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1

TiO2 (B) nanosheets mediate phase selective synthesis of TiO2 nanostructured photocatalyst  

NASA Astrophysics Data System (ADS)

Phase selective synthesis is particularly valuable in revealing performance of photocatalyst existing as several polymorphic phases. In this work, we develop a general soft chemical route that used a TiO2 (B) nanosheet as a precursor to synthesize TiO2 nanostructures of desired phase. Benefiting from the structural similarity and ultrathin thickness feature, TiO2 (B) nanosheet precursor can readily transform to pure phase of anatase, rutile and brookite as well as mixed phase of brookite/anatase. A possible dissolution-recrystallization mechanism is proposed for the phase transition of TiO2 (B) nanosheets to other phases. Photocatalytic activity tests demonstrated that the brookite/anatase mixture had the highest activity in degrading acetaldehyde under UV light irradiation, due to the synergistic effect of high crystallinity, large surface area and mixed phase structure.

Wang, Yuxi; Wang, Changhua; Zhang, Xintong; Sun, Panpan; Kong, Lina; Wei, Yongan; Zheng, Han; Liu, Yichun

2014-02-01

2

Synthesis of TiO2 photocatalyst and study on their improvement technology of photocatalytic activity  

E-print Network

. The optical properties of the water-affinity thin films prepared using TiO2 thin films with/without oxygen Republic Available online 20 April 2005 Abstract Thin films of titanium dioxie (TiO2) were deposited photocatalyst thin films have been prepared by a number of chemical methods such as dip- coating [3], and sol

Boo, Jin-Hyo

3

Water-phase strategy for synthesis of TiO2-graphene composites with tunable structure for high performance photocatalysts  

NASA Astrophysics Data System (ADS)

The controllable synthesis of strongly coupled TiO2/graphene composites has been a long-standing challenge for developing advanced photocatalysts. Here, we report a facile water-phase protocol for synthesis of TiO2-graphene composites using GO aqueous suspension and TiO2 aqueous nanosols as precursors. By controlling the ratio of GO to TiO2, both high-/low-dense TiO2 nanoparticles across graphene and graphene-TiO2-graphene sandwich structured composites are successfully achieved through electrostatic attraction between negatively charged GO nanosheets and positively charged TiO2nanosols. The TiO2-graphene composites show an enhanced photocatalytic activity for the degradation of methylene blue (MB) under UV light. Interestingly, the sandwich structured TiO2-graphene composite exhibits the best photocatalytic activity and the highest photocurrent density, which is 12.2 and 35.46 times as that of pure TiO2, respectively. The outstanding photocatalytic activity of sandwich structured composite is likely due to the following two reasons, two-channel electron conduction path between TiO2 and graphene, as well as the better adsorption capability of MB molecule.

Hu, Changyuan; Chen, Fei; Lu, Tiewen; Lian, Chengjiang; Zheng, Shizheng; Hu, Quanhong; Duo, Shuwang; Zhang, Rongbin

2014-10-01

4

Synthesis and characterization of N-doped TiO2 photocatalysts with tunable response to solar radiation  

NASA Astrophysics Data System (ADS)

Modification of the electronic structure of wide band gap semiconductors by anion doping is an effective strategy for the development of photocatalytic materials operating under solar light irradiation. In the present work, nitrogen-doped TiO2 photocatalysts of variable dopant content were synthesized by annealing a sol-gel derived TiO2 powder under flowing ammonia at temperatures in the range of 450-800 °C, and their physicochemical and optical properties were compared to those of undoped TiO2 samples calcined in air. Results show that materials synthesized at T = 450-600 °C contain relatively small amounts of dopant atoms and their colour varies from pale yellow to dark green due to the creation of localized states above the valence band of TiO2 and the formation of oxygen vacancies. Treatment with NH3 at T > 600 °C results in phase transformation of anatase to rutile, in a significant decrease of the specific surface area and in formation of TiN at the surface of the TiO2 particles. The resulting dark grey (T = 700 °C) and black (T = 800 °C) materials display strong absorption in both the visible and NIR regions, originating from partial reduction of TiO2 and formation of Ti3+ defect states. The present synthesis method enables tailoring of the electronic structure of the semiconductor and could be used for the development of solar light-responsive photocatalysts for photo(electro)chemical applications.

Petala, Athanasia; Tsikritzis, Dimitris; Kollia, Mary; Ladas, Spyridon; Kennou, Stella; Kondarides, Dimitris I.

2014-06-01

5

SURFACTANT TEMPLATED SOL-GEL SYNTHESIS OF MESOPOROUS TIO2 PHOTOCATALYSTS AND THEIR APPLICATION IN THE DESTRUCTION OF CYANOBACTERIAL TOXINS  

EPA Science Inventory

In the symposium, we will present the synthesis and properties of the mesoporous TIO2 films and membranes and fundamental and systematic study on the decomposition pathway of such biological toxins....

6

Synthesis of C, Ag co-modified TiO2 photocatalyst and its application in waste water purification  

NASA Astrophysics Data System (ADS)

Monodispersed C, Ag co-modified TiO2 microspheres were successfully synthesized through a two-step method. Firstly, monodisperse spherical TiO2 particles were obtained via controlled hydrolysis of TBOT (tetrabutyltitanate) in ethanol. Secondly, the C, Ag co-modified TiO2 microspheres were prepared through a simple calcination process, in which the AgNO3 and citric acid was used as Ag and C source, respectively. The physical and chemical properties of C, Ag co-modified TiO2 microspheres were carefully studied by using XRD, SEM, TEM, Raman, PL spectra and UV-vis diffuse reflectance spectra (DRS), while the chemical states of C and Ag were discussed via EDS (energy dispersive spectrometer) and XPS. The photocatalytic activity of the as-prepared products was evaluated by photocatalytic decolorization of Rhodamine B (Rh B) aqueous solution at ambient temperature under UV and visible-light irradiation. The photocatalytic activity research shows that, with the cooperation of two modified materials, C, Ag co-modified TiO2 microspheres exhibit enhanced photocatalytic activity both in ultraviolet and visible-light region compared with that of pure TiO2 and single Ag modified TiO2 microspheres.

Liu, Hui; Dong, Xiaonan; Li, Guangjun; Su, Xing; Zhu, Zhenfeng

2013-04-01

7

Synthesis and characterization of C-N-S-tridoped TiO2 nano-crystalline photocatalyst and its photocatalytic activity for degradation of rhodamine B  

NASA Astrophysics Data System (ADS)

C-N-S-tridoped TiO2 nano-photocatalysts were synthesized through simple one-step sol-gel reactions in the presence of biomolecule cystine. The resulting materials were characterized by X-ray diffraction (XRD), N2 physical adsorption, X-ray photoelectron spectroscopy (XPS), Fourier transition infrared spectra (FT-IR), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). XRD results showed that tridoping with C, N and S could effectively restrain the phase transformation of TiO2 from anatase to rutile and growth of the crystallite sizes. DRS results revealed the light absorption of C-N-S-tridoped TiO2 was red-shifted to visible region. XPS and FT-IR analysis demonstrated that S was incorporated into the lattice of TiO2 through substituting titanium atoms, N might coexist in the forms of N-O-Ti and O-Ti-N in tridoped TiO2, and C could form a mixed layer of carbonate on the surface of TiO2. Further, the activities of the as-synthesized catalysts were evaluated for the photodegradation of rhodamine B (RhB) in aqueous suspension under visible and UV light irradiation. It was found that C-N-S-tridoped TiO2 presented higher photocatalytic activity than that of pure TiO2 and P25 TiO2. The excellent photocatalytic activity of C-N-S-tridoped TiO2 could be attributed to the small crystal size, high surface area, large surface hydroxyl groups, strong light absorption in visible region and narrow band gap.

Cheng, Xiuwen; Yu, Xiujuan; Xing, Zipeng

2013-05-01

8

Metolachlor photocatalytic degradation using TiO 2 photocatalysts  

Microsoft Academic Search

The photocatalytic degradation of the herbicide metolachlor is studied, using TiO2 photocatalysts. Apart from the titania aqueous dispersions, immobilized semiconductor thin films were used in order to evaluate their effectiveness. The films exhibit a rough, nanocrystalline configuration, ideal for heterogeneous processes. Additionally the thin films were silver modified to determine if noble metal nanoclusters affect the photocatalytic efficiency. The kinetics

V. A Sakkas; I. M Arabatzis; I. K Konstantinou; A. D Dimou; T. A Albanis; P Falaras

2004-01-01

9

Preparation and characterization of in-site regenerated TiO2-ACFs photocatalyst  

NASA Astrophysics Data System (ADS)

In-site regenerated titanium dioxide-activated carbon fibers (TiO2-ACFs) photocatalyst was prepared by the sol-gel method. Detailed surface and structural characterization of the TiO2-ACFs photocatalyst was carried out. The photoactivity of TiO2-ACFs under ultraviolet irradiation was compared with original ACFs and pure TiO2 by the degradation of methylene blue aqueous solution. The degradation efficiency by the TiO2 (5wt%)-ACFs sample is much higher than that by TiO2 and ACFs. The results show that the photocatalysis by TiO2-ACFs is a six-step process. The adsorption-transfer-photocatalysis rate of TiO2-ACFs is higher than the adsorption-photocatalysis rate of TiO2, so the photocatalysis rate of the TiO2-ACFs system is higher than that of TiO2 photocatalyst.

Yang, Rong; Liu, Jian-Hua; Li, Song-Mei

2011-06-01

10

Controlled synthesis of monodisperse SiO(2)--TiO(2) microspheres with a yolk-shell structure as effective photocatalysts.  

PubMed

Monodisperse yolk-shell SiO(2) -TiO(2) microspheres were synthesized using core-shell silica microspheres as templates. In the absence of prior surface modifications, a uniform coating of the TiO(2) layer on the core-shell silica was achieved through a sol-gel route. Mesoporous silica shells between the outer TiO(2) shell and the SiO(2) core were selectively removed by using a weak base, yielding yolk-shell SiO(2) -TiO(2) microspheres (ys-SiO(2) @TiO(2) ). Using the same templates, we synthesized Pt-encased microspheres (SiO(2) @Pt-TiO(2) ), in which Pt nanoparticles are embedded between the SiO(2) core and the TiO(2) shell. Selective etching of the silica shells in SiO(2) @Pt-TiO(2) yields Pt-encased yolk-shell SiO(2) -TiO(2) microspheres (ys-SiO(2) @< Pt >TiO(2) ), which contain void spaces suitable for use as nanoreactors. The ys-SiO(2) @< Pt >TiO(2) catalyst shows enhanced hydrogen production from water under UV-light irradiation presumably as a result of multiple reflections within the void spaces and can be reused without losing their activity. Moreover, this core-shell template method is effective for the synthesis of other yolk-shell microspheres with different metal oxides. PMID:23132768

Yoo, Jung Bo; Yoo, Hyo Jin; Lim, Byung Wook; Lee, Kang Hyuk; Kim, Mi Hyun; Kang, Donghyeon; Hur, Nam Hwi

2012-12-01

11

A facile approach for the synthesis of magnetic separable Fe3O4@TiO2, core-shell nanocomposites as highly recyclable photocatalysts  

NASA Astrophysics Data System (ADS)

A facile and efficient approach for the fabrication of Fe3O4@TiO2 nanocomposites with a good core-shell structure has been demonstrated. The approach employed involved the coating of successive titania shell on Fe3O4 core using a mixed solvent method with the catalysis of ammonia followed by the crystallization of TiO2 through solvothermal method. The as-obtained core-shell structure was composed of a central Fe3O4 core with a strong response to external fields, whereas the outer titanium oxide coating was useful for the degradation of organic contaminants. The results showed that Fe3O4@TiO2 nanocomposites exhibited high degree of crystallinity, excellent magnetic properties at room temperature. Furthermore, the as-prepared Fe3O4@TiO2 nanocomposites exhibited good photocatalytic activity toward the degradation of Rhodamine B (RhB) solution, which meant that they can be used as efficient and conveniently recoverable photocatalysts. In addition, the mechanism of coating by ammonia catalysis was also investigated.

Xin, Tiejun; Ma, Mingliang; Zhang, Hepeng; Gu, Junwei; Wang, Shuangjie; Liu, Mengjiao; Zhang, Qiuyu

2014-01-01

12

Comparison between the reactivity of commercial and synthetic TiO 2 photocatalysts  

Microsoft Academic Search

Titanium dioxide in powder form is largely used as a catalyst in the field of detoxification of aqueous effluents by photocatalysis. One of the most efficient commercial photocatalysts is TiO2\\/P25 manufactured by flame hydrolysis. In this work, we compare the reactivity between this commercial TiO2\\/P25 and a synthetic photocatalyst TiO2\\/SG prepared in our laboratory by sol–gel method. The photocatalytic activities

A. Piscopo; D. Robert; J. V. Weber

2001-01-01

13

The preparation of coupled WO 3\\/TiO 2 photocatalyst by ball milling  

Microsoft Academic Search

The coupled photocatalyst WO3\\/TiO2 is prepared by ball milling by doping WO3 into TiO2 and using H2O solution as disperser. The coupled photocatalyst WO3\\/TiO2 is characterized by UV–VIS diffuse reflection spectrum, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM). The results show that the optimum percentage of WO3 doped is 3% and that the photocatalytic

Chen Shifu; Chen Lei; Gao Shen; Cao Gengyu

2005-01-01

14

Enhanced photocatalytic activity from Gd, La codoped TiO2 nanotube array photocatalysts under visible-light irradiation  

NASA Astrophysics Data System (ADS)

Well-aligned TiO2 nanotube arrays were successfully synthesized from electrochemically anodic oxidation, which were further codoped by Gd and La via hydrothermal and sol-gel methods. The visible-light photocatalytic activities of the Gd, La codoped TiO2 nanotube arrays evaluated by photodegrading methyl orange (MO) have been significantly enhanced compared to that of undoped TiO2. Hereinto, the photocatalytic performance of Gd, La codoped TiO2 nanotube array synthesized by a hydrothermal approach was better than that by a sol-gel method. A lower band gap energy was attributed to the enhanced response to visible light. The new concept was helpful to guide the synthesis of robust visible-light photocatalysts, and the interesting results suggested that the Gd, La codoped TiO2 nanotube arrays were very promising for elevated the solar utilization in environment management.

Cai, Hongyuan; Chen, Xiaoxu; Li, Qinghua; He, Benlin; Tang, Qunwei

2013-11-01

15

TiO2 single crystal with four-truncated-bipyramid morphology as an efficient photocatalyst for hydrogen production.  

PubMed

Diverse titanium dioxide (TiO2 ) nanostructures have attracted much attention recently due to their potential application in photocatalytic and photovoltaic fields. Here, the synthesis of a TiO2 single crystal with a novel four-truncated-bipyramid morphology is reported for the first time, produced by a simple hydrothermal method. Both peroxo titanic acid precursor and hydrofluoric acid capping agent are essential for the formation of this unique morphology. Moreover, the as-prepared TiO2 photocatalyst exhibits excellent hydrogen production activity from an ethanol-water solution, which is attributed to exposure of both high-energy {001} oxidative and low-energy {101} reductive facets in an optimal ratio. The current findings will contribute greatly to development of more novel photocatalysts with controllable microscopic structures for hydrogen production. PMID:23780924

Zhang, Kai; Liu, Qian; Wang, Hui; Zhang, Rubo; Wu, Chunhui; Gong, Jian Ru

2013-07-22

16

One-dimensional mesoporous Fe2O3@TiO2 core-shell nanocomposites: Rational design, synthesis and application as high-performance photocatalyst in visible and UV light region  

NASA Astrophysics Data System (ADS)

An ideal photocatalyst for degradation of organic pollutants should combine the features of efficient visible light response, fast electron transport, high electron-hole separation efficiency, and large specific surface area. However, these requirements usually cannot be achieved simultaneously in the present state-of-the-art research. In this work, we develop a rational synthesis strategy for the preparation of one-dimensional (1D) mesoporous Fe2O3@TiO2 core-shell composites. In this strategy, FeOOH nanorods are firstly coated by TiO2 shell, followed by a calcination process. The as-prepared composites are thoroughly investigated with X-ray powder diffraction, scanning electron microscope, energy dispersive spectroscopy, transmission electron microscope, N2 adsorption-desorption isotherms, UV-visible diffuse-reflectance spectra, and photoluminescence spectra. Endowed with the advantages of its composition and specific structural features, the presented sample possesses the combined advantages mentioned above, thus delivering evidently enhanced photocatalytic activity for the degradation of methyl orange under UV light irradiation and Rhodamine B under visible light irradiation. And the possible mechanism of the enhanced photocatalytic performance is proposed.

Zhang, Xiao; Xie, Yaping; Chen, Haoxin; Guo, Jinxue; Meng, Alan; Li, Chunfang

2014-10-01

17

TiO2 Nanotubes/MWCNTs Nanocomposite Photocatalysts: Synthesis, Characterization and Photocatalytic Hydrogen Evolution Under UV-Vis Light Illumination  

SciTech Connect

Nanocomposite of TiO2 nanotubes (TiO2NTs) and multiwalled carbon nanotubes (MWCNTs) has been synthesized by a hydrothermal method and firstly used in photocatalytic hydrogen production. The obtained TiO2 NTs/MWCNTs composites were characterized by X-ray diffraction, transmission electron microscopy, Raman spectrum and ultraviolet-visible diffuse reflectance spectroscopy. The experimental results revealed that the MWCNTs were decorated with well dispersed anatase TiO2 nanotubes with a diameter of 8-15 nm. A slight blue shift and weak symmetry was observed for the strongest Raman peak which resulted from strain gradients originating from interface integration between TiO2 nanotubes and MWCNTs. The photocatalytic activity of the as-prepared samples was evaluated by hydrogen evolution from water splitting using Na2S and Na2SO3 as sacrificial reagents under UV-vis light irradiation. Enhanced photocatalytic activity compared with P25 has been observed for the resulted samples. The nanocomposite with optimized MWCNTs content of 1% displayed a hydrogen production rate of 161 u mol/h/g. Good photocatalytic stability of the as-synthesized samples was observed as well.

Li, Hao-Peng; Zhang, Xiao-Yan; Cui, Xiao-Li; Lin, Yuehe

2012-03-01

18

Plasma surface modification of TiO2 photocatalysts for improvement of catalytic efficiency  

E-print Network

for the synthesis of TiO2 thin films with high catalytic performance. D 2005 Elsevier B.V. All rights reserved plasma system. The optical properties of the water-affinity thin films prepared using TiO2 thin films-746, Korea Available online 30 August 2005 Abstract We have deposited titanium dioxide (TiO2) thin films

Boo, Jin-Hyo

19

Photooxidative desulfurization for diesel using Fe / N - TiO2 photocatalyst  

NASA Astrophysics Data System (ADS)

A series of N - TiO2 with different mol% N was synthesized via sol-gel method and characterized using thermal gravimetric analyzer and raman spectroscopy. 0.2 wt% Fe was incorporated onto the calcined (200°C) N - TiO2 followed by calcination at 200°C, 250°C and 300°C. Photooxidative desulfurization was conducted in the presence of 0.2wt% Fe / N - TiO2 with different mol% N with and without oxidant (H2O2). Oxidative desulfurization was only achieved when H2O2 was used while without H2O2 no major effect on the sulfur removal. 0.2Fe -30N - H2O2 photocatalysts showed best performance at all calcination temperatures as compared to other mol% N - H2O2 photocatalysts. 16.45% sulfur removal was achieved using photocatalysts calcined at 300 °C.

Khan, Muhammad Saqib; Kait, Chong Fai; Mutalib, Mohd Ibrahim Abdul

2014-10-01

20

Disinfection of water using Pt- and Ag-doped TiO2 photocatalysts.  

PubMed

In this article we have reported heterogeneous photocatalytic disinfection using pristine and Ag- and Pt-doped nano TiO2 under near-UV light and solar light irradiation. Disinfection experiments were conducted in slurry reactors with Escherichia coli, artificial light and sunlight. The influence of various amounts of Pt and Ag loading (0.5% to 5%) on the E. coli inactivation was examined and results indicated that 5% Pt-TiO2 and 0.5% Ag-TiO2 showed the highest photocatalytic E. coli inactivation. The Pt- and Ag-doped photocatalysts were characterized using XPS and TEM analysis. The influence of experimental parameters such as various photocatalysts, photocatalyst concentration, reactor geometry effect, pH and temperature on the photocatalytic disinfection was studied. The experimental results show that sunlight or near-UV light with TiO2 photocatalyst strongly inactivates E. coli. The Ag-TiO2 photocatalyst was the most efficient photocatalyst tested for bactericidal activity. A plausible mechanism ofphotocatalysed E. coli inactivation is discussed. In conclusion, the doped nano TiO2 photocatalysts is a potential candidate for E. coli inactivation. PMID:22988625

Suri, Rominder P S; Thornton, Hilary M; Muruganandham, M

2012-01-01

21

Preparation and characterization of the Sb-doped TiO2 photocatalysts  

Microsoft Academic Search

Doped TiO2 photocatalysts have been prepared by a coprecipitation method. Uniformly doped nanocrystalline TiO2 of 10–20 nm sizes was synthesized by calcinating the coprecipitated gels at 400–650°C. Photocatalytic characterization along with the microstructural investigation for each catalyst provides better understanding of the photocatalytic behavior. It was found that the photodegradation of methylene blue (MB) was a complex function of the

Jooho Moon; H. Takagi; Y. Fujishiro; M. Awano

2001-01-01

22

Multinuclear SSNMR, EPR, and XPS studies of anion-doped TiO2 photocatalysts  

Microsoft Academic Search

Visible light-absorbing anion-doped TiO2 photocatalysts (TiO 2-xAx, A = B\\/F, C, N, or P) that have the potential for water splitting and photocatalytic applications, were synthesized via sol-gel methodology and characterized by solid state nuclear magnetic resonance (SSNMR), electron paramagnetic resonance (EPR), X-ray Photoelectron spectroscopy (XPS), and UV\\/Vis diffuse reflectance spectroscopy, and powder X-ray diffraction (XRD). The 15N SSNMR showed

Enrique A Reyes

2007-01-01

23

Development of TiO 2 photocatalyst reaction for water purification  

Microsoft Academic Search

A new type of tubular photocatalytic reactor was developed to realize practical application of TiO2 photocatalyst for water purification. The principal part of the reactor consists of the ceramic cylindrical tube whose inner surface is coated with Pt-loaded TiO2 film and the 30 W ultraviolet light lamp which is set longitudinally in the center of the tube. The water to

Lianfeng Zhang; Tatsuo Kanki; Noriaki Sano; Atsushi Toyoda

2003-01-01

24

Layered silicate as an excellent partner of a TiO2 photocatalyst for efficient and selective green fine-chemical synthesis.  

PubMed

When the partial oxidation of benzene to phenol, which is one of the most important reactions in chemical industry, was conducted using TiO2 in the presence of a phenol-philic adsorbent derived from a layered silicate, phenol was recovered in unprecedentedly high yield and purity. This resulted from the fact that the adsorbent captured the generated phenol promptly, selectively, and effectively to prevent the overoxidation, after which the captured phenol could be easily eluted. PMID:23902420

Ide, Yusuke; Torii, Masato; Sano, Tsuneji

2013-08-14

25

Improvement of Ultrasonic Disinfection Power Using TiO2 Photocatalyst  

NASA Astrophysics Data System (ADS)

The disinfection power of an ultrasonic system was enhanced using TiO2-photocatalyst in the irradiating solutions. Cultures of Legionella were used in the irradiation system with and without TiO2. A significant decrease in the concentration of viable cells was observed during irradiation in the presence of TiO2. The rate of cell killing was higher in the presence of TiO2 than it was with Al2O3, and was proportional to the amount of TiO2 used in the irradiating samples. There was no significant effect of cell concentration on the rate of cell killing in the range of 103 to 107 CFU/ml. Addition of OH radical scavengers such as glutathione, ascorbic acid and histidine to the irradiating solutions reduced the rate of disinfection, thus indicating the primary role of OH radicals in this process.

Dadjour, Mahmoud Farshbaf; Ogino, Chiaki; Matsumura, Susumu; Nakamura, Shinichi; Shimizu, Nobuaki

2005-03-01

26

Design of a photocatalyst for bromate decomposition: surface modification of TiO2 by pseudo-boehmite.  

PubMed

The rate of BrO3- reduction by a commercial TiO2 photocatalyst under UV illumination in an aqueous solution was increased by lowering the pH from 7 to 5. The effect is attributable to an enhancement of the electrical interaction between BrO3- and the positively charged surfaces of the TiO2 photocatalyst. The surface charge can be controlled by a surface modification of the TiO2 photocatalyst without controlling the pH of the water. In fact, the isoelectric point of surface-modified TiO2 was higher than that of the unloaded TiO2 photocatalyst, resulting in an increase in the rate of the photocatalytic reduction of BrO3- at a neutral pH. This increase is explained by an increase in the amount of adsorbed BrO3- on the photocatalyst surface. PMID:12542304

Noguchi, Hiroshi; Nakajima, Akira; Watanabe, Toshiya; Hashimoto, Kazuhito

2003-01-01

27

Cold Spraying of TiO2 Photocatalyst Coating With Nitrogen Process Gas  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) is a promising material for photocatalyst coatings. However, it is difficult to fabricate a TiO2 coating with anatase phase by conventional thermal spray processes due to a thermal transformation to rutile phase. In this paper, anatase TiO2 coatings were fabricated by the cold spray process. To understand the influence of process gas conditions on the fabrication of the coatings, the gas nature (helium or nitrogen) and the gas temperature are investigated. It was possible to fabricate TiO2 coatings with an anatase phase in all spraying conditions. The process gas used is not an important factor to fabricate TiO2 coatings. The thickness of the coatings increased with the process gas temperature increasing. It indicates that the deposition efficiency of the sprayed particles can be enhanced by controlling the spray conditions. The photocatalytic activity of the coatings is similar or better than the feedstock powder due to the formation of a large reaction area. Concludingly, cold spraying is an ideal process for the fabrication of a TiO2 photocatalyst coating.

Yamada, Motohiro; Isago, Hiroaki; Nakano, Hiromi; Fukumoto, Masahiro

2010-12-01

28

Controlled synthesis of hierarchical TiO2 nanoparticles on glass fibres and their photocatalytic performance.  

PubMed

This paper reports the synthesis of novel photocatalysts consisting of TiO2 nanoparticles and glass fibres (GF) using a two-step process. The method involves the hydrolysis of titanium tetrachloride in the presence of GF and a following hydrothermal process under alkaline conditions. Various techniques are employed to characterize the morphology, structure and crystallinity of TiO2 on the fibre surface. The results show that depending on the experiment setups, TiO2 nanoparticles exhibit spherical or flake-like morphology, forming characteristic hierarchical structures along with flexible GF. Flake-like TiO2/GF exhibits much enhanced photocatalytic activity thanks to the large surface area and the hetero-junction of anatase and TiO2-B phases observed in its structure. An interesting observation is that the alkali treatment of GF leads to the formation of porous structures on the fibre surface, facilitating the adsorption-concentration-promoted photocatalytic process. The removal ratio of the organic dye by employing TiO2/GF remains more than 80% after six cyclic runs, showing the reusability of photocatalysts in real application. The novelty of this work lies in the synergy arising from materials with unique morphologies, structures and availabilities as well as capabilities in separating photogenerated electron-hole pairs, which have not been specifically considered previously in photocatalytic semiconductors. PMID:25011616

Chen, Lin; Yang, Sudong; Mäder, Edith; Ma, Peng-Cheng

2014-09-01

29

Fabrication of TiO2 Thick Film for Photocatalyst from Commercial TiO2 Powder  

Microsoft Academic Search

Photocatalytic activity of TiO2 thick film ceramics made of commercial TiO2 powder has been studied. The TiO2 powder was nano sized one that was derived from dried TiO2 suspension. The TiO2 suspension was made by pouring some blended commercial TiO2 powder into some amount of water. The paste of TiO2 was made by mixing the nano sized TiO2 powder with

S. Fuji Asteti; D. Gustaman Syarif

2008-01-01

30

Photocatalytic oxidation of organic dyes with visible-light-driven codoped TiO2 photocatalysts  

NASA Astrophysics Data System (ADS)

A novel copper (II) and zinc (II) codoped TiO2 photocatalyst was synthesized by a modified sol-gel method using titanium (IV) isopropoxide, Zn(NO3)2 · 6H2O and copper(Il) nitrate as precursors. The samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) and photo-luminescence spectra (PL). The XRD results showed undoped and Zn, Cu-codoped TiO2 nanoparticles mainly including anatase phase and a tiny amount of Zn- and Cu-oxides exist in the mixed system, which is attributed to the decomposition of copper and zinc nitrates in the TiO2 gel to form CuO and ZnO and randomly dispersed on the TiO2 surface. On the basis of the optical characterization results, we found that the codoping of copper (II) and zinc (II) resulted a red shift of adsorption and lower recombination probability between electrons and holes, which were the reasons for high photocatalytic activity of Zn, Cu-codoped TiO2 nanoparticles under visible light (? > 400 nm). The photocatalytic activity of samples was tested for degradation of methyl orange (MO) in solutions. The results indicated that the visible-light driven capability of the codoped catalyst were much higher than that of the pure TiO2 catalyst under visible irradiation. Because of the synergetic effect of copper (II) and zinc (II) element, the Zn, Cu-codoped TiO2 catalyst will show higher quantum yield and enhance absorption of visible light. In the end, a key mechanism was proposed in order to account for the enhanced activity.

Zhang, Dongfang; Zeng, Fanbin

2011-06-01

31

ZrO2-modified mesoporous nanocrystalline TiO2-xNx as efficient visible light photocatalysts.  

PubMed

Mesoporous nanocrystalline TiO2-xNx and TiO2-xNx/ZrO2 visible-light photocatalysts have been prepared by a sol-gel method. The photocatalysts were characterized by XRD, N2 adsorption-desorption, TEM, XPS, UV/Vis, and IR spectroscopy. The photocatalytic activity of the samples was evaluated by the decomposition of ethylene in air under visible light (lambda > 450 nm) illumination. Results revealed that nitrogen was doped into the lattice of TiO2 by the thermal treatment of NH3-adsorbed TiO2 hydrous gels, converting the TiO2 into a visible-light responsive catalyst. The introduction of ZrO2 into TiO2-xNx considerably inhibits the undesirable crystal growth during calcination. Consequently, the ZrO2-modified TiO2-xNx displays higher porosity, higher specific surface area, and an improved thermal stability over the corresponding unmodified TiO2-xNx samples. PMID:16646476

Wang, Xinchen; Yu, Jimmy C; Chen, Yilin; Wu, Ling; Fu, Xianzhi

2006-04-01

32

An organometallic synthesis of TiO2 nanoparticles.  

PubMed

We report the synthesis of TiO2 nanoparticles that uses the low-temperature reaction of low-valent organometallic precursors. Bis(cyclooctatetraene)titanium reacts with dimethyl sulfoxide in organic solution at temperatures as low as room temperature to produce TiO2. In the absence of any supporting ligand, the reaction gives precipitation of amorphous TiO2 powder; however, in the presence of basic ligands such as tributylphosphine, tributylphosphine oxide and trioctylphosphine oxide, the precipitation is arrested, and chemically distinct, isolated, internally crystalline TiO2 nanoparticles are formed. PMID:15755111

Tang, Jing; Redl, Franz; Zhu, Yimei; Siegrist, Theo; Brus, Louis E; Steigerwald, Michael L

2005-03-01

33

The preparation of nitrogen-doped TiO 2- xN x photocatalyst coated on hollow glass microbeads  

NASA Astrophysics Data System (ADS)

In this paper, the effective method for nitrogen-doped TiO 2- xN x photocatalyst coated on hollow glass microbeads is described, which uses titanium tetraisopropoxide [Ti( iso-OC 3H 7) 4] as the raw materials and gaseous ammonia as a heat treatment atmosphere. The effects of heat treatment temperature and time on the photocatalytic activity of TiO 2- xN x/beads are studied. The photocatalyst is characterized by the UV-vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis and scanning electron microscopy (SEM). The results show that when the TiO 2- xN x/beads is heated at 650 °C for 5 h, the photocatalytic activity of the TiO 2- xN x/beads is the best. Compared with TiO 2, the photoabsorption wavelength range of nitrogen-doped TiO 2- xN x red shifts of about 60 nm, and the photoabsorption intensity increases as well. The photocatalytic activity of the TiO 2- xN x/beads is higher than that of the TiO 2/beads under visible light irradiation. The presence of nitrogen neither influences on the transformation of anatase to rutile, nor creates new crystal phases. When the TiO 2- xN x/beads is heated at 650 °C for 5 h, the amount of nitrogen-doped is 0.53 wt.% in the TiO 2- xN x. As the density of TiO 2- xN x/beads prepared is lower than 1.0 g/cm 3, it may float on water surface and use broader sunlight spectrum directly.

