispersed palladium-titanium oxide catalyst (Pd1/TiO2) on ethylene glycolate (EG)-stabilized ultrathin TiO2 nanosheets containing Pd up to 1.5%. The Pd1/TiO2 catalyst exhibited high catalytic activity in hydrogenation of C=C bonds, exceeding that of surface Pd atoms on commercial Pd catalysts by a factor of 9. No decay in the activity was observed for 20 cycles. More important, the Pd1/TiO2-EG system could activate H2 in a heterolytic pathway, leading to a catalytic enhancement in hydrogenation of aldehydes by a factor of more than 55. PMID:27174982

  9. Cell performance of Pd-Sn catalyst in passive direct methanol alkaline fuel cell using anion exchange membrane

    NASA Astrophysics Data System (ADS)

    Kim, Jandee; Momma, Toshiyuki; Osaka, Tetsuya

    Direct methanol alkaline fuel cell (DMAFC) using anion exchange membrane (AEM) was operated in passive condition. Cell with AEM exhibits a higher open circuit voltage (OCV) and superior cell performance than those in cell using Nafion. From the concentration dependences of methanol, KOH in fuel and ionomer in anode catalyst layer, it is found that the key factors are to improve the ionic conductivity at the anode and to form a favorable ion conductive path in catalyst layer in order to enhance the cell performance. In addition, by using home-made Pd-Sn/C catalyst as a cathode catalyst on DMAFC, the membrane electrode assembly (MEA) using Pd-Sn/C catalyst as cathode exhibits the higher performance than the usual commercially available Pt/C catalyst in high methanol concentration. Therefore, the Pd-Sn/C catalyst with high tolerance for methanol is expected as the promising oxygen reduction reaction (ORR) catalyst in DMAFC.

  10. Leaky domino-modes in regular arrays of substantially thick metal nanostrips

    NASA Astrophysics Data System (ADS)

    Voroshilov, Pavel M.; Simovski, Constantin R.

    2016-07-01

    In previous works, an efficient light trapping performed by arrays of metal nanoantennas whose building block was a slightly tapered (trapezoidal) substantially thick nanostrip was revealed. This light trapping implied a broad spectrum of solar light concentrated in a subwavelength depth of the semiconductor substrate. This is a very advantageous feature allowing our structure to enhance thin-film solar cells. However, the physics of the broadband resonant absorption in the substrate was not investigated. In the present paper, we show that our arrays support so-called leaky domino-modes, responsible for such the light trapping. These modes are multipole oscillations of the array of substantially thick nanostrips. In this work we have thoroughly studied these leaky modes relating them to resonances of high-order multipole moments and to broadband light-trapping effect.

  11. Novel Au-TiC Catalysts for CO Oxidation and Desulfurization Processes

    SciTech Connect

    J Rodriguez; P Liu; Y Takahashi; F Vines; L Feria; E Florez; K Nakamura

    2011-12-31

    Recent articles dealing with the physical and chemical properties of novel Au-TiC catalysts are reviewed. High-resolution photoemission, scanning tunneling microscopy and first-principles periodic density-functional calculations were used to study the deposition of gold on a TiC(0 0 1) surface. Gold grows forming two-dimensional (very low coverage) and three-dimensional (medium and large coverage) islands on the carbide substrate. A positive shift in the binding energy of the C 1s core level is observed after the deposition of Au on TiC(0 0 1). The results of the density-functional calculations corroborate the formation of Au-C bonds. In general, the bond between Au and the TiC(0 0 1) surface exhibits very little ionic character, but there is a substantial polarization of electrons around Au that facilitates bonding of the adatoms with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). Experimental measurements indicate that Au/TiC(0 0 1) is a very good catalysts for the oxidation of CO, the destruction of SO{sub 2} and the hydrodesulfurization of thiophene. At temperatures below 200 K, Au/TiC(0 0 1) is able to perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction and the full decomposition of SO{sub 2}. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(0 0 1) or Au(1 1 1), a Au/TiC(0 0 1) surface displays a hydrodesulfurization activity higher than that of conventional Ni/MoS{sub x} catalysts. Metal carbides are excellent supports for enhancing the chemical reactivity of gold. The Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces.

  12. Novel Au-TiC Catalysts for CO Oxidation and Desulfurization Processes

    SciTech Connect

    Rodriguez, J.A.; Liu, P.; Takahashi, Y.; Viñes, F.; Feria, L.; Florez, E.; Nakamura, K.; Illas, F.

    2011-05-30

    Recent articles dealing with the physical and chemical properties of novel Au-TiC catalysts are reviewed. High-resolution photoemission, scanning tunneling microscopy and first-principles periodic density-functional calculations were used to study the deposition of gold on a TiC(0 0 1) surface. Gold grows forming two-dimensional (very low coverage) and three-dimensional (medium and large coverage) islands on the carbide substrate. A positive shift in the binding energy of the C 1s core level is observed after the deposition of Au on TiC(0 0 1). The results of the density-functional calculations corroborate the formation of Au-C bonds. In general, the bond between Au and the TiC(0 0 1) surface exhibits very little ionic character, but there is a substantial polarization of electrons around Au that facilitates bonding of the adatoms with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). Experimental measurements indicate that Au/TiC(0 0 1) is a very good catalysts for the oxidation of CO, the destruction of SO{sub 2} and the hydrodesulfurization of thiophene. At temperatures below 200 K, Au/TiC(0 0 1) is able to perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction and the full decomposition of SO{sub 2}. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(0 0 1) or Au(1 1 1), a Au/TiC(0 0 1) surface displays a hydrodesulfurization activity higher than that of conventional Ni/MoS{sub x} catalysts. Metal carbides are excellent supports for enhancing the chemical reactivity of gold. The Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces.

  13. Simulated carbon emissions from land-use change are substantially enhanced by accounting for agricultural management

    NASA Astrophysics Data System (ADS)

    Pugh, T. A. M.; Arneth, A.; Olin, S.; Ahlström, A.; Bayer, A. D.; Klein Goldewijk, K.; Lindeskog, M.; Schurgers, G.

    2015-12-01

    It is over three decades since a large terrestrial carbon sink (S T) was first reported. The magnitude of the net sink is now relatively well known, and its importance for dampening atmospheric CO2 accumulation, and hence climate change, widely recognised. But the contributions of underlying processes are not well defined, particularly the role of emissions from land-use change (E LUC) versus the biospheric carbon uptake (S L; S T = S L - E LUC). One key aspect of the interplay of E LUC and S L is the role of agricultural processes in land-use change emissions, which has not yet been clearly quantified at the global scale. Here we assess the effect of representing agricultural land management in a dynamic global vegetation model. Accounting for harvest, grazing and tillage resulted in cumulative E LUC since 1850 ca. 70% larger than in simulations ignoring these processes, but also changed the timescale over which these emissions occurred and led to underestimations of the carbon sequestered by possible future reforestation actions. The vast majority of Earth system models in the recent IPCC Fifth Assessment Report omit these processes, suggesting either an overestimation in their present-day S T, or an underestimation of S L, of up to 1.0 Pg C a-1. Management processes influencing crop productivity per se are important for food supply, but were found to have little influence on E LUC.

  14. Combined Regional Investments Could Substantially Enhance Health System Performance And Be Financially Affordable.

    PubMed

    Homer, Jack; Milstein, Bobby; Hirsch, Gary B; Fisher, Elliott S

    2016-08-01

    Leaders across the United States face a difficult challenge choosing among possible approaches to transform health system performance in their regions. The ReThink Health Dynamics Model simulates how alternative scenarios could unfold through 2040. This article compares the likely consequences if four interventions were enacted in layered combinations in a prototypical midsize US city. We estimated the effects of efforts to deliver higher-value care; reinvest savings and expand global payment; enable healthier behaviors; and expand socioeconomic opportunities. Results suggest that there may be an effective and affordable way to unlock much greater health and economic potential, ultimately reducing severe illness by 20 percent, lowering health care costs by 14 percent, and improving economic productivity by 9 percent. This would require combined investments in clinical and population-level initiatives, coupled with financial agreements that reduce incentives for costly care and reinvest a share of the savings to ensure adequate long-term financing. PMID:27503969

  15. Enhancing the stability of copper chromite catalysts for the selective hydrogenation of furfural with ALD overcoating (II) – Comparison between TiO2 and Al2O3 overcoatings

    SciTech Connect

    Zhang, Hongbo; Canlas, Christian; Kropf, A. Jeremy; Elam, Jeffrey W.; Dumesic, James A; Marshall, Christopher L.

    2015-01-01

    TiO2 atomic layer deposition (ALD) overcoatings were applied to copper chromite catalysts to increase the stability for 2-furfuraldehyde (“furfural”) hydrogenation. After overcoating, about 75% activity was preserved compared to neat copper chromite: much higher activity than an alumina ALD overcoated catalyst with a similar number of ALD cycles. The effects of ALD TiO2 on the active Cu nanoparticles were studied extensively using both in-situ TPR/isothermal-oxidation and in-situ furfural hydrogenation via Cu XAFS. The redox properties of Cu were modified only slightly by the TiO2 ALD overcoat. However, a subtle electronic interaction was observed between the TiO2 ALD layers and the Cu nanoparticles. With calcination at 500 °C the interaction between the TiO2 overcoat and the underlying catalyst is strong enough to inhibit migration and site blocking by chromite, but is sufficiently weaker than the interaction between the Al2O3 overcoat and copper chromite that it does not strongly inhibit the catalytic activity of the copper nanoparticles.

  16. FCC catalyst selection

    SciTech Connect

    Carter, G.D.L. ); McElhiney, G. )

    1989-09-01

    This paper discusses a commonly used technique for comparing FCC catalytic selectivities based on the ASTM microactivity test (MAT) procedure, ASTM D-3907-80. In its original form the ASTM test provides only very limited information on selectivity. However, extension of the ASTM MAT procedure by using additional product analyses gives a microselectivity test capable of providing detailed yield structure information. This modified MAT procedure thus provides a cost-effective and rapid means of comparing many catalysts.

  17. Fuel cell applications for novel metalloporphyrin catalysts

    SciTech Connect

    Ryba, G.; Shelnutt, J.; Doddapaneni, N.; Zavadil, K.

    1997-04-01

    This project utilized Computer-Aided Molecular Design (CAMD) to develop a new class of metalloporphyrin materials for use as catalysts for two fuel cell reactions. The first reaction is the reduction of oxygen at the fuel cell cathode, and this reaction was the main focus of the research. The second reaction we attempted to catalyze was the oxidation of methanol at the anode. Two classes of novel metalloporphyrins were developed. The first class comprised the dodecaphenylporphyrins whose steric bulk forces them into a non-planar geometry having a pocket where oxygen or methanol is more tightly bound to the porphyrin than it is in the case of planar porphyrins. Significant improvements in the catalytic reduction of oxygen by the dodecaphenyl porphyrins were measured in electrochemical cells. The dodecaphenylporphyrins were further modified by fluorinating the peripheral phenyl groups to varying degrees. The fluorination strongly affected their redox potential, but no effect on their catalytic activity towards oxygen was observed. The second class of porphyrin catalysts was a series of hydrogen-bonding porphyrins whose interaction with oxygen is enhanced. Enhancements in the interaction of oxygen with the porphyrins having hydrogen bonding groups were observed spectroscopically. Computer modeling was performed using Molecular Simulations new CERIUS2 Version 1.6 and a research version of POLYGRAF from Bill Goddard`s research group at the California Institute of Technology. We reoptimized the force field because of an error that was in POLYGRAF and corrected a problem in treatment of the metal in early versions of the program. This improved force field was reported in a J. Am. Chem. Soc. manuscript. Experimental measurements made on the newly developed catalysts included the electrochemical testing in a fuel cell configuration and spectroscopic measurements (UV-Vis, Raman and XPS) to characterize the catalysts.

  18. Steam reforming catalyst

    DOEpatents

    Kramarz, Kurt W.; Bloom, Ira D.; Kumar, Romesh; Ahmed, Shabbir; Wilkenhoener, Rolf; Krumpelt, Michael

    2001-01-01

    A method of forming a hydrogen rich gas from a source of hydrocarbon fuel. A vapor of the hydrocarbon fuel and steam is brought in contact with a two-part catalyst having a dehydrogenation powder portion and an oxide-ion conducting powder portion at a temperature not less than about 770.degree.C. for a time sufficient to generate the hydrogen rich. The H.sub.2 content of the hydrogen gas is greater than about 70 percent by volume. The dehydrogenation portion of the catalyst includes a group VIII metal, and the oxide-ion conducting portion is selected from a ceramic oxide from the group crystallizing in the fluorite or perovskite structure and mixtures thereof. The oxide-ion conducting portion of the catalyst is a ceramic powder of one or more of ZrO.sub.2, CeO.sub.2, Bi.sub.2 O.sub.3, (BiVO).sub.4, and LaGaO.sub.3.

  19. Hydrotreating catalyst selection

    SciTech Connect

    Kellett, T.F.; Trevino, C.A.; Sartor, A.F.

    1980-01-01

    Hydrotreating catalyst selection can be correctly made in most cases by using a decision tree developed for choosing between the commonly used cobalt/molybdenum and nickel/molybdenum. The decision suggests the use of Co/Mo for desulfurizing straight-run feeds (except naphtha) and Ni/Mo for hydrogen uptake (saturating aromatics, treating fluid catalytic-cracking (FCC) feedstocks, improving color or thermal stability, and increasing the octane number) with any feed, and for denitrogenation of cracked feeds or mixed feeds with greater than or equal to 20% cracked materials. For desulfurization of cracked or mixed feeds and for desulfurization or denitrogenation of naphtha, the selection depends on the reaction conditions. Pilot-plant studies with the second-generation commercial Shell 344 (Co/Mo) and Shell 324 (Ni/Mo) catalysts used in hydrotreating vacuum gas oils, flashed distillate, or heavy catalytically cracked gas oil supported the predictions made with the decision tree, but the better performance of the Ni/Mo catalyst in desulfurizing a 20% coker/80% straight-run naphtha at low partial pressures of hydrogen was an unexpected result.