Shifu, Chen; Xuqiang, Liu; Yunzhang, Liu; Gengyu, Cao

2007-01-01

34

Ordered mesoporous black TiO(2) as highly efficient hydrogen evolution photocatalyst.  

PubMed

Mesoporous TiO2 has gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. Herein, we report the facile synthesis of ordered mesoporous black TiO2 (OMBT) materials, which exhibit excellent photocatalytic hydrogen evolution performances. In this case, the employment of a thermally stable and high-surface-area mesoporous TiO2 as the hydrogenation precursor is the key for fabricating the OMBT materials, which not only facilitate H2 gas diffusion into TiO2 and interaction with their structures but also maintain the ordered mesoporous structures as well as inhibit the phase transformation (from anatase to rutile) and crystal growth during hydrogenation at 500 °C. The resultant OMBT materials possess a relatively high surface area of ?124 m(2) g(-1) and a large pore size and pore volume of ?9.6 nm and 0.24 cm(3) g(-1), respectively. More importantly, the OMBT materials can extend the photoresponse from ultraviolet to visible and infrared light regions and exhibit a high solar-driven hydrogen production rate (136.2 ?mol h(-1)), which is almost two times as high as that of pristine mesoporous TiO2 (76.6 ?mol h(-1)). PMID:24937035

Zhou, Wei; Li, Wei; Wang, Jian-Qiang; Qu, Yang; Yang, Ying; Xie, Ying; Zhang, Kaifu; Wang, Lei; Fu, Honggang; Zhao, Dongyuan

2014-07-01

35

Comparative investigation on photocatalytic hydrogen evolution over Cu, Pd, and Au-loaded mesoporous TiO 2 photocatalysts  

Microsoft Academic Search

Photocatalytic activity for hydrogen evolution from water using methanol as hole scavenger was comparatively investigated over mesoporous TiO2 photocatalysts with various contents of Cu, Pd, and Au cocatalyst loadings prepared by single-step sol–gel (SSSG) process with surfactant template. The photocatalysts were analytically characterized by X-ray diffraction (XRD), N2 adsorption–desorption, Brunauer–Emmett–Teller (BET) surface area, Barrett–Joyner–Halenda (BJH) pore size distribution, scanning electron

Thammanoon Sreethawong; Susumu Yoshikawa

2005-01-01

36

Quick and Facile Preparation of Visible light-Driven TiO2 Photocatalyst with High Absorption and Photocatalytic Activity.  

PubMed

Self-doping TiO2 has recently attracted considerable attention for its high photocatalytic activity under visible-light irradiation. However, the literature reported synthetic methods until now were very time-consuming. In this study, we establish a quick and facile method for obtaining self-doping TiO2 with the use of directly treated commercial P25 at a desired temperature for only 5?min through spark plasma sintering technology. With the using of this method, the modified P25 samples exhibit significantly high photoelectric and photocatalytic performance. Furthermore, the sample prepared at 600°C exhibits the optimum catalytic activity. The photodegradation and H2 evolution rates of this samples are significantly higher than those of unmodified P25 sample under visible-light irradiation. The physical origin of the visible-light absorption for the modified P25 samples is investigated in detail according to their structural, optical, and electronic properties. This work will provide a quick and facile method for the large-scale synthesis of visible-light driven photocatalyst for practical applications. PMID:25391987

Yang, Yucheng; Zhang, Ting; Le, Ling; Ruan, Xuefeng; Fang, Pengfei; Pan, Chunxu; Xiong, Rui; Shi, Jing; Wei, Jianhong

2014-01-01

37

Quick and Facile Preparation of Visible light-Driven TiO2 Photocatalyst with High Absorption and Photocatalytic Activity  

PubMed Central

Self-doping TiO2 has recently attracted considerable attention for its high photocatalytic activity under visible-light irradiation. However, the literature reported synthetic methods until now were very time-consuming. In this study, we establish a quick and facile method for obtaining self-doping TiO2 with the use of directly treated commercial P25 at a desired temperature for only 5?min through spark plasma sintering technology. With the using of this method, the modified P25 samples exhibit significantly high photoelectric and photocatalytic performance. Furthermore, the sample prepared at 600°C exhibits the optimum catalytic activity. The photodegradation and H2 evolution rates of this samples are significantly higher than those of unmodified P25 sample under visible-light irradiation. The physical origin of the visible-light absorption for the modified P25 samples is investigated in detail according to their structural, optical, and electronic properties. This work will provide a quick and facile method for the large-scale synthesis of visible-light driven photocatalyst for practical applications. PMID:25391987

Yang, Yucheng; Zhang, Ting; Le, Ling; Ruan, Xuefeng; Fang, Pengfei; Pan, Chunxu; Xiong, Rui; Shi, Jing; Wei, Jianhong

2014-01-01

38

Highly Active TiO2-Based Visible-Light Photocatalyst with Nonmetal Doping and Plasmonic Metal Decoration  

SciTech Connect

A sandwich-structured photocatalyst shows an excellent performance in degradation reactions of a number of organic compounds under UV, visible light, and direct sunlight (see picture). The catalyst was synthesized by a combination of nonmetal doping and plasmonic metal decoration of TiO2 nanocrystals, which improves visible-light activity and enhances light harvesting and charge separation, respectively.

Zhang, Qiao [University of California, Riverside; Lima, Diana Q. [University of California, Riverside; Chi, Miaofang [ORNL; Yin, Yadong [University of California, Riverside

2011-01-01

39

Plasmonic TiO2/AgBr/Ag ternary composite nanosphere with heterojunction structure for advanced visible light photocatalyst  

NASA Astrophysics Data System (ADS)

In this work, TiO2/AgBr/Ag ternary composite nanosphere photocatalyst has been synthesized by in situ deposition of AgBr onto hollow spherical TiO2 template and followed by sun light reduction of AgBr into AgBr/Ag. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images have shown that the diameter of hollow TiO2 nanospheres is 250-350 nm and AgBr/Ag nanoparticles are well dispersed on the outer surface of TiO2 nanosphere. UV-vis spectrum analysis has shown largely improved visible light absorption of this ternary composite, in comparison to pure TiO2 and AgBr. The building-in AgBr/Ag, TiO2/AgBr and TiO2/Ag junctions within the ternary composite enhanced the visible light absorption because of plasmonic resonance and narrow bandgap. The pseudo-first-order rate constant kapp of the TiO2/AgBr/Ag ternary composite for methylene blue photodegradation displays 24.5 times and 3.3 times than the pure TiO2 nanosphere and AgBr/Ag nanoparticles, respectively. Furthermore, the stability of TiO2/AgBr/Ag ternary composite is characterized through cyclic photocatalytic test. Results indicate that 92.7% of photocatalytic degradation can be achieved by TiO2/AgBr/Ag ternary composite even after five recycles.

Dai, Kai; Li, Dongpei; Lu, Luhua; Liu, Qi; Liang, Changhao; Lv, Jiali; Zhu, Guangping

2014-09-01

40

Preparation and characterization of visible-light-driven TiO2 photocatalyst Co-doped with nitrogen and erbium.  

PubMed

A series of nitrogen and erbium co-doped TiO2 photocatalyst was prepared by sol-hydrothermal method. The structure and properties of the photocatalyst were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). The XRD and BET results showed that co-doping inhibited the increase of crystallite size and enlarged specific surface areas. XPS spectroscopy indicated nitrogen atoms were incorporated into TiO2 lattice, and erbium atoms mostly existed in the forms of Er2O3. A shift of the absorption edge to the lower energy and four absorption bands located at 654, 544, 524 and 489 nm attributed to the 4f transitions of 4I15/2 --> 4F2/9, 4I15/2 --> 4S3/2, 4I15/2 --> 2H11/2, 4I15/2 --> 4F7/2 of Er3+ were observed using DRS spectroscopy. The catalytic efficency was evaluated by the photocatalytic degradation of methyl orange (MO) under visible light irradiation. The results showed that the photocatalytic performance of the co-doped TiO2 was related with the hydrothermal temperature and the molar ratio of N/Ti, and they showed higher acitivites than pure TiO2. Results determined by fluorescence technique revealed that irradiation (lambda > 400 nm) of TiO2 photocatalyst dispersed in MO solution induces the generation of the highly active hydroxyl radicals (OH). It indicated the photocatalytic activities of TiO2 photocatalyst were correlation with the formation rate of hydroxyl radicals (OH) and other active oxygen species. PMID:22852309

Chen, Guihua; Wang, Yong; Zhang, Juihui; Wu, Chenglin; Liang, Huading; Yang, Hui

2012-05-01

41

A visible-light-driven composite photocatalyst of TiO2 nanotube arrays and graphene quantum dots.  

PubMed

TiO2 nanotube arrays are well-known efficient UV-driven photocatalysts. The incorporation of graphene quantum dots could extend the photo-response of the nanotubes to the visible-light range. Graphene quantum dot-sensitized TiO2 nanotube arrays were synthesized by covalently coupling these two materials. The product was characterized by Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and UV-vis absorption spectroscopy. The product exhibited high photocatalytic performance in the photodegradation of methylene blue and enhanced photocurrent under visible light irradiation. PMID:24991506

Chan, Donald K L; Cheung, Po Ling; Yu, Jimmy C

2014-01-01

42

Preparation and photocatalytic activity of B, Ce Co-doped TiO2 hollow fibers photocatalyst  

NASA Astrophysics Data System (ADS)

A series of B, Ce co-doped TiO2 (B, Ce-TiO2) photocatalytic materials with a hollow fiber structure were successfully prepared by template method using boric acid, ammonium ceric nitrate and tetrabutyltitanate as precursors and cotton fibers as template, followed by calcination at 500°C in an N2 atmosphere for 2 h. Scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption measurements, and UV-visible spectroscopy (UV-Vis) were employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The photocatalytic performance of the samples was studied by photodegradation phenol in water under UV light irradiation. The results showed that the TiO2 fiber materials have hollow structures, and the fiber structure materials showed better photocatalytic properties for the degradation of phenol than pure TiO2 under UV light. In the experiment condition, the photocatalytic activity of B, Ce co-doped TiO2 fibers was optimal of all the prepared samples. In addition, the possibility of cyclic usage of B, Ce co-doped TiO2 fiber photocatalyst was also confirmed, the photocatalytic activity of TiO2 fibers remained above 90% of that of the fresh sample after being used four times. The material was easily removed by centrifugal separation from the medium. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.

Qiu, Jingping; Sun, Xiaogang; Xing, Jun; Liu, Xiaobo

2014-07-01

43

Characterization and activity of visible-light-driven TiO 2 photocatalyst codoped with nitrogen and cerium  

NASA Astrophysics Data System (ADS)

Nitrogen and cerium codoped TiO 2 photocatalysts were prepared by a modified sol-gel process with doping precursors of cerium nitrate and urea, and characterized by X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (TG-DSC), X-ray photoelectron spectra (XPS) and ultraviolet-visible light diffuse reflectance spectra (UV-vis DRS). Results indicate that anatase TiO 2 is the dominant crystalline type in as-prepared samples, and CeO 2 crystallites appear as the doping ratio of Ce/Ti reaches to 3.0 at%. The TiO 2 starts to transform from amorphous phase to anatase at 987.1 K during calcination, according to the TG-DSC curves. The XPS show that three major metal ions of Ce 3+, Ce 4+, Ti 4+ and one minor metal ion of Ti 3+ coexist on the surface. The codoped TiO 2 exhibits significant absorption within the range of 400-500 nm compared to the non-doped and only nitrogen-doped TiO 2. The enhanced photocatalytic activity of the codoped TiO 2 is demonstrated through degradation of methyl orange under visible light irradiation.

Liu, Chao; Tang, Xinhu; Mo, Cehui; Qiang, Zhimin

2008-04-01

44

Rapid destruction of the rhodamine B using TiO2 photocatalyst in the liquid phase plasma  

PubMed Central

Background Rhodamine B (RhB) is widely used as a colorant in textiles and food stuffs, and is also a well-known water tracer fluorescent. It is harmful to human beings and animals, and causes irritation of the skin, eyes and respiratory tract. The carcinogenicity, reproductive and developmental toxicity, neurotoxicity and chronic toxicity toward humans and animals have been experimentally proven. RhB cannot be effectively removed by biological treatment due to the slow kinetics. Therefore, RhB is chosen as a model pollutant for liquid phase plasma (LPP) treatment in the present investigation. Results This paper presents experimental results for the bleaching of RhB from aqueous solutions in the presence of TiO2 photocatalyst with LPP system. Properties of generated plasma were investigated by optical emission spectroscopy methods. The results of electrical-discharge degradation of RhB showed that the decomposition rate increased with the applied voltage, pulse width, and frequency. The oxygen gas addition to reactant solution increases the degradation rate by active oxygen species. The RhB decomposition rate was shown to increase with the TiO2 particle dosage. Conclusion This work presents the conclusions on the photocatalytic oxidation of RhB, as a function of plasma conditions, oxygen gas bubbling as well as TiO2 particle dosage. We knew that using the liquid phase plasma system with TiO2 photocatalyst at high speed we could remove the organic matter in the water. PMID:24041151

2013-01-01

45

[Decomposition of aqueous sodium pentachlorophenolate (PCP-Na) by using TiO2 coating photocatalyst].  

PubMed

Titanium dioxide (TiO2) photocatalysts were coated on hollow glass beads by sodium silicate (Na2SiO3.9H2O) solution. The coated catalysts were characterized by BET, XRD. Their photoactivity were examined using photocatalytic degradation of sodium pentachlorophenolate(PCP-Na) and glucose solution. The impact of catalysts dosage, PCP-Na initial concentration, initial pH and oxygen concentration on reaction kinetics were also studied in detail. The experiments illustrated that the performance of C3-type catalysts was satisfactory. Conditions of the experiments were following: The initial concentration of PCP-Na and CODCr were 10 mg.L-1 and 400 mg.L-1, respectively, and illumination time was 2 hours and catalysts dosage was 2 g.L-1, the removal rates of CODCr and PCP-Na were above 65% and 92% respectively. Optimum dosage of C3-type catalysts was 2-2.5 g.L-1, DO was no less than 3 mg.L-1. PMID:11382040

Xi, B; Liu, C; Kong, X; Zhou, Y; Liu, H; Qiu, R

2001-01-01

46

Heterostructured (Ba,Sr)TiO3/TiO2 core/shell photocatalysts: Influence of processing and structure on hydrogen production  

E-print Network

Heterostructured (Ba,Sr)TiO3/TiO2 core/shell photocatalysts: Influence of processing and structure (mc-) BaTiO3 and SrTiO3 cores coated with nanostructured (ns-) TiO2 shells were prepared using,5], semiconductor junctions [6,7], and modifications of the crystal structure and morphology [8e11] have been

Rohrer, Gregory S.

47

N-doped TiO 2 photo-catalyst for the degradation of 1,2-dichloroethane under fluorescent light  

Microsoft Academic Search

The photo-catalytic degradation of 1,2-dichloroethane (1, 2-DCE) using nitrogen-doped TiO2 photo-catalysts under fluorescent light irradiation was investigated. Highly pure TiO2 and nitrogen-doped TiO2 were prepared by a sol–gel method and characterized by thermo-gravimetric\\/differential-thermal analysis (TG\\/DTA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The results indicate that the photo-catalysts were mainly nano-size with an anatase-phase

Yi-Hsing Lin; Tang-Chun Chiu; Hsin-Ta Hsueh; Hsin Chu

48

Photocatalytic synthesis of TiO(2) and reduced graphene oxide nanocomposite for lithium ion battery.  

PubMed

In this work, we synthesized graphene oxide (GO) using the improved Hummers' oxidation method. TiO2 nanoparticles can be anchored on the GO sheets via the abundant oxygen-containing functional groups such as epoxy, hydroxyl, carbonyl, and carboxyl groups on the GO sheets. Using the TiO2 photocatalyst, the GO was photocatalytically reduced under UV illumination, leading to the production of TiO2-reduced graphene oxide (TiO2-RGO) nanocomposite. The as-prepared TiO2, TiO2-GO, and TiO2-RGO nanocomposite were used to fabricate lithium ion batteries (LIBs) as the active anode materials and their corresponding lithium ion insertion/extraction performance was evaluated. The resultant LIBs of the TiO2-RGO nanocomposite possesses more stable cyclic performance, larger reversible capacity, and better rate capability, compared with that of the pure TiO2 and TiO2-GO samples. The electrochemical and materials characterization suggest that the graphene network provides efficient pathways for electron transfer, and the TiO2 nanoparticles prevent the restacking of the graphene nanosheets, resulting in the improvement in both electric conductivity and specific capacity, respectively. This work suggests that the TiO2 based photocatalytic method could be a simple, low-cost, and efficient approach for large-scale production of anode materials for lithium ion batteries. PMID:22738305

Qiu, Jingxia; Zhang, Peng; Ling, Min; Li, Sheng; Liu, Porun; Zhao, Huijun; Zhang, Shanqing

2012-07-25

49

Preparation and characterization of N-S-codoped TiO(2) photocatalyst and its photocatalytic activity.  

PubMed

N-S-codoped anatase nanosized TiO(2) photocatalyst (NSTO) was successfully prepared by one-step hydrothermal method from a mixed aqueous solution of Ti(SO(4))(2) and thiourea. The samples were characterized by XRD, UV-vis, XPS, FT-IR and EA. From results of UV-vis, a red shift of the absorption edge was brought out owing to N and S codoping, and the extension for photoabsorption range of NSTO occurred. XRD, XPS, EA and FT-IR studies revealed that N and S were in situ codoped in the lattice of TiO(2) and N concentration decreased from the surface to the center of NSTO. Especially, the photocatalytic tests indicated that NSTO exhibited a high activity for decompositions of methyl orange both under UV-light and vis-light irradiation comparing to S-doped TiO(2) (STO) and undoped TiO(2) (TO). The high activity of NSTO can be related to the results of the synergetic effects of strong absorption in the UV-vis region, red shift in adsorption edge, oxygen vacancies and the enhancement of surface acidity induced by N and S codoping. PMID:18206303

Wei, Fengyu; Ni, Liangsuo; Cui, Peng

2008-08-15

50

Feasibility of silver doped TiO2/glass fiber photocatalyst under visible irradiation as an indoor air germicide.  

PubMed

This study investigated the feasibility of using Ag-TiO2 photocatalyst supported on glass fiber (Ag-TiO2/GF) prepared by a sol-gel method as an indoor air germicide. An experimental model was designed to investigate the bacterial disinfection efficiency of Staphylococcus (Staph), the most popular bacterium in hospitals in Korea, by the Ag-TiO2/GF photocatalyst. The silver content in Ag/TiO2 was altered from 1 to 10% to investigate the optimal ratio of Ag doped on TiO2/glass fiber (TiO2/GF) for photocatalytic disinfection of Staph. This study confirmed that Ag in Ag-TiO2/GF could work as an electron sink or donor to increase photocatalytic activity and promote the charge separation of electron-hole pairs generated from TiO2 after photon absorption. Ag also acts as an intermediate agent for the transfer of photo-generated electrons from the valence band of TiO2 to an acceptor (O2 gas) to promote photo-oxidation processes. The photocatalytic disinfection activity of Ag-TiO2/GF under visible light increased with the increase in silver content up to 7.5% and then slightly decreased with further increasing silver content. The highest disinfection efficiency and disinfection capacity of Staph using 7.5% Ag-TiO2/GF were 75.23% and 20 (CFU?s-1?cm-2) respectively. The medium level of humidity of 60% ± 5% showed better photocatalytic disinfection than the lower (40% ± 5%) or higher (80% ± 5%) levels. PMID:24658408

Pham, Thanh-Dong; Lee, Byeong-Kyu

2014-03-01

51

Nanofibrous TiO2-core/conjugated polymer-sheath composites: synthesis, structural properties and photocatalytic activity.  

PubMed

Nanofibrous TiO2-core/conjugated polymer-sheath composite nanocables were synthesized by in-situ chemical oxidative polymerization of aniline with oxidant in the presence of TiO, nanofibers prepared through an electrospinning process. During the polymerization process, aniline molecules were adsorbed on the surface of TiO2. Upon the addition of oxidant, the polymerization of aniline takes place on the surface of the TiO2 nanofibers and polyaniline (PANI) is gradually deposited on their surface. The resulting TiO2-PANI nanocomposites have a coaxial nanocable structure. The morphological and structural properties of the composite nanocables were analyzed by using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) and UV-visible spectroscopy (UV-vis), respectively. The HRTEM images proved that PANI (20 nm thickness) covered the surface of the TiO2 nanofibers. Also, the photocatalytic activity for the degradation of organic dyes on fibrous photocatalysts under UV-light was studied. The photocatalytic experiments showed that dye could be degraded more efficiently on the TiO2-PANI composite nanocables than on pure TiO2, due to the charge transfer from PANI to TiO2. The method for the synthesis of these unique structured composite nanocables is simple, rapid and reproducible. This facile method may be developed to produce multifunctional nanocomposites of various polymers with metal oxide fibers on a large scale for various technological applications such as sensors, solar cells, and catalysts. PMID:21121282

Reddy, Kakarla Raghava; Nakata, Kazuya; Ochiai, Tsuyoshi; Murakami, Taketoshi; Tryk, Donald A; Fujishima, Akira

2010-12-01

52

Methyl orange removal over Zn-incorporated TiO 2 photo-catalyst  

Microsoft Academic Search

This study focuses on the removal of the methyl orange (sodium p-dimethyl amino azo benzene sulfonate) of a representative dye compound in a liquid photo-system using nanometer-sized Zn-incorporated TiO2 synthesized by a solvothermal method. The Zn-incorporated TiO2 particles exhibited a mixed structure of anatase of TiO2 and ZnTiO3 with a particle size of below 20nm. The absorbance was shifted to

Youngmi Kim; Juhyun Lee; Harim Jeong; Yeji Lee; Myeong-Heon Um; Kyung Mi Jeong; Min-Kyeong Yeo; Misook Kang

2008-01-01

53

Photocatalytic oxidation of methyl orange in water phase by immobilized TiO2-carbon nanotube nanocomposite photocatalyst  

NASA Astrophysics Data System (ADS)

We developed an immobilized carbon nanotube (CNT)-titanium dioxide (TiO2) heterostructure material for the photocatalytic oxidation of methyl orange in aqueous phase. The catalyst material was prepared via sol-gel method using multi-walled CNTs grown on graphite substrate as carriers. The multi-walled CNTs were synthesized from thermal decomposing of hydrocarbon gas directly on thin graphite plate, forming immobilized 3-dimensional network of CNTs. The nanophase TiO2 was synthesized coating on CNTs to form "coral"-shaped nanocomposite 3-dimensional network on graphite substrate, thus bringing effective porous structure and high specific surface area, and possessing the merit of dispersive powder photocatalysts, which is the fully available surface area, while adapting the requirement for clean and convenient manipulation as an immobilized photocatalyst. Moreover, the CNT-TiO2 heterostructure reduced the electron-hole pair recombination rate and enhanced the photoabsorption and the adsorption ability, resulting in elevating the photocatalysis efficiency. These synergistic effects due to the hybrid nature of the materials and interphase interaction greatly improved the catalytic activity, and demonstrated superior photocatalytic performances. Our work can be a significant inspiration for developing hybrid nano-phase materials to realize sophisticated functions, and bear tremendous significance for the development and applications of semiconductor nano-materials.

Dong, Yinmao; Tang, Dongyan; Li, Chensha

2014-03-01

54

THERMALLY STABLE NANOCRYSTALLINE TIO2 PHOTOCATALYSTS SYNTHESIZED VIA SOL-GEL METHODS MODIFIED WITH IONIC LIQUID AND SURFACTANT MOLECULES  

EPA Science Inventory

Recently, sol-gel methods employing ionic liquids (ILs) have shown significant implications for the synthesis of well-defined nanostructured inorganic materials. Herein, we synthesized nanocrystalline TiO2 particles via an alkoxide sol-gel method employing a water-immi...

55

OXYGENATION OF HYDROCARBONS USING NANOSTRUCTURED TIO2 AS A PHOTOCATALYST: A GREEN ALTERNATIVE  

EPA Science Inventory

High-value organic compounds have been synthesized successfully from linear and cyclic saturated hydrocarbons by a photocatalytic oxidation process using a semiconductor material, titanium dioxide (TiO2). Various hydrocarbons were partially oxygenated in both aqueous and gaseous...

56

An efficient and novel porous nanosilica supported TiO2 photocatalyst for pesticide degradation using solar light.  

PubMed

A latex polymer of styrene-acrylic acid emulsion is used as a template for the synthesis of novel porous nanosilica (PNS) material. TiO(2) is dispersed over PNS by solid state dispersion and the composite materials are characterized by XRD, nitrogen adsorption-desorption isotherms, SEM and TEM measurements. The photocatalytic activities of the composite TiO(2)/PNS catalysts are evaluated for degradation of isoproturon pesticide in water with different parameters under solar light. Furthermore, commercial pesticide solutions containing imidacloprid and phosphamidon were also degraded successfully with the composite system using the same developed conditions for isoproturon degradation. The 5 wt% TiO(2)/PNS is found to be active in the present investigation. PMID:19596511

Phanikrishna Sharma, Mangalampalli V; Sadanandam, Gullapelli; Ratnamala, Ajjarapu; Durga Kumari, Valluri; Subrahmanyam, Machiraju

2009-11-15

57

Sandwich SrTiO3/TiO2/H-Titanate nanofiber composite photocatalysts for efficient photocatalytic hydrogen evolution  

NASA Astrophysics Data System (ADS)

SrTiO3/TiO2/H-Titanate nanofiber composites were synthesized through facile thermal treatment of Sr(OH)2 and H-titanate nanofibers in an ethanol/water solution and their photocatalytic activities for H2 evolution from a methanol/water solution under simulated solar irradiation were evaluated. TiO2/H-titanate nanofiber composites were acquired without Sr(OH)2 addition. At low Sr/Ti molar ratios, SrTiO3/TiO2/H-titanate nanofiber composites form. SrTiO3 nanoparticles were found to selectively grow on the surface of TiO2 nanoparticles, forming a unique SrTiO3-TiO2-H-titanate sandwich heterojunction. Upon increasing the Sr/Ti molar ratio, the fraction of TiO2 in the resultant composites decreases and eventually SrTiO3/H-titanate nanofiber composites form. SrTiO3/TiO2/H-titanate nanofiber composites are significantly more photocatalytically active than SrTiO3/H-titanate nanofiber and TiO2/H-titanate nanofiber composites due to the mitigated charge recombination and the accumulation of photo-excited electrons on the photocatalytically active TiO2 component. These results demonstrate an effective strategy of multi-heterojunctions with both appropriately-aligned band structures and appropriately-arranged composite structures to fabricate efficient composite photocatalysts.

Liu, Yuanxu; Wang, Zhonglei; Wang, Wendong; An, Xiaoqiang; Mi, Shiyang; Tang, Junwang; Huang, Weixin

2014-10-01

58

Microporous Ni-doped TiO2 film photocatalyst by plasma electrolytic oxidation.  

PubMed

Ni-doped TiO2 film catalysts were prepared by a plasma electrolytic oxidation (PEO) method and were mainly characterized by means of SEM, EDS, XRD, XPS, and DRS, respectively. The effects of Ni doping on the structure, composition and optical absorption property of the film catalysts were investigated along with their inherent relationships. The results show that the film catalyst is composed of anatase and rutile TiO2 with microporous structure. Doping Ni changes the phase composition and the lattice parameters (interplanar crystal spacing and cell volume) of the films. The optical absorption range of TiO2 film gradually expands and shifts to the red with increasing dosages. Both direct and indirect transition band gaps of the TiO2 films are deduced consequently. Moreover, the photocatalytic activity of the film catalysts for splitting Na2S+Na2SO3 solution into H2 is enhanced by doping with an appropriate amount of Ni. The as-prepared TiO2 film catalyst doping with 10 g/L of Ni(Ac)2 presents the highest photocatalytic reducing activity. PMID:20799710

Yao, Zhongping; Jia, Fangzhou; Tian, Shujun; Li, ChunXiang; Jiang, Zhaohua; Bai, Xuefeng

2010-09-01

59

Synthesis of TiO2 and TiO2-Pt and their application in photocatalytic degradation of humic acid.  

PubMed

The deposit of noble metal on titanium dioxide (TiO2) has been considered as an effective strategy to improve the activity of TiO2. In this study, TiO2 nanoparticles were prepared using a sol-gel route followed by heat treatment at elevated temperatures (573 K, 773 K, and 973 K). TiO2-Pt catalyst (1 wt%) was prepared by depositing Pt on the surface of the prepared TiO2 nanoparticles. TiO2 and TiO2-Pt were used as heterogeneous catalysts to remove humic acid with UV-light (120 W) illumination. TiO2 prepared at low temperature with smaller particle size and larger specific surface area had stronger activity on humic acid degradation. Deposit of Pt would favor separation of photogenerated charges and enhance the photocatalyst activity, but its coating of the active site also inhibited degradation of humic acid. The addition of H202 enhanced degradation of humic acid for more active oxygen produced. Low pH (pH = 4) was helpful to adsorb humic acid on the surface of TiO2 and, correspondingly, enhance degradation of humic acid (44.4%). PMID:24617110

Chen, Wenzhao; Ran, Xianqiang; Jiang, Xu; Min, Hongyang; Li, Dandan; Zou, Liyin; Fan, Jianwei; Li, Guangming

2014-01-01

60

Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes.  

PubMed

A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs) is presented. Anatase TiO2 nanoparticles (NPs) with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA) precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV-visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO) dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2. PMID:20671780

Xie, Yi; Heo, Sunghwan; Yoo, Seunghwa; Ali, Ghafar; Cho, Sungoh

2009-01-01

61

Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs) is presented. Anatase TiO2 nanoparticles (NPs) with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA) precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV-visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO) dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

Xie, Yi; Heo, Sung Hwan; Yoo, Seung Hwa; Ali, Ghafar; Cho, Sung Oh

2010-03-01

62

Anatase TiO 2 nanolayer coating on cobalt ferrite nanoparticles for magnetic photocatalyst  

Microsoft Academic Search

TiO2\\/CoFe2O4 composite nanoparticles with a core–shell structure have been obtained. The core CoFe2O4 nanoparticles were synthesized via co-precipitation method, and the shell TiO2 nanocrystals were derived via sol–gel technology followed by heat-treatment at 450 °C. The morphology and the crystalline structure of composite nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray diffraction, respectively. The as-prepared composite particles can

Wuyou Fu; Haibin Yang; Minghua Li; Minghui Li; Nan Yang; Guangtian Zou

2005-01-01

63

Sonochemical fabrication of morpho-genetic TiO 2 with hierarchical structures for photocatalyst  

Microsoft Academic Search

Titanium oxides (TiO2) with hierarchical structures have been successfully replicated from biotemplate using a sonochemical method. The bio-templates,\\u000a cedarwoods, were irradiated under ultrasonic waves in TiCl4 solutions and then calcined at temperatures between 450 and 600 °C. The fine replications of the biotemplates in TiO2 down to nanometer’s level were verified using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM),\\u000a and

Shenmin ZhuDi; Di Zhang; Zhixin Chen; Gang Zhou; Haibo Jiang; Jinlong Li

2010-01-01

64

Synthesis of anatase TiO 2 supported on porous solids by chemical vapor deposition  

Microsoft Academic Search

Coating anatase TiO2 onto three different particle supports, activated carbon (AC), ?-alumina (Al2O3) and silica gel (SiO2), by chemical vapor deposition (CVD) was studied. The effect of the CVD synthesis conditions on the loading rate of anatase TiO2 was investigated. It was found that introducing water vapor during CVD or adsorbing water before CVD was crucial to obtain anatase TiO2

Zhe Ding; Xijun Hu; Po L Yue; Gao Q Lu; Paul F Greenfield

2001-01-01

65

An efficient bicomponent TiO2/SnO2 nanofiber photocatalyst fabricated by electrospinning with a side-by-side dual spinneret method.  

PubMed

In this communication, we demonstrate that the electrospinning process with a side-by-side dual spinneret can be a simple approach for fabricating bicomponent TiO2/SnO2 nanofibers with controllable heterojunctions. Specifically, both of the TiO2 and SnO2 components in the nanofibers are fully exposed to the surface. This morphology fully utilized the photogenerated holes and electrons during the photocatalytic process, thus leading to a high photocatalytic activity. We believe that this versatile approach can be extended to fabricate other novel high-efficiency bicomponent photocatalysts. PMID:17425281

Liu, Zhaoyang; Sun, Darren Delai; Guo, Peng; Leckie, James O

2007-04-01

66

Understanding electronic and optical properties of anatase TiO2 photocatalysts co-doped with nitrogen and transition metals.  

PubMed

This paper describes an investigation into the general trend in electronic properties of anatase TiO2 photocatalysts co-doped with transition metals and nitrogen employing first-principles density functional theory. Fourteen different transition metals (M), including Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Cd, have been considered. The characteristic band structures of the co-doping systems involving the transition metal series are presented. Our results indicate that the absorption edges of TiO2 are shifted to the visible-light region upon introduction of dopants, due to the reduced conduction band minimum (CBM) and the formation of impurity energy levels (IELs) in the band gap. These IELs are primarily formed from (a) the anti-bonding orbitals of the M-O (M indicates the doped transition metal) bonds, (b) the unsaturated nonbonding d orbitals of the doped transition metal (mainly d(xy), d(yz), and d(xz)), and (c) the Ti-O bonding/Ti-N anti-bonding orbitals of the bond next to the doped transition metal. When the valence d electrons of the doped metal are between 3 and 7, all three types of IELs appear in the band gap of the (M, N) co-doped systems. For systems doped with a metal of more than 7 valence electrons, only types (a) and (c) of IELs as well as the unoccupied pz state of N are observed. Based on our analysis, we propose that the co-doping systems such as (V, N), (Cr, N), and (Mn, N), which have the IELs with a significant bandwidth, are of great potential as candidates for photovoltaic applications in the visible light range. PMID:23652827

Meng, Qingsen; Wang, Tuo; Liu, Enzuo; Ma, Xinbin; Ge, Qingfeng; Gong, Jinlong

2013-06-28

67

Carbon-deposited TiO2 3D inverse opal photocatalysts: visible-light photocatalytic activity and enhanced activity in a viscous solution.  

PubMed

We for the first time demonstrated carbon-deposited TiO2 inverse opal (C-TiO2 IO) structures as highly efficient visible photocatalysts. The carbon deposition proceeded via high-temperature pyrolysis of phloroglucinol/formaldehyde resol, which had been coated onto the TiO2 IO structures. Carbon deposition formed a carbon layer and doped the TiO2 interface, which synergistically enhanced visible-light absorption. We directly measured the visible-light photocatalytic activity by constructing solar cells comprising the C-TiO2 IO electrode. Photocatalytic degradation of organic dyes in a solution was also evaluated. Photocatalytic dye degradation under visible light was only observed in the presence of the C-TiO2 IO sample and was increased with the content of carbon deposition. The IO structures could be readily decorated with TiO2 nanoparticles to increase the surface area and enhance the photocatalytic activity. Notably, the photocatalytic reaction was found to proceed in a viscous polymeric solution. A comparison of the mesoporous TiO2 structure and the IO TiO2 structure revealed that the latter performed better as the solution viscosity increased. This result was attributed to facile diffusion into the fully connected and low-tortuosity macropore network of the IO structure. PMID:24266769

Lee, Sunbok; Lee, Youngshin; Kim, Dong Ha; Moon, Jun Hyuk

2013-12-11

68

Steady hydrogen evolution from water on Eosin Y-fixed TiO 2 photocatalyst using a silane-coupling reagent under visible light irradiation  

Microsoft Academic Search

A chemical fixation of xanthene dyes on platinized TiO2 particles via silane-coupling reagent was attempted in order to construct a stable dye-sensitized photocatalyst system in water. The Eosin Y fixed Pt-TiO2 (E.Y-TiO2) exhibited steady H2 production from aqueous triethanolamine solution (TEOA aq.) under visible light irradiation for long time, and the H2 evolution reproduced even after the exchange of TEOA

Ryu Abe; Koujirou Hara; Kazuhiro Sayama; Kazunari Domen; Hironori Arakawa

2000-01-01

69

Comparison of photodegradative efficiencies and mechanisms of Victoria Blue R assisted by Nafion-coated and fluorinated TiO2 photocatalysts.  

PubMed

The purposes of this research were to study the effects of two modified photocatalysts, Nafion-coated TiO(2) and fluorinated TiO(2), and photocatalytic degradation of Victoria Blue R in aqueous solution. Photocatalytic degradation of Victoria Blue R was accelerated by the modified photocatalysts. Bulk and surface characterizations of the resulting powders were carried out. Attachment of the anions to the TiO(2) surface using the Nafion-coated-TiO(2) possibly results in increased adsorption of the cationic dye, and the degradation rate is larger for the cationic dye. It was found that Victoria Blue R on the two illuminated TiO(2) surfaces underwent very different changes. To obtain a better understanding on the mechanistic details of this modified-TiO(2)-assisted photodegradation of the Victoria Blue R dye with UV irradiation, a large number of intermediates of the process were separated, identified, and characterized by a high-performance liquid chromatography-mass spectrometry technique. Several probable photodegradation pathways were proposed and discussed. PMID:19815344

Chen, K T; Lu, C S; Chang, T H; Lai, Y Y; Chang, T H; Wu, C W; Chen, C C

2010-02-15

70

N-doped TiO 2 photo-catalyst for the degradation of 1,2-dichloroethane under fluorescent light  

NASA Astrophysics Data System (ADS)

The photo-catalytic degradation of 1,2-dichloroethane (1, 2-DCE) using nitrogen-doped TiO 2 photo-catalysts under fluorescent light irradiation was investigated. Highly pure TiO 2 and nitrogen-doped TiO 2 were prepared by a sol-gel method and characterized by thermo-gravimetric/differential-thermal analysis (TG/DTA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The results indicate that the photo-catalysts were mainly nano-size with an anatase-phase structure. The degradation reaction of 1,2-DCE was operated under visible-light irradiation, and the photo-catalytic oxidation was conducted in a batch photo-reactor with various nitrogen doping ratios (N/Ti = 0-25 mol%). The relative humidity (RH) was controlled at 0-20% and the oxygen concentration was controlled at 0-21%. The photo-degradation with nitrogen-doped TiO 2 showed superior photo-catalytic activity compared to that for pure TiO 2. TiO 2 doped with 15 mol% nitrogen exhibited the best photo-catalytic efficiency under the tested conditions. The products from the 1,2-DCE photo-catalytic oxidation were CO 2 and water; the by-products included dichloromethane, methyl chloride, ethyl chloride, carbon monoxide, and hydrogen chloride. The reaction pathway of 1,2-DCE indicates that oxygen molecules are the major factor that causes the degradation of 1,2-DCE in the gas phase.

Lin, Yi-Hsing; Chiu, Tang-Chun; Hsueh, Hsin-Ta; Chu, Hsin

2011-12-01

71

Solid-state NMR studies of the adsorption and photooxidation of ethanol on mixed TiO2--SnO2 photocatalysts.  

PubMed

In situ solid-state NMR methodologies have been used to investigate the photocatalytic oxidation of ethanol (CH3CH2OH) over a series of SnO2-based photocatalysts. The adsorption of ethanol on commercially available SnO2 powder was studied using both cross-polarization 13C NMR and REDOR experiments, and showed the formation of two surface ethanol species, hydrogen-bonded ethanol at surface hydroxyl groups and ethanol chemisorbed to the SnO2 surface (Sn--OCH2CH3). 13C NMR of the adsorbed ethanol was used to characterize the surface of monolayer SnO2--TiO2 coupled photocatalysts supported on porous Vycor glass. In situ solid-state NMR studies showed that the photooxidation of ethanol over the monolayer photocatalysts was slower than that over a supported TiO2 monolayer photocatalyst due to the build-up of reaction intermediates such as acetic acid on the catalyst surface. 119Sn NMR experiments characterized the tin species on the porous Vycor glass support. PMID:14642419

Pilkenton, Sarah; Raftery, Daniel

2003-12-01

72

Novel high potential visible-light-active photocatalyst of CNT/Mo, S-codoped TiO2 hetero-nanostructure  

NASA Astrophysics Data System (ADS)

The current study deals with synthesize of novel nanophotocatalysts of CNT/Mo,S-codoped TiO2 by reacting between titanium isopropoxide (Ti(OC3H7)4) and CNT in aqueous ammonia and subsequent calcining of hydrolysis of the products. The prepared catalysts were characterized by N2 adsorption-desorption measurements, XRD, SEM, TEM, EDX, FT-IR, and UV-vis DRS spectroscopy. SEM and TEM images exhibited uniform coverage of CNT with anatase TiO2 nanoclusters. It was also demonstrated that the presence of S and Mo within the TiO2 acts as electrons traps and prevents the charge recombination and also enables the TiO2 photocatalyst to be active in visible-light region. Moreover, the CNT/Mo,S-doped TiO2 nanohybrids has been proven to has a excellent photocatalytic performance in photodecomposition of Congored (CR), at which the rate of decomposition reaches 100% in only 20 and 30 min under UV and visible-light irradiation, respectively. The enhanced photocatalytic activity was ascribed to the synergetic effects of excellent electrical property of CNT and metal-non-metal codoping. Finally, which to best of our knowledge is done for the first time, we have demonstrated that Mo- and S-doped TiO2 decorated over CNT, or CNT/Mo,S-codoped TiO2, may have high potential applications in photocatalysis and environmental protection with superior catalytic activity under visible-light illumination.

Hamadanian, M.; Shamshiri, M.; Jabbari, V.

2014-10-01

73

High-rate and low-temperature synthesis of TiO2, TiN, and TiO2/TiN/TiO2 thin films and study of their optical and interfacial characteristics  

E-print Network

High-rate and low-temperature synthesis of TiO2, TiN, and TiO2/TiN/TiO2 thin films and study with unbalanced magnetrons, we deposited advanced inorganic functional thin films such as TiO2, TiN, and TiO2/Ti sputtering. The TiO2 101 and TiN 100 thin films were stoichiometric and polycrystalline but highly oriented

Boo, Jin-Hyo

74

Mesoporous yolk-shell SnS2-TiO2 visible photocatalysts with enhanced activity and durability in Cr(vi) reduction  

NASA Astrophysics Data System (ADS)

A novel mesoporous yolk-shell SnS2-TiO2 visible photocatalyst (ST-is) was synthesized by in situ doping TiO2 with SnO2 through solvothermal alcoholysis, followed by sulfurization under hydrothermal conditions. The ST-is displayed higher activity in photocatalytic reduction of Cr(vi) owing to the strong photosensitizing effect of SnS2 in uniform nanoparticles and the enhanced light harvesting via multiple reflections in yolk-shell chambers. Meanwhile, the strong SnS2-TiO2 interaction could generate more heterojunctions which facilitated photoelectron transfer from SnS2 to TiO2, leading to the enhanced activity by inhibiting photoelectron-hole recombination. Moreover, the ST-is displayed strong durability owing to the strong SnS2-TiO2 interaction and the encapsulation of SnS2 nanoparticles in the yolk-shell chamber, which could inhibit SnS2 leaching. Furthermore, because of the electronegative surface and high surface area, the ST-is could thoroughly purify wastewater by completely adsorbing Cr3+ resulting from Cr(vi) reduction. In addition, the presence of photocatalytic degradation of organic compounds promoted Cr(vi) reduction owing to inhibition of photoelectron-hole recombination by consuming holes.A novel mesoporous yolk-shell SnS2-TiO2 visible photocatalyst (ST-is) was synthesized by in situ doping TiO2 with SnO2 through solvothermal alcoholysis, followed by sulfurization under hydrothermal conditions. The ST-is displayed higher activity in photocatalytic reduction of Cr(vi) owing to the strong photosensitizing effect of SnS2 in uniform nanoparticles and the enhanced light harvesting via multiple reflections in yolk-shell chambers. Meanwhile, the strong SnS2-TiO2 interaction could generate more heterojunctions which facilitated photoelectron transfer from SnS2 to TiO2, leading to the enhanced activity by inhibiting photoelectron-hole recombination. Moreover, the ST-is displayed strong durability owing to the strong SnS2-TiO2 interaction and the encapsulation of SnS2 nanoparticles in the yolk-shell chamber, which could inhibit SnS2 leaching. Furthermore, because of the electronegative surface and high surface area, the ST-is could thoroughly purify wastewater by completely adsorbing Cr3+ resulting from Cr(vi) reduction. In addition, the presence of photocatalytic degradation of organic compounds promoted Cr(vi) reduction owing to inhibition of photoelectron-hole recombination by consuming holes. Electronic supplementary information (ESI) available: Details of the FESEM images, TEM images, N2 adsorption-desorption isotherms, FTIR spectra, XRD patterns, XPS spectra, zeta-potential test, Mott-Schottky plots, and the schematic illustration of the charge separation in SnS2-TiO2 photocatalysts under visible light irradiation. See DOI: 10.1039/c2nr33755j

Wang, Jinguo; Li, Xinru; Li, Xi; Zhu, Jian; Li, Hexing

2013-02-01

75

Electrical Properties of Nb-, Ga-, and Y-Substituted Nanocrystalline Anatase TiO2 Prepared by Hydrothermal Synthesis  

E-print Network

We have recently shown that the introduction of electronic point defects in TiO2 is an effective wayElectrical Properties of Nb-, Ga-, and Y-Substituted Nanocrystalline Anatase TiO2 Prepared oxidizing nature of hydrothermal synthesis. I. Introduction THE anatase polymorph of TiO2 is of considerable

Poeppelmeier, Kenneth R.

76

Hydrothermal synthesis and characterization of La 0.66TiO 2.993  

Microsoft Academic Search

In the present paper, we report a novel synthetic method, based on a hydrothermal process, for the synthesis of La0.66TiO2.993. The synthesized La0.66TiO2.993 was characterized by techniques such as XRD, IR, SEM, XPS and chemical analyses. The results indicated that the phase corresponded to orthorhombic perovskite-type La0.66TiO2.993, and the product had a narrower particle size which was about 300 nm.

Wenjun Zheng; Wenqin Pang

1997-01-01

77

Nanostructured AgBr loaded TiO2: An efficient sunlight active photocatalyst for degradation of Reactive Red 120  

PubMed Central

The AgBr loaded TiO2 catalyst was prepared by a feasible approach with AgBr and tetraisopropyl orthotitanate and characterized by BET surface area measurement, diffuse reflectance spectra (DRS), scanning electron microscope (SEM), energy dispersive spectra (EDS), X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscope (AFM) analysis. The results of characterization reveal that AgBr loaded TiO2 has a nanostructure. Formation of the nanostructure in AgBr loaded TiO2 results in substantial shifting of the absorption edge of TiO2 to red and enhancement of visible light absorption. Electrochemical impedance spectroscopy measurements reveal that AgBr loaded TiO2 has a higher photoconductivity than prepared TiO2 due to higher separation efficiency of electron-hole pairs. Cyclic voltammetric studies reveal enhanced conductivity in AgBr loaded TiO2, which causes an increase in its photocatalytic activity. AgBr loaded TiO2 exhibited a higher photocatalytic activity than TiO2-P25 and prepared TiO2 in the photodegradation of Reactive Red 120 (RR 120). PMID:21801445

2011-01-01

78

Simple preparation of Mn-N-codoped TiO2 photocatalyst and the enhanced photocatalytic activity under visible light irradiation  

NASA Astrophysics Data System (ADS)

Mn-N-codoped TiO2 nanocrystal photocatalysts responsive to visible light were synthesized by a simple sol-gel method and calcined at different temperatures. The catalysts with different Mn contents were characterized by XRD, BET, UV-vis DRS, XPS and ESR analyses and their photocatalytic activities for Rhodamine B degradation were studied under visible light irradiation. The results showed that the codoping of Mn and N ions inhibited the growth of crystalline size and the transformation from anatase to rutile phase. The XPS results showed that the introduction of a small amount of Mn facilitated further N uptake. Mn-TiO2 and Mn-N-TiO2 exhibited strong visible light absorptions at 400-650 nm. Mn-TiO2 showed significant photocatalytic activity under visible light irradiation compared to pure TiO2, and the activity was further enhanced by codoping Mn and N into TiO2. The highest photocatalytic activity was achieved on 0.25%Mn-N-TiO2 calcined at 400 °C. The synergistic effect of Mn and N ions narrowed the band gap of TiO2 and inhibited the recombination of the photogenerated electrons and holes, leading to a great improvement in the photocatalytic activity in the visible light region.

Quan, Feng; Hu, Yun; Zhang, Xia; Wei, Chaohai

2014-11-01

79

Design of Composite Photocatalyst of TiO2 and Y-Zeolite for Degradation of 2-Propanol in the Gas Phase under UV and Visible Light Irradiation.  

PubMed

Hydrophobic Y-zeolite (SiO2/Al2O3 = 810) and TiO2 composite photocatalysts were designed by using two different types of TiO2 precursors, i.e., titanium ammonium oxalate and ammonium hexafluorotitanate. The porous structure, surface property and state of TiO2 were investigated by various characterization techniques. By using an ammonium hexafluorotitanate as a precursor, hydrophobic modification of the Y-zeolite surface and realizing visible light sensitivity was successfully achieved at the same time after calcination at 773 K in the air. The prepared sample still maintained the porous structure of Y-zeolite and a large surface area. Highly crystalline anatase TiO2 was also formed on the Y-zeolite surface by the role of fluorine in the precursor. The usages of ammonium hexafluorotitanate were effective for the improvement of the photocatalytic performance of the composite in the degradation of 2-propanol in the gas phase under UV and visible light (? > 420 nm) irradiation. PMID:25314607

Kamegawa, Takashi; Ishiguro, Yasushi; Kido, Ryota; Yamashita, Hiromi

2014-01-01

80

TiO 2 photocatalyst for indoor air remediation: Influence of crystallinity, crystal phase, and UV radiation intensity on trichloroethylene degradation  

Microsoft Academic Search

Nanocrystalline TiO2 photocatalysts prepared through a simple sol–gel process followed by calcination at 100–800°C were evaluated for the decomposition of trichloroethylene (TCE) in simulated indoor air. Catalysts made of pure anatase, anatase\\/rutile mixture and pure rutile with crystal sizes of 5.8–75.8nm and surface areas of 4.3–498m2\\/g were immobilized as thick films on borosilicate glass and installed in a gas-phase, flat-plate

Valeria Puddu; Hyeok Choi; Dionysios D. Dionysiou; Gianluca Li Puma

2010-01-01

81

Preparation of TiO 2 nanoparticles by submerged arc nanoparticle synthesis system  

Microsoft Academic Search

This study investigated the effects of process parameters on geometrical features of titanium dioxide (TiO2) nanoparticles synthesized by the submerged arc nanoparticle synthesis system (SANSS). The synthesis process involves vaporizing a pure titanium rod by a submerged arc in deionized liquid under a controlled vacuum environment, followed by rapid quenching of the vaporized titanium gas by a cooling system, thus

Liang-Chia Chen

2010-01-01

82

Controllable hydrothermal synthesis, optical and photocatalytic properties of TiO2 nanostructures  

NASA Astrophysics Data System (ADS)

Different surface morphologies of TiO2 thin films were prepared by hydrothermal synthesis method on Ti substrates through changing reaction time. The microstructure, composition, optical properties and photocatalytic properties of TiO2 thin films were systematically investigated by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectrometer and ultraviolet-visible spectroscopy. As the reaction time increases, anatase structure and brookite structure of TiO2 films respectively increases and decreases, corresponding to surface morphology changes from irregular structure to regular geometrical shape structure. These structural changes are accompanied by significant variations of optical properties and photocatalytic properties including a widening of the band gap from 2.86 to 3.19 eV, photocatalytic degradation efficiency from 92.5 to 98.1% and photocatalytic degradation rate from 0.032 to 0.048 min-1. Among all samples, TiO2-1 shows the best photocatalytic properties. Compositional analysis indicates that TiO2 surface layer contains Ti and O elements, the ratio of Ti:O is 1:2.28 which is close to the atom ratio of TiO2.

Xu, Yanyan; Zhang, Maocui; Zhang, Miao; Lv, Jianguo; Jiang, Xishun; He, Gang; Song, XuePing; Sun, Zhaoqi

2014-10-01

83

Hydrothermal synthesis spherical TiO2 and its photo-degradation property on salicylic acid  

NASA Astrophysics Data System (ADS)

Anatase TiO2 spheres have been prepared using hydrothermal synthesis. The prepared spheres were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). The TiO2 consisted of well-defined spheres with size of 3-5 ?m. The photocatalytic activity of spherical TiO2 was determined by degradation of salicylic acid under visible light irradiation. It was revealed that the degradation rate of the spherical TiO2 which was processed at 150 °C for 48 h could reach 81.758%. And the kinetics of photocatalytic degradation obeyed first-order kinetic, which the rate constant value was 0.01716 S-1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h). The kinetics of adsorption followed the pseudo-second-order model and the rate constant was 1.2695 g mg-1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h).

Guo, Wenlu; Liu, Xiaolin; Huo, Pengwei; Gao, Xun; Wu, Di; Lu, Ziyang; Yan, Yongsheng

2012-07-01

84

A study of parameter setting and characterization of visible-light driven nitrogen-modified commercial TiO2 photocatalysts.  

PubMed

An optimal condition applied to the Taguchi method with an L(9) orthogonal array for preparing a visible-light driven nitrogen-modified TiO(2) (N-TiO(2)) photocatalyst by a simple hydrolysis method has been examined for material characteristics and a photodecolorization test of methyl blue (MB) under various visible light source (fluorescent and blue LED lamps) irradiations. Results of the material characterization showed that the absorption of prepared N-TiO(2) powder exhibited a significant extension into visible light regimes with an optical bandgap (Eg) of around 2.96 eV, which subsequently improved the visible-light photocatalytic activity of N-TiO(2) samples. The superior photocatalytic properties, the pseudo first-order reaction rate constants (k) and photodecolorization efficiency (?%) of a N-TiO(2) photocatalyst during the photodecolorization test of methyl blue (MB) under two different visible light irradiations were very evident compared to those for pure TiO(2). For photodecolorization of practical dyeing from the waste water from the dyeing and finishing industry, a higher photodecolorization efficiency of N-TiO(2) powder toward Direct blue-86 (DB-86) (Direct Fast Turquoise Blue GL) dye was also achieved. PMID:21555185

Kuo, Yu-Lin; Su, Te-Li; Kung, Fu-Chen; Wu, Tsai-Jung

2011-06-15

85

Characterization, activity and mechanisms of a visible light driven photocatalyst: Manganese and iron co-modified TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

An attempt was made to prepare Mn,Fe-codoped nanostructured TiO2 photocatalyst for visible light assisted degradation of an azo dye (methylene blue) in aqueous solutions by a sol-gel process. The asprepared nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectra (PL) techniques. The photocatalytic activity of Mn,Fe-codoped TiO2 catalyst was evaluated by measuring degradation rates of methylene blue (MB) under visible light. The results showed that doping with the manganese and iron ions significantly enhanced the photocatalytic activity for MB degradation under visible light irradiation. This was ascribed to the fact that a small amount of manganese and iron dopants simultaneously increased MB adsorption capacity and separation efficiency of electron-hole pairs. The results of DRS showed that Mn,Fe-codoped TiO2 had significant absorption between 400 and 500 nm, which increased with the increase of manganese ion content. It is found that the stronger the PL intensity, the higher the photocatalytic activity. This could be explained by the points that PL spectra mainly resulted from surface oxygen vacancies and defects during the process of PL, while surface oxygen vacancies and defects could be favorable in capturing the photoinduced electrons during the process of photocatalytic reactions, so that the recombination of photoinduced electrons and holes could be effectively inhibited.

Zhang, Dongfang; Zeng, Fanbin

2011-10-01

86

Anatase TiO 2 nanoparticles immobilized on ZnO tetrapods as a highly efficient and easily recyclable photocatalyst  

Microsoft Academic Search

Anatase TiO2 nanoparticles in the size of ca. 6nm were immobilized on the single-crystalline tetrapod-like ZnO (denoted as T-ZnO in the text) with dimensions up to 20–50?m by vapor hydrolysis method (VHM). Compared to the wet chemical deposition method, more uniform TiO2 layers with a tunable thickness were achieved by VHM. T-ZnO showed a relatively low efficiency in the photooxidation

Qinghong Zhang; Wugang Fan; Lian Gao

2007-01-01

87

Synthesis of TiO2 nanoparticles by premixed stagnation swirl flames  

E-print Network

laminar premixed stagnation flat flames. Particles in the flow field are determined to be nonSynthesis of TiO2 nanoparticles by premixed stagnation swirl flames Junjing Wang a , Shuiqing Li a, Piscataway, NJ 08854, USA Abstract A new turbulent, premixed, stagnation swirl flame (SSF) is used

Tse, Stephen D.

88

Synthesis and hydrophilic properties of Mo doped TiO2 thin films  

NASA Astrophysics Data System (ADS)

Amorphous undoped TiO2 and Mo-doped TiO2 thin films were obtained by spray pyrolysis. By heat treatment, they became polycrystalline consisting in anatase, or mixed anatase/rutile phases, if deposited on glass or silicon, respectively. Mo enters in the TiO2 matrix as Mo5+, determining a slight red shift of the absorption edge. Based on Fourier transmission infrared analysis, performed on the studied films, before and after irradiation, providing information on the relationship between hydrophilicity and the amount of the adsorbed hydroxyl groups, we certify once again that the anatase phase (present in proportion of 100% in the films deposited on glass) is superior concerning the hydrophilic properties. Mo enhances wettability for the films deposited on silicon, compared to the undoped one, even if determines a rise in the rutile weight percentage, as a combined effect with the substrate nature. The decomposition of the oleic acid confirms that titania films with higher hydrophilic performances are also good photocatalysts, confirming in fact that investigating the hydrophilic properties of these films constitutes a much simpler way to obtain information on their photocatalytic activity.

Mardare, Diana; Cornei, Nicoleta; Luca, Dumitru; Dobromir, Marius; Irimiciuc, ?tefan A.; Pung?, Luciana; Pui, Aurel; Adomniţei, C?t?lin

2014-06-01

89

Study the structure and performance of thermal/plasma modified Au nanoparticle-doped TiO2 photocatalyst  

NASA Astrophysics Data System (ADS)

This study describes the influence of thermal/plasma treatments on the structure and photocatalytic performance of the Au-doped TiO2 catalyst. Au (gold) nanoparticles were attached on TiO2 (Titania) nanoparticle surfaces by conventional deposition precipitation technique and the resulting catalysts were subsequently modified with thermal (at 450°C under vacuum) and plasma (at an ambient temperature under Argon atmosphere for 20 min) treatments. Structural characterization of the modified catalysts was performed by diverse analytical techniques and the photocatalytic activity was evaluated by assessing the degradation of the methylene blue (MB) in water under UV (ultra-violet) irradiations. Results showed that the thermal/plasma treatment significantly influenced the structural features of Au-doped TiO2 catalyst by altering the morphology, increasing the Au nanoparticles population, improving the Au/TiO2 catalytic activity, changing the textural properties and reducing the band gap energies thus tuned Au-doped TiO2 catalyst to higher efficiency. Thermal/plasma treated Au-doped TiO2 was found to exhibit higher photocatalytic activity than the as-synthesized (pristine sample). This improvement in photocatalytic activity might be due to the cathodic influence of gold in suppressing the electron-hole recombination during the reaction.

Mahmood, Asif; Ramay, Shahid M.; Al-Zaghayer, Yousef S.; Atiq, Shahid; Ahmad, Iftikhar; Shar, Muhammad Ali; Khan, Salah Din

2014-10-01

90

Effect of preparation conditions on the characteristics and photocatalytic activity of TiO2/purified diatomite composite photocatalysts  

NASA Astrophysics Data System (ADS)

TiO2/purified diatomite composite materials were prepared through a modified hydrolysis-deposition method under low temperature using titanium tetrachloride as precursor combined with a calcination crystallization process. The microstructure and crystalline phases of the obtained composites prepared under different preparation conditions were characterized by high resolution scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The photocatalytic performance of TiO2/purified diatomite composites was evaluated by Rhodamine B as the target pollutant under UV irradiation, and the optimum preparation conditions of composites were obtained. The TiO2 crystal form in composites prepared under optimum conditions was anatase, the grain size of which was 34.12 nm. The relationships between structure and property of composite materials were analyzed and discussed. It is indicated that the TiO2 nanoparticles uniformly dispersed on the surface of diatoms, and the photocatalytic performance of the composite materials was mainly determined by the dispersity and grain size of loaded TiO2 nanoparticles.

Sun, Zhiming; Hu, Zhibo; Yan, Yang; Zheng, Shuilin

2014-09-01

91

In situ surface hydrogenation synthesis of Ti3+ self-doped TiO2 with enhanced visible light photoactivity  

NASA Astrophysics Data System (ADS)

A novel one-step, vapor-fed aerosol flame synthetic process (VAFS) has been developed to prepare Ti3+ self-doped titanium dioxide (TiO2). The freshly formed TiO2 was in situ surface hydrogenated during the condensation stage by introducing H2 above the flame, and Ti3+ ions were created near the surface of TiO2. The relative content of Ti3+ ions near the surface of TiO2 is estimated to be 8%. Because of the high absorption of visible light and suppression of charge recombination, the photocurrent density and decomposition of MB under visible light irradiation were remarkably enhanced. This study demonstrates a simple, potential method to produce Ti3+ self-doped TiO2 with effective photoactivity in visible light.A novel one-step, vapor-fed aerosol flame synthetic process (VAFS) has been developed to prepare Ti3+ self-doped titanium dioxide (TiO2). The freshly formed TiO2 was in situ surface hydrogenated during the condensation stage by introducing H2 above the flame, and Ti3+ ions were created near the surface of TiO2. The relative content of Ti3+ ions near the surface of TiO2 is estimated to be 8%. Because of the high absorption of visible light and suppression of charge recombination, the photocurrent density and decomposition of MB under visible light irradiation were remarkably enhanced. This study demonstrates a simple, potential method to produce Ti3+ self-doped TiO2 with effective photoactivity in visible light. Electronic supplementary information (ESI) available: Schematic setup for Ti3+ self-doped TiO2 nanoparticles is shown in Fig. S1. The BET specific surface and pore-size distribution of Ti3+ self-doped TiO2 is shown in Fig. S2. XRD patterns of pristine TiO2 and Ti3+ self-doped TiO2 are shown in Fig. S3. HRTEM image of Ti3+ self-doped TiO2 with mixture phase is shown in Fig. S4. The photographs of different colors of Ti3+ self-doped TiO2 with different flow rates of hydrogen are shown in Fig. S5. TEM images of Ti3+ self-doped TiO2 samples with different flow rates of carrier gas are shown in Fig. S6. XPS spectrum of O 1s is shown in Fig. S7. Photodegradation of MB in aqueous solutions using Ti3+ self-doped TiO2, pristine TiO2 and P25 as photocatalysts with irradiation of ultraviolet light is shown in Fig. S8. UV-vis spectra of MB aqueous solutions at different times by using Ti3+ self-doped TiO2 as a photocatalyst under the irradiation of visible light is shown in Fig. S9. See DOI: 10.1039/c4nr00972j

Huo, Junchao; Hu, Yanjie; Jiang, Hao; Li, Chunzhong

2014-07-01

92

Synthesis of TiO2 nanocrystals with a high affinity for amine organic compounds.  