  20. Highly efficient nonprecious metal catalysts towards oxygen reduction reaction based on three-dimensional porous carbon nanostructures.

    PubMed

    Zhu, Chengzhou; Li, He; Fu, Shaofang; Du, Dan; Lin, Yuehe

    2016-02-01

    Developing a low cost, highly active, durable cathode towards an oxygen reduction reaction (ORR) is one of the high-priority research directions for commercialization of low-temperature polymer electrolyte membrane fuel cells (PEMFCs). However, the electrochemical performance of PEMFCs is still hindered by the high cost and insufficient durability of the traditional Pt-based cathode catalysts. Under these circumstances, the search for efficient alternatives to replace Pt for constructing highly efficient nonprecious metal catalysts (NPMCs) has been growing intensively and has received great interest. Combining with the compositional effects, the accurate design of NPMCs with 3D porous nanostructures plays a significant role in further enhancing ORR performance. These 3D porous architectures are able to provide higher specific surface areas and larger pore volumes, not only maximizing the availability of electron transfer within the nanosized electrocatalyst surface area but also providing better mass transport of reactants to the electrocatalyst. In this Tutorial Review, we focus on the rational design and synthesis of different 3D porous carbon-based nanomaterials, such as heteroatom-doped carbon, metal-nitrogen-carbon nanostructures and a series of carbon/nonprecious metal-based hybrids. More importantly, their enhanced ORR performances are also demonstrated by virtue of their favorably porous morphologies and compositional effects. Finally, the future trends and perspectives for the highly efficient porous NPMCs regarding the material design are discussed, with an emphasis on substantial development of advanced carbon-based NPMCs for ORR in the near future. PMID:26658546

  1. Process for treating spent catalyst including antimony halides from chlorofluorocarbon production

    SciTech Connect

    Kalcevic, V.; McGahan, J.F.

    1988-06-14

    A process for treating spent catalyst from chlorofluorocarbon production is described wherein the catalyst includes antimony halides and undergoes hydrolysis in an aqueous medium to produce insoluble antimony compounds and fluoride ions. The process comprises hydrolyzing the catalyst in an aqueous solution of ferric chloride having a sufficient concentration of ferric ions to complex substantially all of the fluoride ions produced upon hydrolysis of the catalyst, neutralizing the reaction mass present following hydrolysis of the catalyst and complexing of the fluoride ions by contacting the reaction mass with an aqueous suspension of a compound selected from the class consisting of calcium hydroxide and magnesium hydroxide, and separating the insoluble antimony compounds from the neutralized reaction mass.

  2. 20 CFR 655.183 - Less than substantial violations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... EMPLOYMENT OF FOREIGN WORKERS IN THE UNITED STATES Labor Certification Process for Temporary Agricultural... streamlined interviewing and referral techniques. The special procedures are designed to enhance U.S. worker... necessary to assure employer compliance with the test of U.S. worker availability and adverse...

  3. Development of GREET Catalyst Module

    SciTech Connect

    Wang, Zhichao; Benavides, Pahola T.; Dunn, Jennifer B.; Cronauer, Donald C.

    2015-09-01

    In this report, we develop energy and material flows for the production of five different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5], Mo/Co/ γ-Al2O3, and Pt/ γ-Al2O3) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module.

  4. RF Sputtering for preparing substantially pure amorphous silicon monohydride

    DOEpatents

    Jeffrey, Frank R.; Shanks, Howard R.

    1982-10-12

    A process for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicon produced by reactive rf sputtering of an amorphous silicon target. There is provided a chamber with an amorphous silicon target and a substrate therein with the substrate and the target positioned such that when rf power is applied to the target the substrate is in contact with the sputtering plasma produced thereby. Hydrogen and argon are fed to the chamber and the pressure is reduced in the chamber to a value sufficient to maintain a sputtering plasma therein, and then rf power is applied to the silicon target to provide a power density in the range of from about 7 watts per square inch to about 22 watts per square inch to sputter an amorphous silicon hydride onto the substrate, the dihydride bond density decreasing with an increase in the rf power density. Substantially pure monohydride films may be produced.

  5. Borehole survey method and apparatus for drilling substantially horizontal boreholes

    SciTech Connect

    Trowsdale, L.S.

    1982-11-30

    A borehole survey method and apparatus are claimed for use in drilling substantially horizontal boreholes through a mineral deposit wherein a dip accelerometer, a roll accelerometer assembly and a fluxgate are disposed near the drill bit, which is mounted on a bent sub, and connected to a surface computation and display unit by a cable which extends through the drill string. The dip angle of the borehole near the drill bit, the azimuth of the borehole near the drill bit and the roll angle or orientation of the bent sub are measured and selectively displayed at the surface while the drill string is in the borehole for utilization in guiding the drill bit through the mineral deposit along a predetermined path.

  6. Clozapine-induced dysphagia with secondary substantial weight loss.

    PubMed

    Osman, Mugtaba; Devadas, Vekneswaran

    2016-01-01

    Dysphagia is listed as a 'rare' side effect following clozapine treatment. In this case report, we describe how significant clozapine-induced dysphagia has led to significant reduction of nutritional intake with subsequent substantial weight loss. An 18-year-old single man with an established diagnosis of treatment-resistant paranoid schizophrenia recovered well on a therapeutic dose of clozapine. However, he was noted to lose weight significantly (up to 20% of his original weight) as the dose was uptitrated. This was brought about by development of dysphagia, likely to be due to clozapine. Addition of nutritional supplementary liquids and initiation of a modified behavioural dietary/swallowing programme, while repeatedly mastering the Mendelsohn manoeuvre technique, alleviated the swallowing difficulties and restored his weight. PMID:27543610

  7. Resonant infrared detector with substantially unit quantum efficiency

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam (Inventor); Mcmurray, Robert E., Jr. (Inventor)

    1994-01-01

    A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.

  8. Method and apparatus for a substantially coaxial injector element

    NASA Technical Reports Server (NTRS)

    Horn, Mark D. (Inventor); Miyata, Shinjiro (Inventor); Farhangi, Shahram (Inventor)

    2006-01-01

    A system to provide a two piece robust fluid injector. According to various embodiments, the fluid injector is a fuel injector for a combustion engine. The injector includes two coaxially formed annuluses. One annulus is formed in a face plate and the second annulus or hole is defined by a tube extending through the face plate. The tube extends through the face plate in a portion of a through bore which also is used to define the second annulus. The second annulus is formed using a throughbore through which the tube extends. This allows the second annulus to always be formed inherently and precisely substantially coaxial with the first annulus. Moreover, the second annulus can be formed with a much greater tolerance than if other independent components needed to be added.