PubMed

This article describes a different approach to the colloidal synthesis of TiO(2) nanocrystals using a polymer melt as a solvent. This approach allowed us to obtain a colloidal dispersion with a high degree of stability in a polymeric solvent, resulting in a transparent colloid. Using this method, it was possible to obtain the TiO(2) nanocrystal with Brønsted acid sites and polymer chains chemically anchored on the nanocrystal surface. The acid surface of those nanocrystals has the chemical property to react in the presence of amine organic compounds and to maintain the colloidal stability. In this way, TiO(2) nanocrystals were combined with a molecular probe containing amine functional groups such as polyaniline. Through the combination of the molecular probe and inorganic nanocrystals, we obtained a hybrid material with interesting chemical, optical, and electronic behavior, making it a promising material for photovoltaic, photochromic, and sensor devices. PMID:20565085

Gonçalves, Ricardo H; Schreiner, Wido Herwig; Leite, Edson R

2010-07-20

93

Synthesis of chiral TiO2 nanofibre with electron transition-based optical activity  

PubMed Central

The optical chirality induced at the absorption bands due to electronic exciton coupling of the transition dipole moments between chromophores in close proximity is ubiquitous in helical organic materials. However, inorganic materials with optical activity resulting from electronic transitions have not been explored. Here we report the synthesis of chiral TiO2 fibres via transcription of the helical structure of amino acid-derived amphiphile fibres through coordination bonding interactions between the organics and the TiO2 source. Upon calcination, the as-prepared amorphous TiO2 double-helical fibres with a pitch length of ~100?nm were converted to double-helical crystalline fibres with stacks of anatase nanocrystals in an epitaxial helical relationship. Both the amorphous and anatase crystalline helical TiO2 fibres exhibited optical response to circularly polarized light at the absorption edge around ~350?nm. This was attributed to the semiconductor TiO2-based electronic transitions from the valence band to the conduction band under an asymmetric electric field. PMID:23169056

Liu, Shaohua; Han, Lu; Duan, Yingying; Asahina, Shunsuke; Terasaki, Osamu; Cao, Yuanyuan; Liu, Ben; Ma, Liguo; Zhang, Jialiang; Che, Shunai

2012-01-01

94

The hybrid photocatalyst of TiO2-SiO2 thin film prepared from rice husk silica  

NASA Astrophysics Data System (ADS)

The TiO2-SiO2 thin film was prepared by self-assembly method by mixing SiO2 precursor with titanium precursor solution and aged to obtain a co-precipitation of silica and titanium crystals. Dip coating method was applied for thin film preparation on glass slide. The X-ray diffraction (XRD) of the self-assembly thin film had no characteristic property of SiO2 and even anatase TiO2 but indicated new crystal structure which was determined from the Fourier Transform Infrared Spectrophotometer (FTIR) as a hybridized Ti-O-Si bonding. The surface area and surface volume of the self-assembly sample were increased when SiO2 was incorporated into the film. The self-assembly TiO2-SiO2 thin film exhibited the enhanced photocatalytic decolorization of methylene blue (MB) dye. The advantages of SiO2 are; (1) to increase the adsorbability of the film and (2) to provide the hydroxyl radical to promote the photocatalytic reaction. The self-assembly thin film with the optimum molar ratio (SiO2:TiO2) as 20:80 gave the best performance for photocatalytic decolorization of MB dye with the overall efficiency of 81%.

Klankaw, P.; Chawengkijwanich, C.; Grisdanurak, N.; Chiarakorn, Siriluk

2012-03-01

95

Formation of TiO2 nanotubes via anodization and potential applications for photocatalysts, biomedical materials, and photoelectrochemical cell  

NASA Astrophysics Data System (ADS)

One-dimensional nanotube systems with high surface-to-volume ratios possess unique properties and are thus utilized in various applications. In this study, self-organized TiO2 nanotubes were prepared by anodization of a Ti foil in glycerol containing 5 wt% ammonium fluoride (NH4F) and 6 wt% ethylene glycol (EG). The surface morphology, average inner diameter, and average length of the nanotubes varied with the electrochemical anodization parameters. Nanotubes with uniform surface morphologies, an average diameter of 85 nm, and an average length of 1.1 ?m were obtained at 30 V for 1 h The as-prepared nanotubes were amorphous but they crystallized in the anatase phase after heating at about 400 °C for 2 h in an argon atmosphere. The photocatalytic activity of the TiO2 nanotubes was evaluated through the degradation of methyl orange (MO) and by investigating their bactericidal effect. Optimum photocatalysis of MO was achieved at a kinetic rate constant of 10-3 min-1. Furthermore, cell viability rapidly decreased on UV illumination and complete killing was achieved at 60 min in the presence of TiO2 nanotubes. For biomedical applications, the cellular activity on TiO2 nanotubes was determined using PA6 cells. Higher cellular activities were achieved using the anatase phase of 85-nm-diameter nanotubes than the amorphous phase. Photoelectrochemical hydrogen generation was investigated using nanotube photoanodes in 1 M potassium hydroxide (KOH) containing 1 wt% EG and xenon lamp. The maximum photocurrent density was 0.55 mA/cm2. These findings demonstrate that TiO2 nanotubes are promising for use in multifunctional applications.

Sreekantan, Srimala; Arifah Saharudin, Khairul; Wei, Lai Chin

2011-03-01

96

Photocatalytic Activity of N-doped TiO2 Photocatalysts Prepared from the Molecular Precursor (NH4)2TiO(C2O4)2  

NASA Astrophysics Data System (ADS)

We developed a novel approach for the preparation of N-doped TiO2 photocatalysts by calcining ammonium titanium oxalate at different temperatures. The structures of N-TiO2 were characterized by powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, diffuse reflectance UV-Vis spectroscopy, and scanning electron microscope. The N-doped TiO2 photocatalysts calcined below 700 °C are the pure anatase phase but that calcined at 700 °C is a mixture of anatase and rutile phases. The doped N locates at the interstitial site of TiO2 which leads to the narrowing of bad gap of pure anatase N-TiO2. Among all photocatalysts, N-TiO2 photocatalysts calcined at 600 and 400 °C exhibit the best performance in the photodegradation of methyl orange under the UV light and all-wavelength light illuminations, respectively; however, because of the perfect crystallinity and the existence of anatase-rutile phase junctions, N-TiO2 photocatalyst calcined at 700 °C exhibits the highest specific photodegradation rate, i.e., the highest quantum yield, under both the UV light and all-wavelength light illuminations.

Bu, Jing; Fang, Jun; Shi, Fu-cheng; Jiang, Zhi-quan; Huang, Wei-xin

2010-02-01

97

Synthesis and growth mechanism of multilayer TiO2 nanotube arrays  

NASA Astrophysics Data System (ADS)

High-aspect-ratio TiO2 nanotube arrays formed by anodic oxidation have drawn extensive attention due to their easy fabrication and various excellent optical, electrical and biomedical properties. In contrast to conventional single-layer TiO2 nanotubes prepared via constant-voltage anodization, we synthesize multilayer TiO2 nanotube arrays with high surface area by using alternating-voltage anodization steps. This work presents synthesis and growth mechanisms of single-layer smooth TiO2 nanotubes, bamboo-type nanotubes and double-layer nanotubes, by tuning various parameters such as voltage, time, and water content in the electrolyte. It is found that ion diffusion inside the nanotubes dominates growth of these three structures. A stable pH and ion-diffusion profile allows the steady growth of smooth TiO2 tubes in NH4F-containing ethylene glycol (EG). The addition of a low-voltage anodization step reduces the pH and ion-diffusion gradient in the nanotubes and induces formation of bamboo-type nanotubes and double-layer nanotubes when a second high-voltage anodization is conducted. Ion diffusion through a nanotube takes time; thus formation of lower-layer TO2 nanotubes costs more time if longer nanotubes are grown in the upper layer, since ions diffuse through these longer nanotubes. This ion-diffusion controlled growth mechanism is further confirmed by tailoring the water content (0-20 vol%) in the electrolyte and the voltage gaps to control the time needed for initiation of lower-layer TiO2 nanotube arrays. The fundamental understanding of the growth characteristics of double-layer TiO2 nanotubes presented in this paper offers us more flexibility in engineering morphology, tuning dimensions and phase compositions of multilayer TiO2 nanotubes. In addition, we synthesize double-layer TiO2 nanotube arrays composed of one layer of anatase phase and another layer of amorphous phase.High-aspect-ratio TiO2 nanotube arrays formed by anodic oxidation have drawn extensive attention due to their easy fabrication and various excellent optical, electrical and biomedical properties. In contrast to conventional single-layer TiO2 nanotubes prepared via constant-voltage anodization, we synthesize multilayer TiO2 nanotube arrays with high surface area by using alternating-voltage anodization steps. This work presents synthesis and growth mechanisms of single-layer smooth TiO2 nanotubes, bamboo-type nanotubes and double-layer nanotubes, by tuning various parameters such as voltage, time, and water content in the electrolyte. It is found that ion diffusion inside the nanotubes dominates growth of these three structures. A stable pH and ion-diffusion profile allows the steady growth of smooth TiO2 tubes in NH4F-containing ethylene glycol (EG). The addition of a low-voltage anodization step reduces the pH and ion-diffusion gradient in the nanotubes and induces formation of bamboo-type nanotubes and double-layer nanotubes when a second high-voltage anodization is conducted. Ion diffusion through a nanotube takes time; thus formation of lower-layer TO2 nanotubes costs more time if longer nanotubes are grown in the upper layer, since ions diffuse through these longer nanotubes. This ion-diffusion controlled growth mechanism is further confirmed by tailoring the water content (0-20 vol%) in the electrolyte and the voltage gaps to control the time needed for initiation of lower-layer TiO2 nanotube arrays. The fundamental understanding of the growth characteristics of double-layer TiO2 nanotubes presented in this paper offers us more flexibility in engineering morphology, tuning dimensions and phase compositions of multilayer TiO2 nanotubes. In addition, we synthesize double-layer TiO2 nanotube arrays composed of one layer of anatase phase and another layer of amorphous phase. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30315a

Guan, Dongsheng; Wang, Ying

2012-04-01

98

Pressure–temperature phase diagrams of pure and Ag-doped nanocrystalline TiO 2 photocatalysts  

Microsoft Academic Search

In situ synchrotron radiation X-ray diffraction methods were used to determine the low pressure–high temperature phase diagrams of nanocrystalline TiO2 powder specimens obtained using a room temperature sol–gel procedure. Nanostructured Ag-doped bulk titania specimens were pressure sintered and their surface microstructural features (mesoporosity, uniform formation of surface metal clusters) optimized for their envisaged application as photocatalytic materials for air and

M. Stir; R. Nicula; E. Burkel

2006-01-01

99

TiO2 Nanotubes: Recent Advances in Synthesis and Gas Sensing Properties  

PubMed Central

Synthesis—particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances. Doping largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes. PMID:24184919

Galstyan, Vardan; Comini, Elisabetta; Faglia, Guido; Sberveglieri, Giorgio

2013-01-01

100

Controllable Hydrothermal Synthesis and Morphology Evolution of TiO2 Nanorod Films  

NASA Astrophysics Data System (ADS)

TiO2 nanorod films with diverse and evolutionary morphologies are synthesized by controllable hydrothermal method under mild conditions. The as-prepared nanorod films are well characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy. Results demonstrate that reasonable control of time of secondary growth could easily and conveniently achieve the goal of morphology adjustment during mild condition hydrothermal synthesis process.

Sun, Zhaozong; Lan, Jie; Li, Yitan; Wang, Xiao; Zhao, Minglin; Yu, Xiaohong

2014-07-01

101

Highly reactive {001} facets of TiO2-based composites: synthesis, formation mechanism and characterization  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) is one of the most widely investigated metal oxides due to its extraordinary surface, electronic and catalytic properties. However, the large band gap of TiO2 and massive recombination of photogenerated electron-hole pairs limit its photocatalytic and photovoltaic efficiency. Therefore, increasing research attention is now being directed towards engineering the surface structure of TiO2 at the most fundamental and atomic level namely morphological control of {001} facets in the range of microscale and nanoscale to fine-tune its physicochemical properties, which could ultimately lead to the optimization of its selectivity and reactivity. The synthesis of {001}-faceted TiO2 is currently one of the most active interdisciplinary research areas and demonstrations of catalytic enhancement are abundant. Modifications such as metal and non-metal doping have also been extensively studied to extend its band gap to the visible light region. This steady progress has demonstrated that TiO2-based composites with {001} facets are playing and will continue to play an indispensable role in the environmental remediation and in the search for clean and renewable energy technologies. This review encompasses the state-of-the-art research activities and latest advancements in the design of highly reactive {001} facet-dominated TiO2via various strategies, including hydrothermal/solvothermal, high temperature gas phase reactions and non-hydrolytic alcoholysis methods. The stabilization of {001} facets using fluorine-containing species and fluorine-free capping agents is also critically discussed in this review. To overcome the large band gap of TiO2 and rapid recombination of photogenerated charge carriers, modifications are carried out to manipulate its electronic band structure, including transition metal doping, noble metal doping, non-metal doping and incorporating graphene as a two-dimensional (2D) catalyst support. The advancements made in these aspects are thoroughly examined, with additional insights related to the charge transfer events for each strategy of the modified-TiO2 composites. Finally, we offer a summary and some invigorating perspectives on the major challenges and new research directions for future exploitation in this emerging frontier, which we hope will advance us to rationally harness the outstanding structural and electronic properties of {001} facets for various environmental and energy-related applications.

Ong, Wee-Jun; Tan, Lling-Lling; Chai, Siang-Piao; Yong, Siek-Ting; Mohamed, Abdul Rahman

2014-01-01

102

Recent progress in design, synthesis, and applications of one-dimensional TiO2 nanostructured surface heterostructures: a review.  

PubMed

One-dimensional TiO2 nanostructured surface heterostructures (1D TiO2NSHs) have been comprehensively studied during the past two decades because of the possible practical applications in various fields, including photocatalysis, dye-sensitized solar cells, sensors, lithium batteries, biomedicine, catalysis, and supercapacitors. Combining extensive advancements in materials science and nanotechnology, a 1D TiO2NSH material with well-controlled size, morphology, and composition has been designed and synthesized. More importantly, its superior properties, including a high aspect ratio structure, chemical stability, large specific surface area, excellent electronic or ionic charge transfer, and a specific interface effect, have attracted a great deal of interest in improving current performance and exploring new applications. In this tutorial review, we introduce the characteristics of 1D TiO2 nanostructures, the design principles for the fabrication of 1D TiO2NSHs, and we also summarize the recent progress in developing synthesis methods and applications of 1D TiO2NSHs in different fields. The relationship between the secondary phase and the 1D TiO2 nanostructure and between the performance in applications and the excellent physical properties of 1D TiO2NSHs are also discussed. PMID:25014328

Tian, Jian; Zhao, Zhenhuan; Kumar, Anil; Boughton, Robert I; Liu, Hong

2014-10-21

103

Synthesis of nanoscale TiO2 and study of the effect of their crystal structure on single cell response.  

PubMed

To study the effect of nanoscale titanium dioxide (TiO(2)) on cell responses, we synthesized four modifications of the TiO(2) (amorphous, anatase, brookite, and rutile) capable of keeping their physicochemical characteristics in a cell culture medium. The modifications of nanoscale TiO(2) were obtained by hydrolysis of TiCl(4) and Ti(i-OC(3)H(7))(4) (TIP) upon variation of the synthesis conditions; their textural, morphological, structural, and dispersion characteristics were examined by a set of physicochemical methods: XRD, BET, SAXS, DLS, AFM, SEM, and HR-TEM. The effect of synthesis conditions (nature of precursor, pH, temperature, and addition of a complexing agent) on the structural-dispersion properties of TiO(2) nanoparticles was studied. The hydrolysis methods providing the preparation of amorphous, anatase, brookite, and rutile modifications of TiO(2) nanoparticles 3-5?nm in size were selected. Examination of different forms of TiO(2) nanoparticles interaction with MDCK cells by transmission electron microscopy of ultrathin sections revealed different cell responses after treatment with different crystalline modifications and amorphous form of TiO(2). The obtained results allowed us to conclude that direct contact of the nanoparticles with cell plasma membrane is the primary and critical step of their interaction and defines a subsequent response of the cell. PMID:22623903

Ismagilov, Z R; Shikina, N V; Mazurkova, N A; Tsikoza, L T; Tuzikov, F V; Ushakov, V A; Ishchenko, A V; Rudina, N A; Korneev, D V; Ryabchikova, E I

2012-01-01

104

Synthesis of Nanoscale TiO2 and Study of the Effect of Their Crystal Structure on Single Cell Response  

PubMed Central

To study the effect of nanoscale titanium dioxide (TiO2) on cell responses, we synthesized four modifications of the TiO2 (amorphous, anatase, brookite, and rutile) capable of keeping their physicochemical characteristics in a cell culture medium. The modifications of nanoscale TiO2 were obtained by hydrolysis of TiCl4 and Ti(i-OC3H7)4 (TIP) upon variation of the synthesis conditions; their textural, morphological, structural, and dispersion characteristics were examined by a set of physicochemical methods: XRD, BET, SAXS, DLS, AFM, SEM, and HR-TEM. The effect of synthesis conditions (nature of precursor, pH, temperature, and addition of a complexing agent) on the structural-dispersion properties of TiO2 nanoparticles was studied. The hydrolysis methods providing the preparation of amorphous, anatase, brookite, and rutile modifications of TiO2 nanoparticles 3–5?nm in size were selected. Examination of different forms of TiO2 nanoparticles interaction with MDCK cells by transmission electron microscopy of ultrathin sections revealed different cell responses after treatment with different crystalline modifications and amorphous form of TiO2. The obtained results allowed us to conclude that direct contact of the nanoparticles with cell plasma membrane is the primary and critical step of their interaction and defines a subsequent response of the cell. PMID:22623903

Ismagilov, Z. R.; Shikina, N. V.; Mazurkova, N. A.; Tsikoza, L. T.; Tuzikov, F. V.; Ushakov, V. A.; Ishchenko, A. V.; Rudina, N. A.; Korneev, D. V.; Ryabchikova, E. I.

2012-01-01

105

X-ray absorption spectroscopy (XAS) study of the semicondutor-insulator interface in TiO 2-based photocatalysts  

NASA Astrophysics Data System (ADS)

The geometrical structure around Ti ions in a system formed by amorphous titania coating on the silica surface has been studied using EXAFS and XANES. Samples were prepared by two methods: (I) impregnation from n-hexane solution of Ti-alcoxide, and (II) homogeneous deposition precipitation from water solutions. Analysis of the EXAPS data indicates that Ti ions are sixfold coordinated in both samples, the distance Ti sbnd O being similar to that of the crystalline TiO 2-anatase in samples prepared by method I, and slightly smaller in samples prepared by method II. Analysis of the higher shells in the EXAPS spectrum shows that although titania forms small aggregates in both cases, particles have grown in three dimensions, further than the monolayer.

Mun˜oz-Paez, A.; Malet, P.

106

Gold-Copper Nanoalloys Supported on TiO2 as Photocatalysts for CO2 Reduction by Water.  

PubMed

Commercial P25 modified by Au-Cu alloy nanoparticles as thin film exhibits, for CO2 reduction by water under sun simulated light, a rate of methane production above 2000 ?mol (g of photocatalyst)(-1) h(-1). Although evolution of hydrogen is observed and O2 and ethane detected, the selectivity of conduction band electrons for methane formation is almost complete, about 97%. This photocatalytic behavior is completely different from that measured for Au/P25 (hydrogen evolution) and Cu/P25 (lower activity, but similar methane selectivity). Characterization by TEM, XPS, and UV-vis spectroscopy shows that Au and Cu are alloyed in the nanoparticles. FT-IR spectroscopy and chemical analysis have allowed one to detect on the photocatalyst surface the presence of CO2(•-), Cu-CO, and elemental C. Accordingly, a mechanism in which the role of Au is to respond under visible light and Cu binds to CO and directs the reduction pathway is proposed. PMID:25329687

Nea?u, Stefan; Maciá-Agulló, Juan Antonio; Concepción, Patricia; Garcia, Hermenegildo

2014-11-12

107

TiO 2 photocatalytic oxidation: I. Photocatalysts for liquid-phase and gas-phase processes and the photocatalytic degradation of chemical warfare agent simulants in a liquid phase  

Microsoft Academic Search

The results of studies on the effect of the preparation procedure on the properties of TiO2-based photocatalysts and the kinetics and mechanism of the photocatalytic oxidation of organic water pollutants are surveyed. The effects of calcination temperature, surface modification with platinum, and acid-base treatment of the surface of titanium dioxide on its activity in model gas-phase and liquid-phase reactions are

A. V. Vorontsov; D. V. Kozlov; P. G. Smirniotis; V. N. Parmon

2005-01-01

108

Study on the synthesis of Ni doped mesoporous TiO 2 and its photocatalytic activity for hydrogen evolution in aqueous methanol solution  

Microsoft Academic Search

Ni doped mesoporous TiO2 photocatalyst was prepared. XRD and EDX results indicated that Ni2+ was incorporated into the framework of the mesoporous TiO2 in a highly dispersed way. The results of photocatalytic hydrogen evolution in aqueous methanol solution under UV–Vis light irradiation showed that activity of hydrogen production strongly depended on the amount of Ni doped. The highest activity was

Dengwei Jing; Yaojun Zhang; Liejin Guo

2005-01-01

109

10BaF2:NaF, Na3AlF6/TiO2 composite as a novel visible-light-driven photocatalyst based on upconversion emission  

NASA Astrophysics Data System (ADS)

A rare-earth free upconversion luminescent material, 10BaF2:NaF, Na3AlF6, is synthesized by a hydrothermal method. The study of fluorescent spectrum indicates that it can convert visible light (550 nm—610 nm) into ultraviolet light (290 nm—350 nm), and two emission peaks at 304 nm and 324 nm are observed under the excitation of 583 nm at room temperature. Subsequently, 10BaF2:NaF, Na3AlF6/TiO2 composite photocatalyst is prepared and its catalytic activity is evaluated by the photocatalytic reduction of CO2 under visible light irradiation (? > 515 nm). The results show that 10BaF2:NaF, Na3AlF6/TiO2 is a more effective photocatalyst for CO2 reduction than pure TiO2, their corresponding methanol yields are 179 and 0 ?mol/g-cat under the same conditions. Additionally, the mechanism of photocatalytic reduction of CO2 on 10BaF2:NaF, Na3AlF6/TiO2 is proposed.

Liu, En-Zhou; Fan, Jun; Hu, Xiao-Yun; Hou, Wen-Qian; Dai, Hong-Zhe

2012-04-01

110

Green Synthesis of Anatase TiO2 Nanocrystals with Diverse Shapes and their Exposed Facets-Dependent Photoredox Activity.  

PubMed

The exposed facets of a crystal are known to be one of the key factors to its physical, chemical and electronic properties. Herein, we demonstrate the role of amines on the controlled synthesis of TiO2 nanocrystals (NCs) with diverse shapes and different exposed facets. The chemical, physical and electronic properties of the as-synthesized TiO2 NCs were evaluated and their photoredox activity was tested. It was found that the intrinsic photoredox activity of TiO2 NCs can be enhanced by controlling the chemical environment of the surface, i.e.; through morphology evolution. In particular, the rod shape TiO2 NCs with ?25% of {101} and ?75% of {100}/{010} exposed facets show 3.7 and 3.1 times higher photocatalytic activity than that of commercial Degussa P25 TiO2 toward the degradation of methyl orange and methylene blue, respectively. The higher activity of the rod shape TiO2 NCs is ascribed to the facetsphilic nature of the photogenerated carriers within the NCs. The photocatalytic activity of TiO2 NCs are found to be in the order of {101}+{100}/{010} (nanorods) > {101}+{001}+{100}/{010} (nanocuboids and nanocapsules) > {101} (nanoellipsoids) > {001} (nanosheets) providing the direct evidence of exposed facets-depended photocatalytic activity. PMID:25188808

Roy, Nitish; Park, Yohan; Sohn, Youngku; Leung, Kam Tong; Pradhan, Debabrata

2014-10-01

111

Hydrothermal synthesis of rutile-anatase TiO2 nanobranched arrays for efficient dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Rutile-anatase TiO2 nanobranched arrays were prepared in two sequential hydrothermal-synthesis steps. The morphologies and crystalline nanostructures of the samples were investigated by controlling growth time and the concentration of the titanium precursor. All samples were characterized by field-emission scanning electron microscopy and X-ray diffraction analysis. It was found that treating the surfaces of rutile TiO2 nanorods with aqueous TiCl4 solutions allows the anatase TiO2 nanobranches to grow perpendicular to the main rutile TiO2 nanorods attached to the FTO glass. Irregularly shaped, dense TiO2 structures formed in the absence of TiCl4 treatment. A light-to-electricity conversion efficiency of 3.45% was achieved using 2.3 ?m tall TiO2 nanobranched arrays in a dye-sensitized solar cell. This value is significantly higher than that observed for pure rutile TiO2 nanorods.

Kwon, Soon Jin; Im, Hyo Been; Nam, Jung Eun; Kang, Jin Kyu; Hwang, Taek Sung; Yi, Kwang Bok

2014-11-01

112

Synthesis of BiVO4/TiO 2 composites and evaluation of their photocatalytic activity under indoor illumination.  

PubMed

BiVO4/TiO2 composites with different weight ratios have been prepared by coprecipitation-based reactions followed by either thermal or hydrothermal treatment with the aim of evaluating the TiO2 photosensitization by BiVO4. The obtained materials present in all cases the desired monoclinic phase of BiVO4 and anatase phase of TiO2. Visible light absorption increased with increasing amount of bismuth vanadate. XPS results reveal the surface enrichment of Ti with respect to the bulk composition in samples characterised by a higher content of BiVO4. The photocatalytic activity of the prepared materials was tested for the degradation of isopropanol in the gas phase under indoor illumination conditions. Although none of the composites was able to improve the activity of TiO2, the low BiVO4 containing samples appear as more suitable for further synthesis tuning. PMID:24535667

Longo, Giulia; Fresno, Fernando; Gross, Silvia; Stangar, Urška Lavren?i?

2014-10-01

113

Synthesis and characterization of TiO 2 and Fe\\/TiO 2 nanoparticles and their performance for photocatalytic degradation of 1,2-dichloroethane  

Microsoft Academic Search

The characterization of nano-sized TiO2 and Fe\\/TiO2 prepared by a sol–gel method was characterized in this study. The synthesized photocatalysts were used for the photodegradation of 1,2-dichloroethane (1,2-DCE). From X-ray powder diffraction data, the crystal phase presents a mixture of anatase and rutile with anatase the dominant phase. As seen in TEM images, the crystallites of photocatalysts are spherical particles

Wen-Chi Hung; Yu-Chun Chen; Hsin Chu; Ting-Ke Tseng

2008-01-01

114

Directed synthesis of mesoporous TiO2 microspheres: catalysts and their photocatalysis for bisphenol A degradation.  

PubMed

This paper describes the fabrication of two different 3D mesoporous TiO2 microspheres via one-step solvothermal process without templates using different titanium sources. The resulting materials were characterized by XRD, FESEM, TEM, and nitrogen adsorption techniques. Their photodegradation of bisphenol A [2,2-bis(4-hydroxyphenyl)propane, BPA] in aqueous suspension was investigated under UV irradiation. The experimental results revealed that the photocatalytic effect of the two 3D mesoporous TiO2 microspheres was superior to the commercial P25 TiO2, and as-prepared samples as catalysts demonstrated that the smaller pore size it is, the higher the effective degradation for BPA is. Particular attention was paid to the identification of intermediates and analysis of photocatalytic degradation mechanism of BPA by HPLC-MS and HPLC-MS-MS. Five main intermediates were formed during photocatalytic degradation, and their evolution was discussed. On the basis of the evidence of oxidative intermediate formation, a detailed degradation pathway of BPA degradation by two mesoporous TiO2 microspheres photocatalysts are proposed. PMID:19928897

Guo, Changsheng; Ge, Ming; Liu, Lu; Gao, Guandao; Feng, Yinchang; Wang, Yuqiu

2010-01-01

115

Homogeneous synthesis of SiO2@TiO2 nanocomposites with controllable shell thickness and their enhanced photocatalytic activity.  

PubMed

Here we report the use of sulfuric acid as a catalyst for the facile and homogeneous synthesis of core-shell SiO(2)@TiO(2) nanocomposites using simple apparatus, under ambient pressure and temperature. The resultant SiO(2)@TiO(2) exhibits an ideal core-shell structure with uniform nanoscale TiO(2) coverage. The shell thickness of SiO(2)@TiO(2) can be conveniently tuned through adjustment of the esterification reaction parameters. Moreover, SiO(2)@TiO(2) shows improved catalytic activity in the photodegradation of methyl orange. PMID:23187454

Yu, Yong; Zhang, Ming-Zhen; Chen, Jun; Zhao, Yuan-Di

2013-01-28

116

Cost effective facile synthesis of TiO2 nanograins for flexible DSSC application using rose bengal dye  

NASA Astrophysics Data System (ADS)

Synthesis of titanium dioxide (TiO2) nanograins using economical successive ionic layer adsorption and reaction (SILAR) method has been carried out. TiO2 thin films are studied for their structural, compositional, optical and morphological properties. A layer by layer process leads to the formation of 2.4 ?m thick nanocrystalline TiO2 film. The heat treated TiO2 thin films are hydrophilic in nature with contact angle of 67°. The interconnected nanograins are employed for dye sensitized solar cells (DSSC) using inexpensive Rose Bengal (RB) dye. RB dye sensitization resulted into shifting of absorption peak from UV to visible region. The photoresponce of the dye sensitized solar cell is evaluated in the polyiodide electrolyte (0.1 M KI + 0.01 M I2) at 40 mWcm-2 illumination intensity. The TiO2 nanograins accompanied with RB sensitizer showed the conversion efficiency ( ?) of 0.89%. These results depict the strong assurance of TiO2 nanograins for DSSC application.

Jambure, Supriya Bapurao; Gund, Girish Sambhaji; Dubal, Deepak Prakash; Shinde, Sujata Sureshrao; Lokhande, Chandrakant Dnyandev

2014-09-01

117

Green synthesis of highly crystalline and visible-light sensitive C-, N- and S- codoped with Ag TiO2 nanocatalyst  

EPA Science Inventory

Titanium dioxide (TiO2) has been a focus of attention as chemically stable, relatively nontoxic, inexpensive and highly efficient photocatalyst applicable for a wide array of uses. However, main disadvantage that severely limits its wider use is the large band gap, 3.0 eV and 3.2...

118

Facile synthesis of TiO2/microcrystalline cellulose nanocomposites: photocatalytically active material under visible light irradiation  

EPA Science Inventory

Doped TiO2 nanocomposites were prepared in situ by a facile and simple synthesis utilizing benign and renewable precursors such as microcrystalline cellulose (MC) and TiCl4 through hydrolysis in alkaline medium without the addition of organic solvents. The as-prepared nanocompos...

119

Synthesis of TiO2-Poly(3-hexylthiophene) Hybrid Particles through Surface-Initiated Kumada Catalyst-Transfer Polycondensation.  

PubMed

TiO2/conjugated polymers are promising materials in solar energy conversion where efficient photoinduced charge transfers are required. Here, a "grafting-from" approach for the synthesis of TiO2 nanoparticles supported with conjugated polymer brushes is presented. Poly(3-hexylthiophene) (P3HT), a benchmark material for organic electronics, was selectively grown from TiO2 nanoparticles by surface-initiated Kumada catalyst-transfer polycondensation. The grafting of the polymer onto the surface of the TiO2 nanoparticles by this method was demonstrated by (1)H and (13)C solid-state NMR, X-ray photoelectron spectrometry, thermogravimetric analysis, transmission electron microscopy, and UV-visible spectroscopy. Sedimentation tests in tetrahydrofuran revealed improved dispersion stability for the TiO2@P3HT hybrid material. Films were produced by solvent casting, and the quality of the dispersion of the modified TiO2 nanoparticles was evaluated by atomic force microscopy. The dispersion of the P3HT-coated TiO2 NPs in the P3HT matrix was found to be homogeneous, and the fibrillar structure of the P3HT matrix was maintained which is favorable for charge transport. Fluorescence quenching measurements on these hybrid materials in CHCl3 indicated improved photoinduced electron-transfer efficiency. All in all, better physicochemical properties for P3HT/TiO2 hybrid material were reached via the surface-initiated "grafted-from" approach compared to the "grafting-onto" approach. PMID:25188446

Boon, Florian; Moerman, David; Laurencin, Danielle; Richeter, Sébastien; Guari, Yannick; Mehdi, Ahmad; Dubois, Philippe; Lazzaroni, Roberto; Clément, Sébastien

2014-09-30

120

Coexistence of an anatase/TiO2(B) heterojunction and an exposed (001) facet in TiO2 nanoribbon photocatalysts synthesized via a fluorine-free route and topotactic transformation.  

PubMed

In this work, we report a novel approach to fabricate hierarchical TiO2 microspheres (HTMS) assembled by ultrathin nanoribbons where an anatase/TiO2(B) heterojunction and high energy facet coexist. The as-adopted approach involves (1) nonaqueous solvothermal treatment of a mixture of tetrabutyl titanate and acetic acid and (2) topotactical transformation into HTMS via thermal annealing. By this approach, the TiO2(B) phase usually synthesized from an alkaline treatment route could be initially formed. Subsequently, phase transition from TiO2(B) to anatase TiO2 occurs upon thermal treatment. It is demonstrated that such phase transition is accompanied by crystallographic orientation along the c-axis of anatase and TiO2(B) crystals, resulting in not only a coherent interface between two phases but also oriented attachment of anatase mesocrystals along the [001] direction, and finally high-energy (001) facet exposure. Interestingly, this work provides an alternative fluorine-free route for the synthesis of TiO2 crystals with high-energy (001) facet exposure. The structural analysis reveals that lattice-match induced topotactic transformation from TiO2(B) to anatase is the sole reason for the (001) facet exposure of anatase TiO2. The photocatalytic test for acetaldehyde decomposition shows that HTMS with anatase/TiO2(B) heterojunction and high-energy (001) facet exhibits superior photocatalytic efficiency compared with the relevant commercial product P25, which can be ascribed to the synergistic effect of large surface area, anatase/TiO2(B) heterojunction as well as high-energy facet exposure. PMID:24699768

Wang, Changhua; Zhang, Xintong; Liu, Yichun

2014-05-21

121

One-pot synthesis of hybrid TiO2-polyaniline nanoparticles by self-catalyzed hydroamination and oxidative polymerization from TiO2-methacrylic acid nanoparticles.  