  9. Method for making oxygen-reducing catalyst layers

    DOEpatents

    O'Brien, Dennis P.; Schmoeckel, Alison K.; Vernstrom, George D.; Atanasoski, Radoslav; Wood, Thomas E.; O'Neill, David G.

    2010-06-22

    Methods are provided for making oxygen-reducing catalyst layers, which include simultaneous or sequential stops of physical vapor depositing an oxygen-reducing catalytic material onto a substrate, the catalytic material comprising a transition metal that is substantially free of platinum; and thermally treating the catalytic material. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  10. Results of catalyst testing using iron-based catalysts

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.

    1993-03-01

    As coal liquefaction catalysts, iron-based products are generally inferior to the more expensive molybdenum, cobalt, or nickel-based materials. However, the lower costs of production and recovery (or in the case of some iron catalysts, non-recovery) give the iron-based materials a potential economic advantage over the more efficient precious and semi-precious metal catalysts for this application. Recent research has shown that a number of different iron-containing materials can be successfully utilized as coal liquefaction catalysts or as catalyst. Pyrrhotite (Fe{sub 1-x}S) or a similar iron-sulfide phase is commonly believed to be the active catalyst in coal liquefaction and model compound pyrolysis reactions, although no specific phase has been yet been isolated as the actual catalyst species. The active iron-containing catalyst is usually generated in situ from an iron-oxide precursor and an elemental sulfur source under reducing conditions in the reactor vessel. Most research has concentrated on the use of common iron-oxide phases such as hematite or goethite (and their derivatives) as the iron-bearing precursor, or on non-specific iron materials produced by the reaction of various iron salts and compounds in the coal or liquefaction reactor. To our knowledge there has been no systematic effort to determine the optimum iron-containing precursor phase for producing active coal liquefaction catalysts, despite the fact that there are over ten iron-(hydroxy)oxide phases which can be easily synthesized in the laboratory. We have undertaken a systematic study to identify the most active iron-oxide catalyst precursor phases, the co-catalysts, and the coal pretreatments which will provide optimum yields in coal liquefaction processes.

  11. Results of catalyst testing using iron-based catalysts

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.

    1993-03-01

    As coal liquefaction catalysts, iron-based products are generally inferior to the more expensive molybdenum, cobalt, or nickel-based materials. However, the lower costs of production and recovery (or in the case of some iron catalysts, non-recovery) give the iron-based materials a potential economic advantage over the more efficient precious and semi-precious metal catalysts for this application. Recent research has shown that a number of different iron-containing materials can be successfully utilized as coal liquefaction catalysts or as catalyst. Pyrrhotite (Fe[sub 1-x]S) or a similar iron-sulfide phase is commonly believed to be the active catalyst in coal liquefaction and model compound pyrolysis reactions, although no specific phase has been yet been isolated as the actual catalyst species. The active iron-containing catalyst is usually generated in situ from an iron-oxide precursor and an elemental sulfur source under reducing conditions in the reactor vessel. Most research has concentrated on the use of common iron-oxide phases such as hematite or goethite (and their derivatives) as the iron-bearing precursor, or on non-specific iron materials produced by the reaction of various iron salts and compounds in the coal or liquefaction reactor. To our knowledge there has been no systematic effort to determine the optimum iron-containing precursor phase for producing active coal liquefaction catalysts, despite the fact that there are over ten iron-(hydroxy)oxide phases which can be easily synthesized in the laboratory. We have undertaken a systematic study to identify the most active iron-oxide catalyst precursor phases, the co-catalysts, and the coal pretreatments which will provide optimum yields in coal liquefaction processes.

  12. Mixed Alcohol Synthesis Catalyst Screening

    SciTech Connect

    Gerber, Mark A.; White, James F.; Stevens, Don J.

    2007-09-03

    National Renewable Energy Laboratory (NREL) and Pacific Northwest National Laboratory (PNNL) are conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). PNNL is tasked with obtaining commercially available or preparing promising mixed-alcohol catalysts and screening them in a laboratory-scale reactor system. Commercially available catalysts and the most promising experimental catalysts are provided to NREL for testing using a slipstream from a pilot-scale biomass gasifier. From the standpoint of producing C2+ alcohols as the major product, it appears that the rhodium catalyst is the best choice in terms of both selectivity and space-time yield (STY). However, unless the rhodium catalyst can be improved to provide minimally acceptable STYs for commercial operation, mixed alcohol synthesis will involve significant production of other liquid coproducts. The modified Fischer-Tropsch catalyst shows the most promise for providing both an acceptable selectivity to C2+ alcohols and total liquid STY. However, further optimization of the Fischer-Tropsch catalysts to improve selectivity to higher alcohols is highly desired. Selection of a preferred catalyst will likely entail a decision on the preferred coproduct slate. No other catalysts tested appear amenable to the significant improvements needed for acceptable STYs.

  13. Method for regenerating, replacing or treating the catalyst in a hydroprocessing reactor

    SciTech Connect

    Epperly, W.R.; Sprague, B.N.; Kelso, D.T.; Bowers, W.E.

    1993-06-01

    A method is described for regenerating, replacing or treating the catalyst in a hydroprocessing reactor, which catalyst comprises a platinum group metal on a support, the method comprising admixing with the feedstock, recycle stream or hydrogen stream of the reactor an additive which comprises a nonionic, organometallic platinum group metal coordination composition wherein said composition (a) has a breakdown temperature between about 40 C. and about 570 C.; and (b) is substantially free from a disadvantageous amount of phosphorus, arsenic, sulfur, antimony or halides, wherein platinum group metal is caused to be deposited on said catalyst.

  14. Method for producing hydrocarbon fuels from heavy polynuclear hydrocarbons by use of molten metal halide catalyst

    DOEpatents

    Gorin, Everett

    1979-01-01

    In a process for hydrocracking heavy polynuclear carbonaceous feedstocks to produce lighter hydrocarbon fuels by contacting the heavy feedstocks with hydrogen in the presence of a molten metal halide catalyst, thereafter separating at least a substantial portion of the carbonaceous material associated with the reaction mixture from the spent molten metal halide and thereafter regenerating the metal halide catalyst, an improvement comprising contacting the spent molten metal halide catalyst after removal of a major portion of the carbonaceous material therefrom with an additional quantity of hydrogen is disclosed.