PubMed

A simple self-catalyzed hydroamination method for creating hybrid TiO(2)-polyaniline core-shell nanoparticles (NP) has been shown. Hybrid NPs with a range of possible sizes are afforded in high yield under mild reaction conditions and simultaneously show improved charge transport and electrochromic behavior compared to either polyaniline alone or physically blended with TiO(2). PMID:21892455

Bae, Woo Jin; Davis, Andrew R; Jung, Jaewoong; Jo, Won Ho; Carter, Kenneth R; Coughlin, E Bryan

2011-10-14

122

One-pot synthesis of peacock-shaped TiO2 light scattering layer with TiO2 nanorods film for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

A titanium dioxide (TiO2) film, showing distinctive functions and morphology, was prepared using the hydrothermal method by controlling the ratio of HCl:CH3COOH in acidic medium. A one-dimensional (1-D) TiO2 nanorod (NR) film was synthesized with a length of 2 ?m using a 1:2 ratio of HCl:CH3COOH, whereas a 1-D TiO2 NR film with peacock shaped TiO2 nanobundles as a light scattering layer (LSL) was acquired by employing a 2:1 ratio of HCl:CH3COOH. This LSL exhibited remarkable dual functions with respect to high light harvesting, which was attributable to the large surface area of the micrometer-sized TiO2 nanobundles, consisting of small-sized TiO2 NRs of 30-40 nm in diameter and a light scattering effect in the long wavelength region of 550-700 nm. Accordingly, the dual functions of the LSL resulted in a sharp increase in conversion efficiency (3.93%) that was about twice that (1.49%) of TiO2 NR film synthesized using a 1:2 ratio of HCl:CH3COOH. In particular, a considerably enhanced short-circuit photocurrent (Jsc) was mainly responsible for the resulting increase in overall efficiency with a moderate increase in fill factor and slightly reduced open-circuit voltage.

Kim, Hyun Sik; Kim, Young-Jea; Lee, Wonjoo; Kang, Soon Hyung

2013-05-01

123

Synthesis and characterization of TiO(2) nanoparticles: applications in research on the interaction of colloidal TiO(2) with human serum albumin by fluorescence spectroscopy.  

PubMed

Titanium dioxide (TiO(2)) nanoparticles (NPs) are widely used as an important kind of biomaterials due to their large surface area, enhanced chemical reactivity and easy penetration into cells. Nano TiO(2) with pure anatase phase was successfully prepared by solvothermal method. Its particle size was about 21 nm, while the larger specific surface area of TiO(2) was 77.43 m(2)/g. The interaction of colloidal TiO(2) with human serum albumin was studied by using absorption spectra and fluorescence spectra. The apparent binding constants (K) were 345.780 × 10(5), 4.376 × 10(5), 0.035 × 10(5) at 298, 303 and 308 K, respectively. In addition, the number of binding sites (n) was gradually decreased with the increase of temperature, which indicated that the quenching mechanism of albumin by colloidal TiO(2) was static fluorescence quenching process. Based on fluorescence resonance energy transfer, the energy transfer efficiency (E) and critical transfer distance (r(0)) between donor (human serum albumin, HSA) and acceptor (colloidal TiO(2)) were calculated to be 0.862 and 6.244 nm, which suggested that non-radiative energy transfer occurred between TiO(2) and HSA. Furthermore, the conformational changes of HSA were shown by synchronous fluorescence. PMID:22687929

Sun, Tao; Liu, Lusha; Sun, Yang; Tan, Chunlei; Yao, Fei; Liang, Xuhua; Wang, Yan; Yang, Yuhao; Hu, Xiaoyun; Fan, Jun

2012-01-01

124

Synthesis of TiO2 nanosheets via an exfoliation route assisted by a surfactant.  

PubMed

Titanium dioxide (TiO2) is an important material for photovoltaics, photocatalysis, sensors and lithium ion batteries. Various morphologies of TiO2 nanomaterials have been synthesized, including zero-dimensional (0D) nanoparticles, one-dimensional (1D) nanowires and nanotubes, as well as three-dimensional (3D) nanostructures. But the two-dimensional (2D) TiO2 nanostructures, which are expected to have more promising properties and applications, are rarely reported. Herein, we report a surfactant-assisted exfoliation method to synthesize TiO2 2D nanosheets. It has been revealed that tetrabutylammonium hydroxide (hereafter TBAOH) as a surfactant plays a crucial role in retaining the 2D nanosheet structures. Compared with TiO2 nanotubes and anatase TiO2 nanoparticles, the as-prepared TiO2 single layered nanosheets delivered much higher capacities as anodes of the coin-type Li ion cells, with a reversible capacity of 82.2 mA h g(-1) at the 630th cycle at a current density of 2000 mA g(-1). PMID:24958361

Leng, Mei; Chen, Yu; Xue, Junmin

2014-08-01

125

Role of oxygen vacancy in the plasma-treated TiO 2 photocatalyst with visible light activity for NO removal  

Microsoft Academic Search

The photocatalytic activity for NO removal under an oxidative atmosphere has been studied over commercial TiO2 and plasma-treated TiO2 powders. By the plasma treatment, the photocatalytic activity for NO removal appeared in the visible light region up to 600nm without a decrease in the ultraviolet light activity. It was found that the NO was removed as nitrate (NO3?) by photocatalytic

Isao Nakamura; Nobuaki Negishi; Shuzo Kutsuna; Tatsuhiko Ihara; Shinichi Sugihara; Koji Takeuchi

2000-01-01

126

Facile electrochemical synthesis of antimicrobial TiO2 nanotube arrays  

PubMed Central

Infection-related complications have been a critical issue for the application of titanium orthopedic implants. The use of Ag nanoparticles offers a potential approach to incorporate antimicrobial properties into the titanium implants. In this work, a novel and simple method was developed for synthesis of Ag (II) oxide deposited TiO2 nanotubes (TiNTs) using electrochemical anodization followed by Ag electroplating processes in the same electrolyte. The quantities of AgO nanoparticles deposited in TiNT were controlled by selecting different electroplating times and voltages. It was shown that AgO nanoparticles were crystalline and distributed throughout the length of the nanotubes. Inductively coupled plasma mass spectrometry tests showed that the quantities of released Ag were less than 7 mg/L after 30 days at 37°C. Antimicrobial assay results show that the AgO-deposited TiNTs can effectively kill the Escherichia coli bacteria. Although the AgO-deposited TiNTs showed some cytotoxicity, it should be controllable by optimization of the electroplating parameters and incorporation of cell growth factor. The results of this study indicated that antimicrobial properties could be added to nanotextured medical implants through a simple and cost effective method.

Zhao, Yu; Xing, Qi; Janjanam, Jagadeesh; He, Kun; Long, Fei; Low, Ke-Bin; Tiwari, Ashutosh; Zhao, Feng; Shahbazian-Yassar, Reza; Friedrich, Craig; Shokuhfar, Tolou

2014-01-01

127

Facile synthesis of carbon-doped mesoporous anatase TiO2 for the enhanced visible-light driven photocatalysis.  

PubMed

Here we report a low-cost and facile synthesis approach for carbon-doped mesoporous anatase TiO2 by using Ti(BuO)4 as a source for both Ti and carbon through xerogel carbonization in a hypoxic atmosphere. The resultant mesoporous C-TiO2 with high crystallinity exhibits excellent photocatalytic activities for degradation of methyl orange (MO) and phenol under visible light irradiation. PMID:25266327

Liu, Juming; Zhang, Qiancheng; Yang, Jucai; Ma, Huiyan; Tade, Moses O; Wang, Shaobin; Liu, Jian

2014-10-16

128

Effect of precursor loading on non-spherical TiO 2 nanoparticle synthesis in a diffusion flame reactor  

Microsoft Academic Search

A numerical method of combining computational fluid dynamics with the particle kinetics theory is developed to study the effect of precursor loading on non-spherical TiO2 nanoparticle synthesis in a diffusion flame reactor. A one-step chemical kinetics approach is employed to model precursor TiCl4 oxidation that leads to particle formation. An efficient quadrature method of moments (QMOM) and the combustion model

Ming-Zhou Yu; Jian-Zhong Lin; Tat-Leung Chan

2008-01-01

129

Facile flame thermal synthesis of SiOx-C/ TiO2 microspheres with enhanced photocatalytic performance  

NASA Astrophysics Data System (ADS)

We report a very simple and novel photocatalyst synthetic strategy for the preparation of SiO x modified TiO2 microspheres and demonstrate their enhanced photocatalytic properties. The as-prepared samples were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectra. XRD results showed that anatase TiO2 was obtained directly without any post-heat treatment, and no obvious effect on the crystal structure was observed with the introduction of a small amount of SiO x . SEM images show microspherical morphology for the synthesized samples with a suitable amount of SiO x but irregular morphology was observed when higher content of SiO x was introduced. XPS results indicated that silicon existed in the forms of SiO2, SiO and Si2O3. Higher photocatalytic activity for the degradation of methylene blue (MB) under UV-vis light illumination was demonstrated with SiO x modification. The results indicated that the feasibility of MB degradation was not only due to morphological properties but also to the SiO x modification. Significantly, SiO x facilitates effective photodegradation through the increasing surface hydroxyl groups as traced by the FT-IR spectra for the resulting samples.

Li, Hui; Ma, Xiaoqing; Cui, Xiaoli

2014-04-01

130

Comparison of Au and TiO2 based catalysts for the synthesis of chalcogenide nanowires  

NASA Astrophysics Data System (ADS)

We present a comparative study of TiO2-based and Au catalysts for the physical vapor deposition of (Bi1-xSbx)2Se3 topological insulator nanowires. The standard Au nanoparticle catalyst was compared to five TiO2 nanoparticle based catalysts (anatase, rutile, P-25, high surface area anatase, and TiO2 supported Au particles). The use of Au nanoparticles seriously harms the properties of nanowires, thereby limiting their application. In contrast, TiO2 based catalysts lead to the residue-free growth of nanowires with a higher degree of crystallinity. Homogeneous nanowire ensembles are achieved with the mixed phase P-25 catalyst, and a possible growth mechanism is proposed.

Schönherr, P.; Prabhakaran, D.; Jones, W.; Dimitratos, N.; Bowker, M.; Hesjedal, T.

2014-06-01

131

Nanocoral architecture of TiO 2 by hydrothermal process: Synthesis and characterization  

NASA Astrophysics Data System (ADS)

TiO2 thin films with novel nanocoral-like morphology were successfully grown directly onto the glass and conducting fluorine doped tin oxide coated glass substrates via multi-step hydrothermal (MSH) process. Titanium chloroalkoxide [TiCl2 (OEt)2 (HOEt)2)] precursor was used in an aqueous saturated NaCl in presence of 1 mM HCl catalyst and HNO3 peptizer at 120 °C. Reaction time varied from 3 to 12 h. The morphological features and physical properties of TiO2 films were investigated by field emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, Fourier transform IR spectroscopy, Fourier transform Raman spectroscopy, room temperature photoluminescence spectroscopy and X-ray photoelectron spectroscopy. The surface morphology revealed the formation of TiO2 corals having nanosized (30-40 nm) polyps. The photoelectrochemical properties of the TiO2 nanocoral electrodes were investigated in 0.1 M NaOH electrolyte under UV illumination. The results presented in this study highlight two major findings: (i) ability to tune the photoelectrochemical response and photoconversion efficiency via controlled thickness of TiO2 nanocorals and (ii) the substantial increase in short circuit photocurrent (Jsc) due to the improved charge transport through TiO2 nanocorals prepared via MSH process. This approach would be quite useful for the fabrication of nanocoral architecture that finds key applications in photocatalysis, dye-sensitized solar cells and hybrid solar cells.

Mali, Sawanta S.; Shinde, Pravin S.; Betty, C. A.; Bhosale, Popatrao N.; Lee, Won J.; Patil, Pramod S.

2011-09-01

132

Preparation of visible-light nano-photocatalysts through decoration of TiO2 by silver nanoparticles in inverse miniemulsions.  

PubMed

Ag/TiO2 nanocomposites were prepared through combination of a sol-gel process of a titanium precursor in inverse miniemulsions and in situ reduction of silver ions in the "nanoreactors". The morphological investigation shows that Ag nanoparticles are mainly located on the surface of TiO2 nano-supports because of the fast reduction rate of Ag ions by hydrazine. Ag/TiO2 nanocomposites with amorphous or anatase TiO2 phase displayed high visible-light catalytic activity for degradation of Rhodamine B. The photoactivity of Ag/anatase TiO2 nanocomposites could be influenced by the Ag content that could be conveniently tuned by the loading of silver salts. The influence of the loading of silver salts on the particle properties of the Ag/TiO2 nanocomposites was investigated systematically. PMID:25217730

Cao, Zhihai; Zhu, Shudi; Qu, Hui; Qi, Dongming; Ziener, Ulrich; Yang, Liu; Yan, Yingjie; Yang, Haitang

2014-12-01

133

Submerged arc spray synthesis of TiO2 nanoparticles with desired form sphericity using process characterization and optimization.  

PubMed

This article presents a study on process characterization and optimization of the metal nanoparticle fabrication process known as the submerged arc spray nanoparticle synthesis system (SANSS) for obtaining desired geometric sphericity of nanoparticles. The geometric shape characteristics of nanoparticles pose significant impact on innovative product and process design. The sphericity and surface roughness of prepared TiO2 nanoparticles can vary widely and are influenced by the process parameters being employed in the SANSS. To improve this, an in-situ nanofluid sampling and measurement approach was developed to analyze the particle shape characteristics and characterize the nanoparticle synthesis process. The particle shape contours obtained from FE-SEM and TEM were employed to quantify the TiO2 nanoparticle sphericity and analyze the effect of process parameters on particle roundness. The optimized process parameters were identified using the Taguchi method. Our results proved that the average sphericity of TiO2 particles prepared using the optimized process parameters was effectively improved up to three folds. PMID:18464365

Chen, Liang-Chia; Ho, Chie-Chan

2008-02-01

134

Hydrothermal synthesis of TiO2 hollow microspheres for the photocatalytic degradation of 4-chloronitrobenzene.  

PubMed

TiO(2) hollow microspheres were synthesized by a simple hydrothermal method followed by calcination at different temperatures ranging from 400 to 800°C. The prepared samples were characterized by XRD, SEM, TEM, SAED, HRTEM, N(2) adsorption, and UV-vis spectroscopy. The photocatalytic activities of the hollow microspheres were evaluated by photocatalytic decomposition of 4-chloronitrobenzene (4-CNB). Results showed that the TiO(2) hollow microspheres, which had an average external diameter of 1.75 ?m, were composed of numerous TiO(2) nanoparticles. Photocatalysis experiments indicated that the TiO(2) hollow microspheres calcined at 500°C exhibited the highest photocatalytic activity, which was nearly 2 and 1.5 times higher than that of the uncalcined sample and Degussa P25, respectively. The catalyst crystallinity, catalyst dosage and 4-CNB concentration were found to have a significant impact on the degradation efficiency whereas solution pH has relatively less effect. The removal of total organic carbon (TOC) and formation of chloride, nitrate (V) anions were monitored to follow the mineralization process of 4-CNB. In addition, it was demonstrated that these TiO(2) hollow microspheres could be recycled easily without decreasing their photocatalytic activities. PMID:20855164

Ye, Miaomiao; Chen, Zhonglin; Wang, Wenshou; Shen, Jimin; Ma, Jun

2010-12-15

135

Synthesis and performance of novel magnetically separable nanospheres of titanium dioxide photocatalyst with egg-like structure.  

PubMed

A magnetically separable photocatalyst TiO(2)/SiO(2)/NiFe(2)O(4) (TSN) nanosphere with egg-like structure was prepared by a unique process that combined a liquid catalytic phase transformation method, reverse micelle technique and chemical precipitation means. The prepared photocatalyst shows high photocatalytic activity for the degradation of methyl orange in water. The magnetic property measurements indicate that the photocatalyst possesses a superparamagnetic nature. It can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for wastewater treatment. A transmission electron microscope (TEM) and an x-ray diffractometer (XRD) were used to characterize the structure of the TSN photocatalyst. The results indicate that nickel ferrite core nanoparticles were completely encapsulated into monodisperse silica nanospheres as carrier, and titania nanoparticle aggregates were coated onto the surface of SN nanospheres, forming an imperfect TiO(2) shell for photocatalysis. The SiO(2) layer between the NiFe(2)O(4) core and the TiO(2) shell effectively prevents the injection of charges from TiO(2) particles to NiFe(2)O(4), which gives rise to an increase in photocatalytic activity. Moreover, the recycled TSN exhibits good repeatability of the photocatalytic activity. PMID:21817681

Xu, Shihong; Shangguan, Wenfeng; Yuan, Jian; Chen, Mingxia; Shi, Jianwei; Jiang, Zhi

2008-03-01

136

TiO 2–SO 4 2? as a novel solid acid catalyst for highly efficient, solvent free and easy synthesis of chalcones under microwave irradiation  

Microsoft Academic Search

TiO2–SO42? has been prepared by the sol–gel method using H2SO4 and used for the synthesis of chalcones under microwave irradiation. Sulfate loading by H2SO4 increases the Lewis acidity of TiO2. This catalyst gives an excellent yield with less reaction time and is an inexpensive, easily recyclable catalyst for this reaction.

B. Krishnakumar; R. Velmurugan; M. Swaminathan

2011-01-01

137

In situ synthesis of TiO2/polyethylene terephthalate hybrid nanocomposites at low temperature  

NASA Astrophysics Data System (ADS)

TiO2 nanoflowers were in situ grown on polyethylene terephthalate (PET) non-woven fabric by hydrolysis of TiCl4 in aqueous solution in the presence of nanocrystal cellulose grafted PET fabric (NCC-g-PET) at a low temperature of 70 °C. Nanocrystal cellulose (NCC) pre-grafted on PET fabric acted as hydrophilic substrate and morphology inducing agent to promote the nucleation and crystal growth of TiO2. Detailed information on the synthetic process was presented. The resulting samples were characterized using FE-SEM, EDS, ATR-IR, Raman microscopy, XRD and TG analysis. The photocatalytic activity of the samples was evaluated by the degradation of orange methyl under solar light. Characteristic results indicate that rutile TiO2 nanoflowers have grown abundantly on PET non-woven fabric, and the established hydrogen bonding strengthens the interfacial interaction between the inorganic particles and the polymeric substrates. The methyl orange decoloration test under natural solar light demonstrates that this TiO2/PET hybrid nanocomposites exhibit excellent self-cleaning performance which is expected to have a good potential for commercialization.

Peng, Xinyan; Ding, Enyong; Xue, Feng

2012-06-01

138

Synthesis, characterization and high natural sunlight photocatalytic performance of cobalt doped TiO2 nanofibers  

NASA Astrophysics Data System (ADS)

Co2+ doped TiO2 nanofibers with different doping percentages were successfully synthesized using a nonaqueous sol-gel method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), x-ray photoelectrons spectroscopy (XPS), FTIR and UV-vis spectroscopy were used to characterize the crystal structures, chemical states, morphologies and photocatalytic properties of Co doped TiO2 nanofibers. Co2+ doping was found to affect the phase transformation from anatase to rutile. Grain growth activation energy of 17.575 kJ/mol was obtained for the TiO2 nanofibers. The photocatalytic activities of the pure and doped nanofibers were investigated with degradation of methyl orange (MO) as a model pollutant. The degradation followed the Langmuir-Hinshelwood (L-H) kinetic model with pseudo-first-order apparent rates of 3.2×10-2, 5.3×10-2, 8.9×10-2 and 7.1×10-2 for Co doped nanofibers of Rt=0.0, 0.0025, 0.005, 0.01 (where Rt is the molar ratio of Co(OAc)2 to Ti(OiPr)4). The result showed that Co2+ doped nanostructure significantly enhanced the photocatalytic degradation of methyl orange under direct sunlight compared to pure TiO2. Rt=0.005 sample showed best sunlight photocatalytic performance among the above samples which is 2.3 times (after 30 min) efficient than that of pure nanostructure.

Sarkar, Debabrata; Mukherjee, S.; Chattopadhyay, Kalyan K.

2013-05-01

139

The Synthesis of Ag-Doped Mesoporous TiO2  

SciTech Connect

Ag-doped mesoporous titanium oxide was prepared using non-ionic surfactants and easily handled titanium precursors, under mild reaction conditions. In contrast to the stabilizing effect of Cd-doping on mesoporous TiO2, Ag-doping was found to significantly destabilize the mesoporous structure.

Li, Xiaohong S.; Fryxell, Glen E.; Wang, Chong M.; Engelhard, Mark H.

2008-04-15

140

Hydrothermal Synthesis of Er-Doped Luminescent TiO2 Nanoparticles  

E-print Network

evidence that the Er ions are doped into the TiO2 nanoparticles and that Er was not present as free Er2O3 for the forma- tion of multilayered thin films,1 optical coatings,2 planar waveguides,3 and photonic band gap

Braun, Paul

141

Facile synthesis of TiO2 inverse opal electrodes for dye-sensitized solar cells.  

PubMed

Engineering of TiO(2) electrode layers is critical to guaranteeing the photoconversion efficiency of dye-sensitized solar cells (DSSCs). Recently, a novel approach has been introduced for producing TiO(2) electrodes using the inverted structures of colloidal crystals. This paper describes a facile route to producing ordered macroporous electrodes from colloidal crystal templates for DSSCs. Using concentrated colloids dispersed in a volatile medium, the colloidal crystal templates were obtained within a few minutes, and the thickness of the template was easily controlled by changing the quantity of colloidal solution deposited. Here, the effects of the structural properties of the inverse opal TiO(2) electrodes on the photovoltaic parameters of DSSCs were investigated. The photovoltaic parameters were measured as a function of pore ordering and electrode film thickness. Moreover, DSSC applications that used either liquid or viscous polymer electrolyte solutions were investigated to reveal the effects of pore size on performance of an inverse opal TiO(2) electrode. PMID:21155579

Shin, Ju-Hwan; Kang, Ji-Hwan; Jin, Woo-Min; Park, Jong Hyeok; Cho, Young-Sang; Moon, Jun Hyuk

2011-01-18

142

Synthesis and formation mechanism of TiO2/Al2O3 nanobelts by electrospinning  

NASA Astrophysics Data System (ADS)

Poly(vinyl pyrrolidone) (PVP)/[Ti(SO4)2 + Al(NO3)3] composite nanobelts were prepared via electrospinning technology, and TiO2/Al2O3 nanobelts were fabricated by calcination of the prepared composite nanobelts. The samples were characterized by thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). XRD results show that the composite nanobelts were amorphous in structure, and pure phase TiO2/Al2O3 nanobelts were obtained by calcination of the relevant composite nanobelts at 950°C for 8 h. SEM analysis indicates that the surface of as-prepared composite nanobelts was smooth, the widths of the composite fibers were in narrow range, and the mean width was ca. 8.9 ± 2.1 ?m, thickness was about 255 nm, and there is no cross-linking among nanobelts. The width of TiO2/Al2O3 nanobelts was ca. 1.3 ± 0.1 ?m and the thickness was about 105 nm. TG-DTA analysis reveals that the N,N-dimethylformamide (DMF), organic compounds and inorganic salts in the composite nanobelts were decomposed and volatilized totally, and the weight of the sample kept constant when sintering temperature was above 900°C, and the total weight loss percentage was 81%. FTIR analysis manifests that crystalline TiO2/Al2O3 nanobelts were formed at 950°C. The possible formation mechanism of the TiO2/Al2O3 nanobelts was preliminarily discussed.

Song, Chao; Dong, Xiangting

2013-09-01

143

Preparation and characterization of TiO 2 photocatalysts supported on various rigid supports (glass, quartz and stainless steel). Comparative studies of photocatalytic activity in water purification  

Microsoft Academic Search

In the present study TiO2 has been supported on several rigid substrates. Deposition on glass and quartz was carried out by a dip coating procedure and the deposition on stainless steel by an electrophoretic deposition process. The resulting materials have been characterized by XPS, SEM\\/EDX, XRD and UV-vis absorption spectroscopy. The materials were then tested for the photocatalytic degradation of

A. Fernández; G. Lassaletta; V. M. Jiménez; A. Justo; A. R. González-Elipe; J.-M. Herrmann; H. Tahiri; Y. Ait-Ichou

1995-01-01

144

The Effect of Fuel to Oxygen Ratios on the Properties of High Velocity Oxy-Fuel TiO2 Nano-Photocatalyst Coatings  

Microsoft Academic Search

A liquid fuel high velocity oxy-fuel (HVOF) thermal spray process has been used to deposit TiO2 photocatalytic coatings utilizing a commercially available anatase\\/rutile nano-powder as the feedstock. The coatings were characterized in terms of the phases present, its crystallite size and coating morphology by means of X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy, respectively. The results indicate

Maryamossadat Bozorgtabar; Mehdi Salehi; Mohammadreza Rahimipour; Mohammadreza Jafarpour

2010-01-01

145

First-principles study on the synergistic effects of codoped anatase TiO2 photocatalysts codoped with N/V or C/Cr  

NASA Astrophysics Data System (ADS)

An effective compensated codoping approach is described to modify the photoelectrochemical properties of anatase TiO2 by doping with nonmetals (N or C) and transition metals (V or Cr) impurities. Here, compensated codoped TiO2 systems are constructed with different dopant species and sources, and then their dopant formation energies and electronic structures are performed to study the stability and visible-light photoactivity by first-principles plane-wave ultrasoft pseudopotential calculations, respectively. The calculated results demonstrate that the codoping with transition metals facilitates the enhancement of the concentration of p-type dopants (N and C) in a host lattice. Especially, compensated codoping not only reduces the energy gap, to enhance the optical absorption, and eliminate the local trapping, to improve carrier mobility and conversion efficiency, but it also keeps the oxidation-reduction potential of the conduction band edge. These results are conducive to the understanding of the synergistic mechanism of the photocatalytic activity of TiO2 that is enhanced by codoping.

Wenhui, Xu; Xinguo, Ma; Tong, Wu; Zhiqi, He; Huihu, Wang; Chuyun, Huang

2014-10-01

146

The Effect of Fuel to Oxygen Ratios on the Properties of High Velocity Oxy-Fuel TiO2 Nano-Photocatalyst Coatings  

NASA Astrophysics Data System (ADS)

A liquid fuel high velocity oxy-fuel (HVOF) thermal spray process has been used to deposit TiO2 photocatalytic coatings utilizing a commercially available anatase/rutile nano-powder as the feedstock. The coatings were characterized in terms of the phases present, its crystallite size and coating morphology by means of X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy, respectively. The results indicate that the sprayed TiO2 coatings were composed of both TiO2 phases, namely anatase and rutile with different phase content and crystallite size. A high anatase content of 80% by volume was achieved at 0.00015 fuel to oxygen ratio with nanostructure coating by grain size smaller than feedstock powder. It is found that fuel to oxygen ratio strongly influenced on temperature and velocity of particles in stream jet consequently on phase transformation of anatase to rutile and their crystallite size and by optimizing the ratio which can promote structural transformation and grain coarsening in coating.

Bozorgtabar, Maryamossadat; Salehi, Mehdi; Rahimipour, Mohammadreza; Jafarpour, Mohammadreza

147

The Comparative Photodegradation Activities of Pentachlorophenol (PCP) and Polychlorinated Biphenyls (PCBs) Using UV Alone and TiO2-Derived Photocatalysts in Methanol Soil Washing Solution  

PubMed Central

Photochemical treatment is increasingly being applied to remedy environmental problems. TiO2-derived catalysts are efficiently and widely used in photodegradation applications. The efficiency of various photochemical treatments, namely, the use of UV irradiation without catalyst or with TiO2/graphene-TiO2 photodegradation methods was determined by comparing the photodegadation of two main types of hydrophobic chlorinated aromatic pollutants, namely, pentachlorophenol (PCP) and polychlorinated biphenyls (PCBs). Results show that photodegradation in methanol solution under pure UV irradiation was more efficient than that with either one of the catalysts tested, contrary to previous results in which photodegradation rates were enhanced using TiO2-derived catalysts. The effects of various factors, such as UV light illumination, addition of methanol to the solution, catalyst dosage, and the pH of the reaction mixture, were examined. The degradation pathway was deduced. The photochemical treatment in methanol soil washing solution did not benefit from the use of the catalysts tested. Pure UV irradiation was sufficient for the dechlorination and degradation of the PCP and PCBs. PMID:25254664

Zhou, Zeyu; Zhang, Yaxin; Wang, Hongtao; Chen, Tan; Lu, Wenjing

2014-01-01

148

Fabrication of hydroxyl group modified monodispersed hybrid silica particles and the h-SiO2/TiO2 core/shell microspheres as high performance photocatalyst  

E-print Network

core/shell microspheres as high performance photocatalyst for dye degradation Zhe-Ying Shen a , Long-coated silica particles showed good photocatalytic performance in degradation of methyl orange aqueous solution particles as a heterogeneous photo- catalyst have attracted significant attention in the last few decades

Li, Yat

149

Synthesis and visible-light-induced catalytic activity of Ag2S-coupled TiO2 nanoparticles and nanowires  

NASA Astrophysics Data System (ADS)

We present the synthesis and visible-light-induced catalytic activity of Ag2S-coupled TiO2 nanoparticles (NPs) and TiO2 nanowires (NWs). Through a simple wet chemical process from a mixture of peroxo titanic acid (PTA) solution, thiourea and AgAc, a composite of Ag2S NPs and TiO2 NPs with sizes of less than 7 nm was formed. When the NP composite was further treated with NaOH solution followed by annealing at ambient conditions, a new nanocomposite material comprising Ag2S NPs on TiO2 NWs was created. Due to the coupling with such a low bandgap material as Ag2S, the TiO2 nanocomposites could have a visible-light absorption capability much higher than that of pure TiO2. As a result, the synthesized Ag2S/TiO2 nanocomposites exhibited much higher catalytic efficiency for the decomposition of methyl orange than commercial TiO2 (Degussa P25, Germany) under visible light.

Xie, Yi; Heo, Sung Hwan; Kim, Yong Nam; Yoo, Seung Hwa; Cho, Sung Oh

2010-01-01

150

Synthesis and visible-light-induced catalytic activity of Ag2S-coupled TiO2 nanoparticles and nanowires.  

PubMed

We present the synthesis and visible-light-induced catalytic activity of Ag(2)S-coupled TiO(2) nanoparticles (NPs) and TiO(2) nanowires (NWs). Through a simple wet chemical process from a mixture of peroxo titanic acid (PTA) solution, thiourea and AgAc, a composite of Ag(2)S NPs and TiO(2) NPs with sizes of less than 7 nm was formed. When the NP composite was further treated with NaOH solution followed by annealing at ambient conditions, a new nanocomposite material comprising Ag(2)S NPs on TiO(2) NWs was created. Due to the coupling with such a low bandgap material as Ag(2)S, the TiO(2) nanocomposites could have a visible-light absorption capability much higher than that of pure TiO(2). As a result, the synthesized Ag(2)S/TiO(2) nanocomposites exhibited much higher catalytic efficiency for the decomposition of methyl orange than commercial TiO(2) (Degussa P25, Germany) under visible light. PMID:19946150

Xie, Yi; Heo, Sung Hwan; Kim, Yong Nam; Yoo, Seung Hwa; Cho, Sung Oh

2010-01-01

151

Non-solvolytic synthesis of aqueous soluble TiO2 nanoparticles and real-time dynamic measurements of the nanoparticle formation  

PubMed Central

Highly aqueously dispersible (soluble) TiO2 nanoparticles are usually synthesized by a solution-based sol–gel (solvolysis/condensation) process, and no direct precipitation of titania has been reported. This paper proposes a new approach to synthesize stable TiO2 nanoparticles by a non-solvolytic method - direct liquid phase precipitation at room temperature. Ligand-capped TiO2 nanoparticles are more readily solubilized compared to uncapped TiO2 nanoparticles, and these capped materials show distinct optical absorbance/emission behaviors. The influence of ligands, way of reactant feeding, and post-treatment on the shape, size, crystalline structure, and surface chemistry of the TiO2 nanoparticles has been thoroughly investigated by the combined use of X-ray diffraction, transmission electron microscopy, UV-visible (UV–vis) spectroscopy, and photoluminescence (PL). It is found that all above variables have significant effects on the size, shape, and dispersivity of the final TiO2 nanoparticles. For the first time, real-time UV–vis spectroscopy and PL are used to dynamically detect the formation and growth of TiO2 nanoparticles in solution. These real-time measurements show that the precipitation process begins to nucleate after an initial inhibition period of about 1?h, thereafter a particle growth occurs and reaches the maximum point after 2?h. The synthesis reaction is essentially completed after 4?h. PMID:22676412

2012-01-01

152

Synthesis of TiO2/GO composite film via an electrochemical route.  