  15. A broadly applicable and practical oligomeric (salen) Co catalyst for enantioselective epoxide ring-opening reactions

    PubMed Central

    White, David E.; Tadross, Pamela M.; Lu, Zhe

    2014-01-01

    The (salen) Co catalyst (4a) can be prepared as a mixture of cyclic oligomers in a short, chromatography-free synthesis from inexpensive, commercially available precursors. This catalyst displays remarkable enhancements in reactivity and enantioselectivity relative to monomeric and other multimeric (salen) Co catalysts in a wide variety of enantioselective epoxide ring-opening reactions. The application of catalyst 4a is illustrated in the kinetic resolution of terminal epoxides by nucleophilic ring-opening with water, phenols, and primary alcohols; the desymmetrization of meso epoxides by addition of water and carbamates; and the desymmetrization of oxetanes by intramolecular ring opening with alcohols and phenols. The favorable solubility properties of complex 4a under the catalytic conditions facilitated mechanistic studies, allowing elucidation of the basis for the beneficial effect of oligomerization. Finally, a catalyst selection guide is provided to delineate the specific advantages of oligomeric catalyst 4a relative to (salen) Co monomer 1 for each reaction class. PMID:25045188

  16. Toluene oxidation by non-thermal plasma combined with palladium catalysts.

    PubMed

    Magureanu, Monica; Dobrin, Daniela; Mandache, Nicolae B; Cojocaru, Bogdan; Parvulescu, Vasile I

    2013-01-01

    The oxidation of toluene in air was investigated using a dielectric barrier discharge (DBD) combined with a Pd/Al2O3 catalyst. When using only plasma, rather low selectivity toward CO2 was obtained: 32-35%. By filling the DBD reactor with Pd/Al2O3 catalyst the CO2 selectivity was significantly enhanced (80-90%), however, a large amount of toluene was desorbed from the catalyst when the discharge was operated. By filling a quarter of the discharge gap with catalyst and placing the rest of the catalyst downstream of the plasma reactor, an important increase of CO2 selectivity (~75%) and a 15% increase in toluene conversion were achieved as compared to the results with plasma alone. The catalyst exhibited a very good stability in this reaction. PMID:24790936

  17. Pursuing DNA Catalysts for Protein Modification

    PubMed Central

    Silverman, Scott K.

    2015-01-01

    modified DNA nucleotides, which we have recently found to enable this cleavage reaction. In numerous other efforts, we have investigated DNA-catalyzed peptide side chain modification reactions. Key successes include nucleopeptide formation (attachment of oligonucleotides to peptide side chains) and phosphatase and kinase activities (removal and attachment of phosphoryl groups to side chains). Through all of these efforts, we have learned the importance of careful selection design, including the frequent need to develop specific “capture” reactions that enable the selection process to provide only those DNA sequences that have the desired catalytic functions. We have established strategies for identifying deoxyribozymes that accept discrete peptide and protein substrates, and we have obtained data to inform the key choice of random region length at the outset of selection experiments. Finally, we have demonstrated the viability of modular deoxyribozymes that include a small-molecule-binding aptamer domain, although the value of such modularity is found to be minimal, with implications for many selection endeavors. Advances such as those summarized in this Account reveal that DNA has considerable catalytic abilities for biochemically relevant reactions, specifically including covalent protein modifications. Moreover, DNA has substantially different, and in many ways better, characteristics than do small molecules or proteins for a catalyst that is obtained “from scratch”, without demanding any existing information on catalyst structure or mechanism. Therefore, prospects are very strong for continued development and eventual practical applications of deoxyribozymes for peptide and protein modification. PMID:25939889

  18. Support chemistry, surface area, and preparation effects on sulfided NiMo catalyst activity

    SciTech Connect

    Gardner, T.J.; McLaughlin, L.I.; Sandoval, R.S.

    1996-06-01

    Hydrous Metal Oxides (HMOs) are chemically synthesized materials which contain a homogeneous distribution of ion exchangeable alkali cations that provide charge compensation to the metal-oxygen framework. In terms of the major types of inorganic ion exchangers defined by Clearfield, these amorphous HMO materials are similar to both hydrous oxides and layered oxide ion exchangers (e.g., alkali metal titanates). For catalyst applications, the HMO material serves as an ion exchangeable support which facilitates the uniform incorporation of catalyst precursor species. Following catalyst precursor incorporation, an activation step is required to convert the catalyst precursor to the desired active phase. Considerable process development activities at Sandia National Laboratories related to HMO materials have resulted in bulk hydrous titanium oxide (HTO)- and silica-doped hydrous titanium oxide (HTO:Si)-supported NiMo catalysts that are more active in model reactions which simulate direct coal liquefaction (e.g., pyrene hydrogenation) than commercial {gamma}-Al{sub 2}O{sub 3}-supported NiMo catalysts. However, a fundamental explanation does not exist for the enhanced activity of these novel catalyst materials; possible reasons include fundamental differences in support chemistry relative to commercial oxides, high surface area, or catalyst preparation effects (ion exchange vs. incipient wetness impregnation techniques). The goals of this paper are to identify the key factors which control sulfided NiMo catalyst activity, including those characteristics of HTO- and HTO:Si-supported NiMo catalysts which uniquely set them apart from conventional oxide supports.

  19. Alumoxane precursors to designer catalysts and catalyst supports: Catalytic oxidation of dichloromethane

    SciTech Connect

    Cook, R.L.; Wong, C.; Harlan, C.J.; Kareiva, A.; Barron, A.R.

    1997-12-31

    Carboxylato-alumoxanes are aluminum-oxygen macromolecules consisting of a boehmite-like core surrounded by a sheath of carboxylate groups. The alumoxanes may be processed like organic polymers yet when fired are readily transformed into ceramic oxides. The alumoxanes can be precisely doped at room temperature in aqueous solution with a range of metal cations to prepare novel catalyst and catalyst support materials. The ease of introduction of multiple cations into the alumina lattice via the alumoxane approach provides a method for fine-tuning catalyst support properties and the fabrication of new catalyst materials themselves. Manganese-doped alumina (Mn-Al{sub 2}O{sub 3}), formed via the doping of an alumoxane with Mn at room temperature, is presented as an example where the alumoxane route provides enhanced catalytic performance over traditional approaches for the low temperature catalytic oxidation of chlorinated hydrocarbons (CHCs). The Mn-Al{sub 2}O{sub 3} formed from the Mn-doped alumoxane is compared with MnO{sub 2}/Al{sub 2}O{sub 3} prepared by the incipient wetness method, and commercial Pt/Al{sub 2}O{sub 3} for the oxidation/destruction of dichloromethane (CH{sub 2}Cl{sub 2}).

  20. Improvements in FCC catalyst technology for light hydrocarbon production

    SciTech Connect

    Ritter, R.E.; Habib, E.T.; Peters, A.W.; Rheaume, L.; Thiel, P.G.; Wallace, D.N.; Wormsbecher, R.F.

    1985-03-01

    As the refining industry continues to undergo dramatic changes due to crude pricing, environmental demands, and product demand, cracking catalyst manufacturers continue to make significant strides in the understanding of the processes and products to meet the refiners' needs. This paper builds on information reported to the industry in previous articles, with the aim of keeping the industry informed of the many dramatic changes taking place in cracking catalyst technology. From our vantage point, the key refining industry concerns today are gasoline octane quality due to the lead phase-down, atmospheric emissions due to increasingly strict EPA and local limits on SOx emissions, and catalytic upgrading of resid feeds due to an expected long term price differential between high and low quality crudes. Hence, we focus here on the significant changes in cracking catalyst technology which will help the refiner handle these issues. In particular, we discuss the catalytic enhancement of gasoline octane with Davison's Octacat and GXO catalyst families, the reduction of FCC SOx emissions with Davison's Additive R SOx catalyst, and the passivation of vanadium with Davison's DVT, so that catalyst deactivation is minimized.

  1. Growth of carbon nanotubes using nanocrystalline carbon catalyst

    NASA Astrophysics Data System (ADS)

    Park, Yong Seob; Choi, Eun Chang; Hong, Byungyou

    2009-03-01

    The basic growth of carbon nanotubes (CNTs) involves dissociation of hydrocarbon molecules over a metal layer as a catalyst. Generally, the metals used for the catalyst include nickel, cobalt, gold, iron, platinum, and palladium. However, the metal catalyst used with CNTs could have a harmful influence on the electrical properties of electronic devices. Therefore, we propose the use of nanocrystalline carbon (nc-C) as the catalyst for the growth of CNTs. We used a nc-C catalyst layer deposited by the closed-field unbalanced magnetron (CFUBM) sputtering method, and CNTs were grown by the hot filament plasma-enhanced chemical vapor deposition (HF-PECVD) method with ammonia (NH 3) as a pretreatment and acetylene gas (C 2H 2) as a carbon source. The CNTs were grown on the nc-C layers pretreated with a variation of the pretreatment time. The characteristics of the pretreated nc-C layers and the grown CNTs were investigated by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) measurements. Also, the structural variation of the pretreated nc-C layers was investigated by Raman measurement. We used the nc-C catalyst without metal, and we confirmed that our CNTs were composed with only carbon elements through an EDS measurement. Also, the pretreatment time was attributed to the growth of CNTs.

  2. DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE

    EPA Science Inventory

    The objectives of this project were to better understand the effect of different catalyst preparation parameters, the effect of different catalyst treatment parameters, and the mechanism of deactivation. Accordingly, catalysts were made using various preparation methods and with...

  3. Minimalist Design of Allosterically Regulated Protein Catalysts.

    PubMed

    Makhlynets, O V; Korendovych, I V

    2016-01-01

    Nature facilitates chemical transformations with exceptional selectivity and efficiency. Despite a tremendous progress in understanding and predicting protein function, the overall problem of designing a protein catalyst for a given chemical transformation is far from solved. Over the years, many design techniques with various degrees of complexity and rational input have been developed. Minimalist approach to protein design that focuses on the bare minimum requirements to achieve activity presents several important advantages. By focusing on basic physicochemical properties and strategic placing of only few highly active residues one can feasibly evaluate in silico a very large variety of possible catalysts. In more general terms minimalist approach looks for the mere possibility of catalysis, rather than trying to identify the most active catalyst possible. Even very basic designs that utilize a single residue introduced into nonenzymatic proteins or peptide bundles are surprisingly active. Because of the inherent simplicity of the minimalist approach computational tools greatly enhance its efficiency. No complex calculations need to be set up and even a beginner can master this technique in a very short time. Here, we present a step-by-step protocol for minimalist design of functional proteins using basic, easily available, and free computational tools. PMID:27586334

  4. Novel Reforming Catalysts

    SciTech Connect

    Pfefferle, Lisa D; Haller, Gary L

    2012-10-16

    Aqueous phase reforming is useful for processing oxygenated hydrocarbons to hydrogen and other more useful products. Current processing is hampered by the fact that oxide based catalysts are not stable under high temperature hydrothermal conditions. Silica in the form of structured MCM-41 is thermally a more stable support for Co and Ni than conventional high surface area amorphous silica but hydrothermal stability is not demonstrated. Carbon nanotube supports, in contrast, are highly stable under hydrothermal reaction conditions. In this project we show that carbon nanotubes are stable high activity/selectivity supports for the conversion of ethylene glycol to hydrogen.

  5. Molecular water oxidation catalyst

    DOEpatents

    Gratzel, Michael; Munavalli, Shekhar; Pern, Fu-Jann; Frank, Arthur J.

    1993-01-01

    A dimeric composition of the formula: ##STR1## wherein L', L", L'", and L"" are each a bidentate ligand having at least one functional substituent, the ligand selected from bipyridine, phenanthroline, 2-phenylpyridine, bipyrimidine, and bipyrazyl and the functional substituent selected from carboxylic acid, ester, amide, halogenide, anhydride, acyl ketone, alkyl ketone, acid chloride, sulfonic acid, phosphonic acid, and nitro and nitroso groups. An electrochemical oxidation process for the production of the above functionally substituted bidentate ligand diaqua oxo-bridged ruthenium dimers and their use as water oxidation catalysts is described.

  6. Rhodium complex immobilized on graphene oxide as an efficient and recyclable catalyst for hydrogenation of cyclohexene.

    PubMed

    Zhao, Qingshan; Chen, Dafa; Li, Yang; Zhang, Guoliang; Zhang, Fengbao; Fan, Xiaobin

    2013-02-01

    Rhodium complexes can be homogeneously immobilized on functionalized graphene oxide through coordination interaction. The obtained catalyst can be readily recycled and shows enhanced activity in the catalytic hydrogenation of cyclohexene. PMID:23238302

  7. CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS

    SciTech Connect

    Kamil Klier; Richard G. Herman; Heock-Hoi Kwon; James G. C. Shen; Qisheng Ma; Robert A. Hunsicker; Andrew P. Butler; Scott J. Bollinger

    2003-03-01

    A tungstena-zirconia (WZ) catalyst has been investigated for coupling methanol and isobutanol to unsymmetrical ethers, i.e. methyl isobutyl ether (MIBE) and compared with earlier studied sulfated-zirconia (SZ) and Nafion-H catalysts. In all cases, the ether synthesis mechanism is a dual site S{sub N}2 process involving competitive adsorption of reactants on proximal acid sites. At low reaction temperatures, methylisobutylether (MIBE) is the predominant product. However, at temperatures >135 C the WZ catalyst is very good for dehydration of isobutanol to isobutene. The surface acid sites of the WZ catalyst and a Nafion-H catalyst were diagnosed by high resolution X-ray photoelectron spectroscopy (XPS) of N 1s shifts after adsorption of amines. Using pyridine, ethylenediamine, and triethylamine, it is shown that WZ has heterogeneous strong Broensted acid sites. Theoretical study located the transition state of the alcohol coupling reaction on proximal Broensted acid sites and accounted well for XPS core-level shifts upon surface acid-base interactions. While computations have not been carried out with WZ, it is shown that the SZ catalyst is a slightly stronger acid than CF{sub 3}SO{sub 3}H (a model for Nafion-H) by 1.3-1.4 kcal/mol. A novel sulfated zirconia catalyst having proximal strong Broensted acid sites was synthesized and shown to have significantly enhanced activity and high selectivity in producing MIBE or isobutene from methanol/isobutanol mixtures. The catalyst was prepared by anchoring 1,2-ethanediol bis(hydrogen sulfate) salt precursor onto zirconium hydroxide, followed by calcination to remove the -(CH{sub 2}CH{sub 2})- bridging residues.