PubMed

A nano-structured film composed of TiO2 and reduced graphite oxide (GO) was synthesized on ITO glass via a typical electrochemical route. A mixed solvent of Ti(SO4)2 and GO was prepared, with the addition of H2O2, HNO3 and DMF at different ratio. A setup of two electrodes of ITO glass in a plastic cell and an electrochemical analyzer is used for the film forming. The film is characterized with a microstructure of GO plates being perpendicular to the glass substrate, since GO in the electrolyte solvent is separated as small plates at about several nanometers in diameter. TiO2 is found being deposited between these GO plates. This microstructure is quite different from the film formed by normal deposition, where the GO plates are generally parallel to the substrate. The oxygen containing groups of C=O, C-O-C and C-OH on the GO surface are reduced because of neighboring to TiO2, it means two phases being bonded to each other at the interface. The photoelectric current of the composite film is compared with the pure TiO2 film, the former one is almost one time higher than the latter one. The degradation of methyl orange of two kinds of film is also analyzed under the irradiation of ultraviolet light. The photocatalytic activity of two kinds of film presents the same trend of variation as that of photoelectric current. These results suggest that the photoexcited electrons of TiO2 may quickly transfer to the glass substrate through the reduced GO neighbor, that owns a better conductivity, and so far decrease the recovery of excited electron-hole. The unordinary microstructure of the composite film may favor both to the electron transmission between the GO and ITO glass substrate, and to the light excitation of TiO2. The microstructure of different films was studies by AFM, XPS, FESEM. The photo-electrochemical property was measured by an electrochemical instrument Model CHI660C with Blupoint4 as a UV light source. PMID:21137873

He, Yunqiu; Wang, Ruihua; Zhang, Qiong; Chen, Xiaogang; Li, Linjiang; Hu, Donghu

2010-11-01

153

Synthesis of monodisperse TiO2-paraffin core-shell nanoparticles for improved dielectric properties.  

PubMed

Core-shell structures of oxide nanoparticles having a high dielectric constant, and organic shells with large breakdown field are attractive candidates for large electrical energy storage applications. A high growth temperature, however, is required to obtain the dielectric oxide nanoparticles, which affects the process of core-shell formation and also leads to poor control of size, shape, and size-distribution. In this communication, we report a new synthetic process to grow core-shell nanoparticles by means of an experimental method that can be easily adapted to synthesize core-shell structures from a variety of inorganic-organic or inorganic-inorganic materials. Monodisperse and spherical TiO2 nanoparticles were produced at room temperature as a collimated cluster beam in the gas phase using a cluster-deposition source and subsequently coated with uniform paraffin nanoshells using in situ thermal evaporation, prior to deposition on substrates for further characterization and device processing. The paraffin nanoshells prevent the TiO2 nanoparticles from contacting each other and also act as a matrix in which the volume fraction of TiO2 nanoparticles was varied by controlling the thickness of the nanoshells. Parallel-plate capacitors were fabricated using dielectric core-shell nanoparticles having different shell thicknesses. With respect to the bulk paraffin, the effective dielectric constant of TiO2-paraffin core-shell nanoparticles is greatly enhanced with a decrease in the shell thickness. The capacitors show a minimum dielectric dispersion and low dielectric losses in the frequency range of 100 Hz-1 MHz, which are highly desirable for exploiting these core-shell nanoparticles for potential applications. PMID:20359188

Balasubramanian, Balamurugan; Kraemer, Kristin L; Reding, Nicholas A; Skomski, Ralph; Ducharme, Stephen; Sellmyer, David J

2010-04-27

154

Synthesis and characterization of Fe3O4-TiO2 core-shell nanoparticles  

NASA Astrophysics Data System (ADS)

Composite core-shell nanoparticles may have morpho-structural, magnetic, and optical (photoluminescence (PL)) properties different from each of the components considered separately. The properties of Fe3O4-TiO2 nanoparticles can be controlled by adjusting the titania amount (shell thinness). Core-shell nanoparticles were prepared by seed mediated growth of semiconductor (TiO2) through a modified sol-gel process onto preformed magnetite (Fe3O4) cores resulted from the co-precipitation method. The structure and morphology of samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), and high resolution-TEM respectively. X-ray photoelectron spectroscopy was correlated with ICP-AES. Magnetic measurements, optical absorption spectra, as well as PL spectroscopy indicate the presence of a charge/spin transfer from the conduction band of magnetite into the band gap of titania nanocrystals. The process modifies both Fe3O4 and TiO2 magnetic and optical properties, respectively.

Stefan, M.; Pana, O.; Leostean, C.; Bele, C.; Silipas, D.; Senila, M.; Gautron, E.

2014-09-01

155

Bamboo leaf-assisted formation of carbon/nitrogen co-doped anatase TiO2 modified with silver and graphitic carbon nitride: novel and green synthesis and cooperative photocatalytic activity.  

PubMed

We report a novel synthesis approach employing bamboo leaves as sources of both the C/N dopant and reductant to the formation of C/N co-doped TiO2 modified with Ag and g-C3N4 (Ag/CN-TiO2@g-C3N4). In this case, the ternary composite has a hierarchical structure and a large surface area, which increases the contact area of reactants. Degradation of rhodamine B (RhB) and hydrogen generation were carried out to evaluate the photocatalytic activity of as-prepared samples under visible light irradiation. It is found that with respect to single and binary catalysts, the Ag/CN-TiO2@g-C3N4 ternary composite shows the highest photocatalytic activity (degradation of RhB, H2 evolution from water splitting) as a result of the fast generation, separation and transportation of the photogenerated carriers, which was evidenced by photoluminescence measurements and free radical/hole scavenging experiments. At last, a possible photocatalytic mechanism under visible light irradiation was proposed. The novel and green synergistic approach presented here could provide a facile yet effective method for designing other visible light active non-metal co-doped TiO2 based photocatalysts with enhanced activity and high chemical stability. PMID:25102976

Jiang, Zhifeng; Liu, Dong; Jiang, Deli; Wei, Wei; Qian, Kun; Chen, Min; Xie, Jimin

2014-09-28

156

Self-organized TiO2 nanotube arrays: synthesis by anodization in an ionic liquid and assessment of photocatalytic properties.  

PubMed

Self-organized TiO(2) nanotube (NT) arrays were produced by anodization in ethylene glycol (EG) electrolytes containing 1-n-butyl-3-methyl-imidazolium tetrafluoroborate (BMI.BF(4)) ionic liquid and water. The morphology of the as-formed NTs was considerably affected by changing the anodization time, voltage, and water and ionic liquid electrolyte concentrations. In general, a nanoporous layer was formed on the top surface of the TiO(2) NTs, except for anodization at 100 V with 1 vol % of BMI.BF(4), where the NT's mouth was revealed. The length and bottom diameter of the NTs as well as the pore diameter of the top layer showed a linear relationship with increased anodization voltage. These TiO(2) NTs were tested as photocatalysts for methyl orange photodegradation and hydrogen evolution from water/methanol solutions by UV light irradiation. The results show that the TiO(2) NTs obtained by anodization in EG/H(2)O/BMI.BF(4) electrolytes are active and efficient for both applications. PMID:21443251

Wender, Heberton; Feil, Adriano F; Diaz, Leonardo B; Ribeiro, Camila S; Machado, Guilherme J; Migowski, Pedro; Weibel, Daniel E; Dupont, Jairton; Teixeira, Sérgio R

2011-04-01

157

First Principles Simulations on Doped TiO2 and SrTiO3 Nanotubular Photocatalysts for Water-Splitting Hydrogen Generation  

NASA Astrophysics Data System (ADS)

First principles calculations have been performed to investigate ground state properties of monoperiodic TiO2 and SrTiO3 single-walled nanotubes containing extrinsic point defects. The hybrid exchange-correlation functionals B3LYP and B3PW within the framework of density functional theory have been applied to calculations for nanotubes with the following substitution impurities: CO, NO, SO, and FeTi. Variations in the formation energies obtained for equilibrium defective nanostructures allow us to predict the most stable compositions, irrespectively of the changes in growth conditions. Changes in the electronic structure show mid-gap states induced by defects.

Zhukovskii, Yu. F.; Piskunov, S.; Lisovski, O.; Begens, J.

2013-05-01

158

High performance sulfur, nitrogen and carbon doped mesoporous anatase-brookite TiO2 photocatalyst for the removal of microcystin-LR under visible light irradiation.  

PubMed

Carbon, nitrogen and sulfur (C, N and S) doped mesoporous anatase-brookite nano-heterojunction titania photocatalysts have been synthesized through a simple sol-gel method in the presence of triblock copolymer Pluronic P123. XRD and Raman spectra revealed the formation of anatase and brookite mixed phases. XPS spectra indicated the presence of C, N and S dopants. The TEM images demonstrated the formation of almost monodisperse titania nanoparticles with particle sizes of approximately 10nm. N2 isotherm measurements confirmed that both doped and undoped titania anatase-brookite materials have mesoporous structure. The photocatalytic degradation of the cyanotoxin microcystin-LR (MC-LR) has been investigated using these novel nanomaterials under visible light illumination. The photocatalytic efficiency of the mesoporous titania anatase-brookite photocatalyst dramatically increased with the addition of the C, N and S non-metal, achieving complete degradation (?100%) of MC-LR. The results demonstrate the advantages of the synthetic approach and the great potential of the visible light activated C, N, and S doped titania photocatalysts for the treatment of organic micropollutants in contaminated waters under visible light. PMID:25238189

El-Sheikh, Said M; Zhang, Geshan; El-Hosainy, Hamza M; Ismail, Adel A; O'Shea, Kevin E; Falaras, Polycarpos; Kontos, Athanassios G; Dionysiou, Dionysios D

2014-09-15

159

Synthesis and characterization of TiO 2 and Fe/TiO 2 nanoparticles and their performance for photocatalytic degradation of 1,2-dichloroethane  

NASA Astrophysics Data System (ADS)

The characterization of nano-sized TiO 2 and Fe/TiO 2 prepared by a sol-gel method was characterized in this study. The synthesized photocatalysts were used for the photodegradation of 1,2-dichloroethane (1,2-DCE). From X-ray powder diffraction data, the crystal phase presents a mixture of anatase and rutile with anatase the dominant phase. As seen in TEM images, the crystallites of photocatalysts are spherical particles with a crystallite size about 10-20 nm. UV-vis absorption spectra of Fe/TiO 2 show a slightly increase in absorbancy in the visible light region with the increasing iron ion doping concentration. The X-ray photoelectron spectroscopy (XPS) results indicate that the Ti 2p 3/2 and Ti 2p 1/2 photoelectrons for TiO 2 and Fe/TiO 2 are located at binding energies of 459 and 465 eV, respectively, which represent the values of Ti 4+ in the TiO 2 lattices. The XPS data also indicate that the doped Fe ions exist in the forms of Fe(III). The Fe(III) may alleviate the surface poison phenomenon and act as both h +/e - traps to reduce the recombination rate of h +/e - pairs, and the optimum iron doping amount is 0.001 mol%. From 1,2-DCE photocatalytic degradation, the photocatalytic performance is a function of retention time and it would have a competitive adsorption on the active site of TiO 2 between water vapor and 1,2-DCE. The byproducts of 1,2-DCE photodegradation include H 2O, CO, CO 2, C 2H 5Cl, CH 2Cl 2, and HCl.

Hung, Wen-Chi; Chen, Yu-Chun; Chu, Hsin; Tseng, Ting-Ke

2008-12-01

160

Synthesis and Characterization of Rutile TiO2Nanopowders Doped with Iron Ions  

PubMed Central

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5–7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO2into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence. PMID:20596442

2009-01-01

161

Clean and time-effective synthesis of anatase TiO2 nanocrystalline by microwave-assisted solvothermal method for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

In this article, we report a clean and time-effective solvothermal synthesis route using microwave-assisted heating method to prepare nanocrystalline anatase TiO2 with its application for dye-sensitized solar cells. With this proposed method, pure anatase TiO2 nanoparticles with size about 20 nm are successfully obtained at 220 °C for 30 min. Our method of microwave-assisted organic solvothermal route significantly reduces the elaborating process of washing and solvent exchange for the subsequent paste formation. The as-synthesized TiO2 colloidal solution is ready for particle dispersion that markedly simplified the preparation procedures. Material characterizations of the anatase TiO2 nanoparticles are performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. The photovoltaic performances of the dye-sensitized solar cells assembled with the as-synthesized TiO2 nanocrystallines as photoanodes in various film thicknesses are examined. An excellent energy conversion efficiency of 7.8% is achieved which is comparable to the previously reported dye-sensitized solar cells made of hydrothermal microwave-synthesized TiO2.

Shen, Po-Shen; Tai, Yu-Chuen; Chen, Peter; Wu, Yu-Chun

2014-02-01

162

Synthesis, characterization, and photoconductivity studies on nanocrystalline TiO2 films doped with gold nanoparticles  

NASA Astrophysics Data System (ADS)

Nanocrystalline TiO2 films doped with gold nanoparticles were synthesized by the sol-gel process at room temperature. The TiO2 films were synthesized by using tetrabutyl orthotitanate as the inorganic precursor. The films were spin-coated on glass wafers. The samples were annealed at 100°C for 30 minutes and sintered at 520°C for 1 hour to generated anatase and rutile phases. The films were characterized using UV-Vis absorption spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. An absorption peak located at around 651 nm is due to the surface plasmon resonance of the gold nanoparticles. Optical absorption spectrum was fitted by Gans model by using a high refractive index (nlocal = 2.6). This high index is related to the high content of anatase nanoparticles embedded in the film. Photoconductivity studies were performed on nanocrystalline (anatase phase) films. The experimental data were fitted with straight lines at darkness and under illumination at 515 nm and 645 nm. This indicates an ohmic behavior. Transport parameters were calculated. Results are discussed.

Valverde-Aguilar, G.; García-Macedo, J. A.; Galván-Ramírez, P.; Rentería-Tapia, V.

2009-08-01

163

In Situ Synthesis of Graphene Molecules on TiO2: Application in Sensitized Solar Cells.  

PubMed

We present a method for preparation of graphene molecules (GMs), whereby a polyphenylene precursor functionalized with surface anchoring groups, preadsorbed on surface of TiO2, is oxidatively dehydrogenated in situ via a Scholl reaction. The reaction, performed at ambient conditions, yields surface adsorbed GMs structurally and electronically equivalent to those synthesized in solution. The new synthetic approach reduces the challenges associated with the tendency of GMs to aggregate and provides a convenient path for integration of GMs into optoelectronic applications. The surface synthesized GMs can be effectively reduced or oxidized via an interfacial charge transfer and can also function as sensitizers for metal oxides in light harvesting applications. Sensitized solar cells (SSCs) prepared from mesoscopic TiO2/GM films and an iodide-based liquid electrolyte show photocurrents of ?2.5 mA/cm(2), an open circuit voltage of ?0.55 V and fill factor of ?0.65 under AM 1.5 illumination. The observed power conversion efficiency of ? = 0.87% is the highest reported efficiency for the GM sensitized solar cell. The performance of the devices was reproducible and stable for a period of at least 3 weeks. We also report first external and internal quantum efficiency measurements for GM SSCs, which point to possible paths for further performance improvements. PMID:25322280

Ji, Zhiqiang; Wu, Ruilian; Adamska, Lyudmyla; Velizhanin, Kirill A; Doorn, Stephen K; Sykora, Milan

2014-11-26

164

Synthesis, characterization and degradation of Bisphenol A using Pr, N co-doped TiO 2 with highly visible light activity  

NASA Astrophysics Data System (ADS)

Praseodymium and nitrogen co-doped titania (Pr/N-TiO 2) photocatalysts, which could degrade Bisphenol A (BPA) under visible light irradiation, were prepared by the modified sol-gel process. Tetrabutyl titanate, urea and praseodymium nitrate were used as the sources of titanium, nitrogen and praseodymium, respectively. The resulting materials were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV-vis absorbance spectroscopy, X-ray photoelectron spectroscopy (XPS), N 2 adsorption-desorption isotherm and Fourier transform infrared spectra (FTIR). It was found that Pr doping inhibited the growth of crystalline size and the transformation from anatase to rutile. The degradation of BPA under visible light illumination was taken as probe reaction to evaluate the photo-activity of the co-doped photocatalyst. In our experiments, the optimal dopant amount of Pr was 1.2 mol% and the calcination temperature was 500 °C for the best photocatalytic activity. Pr/N-TiO 2 samples exhibited enhanced visible-light photocatalytic activity compared to N-TiO 2, undoped TiO 2 and commercial P25. The nitrogen atoms were incorporated into the crystal of titania and could narrow the band gap energy. Pr doping could slow the radiative recombination of photogenerated electrons and holes in TiO 2. The improvement of photocatalytic activity was ascribed to the synergistic effects of nitrogen and Pr co-doping.

Yang, Juan; Dai, Jun; Li, Jiantong

2011-08-01

165

A direct synthesis of B-doped TiO2 and its photocatalytic performance on degradation of RhB  

NASA Astrophysics Data System (ADS)

B-doped TiO2 was synthesized by a direct hydrolyzation of n-tetrabutyl titanate in a solution of boric acid, and was treated by hydro-thermal synthesis. The powder was characterized by X-ray diffraction (XRD), FT-IR, scanning and transmission electron microscopy (SEM and TEM), surface photoviolet spectra, UV-visible absorption spectra and X-ray photoelectron spectroscopy (XPS). Rhodamine B (RhB) degradation was used as a probe reaction to evaluate the photocatalytic activity of B-doped TiO2 under simulate sunlight, and excellent photocatalytic performance was achieved.

Li, Liang; Yang, Yulin; Liu, Xinrong; Fan, Ruiqing; Shi, Yan; Li, Shuo; Zhang, Lingyun; Fan, Xiao; Tang, Pengxiao; Xu, Rui; Zhang, Wenzhi; Wang, Yazhen; Ma, Liqun

2013-01-01

166

Synthesis of capped TiO2 nanocrystals of controlled shape and their use with MEH-PPV conjugated polymer to develop nanocomposite films for photovoltaic applications  

NASA Astrophysics Data System (ADS)

This study presents the synthesis details of titanium dioxide (TiO2) nanoparticles (NPs) of different shapes (nanospheres, nanorods and nanorhombics) using oleic acid (OA) and oleyl amine (OM) as capping agents. In order to develop nanocomposite thin films for photovoltaic cells, these TiO2 NPs were carefully dispersed in 2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene (MEH-PPV) matrix. The properties of synthesized TiO2 NPs and MEH-PPV/TiO2 nanocomposites were characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), UV-Visible spectroscopy, and Photoluminescence technique. It was found that the shape of NPs and the amount of OA and OM surfactants capped on their surface have an effect on their energy bandgap and also on the dispersion quality of MEH-PPV/TiO2 nanocomposites. Even though there was no evidence of chemical bonding between MEH-PPV matrix and TiO2 dispersed NPs, MEH-PPV/TiO2 nanocomposites showed very promising results for light absorption properties and charge transfer at the interface of the conjugated MEH-PPV matrix and TiO2 dispersed NPs, which are two main characteristics for photovoltaic materials.

Mighri, F.; Duong, Vu Thi Thuy; On, Do Trong; Ajji, A.

2014-05-01

167

Synthesis and characterization of polypyrrole/Sn-doped TiO 2 nanocomposites (NCs) as a protective pigment  

NASA Astrophysics Data System (ADS)

We have chemically polymerized pyrrole in the presence of Sn-doped TiO 2 nanoparticles (NPs) and TiO 2 (NPs) which act as a protective pigment. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results show a core-shell structure of pigments in which TiO 2 and Sn-doped TiO 2 NPs have a nucleus effect and caused a homogenous PPy core-shell type morphology leading to coverage of the TiO 2 and Sn-doped TiO 2 NPs by PPy deposit. The XRD results indicate that the crystalline size of polypyrrole/TiO 2 NCs and polypyrrole/Sn-doped TiO 2 NCs were approximately 93.46 ± 0.06 and 23.36 ± 0.06 nm respectively. The electrochemical impedance spectroscopy (EIS) results show that the performance of polypyrrole/Sn-doped TiO 2 NCs is better than polypyrrole/TiO 2 NCs. The results indicate that increasing the area of synthesized polypyrrole in the presence of Sn-doped TiO 2 NPs can increase its ability to interact with the ions liberated during the corrosion reaction of steel in the presence of NaCl. The UV-vis results show that the band gap of TiO 2 NPs increases with doped of Sn in lattice of TiO 2. The increase of the band gap of TiO 2 with doping of Sn can decrease the charge transfer through the coating.

Mahmoudian, M. R.; Basirun, W. J.; Alias, Y.; Ebadi, M.

2011-08-01

168

Aqueous Synthesis and Concentration-Dependent Dermal Toxicity of TiO 2 Nanoparticles in Wistar Rats  

Microsoft Academic Search

A number of dermal toxicological studies using TiO2 nanoparticles exist which are based on the study of various animal models like mice, rabbits etc. However, a well-defined\\u000a study is lacking on the dermal toxic effects of TiO2 nanoparticles on rats, which are the appropriate model for systemic absorption study of nanoparticles. Furthermore, toxicity\\u000a of TiO2 nanoparticles varies widely depending upon

Jyotisree Unnithan; Muneeb U. Rehman; Farhan J. Ahmad; M. Samim

169

Facile Synthesis of Hierarchical Porous TiO2 Ceramics with Enhanced Photocatalytic Performance for Micropolluted Pesticide Degradation.  

PubMed

In this research, hierarchical porous TiO2 ceramics were successfully synthesized through a camphene-based freeze-drying route. The well-dispersed TiO2 slurries were first frozen and dried at room temperature, followed by high-temperature sintering. The ceramics were analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. Results indicated that the obtained TiO2 ceramics could inhibit undesirable anatase-to-rutile phase transformation and grain growth even at temperatures as high as 800 °C. In this experiment, optimal compressive strength and porosity of the TiO2 ceramics were produced with the initial TiO2 slurry content of ?15 wt %. The resultant TiO2 ceramics performed excellently in the photodegradation of atrazine and thiobencarb, and the total organic carbon removal efficiency was up to 95.7% and 96.7%, respectively. More importantly, the TiO2 ceramics were easily recyclable. No obvious changes of the photocatalytic performance were observed after six cycles. Furthermore, the ceramics also effectively degraded other pesticides such as dimethoate, lindane, dipterex, malathion, and bentazone. These hierarchical porous TiO2 ceramics have potential applications in environmental cleanup. PMID:25198508

Xing, Zipeng; Zhou, Wei; Du, Fan; Zhang, Linlin; Li, Zhenzi; Zhang, Hang; Li, Wei

2014-10-01

170

Application of graphene oxide as a hydrothermal catalyst support for synthesis of TiO2 whiskers.  

PubMed

How graphene oxide (GO) with its step edges and wrinkles (?1-2 nm) acts as a catalyst in hydrothermal nucleation and growth is demonstrated. TiO2 whiskers were prepared by using GO as a support, while TiO2 nanograss was prepared without using GO. PMID:25327616

Parmar, Kaushal R; Basha, Shaik; Murthy, Z V P

2014-11-01

171

Self-cleaning properties of TiO2/palygorskite and TiO2/halloysite nanocomposite coatings  

NASA Astrophysics Data System (ADS)

Tubular halloysite and microfibrous palygorskite clay mineral combined with nanocrystalline TiO2 are involved in the preparation of nanocomposite films on glass substrates via sol-gel route at 450°C. The synthesis employing nonionic surfactant molecule as pore directing agent along with the acetic acid-based sol-gel route without addition of water molecules. Drying and thermal treatment of composite films ensure elimination of organic material lead to the formation of TiO2 nanoparticles homogeneously distributed on the palygorskite and halloysite surfaces. Nanocomposite films without cracks of active anatase crystal phase on palygorskite and halloysite surfaces are characterized by microscopy techniques, UV-Vis spectroscopy, and porosimetry methods in order to examine their structural properties. The composite palygorskite-TiO2 and halloysite/TiO2 films with variable quantities of palygorskite and halloysite were tested as photocatalysts in the photo-oxidation of Basic Blue 41 azo dye in water. These nanocomposite films proved to be most promising photocatalysts and highly effective to dye's decoloration in spite of small amount of palygorskite/TiO2 or halloysite/TiO2 catalyst immobilized onto glass substrates.

Panagiotaras, Dionisios; Kaplani, Eleni; Stathatos, Elias; Papoulis, Dimitrios

2014-10-01

172

One-step synthesis of TiO2 nanorod arrays on Ti foil for supercapacitor application  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) nanorod arrays grown directly on Ti metal foil were prepared by a facile one-step hydrothermal method, in which the Ti foil serves as both substrate and precursor. The nanorods are tetragonal rutile single crystal with growth orientation along the [001] direction. The electrochemical properties of the TiO2 nanorod arrays were systematically investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy using a three-electrode system. As a result, the TiO2 nanorod arrays exhibit good areal specific capacitance and excellent cyclic stability by retaining more than 98% of the initial specific capacitance after 1000 cycles. In addition, a good flexibility of the Ti foil with TiO2 nanorod arrays was demonstrated by the stable electrochemical performance under different bending angles, which indicates that TiO2 nanorod arrays grown on Ti foil could be a promising electrode material for flexible supercapacitor application.

Zheng, Zhi; Chen, Jiajun; Yoshida, Ryuji; Gao, Xiang; Tarr, Kayla; Ikuhara, Yumi H.; Zhou, Weilie

2014-10-01

173

Characterisation of the photocatalyst Pilkington Activ™: a reference film photocatalyst?  

Microsoft Academic Search

Pilkington Glass Activ™ represents a possible suitable successor to P25 TiO2, especially as a benchmark photocatalyst film for comparing other photocatalyst or PSH self-cleaning films. Activ™ is a glass product with a clear, colourless, effectively invisible, photocatalytic coating of titania that also exhibits PSH. Although not as active as a film of P25 TiO2, Activ™ vastly superior mechanical stability, very

Andrew Mills; Anne Lepre; Nicholas Elliott; Sharan Bhopal; Ivan P. Parkin; S. A. O’Neill

2003-01-01

174

Photodegradation of Orange II by mesoporous TiO2.  

PubMed

Mesoporous TiO(2) microspheres were prepared by a hydrothermal reaction and are characterized in this paper. Decoloration and mineralization during photodegradation of Orange II by mesoporous TiO(2) at different pH values, formation of sulfate, relative luminosity to luminous bacteria and recycling experiments of the catalyst were studied. The FTIR results further suggested that the novel mesoporous TiO(2) can not only decolor and mineralize dyes completely but also can be effectively reused several times. On the basis of the research, mesoporous TiO(2) would be a promising photocatalyst for practical use. PMID:21833403

Kuang, Liyuan; Zhao, Yaping; Liu, Lu

2011-09-01

175

Facile and fast synthesis of porous TiO2 spheres for use in lithium ion batteries.  

PubMed

Porous anatase TiO2 spheres have been synthesized by a microwave-assisted hydrothermal reaction of spherical particle precursors followed by annealing in air. The synthesized TiO2 spheres are formed by interconnected nanocrystals with size of 8.7 nm in average and have grain diameters of 250-400 nm. After annealing at 500°C, the TiO2 samples maintain spherical shape and develop highly mesoporous characteristics with a specific surface area of 151 m(2) g(-1). The TiO2 samples annealed at 750°C consist of larger aggregated particles with diameters of 500-900 nm and still retain mesoporous anatase structure, but with a reduced specific surface area of 25.6 m(2) g(-1). Electrochemical studies reveal that the porous TiO2 spheres annealed at 500°C own very high and stable lithium ion (Li(+)) storage capacities of 207, 184, 166, and 119 mA h g(-1) at 0.5, 1, 2, and 5C (850 mA g(-1)) rates, respectively, owing to their highly porous nanostructures and fine spherical morphology. In contrast, the TiO2 spheres annealed at 700°C exhibit modest electrochemical performance due to their reduced pore structures and larger crystallite size. The prepared porous TiO2 spherical particles show great promise for use as high performance anode materials for lithium ion batteries (LIBs). PMID:24407670

Wang, Hong-En; Jin, Jun; Cai, Yi; Xu, Jun-Meng; Chen, Dai-Song; Zheng, Xian-Feng; Deng, Zhao; Li, Yu; Bello, Igor; Su, Bao-Lian

2014-03-01

176

Fe2 O3 -TiO2 Nanocomposites for Enhanced Charge Separation and Photocatalytic Activity.  

PubMed

Photocatalysis provides a cost effective method for both renewable energy synthesis and environmental purification. Photocatalytic activity is dominated by the material design strategy and synthesis methods. Here, for the first time, we report very mild and effective photo-deposition procedures for the synthesis of novel Fe2 O3 -TiO2 nanocomposites. Their photocatalytic activities have been found to be dramatically enhanced for both contaminant decomposition and photoelectrochemical water splitting. When used to decompose a model contaminant herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), monitored by both UV/Vis and total organic carbon (TOC) analysis, 10?% Fe-TiO2 -H2 O displayed a remarkable enhancement of more than 200?% in the kinetics of complete mineralisation in comparison to the commercial material P25 TiO2 photocatalyst. Furthermore, the photocurrent is nearly double that of P25. The mechanism for this improvement in activity was determined using density functional theory (DFT) and photoluminescence. These approaches ultimately reveal that the photoelectron transfer is from TiO2 to Fe2 O3 . This favours O2 reduction which is the rate-determining step in photocatalytic environmental purification. This in situ charge separation also allows for facile migration of holes from the valence band of TiO2 to the surface for the expected oxidation reactions, leading to higher photocurrent and better photocatalytic activity. PMID:25280047

Moniz, Savio J A; Shevlin, Stephen A; An, Xiaoqiang; Guo, Zheng-Xiao; Tang, Junwang

2014-11-17

177

Synthesis and characterization of TiO 2/Ag/polymer ternary nanoparticles via surface-initiated atom transfer radical polymerization  

NASA Astrophysics Data System (ADS)

We report on the novel ternary hybrid materials consisting of semiconductor (TiO 2), metal (Ag) and polymer (poly(oxyethylene methacrylate) (POEM)). First, a hydrophilic polymer, i.e. POEM, was grafted from TiO 2 nanoparticles via the surface-initiated atom transfer radical polymerization (ATRP) technique. These TiO 2-POEM brush nanoparticles were used to template the formation of Ag nanoparticles by introduction of a AgCF 3SO 3 precursor and a NaBH 4 aqueous solution for reduction process. Successful grafting of polymeric chains from the surface of TiO 2 nanoparticles and the in situ formation of Ag nanoparticles within the polymeric chains were confirmed using transmission electron microscopy (TEM), UV-vis spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). FT-IR spectroscopy also revealed the specific interaction of Ag nanoparticles with the C dbnd O groups of POEM brushes. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the semiconductor, producing ternary hybrid inorganic-organic nanomaterials.

Park, Jung Tae; Koh, Joo Hwan; Seo, Jin Ah; Cho, Yong Soo; Kim, Jong Hak

2011-08-01

178

Synthesis of {100} Facet Dominant Anatase TiO2 Nanobelts and the Origin of Facet-Dependent Photoreactivity.  

PubMed

Sword-like anatase TiO2 nanobelts exposed with 78?% clean {100} facets were synthesized and the facet-dependent photoreactivity of anatase TiO2 was investigated. By quantitative comparison with the reference {001} facets, the {100} facets possessed about ten-times higher active sites density than that on {001} facets, resulting in higher photoreaction efficiency. After the active sites density normalization, the {100} and {001} facets exhibited distinct wavelength-dependent photocatalytic performance, attributed to the anisotropic electronic structures in TiO2 crystals. PMID:25255881

Pan, Feng; Wu, Kai; Li, Hexing; Xu, Guoqin; Chen, Wei

2014-11-10

179

Synthesis of TiO 2 nanorods by oriented attachment using EDTA modifier: a novel approach towards 1D nanostructure development  

Microsoft Academic Search

The synthesis of TiO2 nanorods with anatase structure has been achieved from the necking of truncated nanoparticles by oriented attachment using\\u000a titanium ethylenediaminetetraacetic acid (EDTA) chelated complex as a molecular precursor. The preparation was carried out\\u000a under mild conditions using a simple solvothermal process. The influence of EDTA over the growth of nanocrystallites and the\\u000a various other factors which contribute

P. Dennis Christy; N. Melikechi; N. S. Nirmala Jothi; A. R. Baby Suganthi; P. Sagayaraj

2010-01-01

180

Influence of TiO2 on prebiotic thermal synthesis of the Gly-Gln polymer.  