  8. STRONTIUM AS AN EFFICIENT PROMOTER FOR SUPPORTED PALLADIUM HYDROGENATION CATALYSTS

    EPA Science Inventory

    The effect of strontium promotion is studied for a series of supported palladium catalysts such as Pd/zeolite-β, Pd/Al2O3, Pd/SiO2, Pd/hydrotalcite and Pd/MgO. Strontium is found to be an effective promoter for enhancing the metal area, perce...

  9. Neutron star glitches have a substantial minimum size

    NASA Astrophysics Data System (ADS)

    Espinoza, C. M.; Antonopoulou, D.; Stappers, B. W.; Watts, A.; Lyne, A. G.

    2014-05-01

    Glitches are sudden spin-up events that punctuate the steady spin-down of pulsars and are thought to be due to the presence of a superfluid component within neutron stars. The precise glitch mechanism and its trigger, however, remain unknown. The size of glitches is a key diagnostic for models of the underlying physics. While the largest glitches have long been taken into account by theoretical models, it has always been assumed that the minimum size lay below the detectability limit of the measurements. In this paper we define general glitch detectability limits and use them on 29 yr of daily observations of the Crab pulsar, carried out at Jodrell Bank Observatory. We find that all glitches lie well above the detectability limits and by using an automated method to search for small events we are able to uncover the full glitch size distribution, with no biases. Contrary to the prediction of most models, the distribution presents a rapid decrease of the number of glitches below ˜0.05 μHz. This substantial minimum size indicates that a glitch must involve the motion of at least several billion superfluid vortices and provides an extra observable which can greatly help the identification of the trigger mechanism. Our study also shows that glitches are clearly separated from all the other rotation irregularities. This supports the idea that the origin of glitches is different to that of timing noise, which comprises the unmodelled random fluctuations in the rotation rates of pulsars.

  10. Familial Influences on Recantation in Substantiated Child Sexual Abuse Cases.

    PubMed

    Malloy, Lindsay C; Mugno, Allison P; Rivard, Jillian R; Lyon, Thomas D; Quas, Jodi A

    2016-08-01

    The underlying reasons for recantation in children's disclosure of child sexual abuse (CSA) have been debated in recent years. In the present study, we examined the largest sample of substantiated CSA cases involving recantations to date (n = 58 cases). We specifically matched those cases to 58 nonrecanters on key variables found to predict recantation in prior research (i.e., child age, alleged parent figure perpetrator, and caregiver unsupportiveness). Bivariate analyses revealed that children were less likely to recant when they were (1) initially removed from home postdisclosure and (2) initially separated from siblings postdisclosure. Multivariate analyses revealed that children were less likely to recant when family members (other than the nonoffending caregiver) expressed belief in the children's allegations and more likely to recant when family members (other than the nonoffending caregiver) expressed disbelief in the allegations and when visitations with the alleged perpetrator were recommended at their first hearing. Results have implications for understanding the complex ways in which social processes may motivate some children to retract previous reports of sexual abuse. PMID:27234520

  11. Process for preparing superconducting film having substantially uniform phase development

    DOEpatents

    Bharacharya, Raghuthan; Parilla, Philip A.; Blaugher, Richard D.

    1995-01-01

    A process for preparing a superconducting film, such as a thallium-barium-calcium-copper oxide superconducting film, having substantially uniform phase development. The process comprises providing an electrodeposition bath having one or more soluble salts of one or more respective potentially superconducting metals in respective amounts adequate to yield a superconducting film upon subsequent appropriate treatment. Should all of the metals required for producing a superconducting film not be made available in the bath, such metals can be a part of the ambient during a subsequent annealing process. A soluble silver salt in an amount between about 0.1% and about 4.0% by weight of the provided other salts is also provided to the bath, and the bath is electrically energized to thereby form a plated film. The film is annealed in ambient conditions suitable to cause formation of a superconductor film. Doping with silver reduces the temperature at which the liquid phase appears during the annealing step, initiates a liquid phase throughout the entire volume of deposited material, and influences the nucleation and growth of the deposited material.

  12. Process for preparing superconducting film having substantially uniform phase development

    DOEpatents

    Bharacharya, R.; Parilla, P.A.; Blaugher, R.D.

    1995-12-19

    A process is disclosed for preparing a superconducting film, such as a thallium-barium-calcium-copper oxide superconducting film, having substantially uniform phase development. The process comprises providing an electrodeposition bath having one or more soluble salts of one or more respective potentially superconducting metals in respective amounts adequate to yield a superconducting film upon subsequent appropriate treatment. Should all of the metals required for producing a superconducting film not be made available in the bath, such metals can be a part of the ambient during a subsequent annealing process. A soluble silver salt in an amount between about 0.1% and about 4.0% by weight of the provided other salts is also provided to the bath, and the bath is electrically energized to thereby form a plated film. The film is annealed in ambient conditions suitable to cause formation of a superconductor film. Doping with silver reduces the temperature at which the liquid phase appears during the annealing step, initiates a liquid phase throughout the entire volume of deposited material, and influences the nucleation and growth of the deposited material. 3 figs.

  13. Substantial proportion of global streamflow less than three months old

    NASA Astrophysics Data System (ADS)

    Jasechko, Scott; Kirchner, James W.; Welker, Jeffrey M.; McDonnell, Jeffrey J.

    2016-02-01

    Biogeochemical cycles, contaminant transport and chemical weathering are regulated by the speed at which precipitation travels through landscapes and reaches streams. Streamflow is a mixture of young and old precipitation, but the global proportions of these young and old components are not known. Here we analyse seasonal cycles of oxygen isotope ratios in rain, snow and streamflow compiled from 254 watersheds around the world, and calculate the fraction of streamflow that is derived from precipitation that fell within the past two or three months. This young streamflow accounts for about a third of global river discharge, and comprises at least 5% of discharge in about 90% of the catchments we investigated. We conclude that, although typical catchments have mean transit times of years or even decades, they nonetheless can rapidly transmit substantial fractions of soluble contaminant inputs to streams. Young streamflow is less prevalent in steeper landscapes, which suggests they are characterized by deeper vertical infiltration. Because young streamflow is derived from less than 0.1% of global groundwater storage, we conclude that this thin veneer of aquifer storage will have a disproportionate influence on stream water quality.

  14. Substantial SNP-based heritability estimates for working memory performance

    PubMed Central

    Vogler, C; Gschwind, L; Coynel, D; Freytag, V; Milnik, A; Egli, T; Heck, A; de Quervain, D J-F; Papassotiropoulos, A

    2014-01-01

    Working memory (WM) is an important endophenotype in neuropsychiatric research and its use in genetic association studies is thought to be a promising approach to increase our understanding of psychiatric disease. As for any genetically complex trait, demonstration of sufficient heritability within the specific study context is a prerequisite for conducting genetic studies of that trait. Recently developed methods allow estimating trait heritability using sets of common genetic markers from genome-wide association study (GWAS) data in samples of unrelated individuals. Here we present single-nucleotide polymorphism (SNP)-based heritability estimates (h2SNP) for a WM phenotype. A Caucasian sample comprising a total of N=2298 healthy and young individuals was subjected to an N-back WM task. We calculated the genetic relationship between all individuals on the basis of genome-wide SNP data and performed restricted maximum likelihood analyses for variance component estimation to derive the h2SNP estimates. Heritability estimates for three 2-back derived WM performance measures based on all autosomal chromosomes ranged between 31 and 41%, indicating a substantial SNP-based heritability for WM traits. These results indicate that common genetic factors account for a prominent part of the phenotypic variation in WM performance. Hence, the application of GWAS on WM phenotypes is a valid method to identify the molecular underpinnings of WM. PMID:25203169

  15. Correlation between Fischer-Tropsch catalytic activity and composition of catalysts.

    PubMed

    Ali, Sardar; Mohd Zabidi, Noor Asmawati; Subbarao, Duvvuri

    2011-01-01

    This paper presents the synthesis and characterization of monometallic and bimetallic cobalt and iron nanoparticles supported on alumina. The catalysts were prepared by a wet impregnation method. Samples were characterized using temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), CO-chemisorption, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM-EDX) and N2-adsorption analysis. Fischer-Tropsch synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K and 1 atm, with H2/CO = 2 v/v and space velocity, SV = 12L/g.h. The physicochemical properties and the FTS activity of the bimetallic catalysts were analyzed and compared with those of monometallic cobalt and iron catalysts at similar operating conditions.H2-TPR analysis of cobalt catalyst indicated three temperature regions at 506°C (low), 650°C (medium) and 731°C (high). The incorporation of iron up to 30% into cobalt catalysts increased the reduction, CO chemisorption and number of cobalt active sites of the catalyst while an opposite trend was observed for the iron-riched bimetallic catalysts. The CO conversion was 6.3% and 4.6%, over the monometallic cobalt and iron catalysts, respectively. Bimetallic catalysts enhanced the CO conversion. Amongst the catalysts studied, bimetallic catalyst with the composition of 70Co30Fe showed the highest CO conversion (8.1%) while exhibiting the same product selectivity as that of monometallic Co catalyst. Monometallic iron catalyst showed the lowest selectivity for C5+ hydrocarbons (1.6%). PMID:22047220

  16. Correlation between Fischer-Tropsch catalytic activity and composition of catalysts

    PubMed Central

    2011-01-01

    This paper presents the synthesis and characterization of monometallic and bimetallic cobalt and iron nanoparticles supported on alumina. The catalysts were prepared by a wet impregnation method. Samples were characterized using temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), CO-chemisorption, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM-EDX) and N2-adsorption analysis. Fischer-Tropsch synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K and 1 atm, with H2/CO = 2 v/v and space velocity, SV = 12L/g.h. The physicochemical properties and the FTS activity of the bimetallic catalysts were analyzed and compared with those of monometallic cobalt and iron catalysts at similar operating conditions. H2-TPR analysis of cobalt catalyst indicated three temperature regions at 506°C (low), 650°C (medium) and 731°C (high). The incorporation of iron up to 30% into cobalt catalysts increased the reduction, CO chemisorption and number of cobalt active sites of the catalyst while an opposite trend was observed for the iron-riched bimetallic catalysts. The CO conversion was 6.3% and 4.6%, over the monometallic cobalt and iron catalysts, respectively. Bimetallic catalysts enhanced the CO conversion. Amongst the catalysts studied, bimetallic catalyst with the composition of 70Co30Fe showed the highest CO conversion (8.1%) while exhibiting the same product selectivity as that of monometallic Co catalyst. Monometallic iron catalyst showed the lowest selectivity for C5+ hydrocarbons (1.6%). PMID:22047220

  17. Catalysts for low temperature oxidation

    DOEpatents

    Toops, Todd J.; Parks, III, James E.; Bauer, John C.

    2016-03-01

    The invention provides a composite catalyst containing a first component and a second component. The first component contains nanosized gold particles. The second component contains nanosized platinum group metals. The composite catalyst is useful for catalyzing the oxidation of carbon monoxide, hydrocarbons, oxides of nitrogen, and other pollutants at low temperatures.

  18. Transition metal sulfide loaded catalyst

    DOEpatents

    Maroni, Victor A.; Iton, Lennox E.; Pasterczyk, James W.; Winterer, Markus; Krause, Theodore R.

    1994-01-01

    A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

  19. Doped palladium containing oxidation catalysts

    DOEpatents

    Mohajeri, Nahid

    2014-02-18

    A supported oxidation catalyst includes a support having a metal oxide or metal salt, and mixed metal particles thereon. The mixed metal particles include first particles including a palladium compound, and second particles including a precious metal group (PMG) metal or PMG metal compound, wherein the PMG metal is not palladium. The oxidation catalyst may also be used as a gas sensor.

  20. Catalyst design for biorefining.

    PubMed

    Wilson, Karen; Lee, Adam F

    2016-02-28

    The quest for sustainable resources to meet the demands of a rapidly rising global population while mitigating the risks of rising CO2 emissions and associated climate change, represents a grand challenge for humanity. Biomass offers the most readily implemented and low-cost solution for sustainable transportation fuels, and the only non-petroleum route to organic molecules for the manufacture of bulk, fine and speciality chemicals and polymers. To be considered truly sustainable, biomass must be derived from resources which do not compete with agricultural land use for food production, or compromise the environment (e.g. via deforestation). Potential feedstocks include waste lignocellulosic or oil-based materials derived from plant or aquatic sources, with the so-called biorefinery concept offering the co-production of biofuels, platform chemicals and energy; analogous to today's petroleum refineries which deliver both high-volume/low-value (e.g. fuels and commodity chemicals) and low-volume/high-value (e.g. fine/speciality chemicals) products, thereby maximizing biomass valorization. This article addresses the challenges to catalytic biomass processing and highlights recent successes in the rational design of heterogeneous catalysts facilitated by advances in nanotechnology and the synthesis of templated porous materials, as well as the use of tailored catalyst surfaces to generate bifunctional solid acid/base materials or tune hydrophobicity. PMID:26755755