PubMed

The role of the titanium dioxide (rutile and anatase) with and without room light on the thermal synthesis of the glycine-L-glutamine (Gly-Gln) polymer is described. The efficiency in percentage of polymerization with room light was increased in 6% in the presence of rutile and in 23% in the presence of anatase. The thermal synthesis in the molten state was carried out in the absence and presence of both oxides. In all cases, the vibrational spectra showed characteristic group frequencies corresponding to a polypeptide structure. No spectral differences were observed by room light effect on the polymer on rutile. However, the polymer obtained in the presence of anatase and room light shows spectral changes associated with the formation of shorter new abundant and conformationally different species compared with the original polymer. The SEM-EDX characterization of the solid phase involved in the thermal synthesis showed that the morphology of the polypeptide is different in the presence of rutile compared to anatase. The SDS-PAGE and GPC results suggest that smaller chains are formed in the presence of both oxides and the distribution of the size and weight of each polymer molecule is completely different when the condensation is performed in the presence of anatase or rutile. Nuclear magnetic resonance analyses confirmed the incorporation of both Gly and Gln residues in the polymers, with a prevalence of Gly. Both possible sequences N-GlyGln-C and N-GlnGly-C were also detected. PMID:21607746

Leyton, P; Saladino, R; Crestini, C; Campos-Vallette, M; Paipa, C; Berríos, A; Fuentes, S; Zárate, R A

2012-06-01

181

Photocatalytic performance of TiO2-zeolite templated carbon composites in organic contaminant degradation.  

PubMed

TiO2 composites with zeolite templated carbon (TiO2-ZTC) and activated carbon (TiO2-AC) were prepared and used as the photocatalysts for comparative studies with pure TiO2. TiO2-ZTC exhibited the highest rate of methylene blue degradation with a rate approximately 4 and 400 times higher than those of TiO2-AC and pure TiO2, respectively. Moreover, the highest catalytic performance of TiO2-ZTC in gas-phase degradation of acetone was approximately 1.1 and 12.9 times higher than TiO2-AC and pure TiO2, respectively. These outstanding performances could be attributed to high surface area, pore volume, and hydrophobic surface properties, leading to improvement in the adsorption properties of organic molecules. PMID:25328126

Donphai, Waleeporn; Kamegawa, Takashi; Chareonpanich, Metta; Nueangnoraj, Khanin; Nishihara, Hirotomo; Kyotani, Takashi; Yamashita, Hiromi

2014-10-22

182

Synthesis and visible light photocatalysis of Fe-doped TiO 2 mesoporous layers deposited on hollow glass microbeads  

NASA Astrophysics Data System (ADS)

Nano-composite of Fe-doped anatase TiO 2 nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition and calcining treatment. The adherence of TiO 2 mesoporous layers to the surfaces of hollow glass microbeads prevented the aggregation of TiO 2 nanoparticles and benefited to their catalytic activity. The doping of Fe ions makes the absorption edge of the TiO 2 based nano-composite red-shifted into the visible region. An effective photodegradation of the methyl orange aqueous solution was achieved under visible light ( ?>420 nm) irradiation, revealing the potential applicability of such nano-composite in some industry fields, such as air and water purifications.

Cui, Lifeng; Wang, Yuansheng; Niu, Mutong; Chen, Guoxin; Cheng, Yao

2009-10-01

183

Synthesis and photocatalytic activity of N-doped TiO2 produced in a solid phase reaction  

NASA Astrophysics Data System (ADS)

N-doped TiO2 was synthesized by calcining a mixture of titanic acid and graphitic carbon nitride (g-C3N4) at temperatures above 500 °C. The final samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and UV-vis diffuse reflectance spectra. The photocatalytic activity of N-doped TiO2 was studied by assessing the degradation of methylene blue in an aqueous solution, under visible light and UV light irradiation. It was found that the N-doped TiO2 displayed higher photocatalytic activity than pure TiO2, under both visible and UV light.

Xin, Gang; Pan, Hongfei; Chen, Dan; Zhang, Zhihua; Wen, Bin

2013-02-01

184

Synthesis and structure of Al clusters supported on TiO2,,110...: A scanning tunneling microscopy study  

E-print Network

­ceramic bonding, catalysis and sensor application,1­3 therefore extensive work has addressed the nucleation thermocouple, which was glued onto the edge of the TiO2 crystal using a high temperature ceramic adhesive

Goodman, Wayne

185

Synthesis of a CNT-grafted TiO2 nanocatalyst and its activity triggered by a DC voltage  

Microsoft Academic Search

Carbon nanotube (CNT)-grafted TiO2 (CNT\\/TiO2) was synthesized as an electrically conductive catalyst that exhibits redox ability under electrical excitation besides ultraviolet (UV) irradiation. The CNT\\/TiO2 material was synthesized by a two-step process. Ni nanoparticles were photodeposited onto TiO2 first. The Ni nanoparticles then served as seeds for the growth of CNTs using the chemical vapor deposition (CVD) of C2H2. The

Chien-Sheng Kuo; Yao-Hsuan Tseng; Hong-Ying Lin; Chia-Hung Huang; Chih-Yen Shen; Yuan-Yao Li; S. Ismat Shah; Chin-Pao Huang

2007-01-01

186

Synthesis of uniform anatase TiO2 nanoparticles by gel-sol method. 3. Formation process and size control.  

PubMed

Uniform anatase-type TiO(2) nanoparticles were prepared by the gel-sol process from a condensed Ti(OH)(4) gel preformed by the hydrolysis of a Ti-triethanolamine (TEOA) complex. The particle size of the anatase TiO(2) was increased from ca. 5 to 30 nm with pH increasing from 0.6 to 12 by aging the Ti(OH)(4) gel at 140 degrees C for 72 h, while the yield of the anatase TiO(2), 100% below pH 9.6, started to decrease from pH 10, to 67% at pH 11.5 and only 9% at pH 12.2. These results reveal a significant reduction of the nucleation rate of the anatase TiO(2) with increasing pH, as is explained by the reduction of the concentration of a precursor complex, Ti(OH)(3)(+), and the adsorption of hydroxide ion onto the embryos of TiO(2). Triethanolamine appeared to enhance the pH effect on the nucleation rate of anatase TiO(2) particles by adsorption onto their embryos, leading to the wide range of the size control. Triethanolamine was also found to act as a shape controller of the anatase TiO(2) particles for yielding ellipsoidal particles from Ti(OH)(4) gel at a relatively high pH above 11. The particle size was also controlled by seeding of anatase TiO(2). Moreover, the seeding experiment suggested that the rate-determining step of the gel-sol process was not the dissolution of the hydroxide gel, but the deposition of the monomeric precursor from the solution phase. PMID:12651132

Sugimoto, Tadao; Zhou, Xingping; Muramatsu, Atsushi

2003-03-01

187

Solvothermal synthesis and enhanced photocatalytic activity of flowerlike nanoarchitectures assembled from anatase TiO2 nanoflakes  

NASA Astrophysics Data System (ADS)

TiO2 nanoflakes assembled flowerlike nanoarchitectures with diameters of 1.70-2.20 ?m were synthesized by a solvothermal reaction of butyl titanate with isopropyl alcohol, HF and H2O at 180 °C for 12 h. The constituent nanoflakes have perfect rectangular shapes with the typical widths of 0.81-0.95 ?m, lengths of 1.04-1.20 ?m and thicknesses of 0.10-0.12 ?m. The constituent nanoflakes are formed due to the selective adsorption of isopropyl alcohol on (0 1 0) surface of anatase TiO2. These anatase TiO2 nanoflakes assemble into flowerlike structures driven by the electrostatic attraction. The as-prepared TiO2 flowerlike nanoarchitectures exhibit enhanced photocatalytic ability to degrade methyl orange dye in comparison with commercial TiO2 powders. The photodegradation of methyl orange dye catalyzed by the anatase TiO2 nanoflake assembled flowerlike nanostructures fits a pseudo first-order reaction.

Cui, Meng; Tian, Sha; Zhao, Hua; Jin, Rong; Chen, Yan; Liu, Bin; Yang, Heqing

2012-07-01

188

Synthesis and photolysis of NaYF4@SiO2@TiO2 core-shell nanocomposites  

NASA Astrophysics Data System (ADS)

Monodisperse ?-NaYF4 nanocrystals were synthesized with oleic acid as capping ligands by solvothermal method, and then, SiO2 and TiO2 were coated successively. Intense ultraviolet light is emitted from NaYF4:Yb/Tm under the 980 nm laser and the intensity of ultraviolet light reduce dramatically after these nanocrystals were coated with SiO2 and TiO2 shells, which means NaYF4@SiO2@TiO2 core-shell nanocomposites can be used to realize the infared photocatalysis. Photocatalytic activity of these nanocomposites is demonstrated using methyl orange (MO) as a chemical probe under the 980 nm laser excitation.

Shi, Guoyou; Mao, Yifu; Ren, Guozhong; Gong, Lunjun; Zhi, Zhugong

2014-12-01

189

Modified microwave method for the synthesis of visible light-responsive TiO2/MWCNTs nanocatalysts  

NASA Astrophysics Data System (ADS)

Recently, TiO2/multi-walled carbon nanotube (MWCNT) hybrid nanocatalysts have been a subject of high interest due to their excellent structures, large surface areas and peculiar optical properties, which enhance their photocatalytic performance. In this work, a modified microwave technique was used to rapidly synthesise a TiO2/MWCNT nanocatalyst with a large surface area. X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller measurements were used to characterise the structure, morphology and the surface area of the sample. The photocatalytic activity of the hybrid nanocatalysts was evaluated through a comparison of the degradation of methylene blue dye under irradiation with ultraviolet and visible light. The results showed that the TiO2/MWCNT hybrid nanocatalysts degraded 34.9% of the methylene blue (MB) under irradiation with ultraviolet light, whereas 96.3% of the MB was degraded under irradiation with visible light.

Alosfur, Firas K. Mohamad; Jumali, Mohammad Hafizuddin Haji; Radiman, Shahidan; Ridha, Noor J.; Yarmo, Mohd Ambar; Umar, Akrajas Ali

2013-08-01

190

Modified microwave method for the synthesis of visible light-responsive TiO2/MWCNTs nanocatalysts.  

PubMed

Recently, TiO2/multi-walled carbon nanotube (MWCNT) hybrid nanocatalysts have been a subject of high interest due to their excellent structures, large surface areas and peculiar optical properties, which enhance their photocatalytic performance. In this work, a modified microwave technique was used to rapidly synthesise a TiO2/MWCNT nanocatalyst with a large surface area. X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller measurements were used to characterise the structure, morphology and the surface area of the sample. The photocatalytic activity of the hybrid nanocatalysts was evaluated through a comparison of the degradation of methylene blue dye under irradiation with ultraviolet and visible light. The results showed that the TiO2/MWCNT hybrid nanocatalysts degraded 34.9% of the methylene blue (MB) under irradiation with ultraviolet light, whereas 96.3% of the MB was degraded under irradiation with visible light. PMID:23919496

Alosfur, Firas K Mohamad; Jumali, Mohammad Hafizuddin Haji; Radiman, Shahidan; Ridha, Noor J; Yarmo, Mohd Ambar; Umar, Akrajas Ali

2013-01-01

191

Synthesis and visible light photocatalytic properties of polyoxometalate-thionine composite films immobilized on porous TiO2 microspheres.  

PubMed

Multilayer films (PW(12)-TH)(n) (PW(12)=PW(12)O(40)(3-), TH=thionine) were immobilized on porous anatase TiO(2) microspheres by layer-by-layer (LbL) self-assembly method. The porous structure of TiO(2) was confirmed by transmission electron microscopy (TEM). Scanning electron microscopy (SEM) showed that TiO(2) template particles had a round shape with an average diameter of 250 nm. The composite films were characterized by FTIR spectroscopy, UV diffuse reflectance spectroscopy and XRD spectroscopy. The results confirmed the successful immobilization of (PW(12)-TH)(n) composite films onto TiO(2) microspheres, and the growth of PW(12)-TH layer pair was uniform. SEM and TEM were also used to characterize the morphology. When PW(12)-TH composite films were assembled on the template, the surface became rougher with the increasing number of layer pair. The lattice fringe of TiO(2) became weaker when immobilized (PW(12)-TH)(n). The photocatalytic properties of the microspheres toward a rhodamine B (RhB) solution were investigated under visible light irradiation. The combination of TiO(2) and PW(12) showed an excellent photocatalytic performance. Both TH sensitization and PW(12) adsorption played important roles during the process of photocatalysis. Moreover, the catalytic property and reusability of as-prepared catalyst were relevant to the number of PW(12)-TH bilayer. The kinetics of the photodecomposition to rhodamine B followed the first-order reaction. PMID:22425252

Yang, Zhen; Gao, Shuiying; Li, Hongfang; Cao, Rong

2012-06-01

192

Synthesis of a CNT-grafted TiO2 nanocatalyst and its activity triggered by a DC voltage  

NASA Astrophysics Data System (ADS)

Carbon nanotube (CNT)-grafted TiO2 (CNT/TiO2) was synthesized as an electrically conductive catalyst that exhibits redox ability under electrical excitation besides ultraviolet (UV) irradiation. The CNT/TiO2 material was synthesized by a two-step process. Ni nanoparticles were photodeposited onto TiO2 first. The Ni nanoparticles then served as seeds for the growth of CNTs using the chemical vapor deposition (CVD) of C2H2. The CNT/TiO2 nanocomposite exhibits strong oxidation activity toward NO gas molecules via both photocatalysis under UV irradiation and electrocatalysis under a DC voltage of 500 V in dark conditions.

Kuo, Chien-Sheng; Tseng, Yao-Hsuan; Lin, Hong-Ying; Huang, Chia-Hung; Shen, Chih-Yen; Li, Yuan-Yao; Shah, S. Ismat; Huang, Chin-Pao

2007-11-01

193

TiO2-ITO and TiO2-ZnO nanocomposites: application on water treatment  

NASA Astrophysics Data System (ADS)

One of the most promising ideas to enhance the photocatalytic efficiency of the TiO2 is to couple this photocatalyst with other semiconductors. In this work, we report on the development of photo-catalytic properties of two types of composites based on TiO2 - ITO (Indium Tin Oxide) and TiO2 - ZnO deposited on conventional ceramic substrates. The samples were characterized by X-ray diffraction (XRD) and transmission Electron Microscopy (TEM). The photo-catalytic test was carried out under UV light in order to reduce/oxidize a typical textile dye (Cibacron Yellow). The experiment was carried out in a bench scale reactor using a solution having a known initial dye concentration. After optimization, we found that both nanocomposites exhibit better photocatalytic activity compared to the standard photocatalyst P25 TiO2.

Chorfi, H.; Saadoun, M.; Bousselmi, L.; Bessais, B.

2012-06-01

194

Synthesis of Au/TiO2 Core-Shell Nanoparticles from Titanium Isopropoxide and Thermal Resistance Effect of TiO2 Shell  

NASA Astrophysics Data System (ADS)

On the synthesis of Au/TiO2 core-shell structure nanoparticles, the effect of the concentration of Ti4+ on the morphology and optical property of Au/TiO2 core-shell nanoparticles was examined. A gold colloid was prepared by mixing HAuCl4\\cdot4H2O and C6H5Na3\\cdot2H2O. Titanium stock solution was prepared by mixing solutions of titanium(IV) isopropoxide (TTIP) and triethanolamine (TEOA). The concentration of the Ti4+ stock solution was adjusted to 0.01-0.3 mM, and then the gold colloid was added to the Ti4+ stock solution. Au/TiO2 core-shell structure nanoparticles could be prepared by the hydrolysis of the Ti4+ stock solution at 80 °C. The size of the as-prepared Au nanoparticles was 15 nm. The thickness of the TiO2 shell on the surface of gold particles was about 10 nm. The absorption peak of the Au/TiO2 core-shell nanoparticles shifted towards the red end of the spectrum by about 3 nm because of the formation of the TiO2 shell on the surface of the gold particles. The crystal structure of the TiO2 shell showed an anatase phase. The increase in the Au crystallite size of the Au/TiO2 nanoparticles with increasing heat treatment temperature is smaller than that in the pure Au nanoparticles. This may be due to the encapsulation of Au particles with the TiO2 shell that prevents the growth of the nanoparticle nucleation.

Kwon, Hyun-Woo; Lim, Young-Min; Tripathy, Suraj Kumar; Kim, Byoung-Gyu; Lee, Min-Sang; Yu, Yeon-Tae

2007-04-01

195

Photocatalytic degradation of methyl orange over nitrogen-fluorine codoped TiO2 nanobelts prepared by solvothermal synthesis.  

PubMed

Anatase type nitrogen-fluorine (N-F) codoped TiO(2) nanobelts were prepared by a solvothermal method in which amorphous titania microspheres were used as the precursors. The as-prepared TiO(2) nanobelts are composed of thin narrow nanobelts and it is noted that there are large amount of wormhole-like mesopores on these narrow nanobelts. Photocatalytic activity of the N-F codoped TiO(2) nanobelts was measured by the reaction of photocatalytic degradation of methyl orange. Results indicate that the photocatalytic activity of the N-F codoped TiO(2) nanobelts is higher than that of P25, which is mainly ascribed to wormhole-like mesopores like prison, larger surface area, and enhanced absorption of light due to N-F codoping. Interestingly, it is also found that the photocatalytic activity can be further enhanced when tested in a new testing method because more photons can be captured by the nanobelts to stimulate the formation of the hole-electron pair. PMID:23148575

He, Zuoli; Que, Wenxiu; Chen, Jing; Yin, Xingtian; He, Yucheng; Ren, Jiangbo

2012-12-01

196

Synthesis and visible light photoactivity of anatase Ag, and garlic loaded TiO2 nanocrystalline catalyst  

EPA Science Inventory

An excellent visible light activated Ag and S doped TiO2 nanocatalyst was prepared by using AgNO3 and garlic (Allium sativum) as Ag+ and sulfur sources, respectively. The catalyst resisted the change from anatase to rutile phase even at calcination at 700 oC. The photocatalytic e...

197

Synthesis, phase to phase deposition and characterization of rutile nanocrystalline titanium dioxide (TiO2) thin films  

NASA Astrophysics Data System (ADS)

In this work the preparation, deposition and structural properties of titanium oxide (TiO2) thin films were investigated. The films were deposited by means of the e-beam physical vapor deposition (EBPVD) method in high vacuum (10-7 Torr). A controlled deposition rate in the range of 0.1-0.3 Å/s was monitored in situ employing quartz crystal. The films were deposited on the oxidized Si (1 0 0) wafer, glass micro slides. These films were analyzed using Grazing Angle X-ray diffraction (GA-XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy (RAMAN), Atomic Force Microscopy (AFM) and UV-visible Spectroscopy (UV-vis). Structural characterization results showed mainly presence of the crystalline rutile phase, however an interfacial SiO2 layer between TiO2 and the substrate and the minor anatase crystalline phase of TiO2 was also identified in FTIR analysis. Grain size was found to be in the range of 100-125 nm while grain boundary was estimated to be 20 nm. Direct and indirect optical band gap was estimated to be 3.64 and 3.04 eV, respectively. A process induced self annealing of deposited film shows a strong effect on the structural, morphological and optical properties. Furthermore, low deposition rate and high vacuum allows rutile to rutile phase transformation from indigenously prepared TiO2 target to thin film.

Gupta, Sanjeev K.; Singh, Jitendra; Anbalagan, K.; Kothari, Prateek; Bhatia, Ravi Raj; Mishra, Pratima K.; Manjuladevi, V.; Gupta, Raj K.; Akhtar, J.

2013-01-01

198

Synthesis of TiO2 nanotubes with ZnO nanoparticles to achieve antibacterial properties and stem cell compatibility  

NASA Astrophysics Data System (ADS)

To endow titanium (Ti) with antibacterial properties, different concentrations of zinc oxide (ZnO) nanoparticles were decorated on anodized titanium dioxide (TiO2) nanotubes by a simple hydrothermal treatment method. The particle sizes of ZnO, which were evenly distributed and tightly adherent to the walls of the Ti nanotubes, ranged from 20-50 nm. Results from this study showed that Zn was released from the TiO2 nanotubes in a constant, slow, and biologically inspired manner. Importantly, the results showed that the ZnO decorated TiO2 nanotubular samples inhibited Streptococcus mutants and Porphyromonas gingivalis growth compared to control unmodified Ti samples. Specifically, S. mutants and P. gingivalis growth were both reduced 45-85% on the ZnO decorated Ti samples compared to Ti controls after 7 days of culture. When examining the mechanism of action, it has been further found for the first time that the ZnO decorated Ti samples inhibited the expression of Streptococcus mutans bacterial adhesion genes. Lastly, the results showed that the same samples which decreased bacterial growth the most (0.015 M precursor Zn(NO3)2 samples) did not inhibit mesenchymal stem cell growth compared to Ti controls for up to 7 days. In summary, results from this study showed that compared to plain TiO2 nanotubes, TiO2 decorated with 0.015 M ZnO provided unprecedented antibacterial properties while maintaining the stem cell proliferation capacity necessary for enhancing the use of Ti in numerous medical applications, particularly in dentistry.

Liu, Wenwen; Su, Penglei; Chen, Su; Wang, Na; Ma, Yuanping; Liu, Yiran; Wang, Jinshu; Zhang, Zhenting; Li, Hongyi; Webster, Thomas J.

2014-07-01

199

Non-solvolytic synthesis of aqueous soluble TiO2 nanoparticles and real-time dynamic measurements of the nanoparticle formation  

E-print Network

, Montgomery SA: Efficient microwave hydrothermal preparation of nanocrystalline anatase TiO2 colloids. J Mater Chem 2002, 12:1787–1791.Submit your manuscript to a journal and benefi t from: 7 Convenient online submission 7 Rigorous peer review 7 Immediate... on the solvent used as the reactant in the first step, it can be described as hydrolysis (reaction with water) [22-25], alcoholysis (reaction with alcohols) [26-28], and ammonolysis (reaction with ammonium ions) [29,30]. The synthesis reaction and subsequent...

Chen, Lan; Rahme, Kamil; Holmes, Justin D; Morris, Michael A; Slater, Nigel KH

2012-06-07

200

Synthesis of the double-shell anatase-rutile TiO2 hollow spheres with enhanced photocatalytic activity  

NASA Astrophysics Data System (ADS)

A novel double-shell TiO2 hollow sphere with an inner anatase shell and an outer rutile shell was synthesized by a simple sol-gel method and silica protected calcination process. The structure and formation mechanism was proposed based on characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The double-shell spheres have a uniform diameter of 360 nm and a typical yolk-shell structure. Moreover, the double-shell TiO2 hollow spheres possess a large specific surface area (169 m2 g-1). Due to the high surface area, multiple light reflection and beneficial electron conduction between the inner anatase and outer rutile shell of this special structure, the as-prepared double-shell TiO2 catalysts show remarkably enhanced photoactivity compared to the commercial P25 catalyst. In particular, rhodamine B molecules can be completely decomposed in the presence of the double-shell spheres after 60 minutes of irradiation with UV light. In addition, the high activity is retained after five cycles, indicating the stability and reusability of the double-shell catalyst.A novel double-shell TiO2 hollow sphere with an inner anatase shell and an outer rutile shell was synthesized by a simple sol-gel method and silica protected calcination process. The structure and formation mechanism was proposed based on characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The double-shell spheres have a uniform diameter of 360 nm and a typical yolk-shell structure. Moreover, the double-shell TiO2 hollow spheres possess a large specific surface area (169 m2 g-1). Due to the high surface area, multiple light reflection and beneficial electron conduction between the inner anatase and outer rutile shell of this special structure, the as-prepared double-shell TiO2 catalysts show remarkably enhanced photoactivity compared to the commercial P25 catalyst. In particular, rhodamine B molecules can be completely decomposed in the presence of the double-shell spheres after 60 minutes of irradiation with UV light. In addition, the high activity is retained after five cycles, indicating the stability and reusability of the double-shell catalyst. Electronic supplementary information (ESI) available: UV-vis diffuse reflection spectra and the summarisation of BET surface and average pore size. See DOI: 10.1039/c3nr04043g

Li, Shunxing; Chen, Jie; Zheng, Fengying; Li, Yancai; Huang, Fuying

2013-11-01

201

Preparation and performance of photocatalytic TiO 2 immobilized on palladium-doped carbon fibers  

NASA Astrophysics Data System (ADS)

Pd-modified carbon fibers (CFs) are obtained by a facile oxidation-reduction method and then dip-coated in a sol-gel of titanium dioxide (TiO 2) to form supported TiO 2/Pd-CF photocatalysts. The morphology of the Pd-modified CFs and the amount Pd deposited are characterized by field emission scanning electron microscopy and atomic absorption spectrometry, respectively. X-ray diffraction is used to investigate the crystal structures of the TiO 2 photocatalyst. Acid orange II is used as a model contaminant to evaluate the photocatalytic properties of the photocatalyst under UV irradiation. TiO 2/Pd-CF exhibits higher catalytic activity than TiO 2/CF towards the degradation of acid orange II. Optimum photocatalytic performance and support properties are achieved when the Pd particle loading is about 10.8 mg/g.

Zhu, Yaofeng; Fu, Yaqin; Ni, Qing-Qing

2011-01-01

202

Synthesis of a CNT-grafted TiO(2) nanocatalyst and its activity triggered by a DC voltage.  

PubMed

Carbon nanotube (CNT)-grafted TiO(2) (CNT/TiO(2)) was synthesized as an electrically conductive catalyst that exhibits redox ability under electrical excitation besides ultraviolet (UV) irradiation. The CNT/TiO(2) material was synthesized by a two-step process. Ni nanoparticles were photodeposited onto TiO(2) first. The Ni nanoparticles then served as seeds for the growth of CNTs using the chemical vapor deposition (CVD) of C(2)H(2). The CNT/TiO(2) nanocomposite exhibits strong oxidation activity toward NO gas molecules via both photocatalysis under UV irradiation and electrocatalysis under a DC voltage of 500 V in dark conditions. PMID:21730487

Kuo, Chien-Sheng; Tseng, Yao-Hsuan; Lin, Hong-Ying; Huang, Chia-Hung; Shen, Chih-Yen; Li, Yuan-Yao; Ismat Shah, S; Huang, Chin-Pao

2007-11-21

203

Photoelectrochemical synthesis, optical properties and plasmon-induced charge separation behaviour of gold nanodumbbells on TiO2.  

PubMed

Chemically synthesized, commercially available Au nanorods were adsorbed on a TiO2 thin film, and photoelectrochemically transformed to Au nanodumbbells by photoelectrochemical deposition of Au at both ends of the NRs under UV irradiation. The nanodumbbells show about fourfold greater light absorption than the nanorods based on localized surface plasmon resonance (LSPR) in the visible to near infrared region. The absorption intensities and wavelengths of the Au nanodumbbells depend on the size of their spheroidal caps, which can be controlled by UV exposure time. The nanodumbbells can be applied to LSPR sensors, as their absorption peak redshifts with increasing local refractive index near the metal surface. The Au nanodumbbells on TiO2 are also suitable for photofunctional materials and devices based on plasmon-induced charge separation (PICS) at the Au-TiO2 interface, because of their higher photoabsorption intensity, better wavelength tunability and greater PICS efficiency than nanorods. PMID:25350687

Katagi, Yu; Kazuma, Emiko; Tatsuma, Tetsu

2014-11-01

204

Room-Temperature Synthesis of Iron-Doped Anatase TiO2 for Lithium-Ion Batteries and Photocatalysis.  

PubMed

Iron-doped nanocrystalline particles of anatase TiO2 (denoted x% Fe-TiO2, with x the nominal [Fe] atom % in solution) have been successfully synthesized at room temperature by a controlled two-step process. Hydrolysis of titanium isopropoxide is first achieved to precipitate Ti(OH)4 species. A fine control of the pH allows one to maintain (i) soluble iron species and (ii) a sluggish solubility of Ti(OH)4 to promote a dissolution and condensation of titanium clusters incorporating iron, leading to the precipitation of iron-doped anatase TiO2. The pH does then influence both the nature and crystallinity of the final phase. After 2 months of aging at pH = 2, well-dispersed nanocrystalline iron-doped TiO2 particles have been achieved, leading to 5-6 nm particle size and offering a high surface area of ca. 280 m(2)/g. This dissolution/recrystallization process allows the incorporation of a dopant concentration of up to 7.7 atom %; the successful incorporation of iron in the structure is demonstrated by X-ray diffraction, high-resolution transmission electron microscopy, and Mössbauer spectroscopy. This entails optical-band-gap narrowing from 3.05 to 2.30 eV. The pros and cons effects of doping on the electrochemical properties of TiO2 versus lithium are herein discussed. We reveal that doping improves the power rate capability of the electrode but, in turn, deserves the electrolyte stability, leading to early formation of SEI. Finally, we highlight a beneficial effect of low iron introduction into the anatase lattice for photocatalytic applications under standard AM1.5G visible-light illumination. PMID:25211065

Andriamiadamanana, Christian; Laberty-Robert, Christel; Sougrati, Moulay T; Casale, Sandra; Davoisne, Carine; Patra, Snehangshu; Sauvage, Frédéric

2014-10-01

205

A simple, template-free route for the synthesis of bicrystalline mesoporous TiO2 materials.  

PubMed

A simple, low-temperature and green template-free synthetic route has been used to prepare mesoporous TiO2 with anatase and brookite bicrystalline framework. This route combines a quick hydrolysis at ambient temperature and sequent hydrothermal treatment at 80-180 egrees C without further calcination. The resultant materials were characterized by XRD, TEM and nitrogen adsorption. It was found that the wormhole-like mesostructure and the bicrystalline framework could be formed in the hydrothermal treatment, and high surface areas of 160-250 m2 x g(-1) could be obtained due to the avoidance of calcination at high temperature. The effect of hydrothermal temperature on mesoporosity and crystallinity was also investigated and discussed. The as-prepared TiO2 samples exhibited higher photocatalytic activities than pure anatase TiO2 and corresponding calcined samples in the degradation of methyl orange, which can be attributed to the combined effect of composite crystalline phase and high surface area. PMID:19908583

Su, Zhili; Yang, Chun

2009-11-01

206

Biodiesel synthesis by TiO2-ZnO mixed oxide nanocatalyst catalyzed palm oil transesterification process.  

PubMed

Biodiesel is a promising alternating environmentally benign fuel to mineral diesel. For the development of easier transesterification process, stable and active heterogeneous mixed metal oxide of TiO2-ZnO and ZnO nanocatalysts were synthesized and exploited for the palm oil transesterification process. The synthesized catalysts were characterized by XRD, FT-IR, and FE-SEM studies for their structural and morphological characteristics. It was found that TiO2-ZnO nanocatalyst exhibits good catalytic activity and the catalytic performance was greatly depends on (i) catalyst concentration (ii) methanol to oil molar ratio (iii) reaction temperature and (iv) reaction time. A highest 98% of conversion was obtained at the optimum reaction parameters with 200 mg of catalyst loading and the biodiesel was analyzed by TLC and (1)H NMR techniques. The TiO2-ZnO nanocatalyst shows good catalytic performance over the ZnO catalyst, which could be a potential candidate for the large-scale biodiesel production from palm oil at the reduced temperature and time. PMID:24148858

Madhuvilakku, Rajesh; Piraman, Shakkthivel

2013-12-01

207

CuInS2 quantum dot-sensitized TiO2 nanorod array photoelectrodes: synthesis and performance optimization.  

PubMed

CuInS2 quantum dots (QDs) were deposited onto TiO2 nanorod arrays for different cycles by using successive ionic layer adsorption and reaction (SILAR) method. The effect of SILAR cycles on the light absorption and photoelectrochemical properties of the sensitized photoelectrodes was studied. With optimization of CuInS2 SILAR cycles and introduction of In2S3 buffer layer, quantum dot-sensitized solar cells assembled with 3-?m thick TiO2 nanorod film exhibited a short-circuit current density (Isc) of 4.51 mA cm-2, an open-circuit voltage (Voc) of 0.56 V, a fill factor (FF) of 0.41, and a power conversion efficiency (?) of 1.06%, respectively. This study indicates that SILAR process is a very promising strategy for preparing directly anchored semiconductor QDs on TiO2 nanorod surface in a straightforward but controllable way without any complicated fabrication procedures and introduction of a linker molecule. PMID:23181940

Zhou, Zhengji; Yuan, Shengjie; Fan, Junqi; Hou, Zeliang; Zhou, Wenhui; Du, Zuliang; Wu, Sixin

2012-01-01

208

Synthesis and photoelectrochemical response of CdS quantum dot-sensitized TiO2 nanorod array photoelectrodes  

PubMed Central

A continuous and compact CdS quantum dot-sensitive layer was synthesized on TiO2 nanorods by successive ionic layer adsorption and reaction (SILAR) and subsequent thermal annealing. The thickness of the CdS quantum dot layer was tuned by SILAR cycles, which was found to be closely related to light absorption and carrier transformation. The CdS quantum dot-sensitized TiO2 nanorod array photoelectrodes were characterized by scanning electron microscopy, X-ray diffraction, ultraviolet–visible absorption spectroscopy, and photoelectrochemical property measurement. The optimum sample was fabricated by SILAR in 70 cycles and then annealed at 400°C for 1 h in air atmosphere. A TiO2/CdS core-shell structure was formed with a diameter of 35 nm, which presented an improvement in light harvesting. Finally, a saturated photocurrent of 3.6 mA/cm2 was produced under the irradiation of AM1.5G simulated sunlight at 100 mW/cm2. In particular, the saturated current density maintained a fixed value of approximately 3 mA/cm2 without decadence as time passed under the light conditions, indicating the steady photoelectronic property of the photoanode. PMID:23663590

2013-01-01

209

CuInS2 quantum dot-sensitized TiO2 nanorod array photoelectrodes: synthesis and performance optimization  

PubMed Central

CuInS2 quantum dots (QDs) were deposited onto TiO2 nanorod arrays for different cycles by using successive ionic layer adsorption and reaction (SILAR) method. The effect of SILAR cycles on the light absorption and photoelectrochemical properties of the sensitized photoelectrodes was studied. With optimization of CuInS2 SILAR cycles and introduction of In2S3 buffer layer, quantum dot-sensitized solar cells assembled with 3-?m thick TiO2 nanorod film exhibited a short-circuit current density (Isc) of 4.51 mA cm?2, an open-circuit voltage (Voc) of 0.56 V, a fill factor (FF) of 0.41, and a power conversion efficiency (?) of 1.06%, respectively. This study indicates that SILAR process is a very promising strategy for preparing directly anchored semiconductor QDs on TiO2 nanorod surface in a straightforward but controllable way without any complicated fabrication procedures and introduction of a linker molecule. PMID:23181940

2012-01-01

210

Direct electrochemistry of horseradish peroxidase on TiO(2) nanotube arrays via seeded-growth synthesis.  

PubMed

Horseradish peroxidase (HRP) was successfully immobilized on vertically oriented TiO(2) nanotube arrays (NTAs), which was prepared by a seeded-growth mechanism. The nanotubular structure of TiO(2) was characterized by scanning electron microscope (SEM). After encapsulated HRP on TiO(2) nanotube arrays, the direct electron transfer of HRP was observed. Owing to the redox reaction of electroactive center of HRP, the HRP/TiO(2) NTAs modified electrode exhibited a pair of quasi-reversible peaks with the peak-to-peak separation of 70 mV and the formal potential of -0.122 V (vs. SCE) in 0.2mol L(-1) phosphate buffer solution (PBS, pH 7.0). The number of transference electron was 0.84 and the direct electron transfer (ET) constant (k(s)) was 3.82 s(-1). The HRP/TiO(2) NTAs modified electrode displayed an excellent electrocatalytic performance for H(2)O(2) and the formal Michaelis-Menten constant (K(m)(app)) was 1.9 mmol L(-1). The response currents had a good linear relation with the concentration of H(2)O(2) from 5.0 x 10(-7) mol L(-1) to 1.0 x 10(-5) mol L(-1) and 5.0 x 10(-5) mol L(-1) to 1.0 x10(-3) mol L(-1), respectively. PMID:18485691

Wu, Fanghua; Xu, Jingjing; Tian, Yuan; Hu, Zhichao; Wang, Liwei; Xian, Yuezhong; Jin, Litong

2008-10-15

211

Synthesis and characterization of rice grains like Nitrogen-doped TiO 2 nanostructures by electrospinning–photocatalysis  

Microsoft Academic Search

Rice grain-shaped Nitrogen-doped titanium dioxide (N–TiO2) nano\\/mesostructures were fabricated through a combination of sol–gel and electrospinning methods. As-spun nanofibers were continuous and upon thermal treatment at 500°C for 1h in air, the continuous fibers break into rice grain-shaped TiO2 nanostructures of average diameter 50–80nm. The nanostructures were characterized by spectroscopy, microscopy and powder X-ray diffraction. The rice grains consist of

Veluru Jagadeesh Babu; Appukuttan Sreekumaran Nair; Zhu Peining; Seeram Ramakrishna

2011-01-01

212

TiO2 nanorods: a facile size- and shape-tunable synthesis and effective improvement of charge collection kinetics for dye-sensitized solar cells.  

PubMed

In this paper, we present a novel, high-yield, and cost-effective hydrothermal method for the preparation of single crystal-like anatase TiO2 nanorods (NRs) with specific {101} exposed crystal planes and preferred [001] growth direction, which is governed by the "oriented attachment" mechanism. The successful synthesis of TiO2 NRs and fine tuning on their size and shape could be easily accomplished by adjusting the solvent compositions. The salient feature of these NRs, in lieu of traditional nanoparticles as building blocks of photoanodes in dye-sensitized solar cell (DSSC) system, rests with their significantly reduced grain boundaries. The electron diffusion and recombination kinetics have been critically compared for the first time with respect to the size and shape of the novel building blocks. A high efficiency of 8.87% has finally been achieved for DSSC based on long-thin NRs rather than short-thin or long-thick NRs, which possesses balanced optimizations on charge collection and light-harvesting properties. PMID:24833257

Zhang, Wenjun; Xie, Yan; Xiong, Dehua; Zeng, Xianwei; Li, Zhihong; Wang, Mingkui; Cheng, Yi-Bing; Chen, Wei; Yan, Keyou; Yang, Shihe

2014-06-25

213

Synthesis of crystalline TiO 2 nanostructure arrays by direct microwave irradiation on a metal substrate  

NASA Astrophysics Data System (ADS)

We report a method for synthesizing TiO 2 nanostructures by applying microwave irradiation (1200 W, 2.45 GHz, single-mode) to a Ti substrate under an atmosphere comprising of O 2 and Ar. After 1200 W microwave irradiation, one-dimensional (1D) nanostructure arrays were synthesized on the surface of the substrate. The average dimensions of the 1D structures were 200 nm in length and 30 nm in diameter. The structures were single crystalline. The EDX elemental maps of the areas examined using HAADF-STEM demonstrated that Ti and O were distributed homogeneously throughout the nanostructure. Quantitative analysis of the mean atomic ratios in the nanostructures disclosed a Ti:O ratio of 0.331:0.669. XPS analysis demonstrated that the predominant oxidation state of Ti in the samples was +4. On the basis of these results, we propose a possible mechanism for the formation of the TiO 2 nanostructures via microwave irradiation.

Cho, Seungho; Lee, Kun-Hong

2010-04-01

214

Tuning TiO2 nanoparticle morphology in graphene-TiO2 hybrids by graphene surface modification  

NASA Astrophysics Data System (ADS)

We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as a shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shapes and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted truncated bipyramids, bonded to graphene via the {100} facets. Belted truncated bipyramids formed on unfunctionalized GNP too, however the NPs were more irregular and rounded. These effects were ascribed to pH variations in the proximity of the functionalized GNP sheets, due to the high density of COOH or NH2 groups. Because of the different reactivity of anatase {100} and {101} crystalline facets, we hypothesize that the hybrid materials will behave differently as photocatalysts, and that the COOH-GNP-TiO2 hybrids will be better photocatalysts for water splitting and H2 production.We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as a shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shapes and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted truncated bipyramids, bonded to graphene via the {100} facets. Belted truncated bipyramids formed on unfunctionalized GNP too, however the NPs were more irregular and rounded. These effects were ascribed to pH variations in the proximity of the functionalized GNP sheets, due to the high density of COOH or NH2 groups. Because of the different reactivity of anatase {100} and {101} crystalline facets, we hypothesize that the hybrid materials will behave differently as photocatalysts, and that the COOH-GNP-TiO2 hybrids will be better photocatalysts for water splitting and H2 production. Electronic supplementary information (ESI) available: Statistical analysis of the D : G intensity ratio, additional XPS analysis and TEM micrographs. See DOI: 10.1039/c4nr01322k

Sordello, Fabrizio; Zeb, Gul; Hu, Kaiwen; Calza, Paola; Minero, Claudio; Szkopek, Thomas; Cerruti, Marta

2014-05-01

215

Room temperature synthesis of nanocrystalline anatase sols and preparation of uniform nanostructured TiO2 thin films: optical and structural properties  

Microsoft Academic Search

Transparent TiO2 thin films were deposited on soda-lime glass substrates via the sol-gel method using a nanocrystalline TiO2 sol solution prepared at room temperature employing the dip-coating method. The effects of pH on crystallinity, particle size and stability of the synthesized TiO2 sols were investigated, systematically. TiO2 thin films were thickened by means of a sequential dip-coating process. The TiO2

M. Hosseingholi; M. Pazouki; A. Hosseinnia; S. H. Aboutalebi

2011-01-01

216

Laponite-supported titania photocatalysts.  

E-print Network

??This thesis describes the synthesis and characterisation of titania photocatalysts for incorporation into a polyethylene film. Monodisperse, anatase-phase titania nanoparticles are prepared and the synthesis… (more)

Daniel, Lisa Maree

2007-01-01

217

Synthesis of TiO2 nanotube arrays and its application in mini-3D dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Here we report a mini-three-dimensional dye-sensitized solar cell (3D DSSC) based on TiO2 nanotube arrays (TNAs). TNAs were directly grown on spiral-shaped titanium wire via a facile potentiostatic anodization. Furthermore, the TNAs film was characterized by scanning electron microscopy, x-ray diffraction and transmission electron microscopy, indicating that the annealed TNAs were composed of single-crystalline anatase particles. Unlike conventional flat DSSC, this mini-3D DSSC could easily hold liquid electrolyte due to the capillary force which facilitated sealing the cell. This mini-3D DSSC showed an energy conversion efficiency of 4.1% under the AM 1.5 condition, which was much higher compared with that (3.2%) of the backside illuminated TNAs based DSSC of the same projected area.

Liu, Yong; Li, Ming; Wang, Hai; Zheng, Jiemin; Xu, Hongmei; Ye, Qihong; Shen, Hui

2010-05-01

218

Enhanced photocatalytic efficacy of hetropolyacid pillared TiO2 nanocomposites.  

PubMed

The removal of dye from industrial effluents is prime important, photo-catalysis is a finest method to combat dye from effluents. This study concerns about the investigation of photocatalytic activity of TiO2-HPAs (Hetropolyacids) nanocomposite namely TiO2-Phosphomolybdic nanocomposite [TiO2-HMA] and TiO2-Phosphotungstic nanocomposite [TiO2-HWA] which were prepared by Sol-gel method and the same were characterized by using XRD, SEM-EDAX. The photocatalytic activity of prepared photo-catalysts were evaluated and compared by the degradation of Methylene Blue dye in water solution under UV irradiation. In that TiO2-HMA nanocomposite showed superior photocatalytic activity than TiO2-HWA. PMID:24738400

Nivea, R; Gunasekaran, V; Kannan, R; Sakthivel, T; Govindan, K

2014-06-01

219

Designed synthesis and stacking architecture of solid and mesoporous TiO(2) nanoparticles for enhancing the light-harvesting efficiency of dye-sensitized solar cells.  

PubMed

We fabricated solid and mesoporous TiO2 nanoparticles (NPs) with relatively large primary sizes of approximately 200 nm via inorganic templates for aero-sol-gel and subsequent aqueous-washing processes. The amount of dye molecules adsorbed by the internal pores in the mesoporous TiO2 NPs was increased by creating the nanopores within the solid TiO2 NPs. Simultaneously, the light-scattering effect of the mesoporous TiO2 NPs fabricated by this approach was secured by maintaining their spherical shape and relatively large average size. By precisely accumulating the fabricated solid or mesoporous 200 nm diameter TiO2 NPs on top of a conventional 25 nm diameter TiO2 NP-based underlayer, we could systematically examine the effect of the solid and mesoporous TiO2 NPs on the photovoltaic performance of dye-sensitized solar cells (DSSCs). Consequently, the stacking architecture of the mesoporous TiO2 NP-based overlayer, which functioned as both a light-scattering and dye-supporting medium, on top of a conventional solid TiO2 NP-based underlayer in a DSSC photoelectrode (i.e., double-layer structures) was found to be very promising for significantly improving the photovoltaic properties of conventional solid TiO2 NP single-layer-based DSSCs. PMID:24377279

Ahn, Ji Young; Moon, Kook Joo; Kim, Ji Hoon; Lee, Sang Hyun; Kang, Jae Wook; Lee, Hyung Woo; Kim, Soo Hyung

2014-01-22

220

Study of nano-Ag particles doped TiO2 prepared by photocatalysis.  

PubMed

Nano-silver (Ag) particle doped TiO2 composite photocatalyst was prepared by photocatalytic reaction of anatase TiO2 with AgNO3 solution. Microstructures of these particles were characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDAX) and transmission electron microscopy (TEM). Its photocatalytic behavior was examined by the degradations of two dyes, methyl orange and methylene blue. In contrast to Ag free TiO2 particles, the nano-Ag particle doped TiO2 photocatalyst exhibits much higher catalytic activity. It was also found that 1.0 wt% Ag doped to the TiO2 particles, synthesized through 10 hour ultraviolet (UV) irradiation, offer the best photocatalytic property. PMID:19504939

Zhang, Yun; Huang, Yizhong; Wang, Yuan; Ji, Xiaobo; Shih, Shao-Ju; Jia, Buduo

2009-06-01

221

Degradation of 4-chlorophenol in TiO2, WO3, SnO2, TiO2/WO3 and TiO2/SnO2 systems.  

PubMed

The present study was undertaken to evaluate the degradation performance of 4-chlorophenol (4-CP) using TiO2/WO3 and TiO2/SnO2 systems. A BET surface area analyzer, UV-vis spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron spectroscopy for chemical analysis (ESCA) were employed to characterize the photocatalyst. The band edge wavelength increased to 475 nm and gap energy decreased to 2.61 eV in the TiO2/WO3 system as compare to the single TiO2. Although the specific surfaces area of TiO2/WO3 decreases due to its larger size as compared to either TiO2 or WO3, the 4-CP degradation efficiency significantly increased as compared to single TiO2 or WO3 system at 435 nm wavelength. The TiO2/WO3 degradation of 4-CP at 369 nm was in fact inhibited. For TiO2/SnO2, the degradation efficiency also suffered at 369 nm, and only slightly increased compared to otherwise hardly 4-CP degraded in single TiO2 or SnO2 system. Since there is a significant accumulation of byproducts, the buildup of these intermediates on the catalyst surface may be responsible for their poor performance. PMID:18160216

Lin, Cheng-Fang; Wu, Chung-Hsin; Onn, Zong-Nan

2008-06-15

222

Facile synthesis of tetragonal columnar-shaped TiO2 nanorods for the construction of sensitive electrochemical glucose biosensor.  

PubMed

A tetragonal columnar-shaped TiO2 (TCS-TiO2) nanorods are synthesized via a facile route for the immobilization of glucose oxidase (GOx). A novel electrochemical glucose biosensor is constructed based on the direct electrochemistry of GOx at TCS-TiO2 modified glassy carbon electrode. The fabricated biosensor is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectra and cyclic voltammetry. The immobilized enzyme molecules on TCS-TiO2 nanorods retain its native structure and bioactivity and show a surface controlled, quasi-reversible and fast electron transfer process. The TCS-TiO2 nanorods have large surface area and provide a favorable microenvironment for enhancing the electron transfer between enzyme and electrode surface. The constructed glucose biosensor shows wide linear range from 5.0×10(-6) to 1.32×10(-3) M with a high sensitivity of 23.2 mA M(-1) cm(-2). The detection limit is calculated to be 2.0×10(-6) M at signal-to-noise of 3. The proposed glucose biosensor also exhibits excellent selectivity, good reproducibility, and acceptable operational stability. Furthermore, the biosensor can be successfully applied in the detection of glucose in serum sample at the applied potential of -0.50 V. The TCS-TiO2 nanorods provide an efficient and promising platform for the immobilization of proteins and development of excellent biosensors. PMID:24325982

Yang, Zhanjun; Tang, Yan; Li, Juan; Zhang, Yongcai; Hu, Xiaoya

2014-04-15

223

Facile synthesis and enhanced visible light photocatalytic activity of N and Zr co-doped TiO2 nanostructures from nanotubular titanic acid precursors  

NASA Astrophysics Data System (ADS)

Zr/N co-doped TiO2 nanostructures were successfully synthesized using nanotubular titanic acid (NTA) as precursors by a facile wet chemical route and subsequent calcination. These Zr/N-doped TiO2 nanostructures made by NTA precursors show significantly enhanced visible light absorption and much higher photocatalytic performance than the Zr/N-doped P25 TiO2 nanoparticles. Impacts of Zr/N co-doping on the morphologies, optical properties, and photocatalytic activities of the NTA precursor-based TiO2 were thoroughly investigated. The origin of the enhanced visible light photocatalytic activity is discussed in detail.

Zhang, Min; Yu, Xinluan; Lu, Dandan; Yang, Jianjun

2013-12-01

224

Facile synthesis and enhanced visible light photocatalytic activity of N and Zr co-doped TiO2 nanostructures from nanotubular titanic acid precursors.  

PubMed

Zr/N co-doped TiO2 nanostructures were successfully synthesized using nanotubular titanic acid (NTA) as precursors by a facile wet chemical route and subsequent calcination. These Zr/N-doped TiO2 nanostructures made by NTA precursors show significantly enhanced visible light absorption and much higher photocatalytic performance than the Zr/N-doped P25 TiO2 nanoparticles. Impacts of Zr/N co-doping on the morphologies, optical properties, and photocatalytic activities of the NTA precursor-based TiO2 were thoroughly investigated. The origin of the enhanced visible light photocatalytic activity is discussed in detail. PMID:24369051

Zhang, Min; Yu, Xinluan; Lu, Dandan; Yang, Jianjun

2013-01-01

225

Facile synthesis and enhanced visible light photocatalytic activity of N and Zr co-doped TiO2 nanostructures from nanotubular titanic acid precursors  

PubMed Central

Zr/N co-doped TiO2 nanostructures were successfully synthesized using nanotubular titanic acid (NTA) as precursors by a facile wet chemical route and subsequent calcination. These Zr/N-doped TiO2 nanostructures made by NTA precursors show significantly enhanced visible light absorption and much higher photocatalytic performance than the Zr/N-doped P25 TiO2 nanoparticles. Impacts of Zr/N co-doping on the morphologies, optical properties, and photocatalytic activities of the NTA precursor-based TiO2 were thoroughly investigated. The origin of the enhanced visible light photocatalytic activity is discussed in detail. PMID:24369051

2013-01-01

226

Decomposition of pollutants in wastewater using magnetic photocatalyst particles  

NASA Astrophysics Data System (ADS)

The magnetic photocatalyst particles with a core-shell structure of three layers coating Fe 3O 4 core particles with SiO 2 and TiO 2 were prepared. Methylene blue, red basic dye, blue basic dye, nonylphenol, and octylphenol were used as pollutants. The magnetic photocatalyst particles efficiently decomposed those organic substances. The adsorption of those substances on the magnetic photocatalyst particles was found to be effective. The magnetic photocatalyst particles were easily recovered using magnetic separation.

Kurinobu, S.; Tsurusaki, K.; Natui, Y.; Kimata, M.; Hasegawa, M.

227

Plasma-electrolysis synthesis of TiO2 nano/microspheres with optical absorption extended into the infra-red region.  

PubMed

A novel plasma-electrolysis method is introduced to synthesize high-quality TiO(2) nano/microspheres that exhibited excellent optical absorption covering the range from ultraviolet to infra-red. Both experimental and theoretical results show that the oxygen vacancies in the TiO(2) spheres are primarily responsible for this wide absorption. PMID:21709878

Zhang, Zhi-Kun; Bai, Mei-Lin; Guo, Deng-Zhu; Hou, Shi-Min; Zhang, Geng-Min

2011-08-01

228

Photodegradation of nalidixic acid assisted by TiO(2) nanorods/Ag nanoparticles based catalyst.  

PubMed

Two different nanosized TiO2-based catalysts supported onto glass with tailored photocatalytic properties upon irradiation by UV light were successfully employed for the degradation of nalidixid acid, a widely diffused antibacterial agent of environmental relevance known to be non-biodegradable. Anatase rod-like TiO2 nanocrystals (TiO2NRs) and a semiconductor oxide-noble metal nanocomposite TiO2 NRs/Ag nanoparticles (NPs), synthesized by colloidal chemistry routes, were cast onto glass slide and employed as photocatalysts. A commercially available catalyst (TiO2 P25), also immobilized onto a glass slide, was used as a reference material. It was found that both TiO2 NRs/Ag NPs composite and TiO2 NRs demonstrated a photocatalytic efficiency significantly higher than the reference TiO2 P25. Specifically, TiO2 NRs/Ag NPs showed a photoactivity in nalidixic acid degradation 14 times higher than TiO2 P25 and 4 times higher than bare TiO2 NRs in the first 60min of reaction. Several by-products were identified by HPLC-MS along the nalidixic acid degradation, thus getting useful insight on the degradation pathway. All the identified by-products resulted completely removed after 6h of reaction. PMID:23466278

Petronella, F; Diomede, S; Fanizza, E; Mascolo, G; Sibillano, T; Agostiano, A; Curri, M L; Comparelli, R

2013-05-01

229

TiO2/palygorskite composite nanocrystalline films prepared by surfactant templating route: synergistic effect to the photocatalytic degradation of an azo-dye in water.  

PubMed

Microfibrous palygorskite clay mineral and nanocrystalline TiO(2) are incorporating in the preparation of nanocomposite films on glass substrates via sol-gel route at 500°C. The synthesis involves a simple chemical method employing nonionic surfactant molecule as pore directing agent along with the acetic acid-based sol-gel route without direct addition of water molecules. Drying and thermal treatment of composite films lead to the elimination of organic material while ensure the formation of TiO(2) nanoparticles homogeneously distributed on the surface of the palygorskite microfibers. TiO(2) nanocomposite films without cracks consisted of small crystallites in size (12-16 nm) and anatase crystal phase was found to cover palygorskite microfibers. The composite films were characterized by microscopy techniques, UV-vis, IR spectroscopy, and porosimetry methods in order to examine their structural properties. Palygorskite/TiO(2) composite films with variable quantities of palygorskite (0-2 w/w ratio) were tested as new photocatalysts in the photo-discoloration of Basic Blue 41 azo-dye in water. These nanocomposite films proved to be very promising photocatalysts and highly effective to dye's discoloration in spite of the small amount of immobilized palygorskite/TiO(2) catalyst onto glass substrates. 3:2 palygorskite/TiO(2) weight ratio was finally the most efficient photocatalyst while reproducible discoloration results of the dye were obtained after three cycles with same catalyst. It was also found that palygorskite showed a positive synergistic effect to the TiO(2) photocatalysis. PMID:22177018

Stathatos, E; Papoulis, D; Aggelopoulos, C A; Panagiotaras, D; Nikolopoulou, A

2012-04-15

230

Dramatic visible photocatalytic degradation performances due to synergetic effect of TiO2 with PANI.  

PubMed

The dramatic visible light photocatalytic activity was obtained for the degradation of Methylene Blue (MB) and Rhodamine B (RhB) under visible light irradiation (lambda > 450 nm) after TiO2 photocatalysts were modified with monolayer dispersed polyaniline (PANI) via a facile chemisorption approach. Under visible light irradiation, PANI generated pi-pi* transition, delivering the excited electrons into the conduction band of TiO2, and then the electrons transferred to an adsorbed electron acceptor to yield oxygenous radicals to degrade pollutants. Also, the ultraviolet photocatalytic performance was enhanced to about two times compared with that of P-25 TiO2 photocatalyst. The high photocatalytic activity came from the synergetic effect between PANI and TiO2, which promoted the migration efficiency of photogenerated carriers on the interface of PANI and TiO2. Under ultraviolet light irradiation, photoinduced holes in TiO2 valence band could transfer into HOMO orbital of PANI and then emigrate to the photocatalyst surface and oxidize the adsorbed contaminants directly. The optimum synergetic effect was found at a weight ratio of 3.0 wt % (PANI/ TiO2). PMID:18546726

Zhang, Hao; Zong, Ruilong; Zhao, Jincai; Zhu, Yongfa

2008-05-15

231

Electrochemical characterization of TiO2/WOx nanotubes for photocatalytic application  

PubMed Central

TiO2/WOx nanotubes have unique photo-energy retention properties that have gathered scientific interest. Herein, we report the synthesis, morphological characterization, and the electrochemical characterization of TiO2/WOx nanotubes compared with pure TiO2 nanotubes, prepared by anodization technique. Significant structural differences were not observed in TiO2/WOx nanotubes as observed by using scanning electron microscopy and transmission electron microscopy. The charge transfer resistance of TiO2/WOx before and after photo irradiation determined by using electrochemical impedance spectroscopy proves the inherent energy retention property which was not observed in pure TiO2 nanotubes.

2014-01-01

232

Photodegradation of bisphenol-A with TiO 2 immobilized on the glass tubes including the UV light lamps  

Microsoft Academic Search

Photodegradation experiments of bisphenol-A (BPA) were performed with TiO2 particles as a photocatalyst, where particles were immobilized using a titanium sol-solution synthesized by a sol–gel method. The effects of immobilized TiO2-film thickness, UV radiation intensity, and pH on the photodegradation of BPA were investigated. Apparent rate constant of the first order increased with increasing TiO2-coating time from 1 to 3,

Jong-Min Lee; Moon-Sun Kim; Byung-Woo Kim

2004-01-01

233

Effects of synthesis parameters on the physico-chemical and photoactivity properties of titania–silica mixed oxide prepared via basic hydrolyzation  

Microsoft Academic Search

Titania–silica mixed oxide (TiO2–SiO2) was prepared from the alkoxides: titanium tetrabutoxide (TBOT) and tetraethyl orthosilicate (TEOS), by using an ammonia–water solution as the hydrolysis catalyst. Variables included synthesis route, aging time, the type of alcohol, and calcination temperature. The materials were then evaluated as photocatalysts for the decomposition of n-heptane. Experimental results revealed: (1) the photoactivity of TiO2–SiO2 prepared via

Qiujing Yang; Chao Xie; Zili Xu; Zhongmin Gao; Ziheng Li; Dejun Wang; Yaoguo Du

2005-01-01

234

Laser processing of nanocrystalline TiO2 films for dye-sensitized solar cells  

E-print Network

produced via colloidal synthesis of TiO2 nanoparticles and subsequent deposition of the TiO2 colloidal, Washington, DC 20375 (Received 5 February 2004; accepted 19 May 2004) Pulsed-laser deposition and laser direct-write have been applied to deposit dense (30 nm thick) and porous nanocrystalline TiO2 (nc-TiO2, 5

Arnold, Craig B.

235

Facile synthesis of anatase TiO(2) quantum-dot/graphene-nanosheet composites with enhanced electrochemical performance for lithium-ion batteries.  

PubMed

A facile method to synthesize well-dispersed TiO2 quantum dots on graphene nanosheets (TiO2 -QDs/GNs) in a water-in-oil (W/O) emulsion system is reported. The TiO2 /graphene composites display high performance as an anode material for lithium-ion batteries (LIBs), such as having high reversible lithium storage capacity, high Coulombic efficiency, excellent cycling stability, and high rate capability. The excellent electrochemical performance and special structure of the composites thus offer a way to prepare novel graphene-based electrode materials for high-energy-density and high-power LIBs. PMID:24347361

Mo, Runwei; Lei, Zhengyu; Sun, Kening; Rooney, David

2014-04-01

236

TiO2@C core-shell nanoparticles formed by polymeric nano-encapsulation  

PubMed Central

TiO2 semiconducting nanoparticles are known to be photocatalysts of moderate activity due to their high band-gap and high rate of electron-hole recombination. The formation of a shell of carbon around the core of TiO2, i.e., the formation of TiO2@C nanoparticles, is believed to partly alleviate these problems. It is usually achieved by a hydrothermal treatment in a presence of a sugar derivative. We present here a novel method for the formation of highly uniform C shell around TiO2 nanoparticles. For this purpose, TiO2 nanoparticles were dispersed in water using an oligomeric dispersant prepared by Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. Then the nanoparticles were engaged into an emulsion polymerization of acrylonitrile, resulting in the formation of a shell of polyacrylonitrile (PAN) around each TiO2 nanoparticles. Upon pyrolysis, the PAN was transformed into carbon, resulting in the formation of TiO2@C nanoparticles. The structure of the resulting particles was elucidated by X-Ray diffraction, FTIR, UV-VIS and Raman spectroscopy as well as TEM microscopy. Preliminary results about the use of the TiO2@C particles as photocatalysts for the splitting of water are presented. They indicate that the presence of the C shell is responsible for a significant enhancement of the photocurrent. PMID:25072054

Vasei, Mitra; Das, Paramita; Cherfouth, Hayet; Marsan, Benoit; Claverie, Jerome P.

2014-01-01

237

UV-vis light activated Ag decorated monodisperse TiO2 for treatment of pharmaceuticals in water  

EPA Science Inventory

Recently, many researchers have made a lot of effort to utilize the visible light portion of the solar spectrum to activate TiO2 photocatalyst for environmental applications, such as water, air, and soil remediation. The deposition of noble metals on photocatalysts is of great in...

238

Enhanced photocatalytic activity of In2O3-decorated TiO2  

NASA Astrophysics Data System (ADS)

Titania (TiO2)-based photocatalysts decorated with different amounts of indium oxide (In2O3) were prepared by a pore impregnating method and characterized by the Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The separation efficiency of photogenerated charges was investigated using benzoquinone (BQ) as scavenger. The activities of the photocatalysts were evaluated by decolorization of methyl orange (MO) aqueous solution under ultraviolet-light irradiation. Compared to TiO2, In2O3/TiO2 composites show improved photocatalytic performance due to the coupling effect of TiO2 and In2O3, which greatly improves the separation of photogenerated electrons and holes.

Zhong, Junbo; Li, Jianzhang; Zeng, Jun; He, Xiyang; Huang, Shengtiang; Jiang, Weidong; Li, Minjiao

2014-06-01

239

Photocatalytic oxidation of dibenzothiophene using TiO 2 \\/bamboo charcoal  

Microsoft Academic Search

Photocatalytic oxidation of dibenzothiophene (DBT) using TiO2-loaded bamboo charcoals (BC) prepared by wet impregnation was studied. Results obtained here can be used as the reference\\u000a for evaluating reactions in hydrocarbons, which aims at the development of an oxidative desulfurization process for fuel oils.\\u000a Technological conditions (the amount of photocatalysts, hydrogen peroxide, and TiO2 loading) were also investigated in detail. The

Juan Zhang; Dishun Zhao; Jinlong Wang; Liyan Yang

2009-01-01

240

Studies on TiO 2\\/ZnO photocatalysed degradation of lignin  

Microsoft Academic Search

The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO2 and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO2. The different variables studied, include catalyst dose, solution pH, oxidant concentration and initial concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of

S. K. Kansal; M. Singh; D. Sud

2008-01-01

241

Photocatalytic antibacterial performance of TiO2 and Ag-doped TiO2 against S. aureus. P. aeruginosa and E. coli.  

PubMed

This paper reports the structural and optical properties and comparative photocatalytic activity of TiO2 and Ag-doped TiO2 nanoparticles against different bacterial strains under visible-light irradiation. The TiO2 and Ag-doped TiO2 photocatalysts were synthesized by acid catalyzed sol-gel technique and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis spectroscopy and photoluminescence (PL). The XRD pattern revealed that the annealed sample of TiO2 has both anatase and rutile phases while only an anatase phase was found in Ag-doped TiO2 nanoparticles. The decreased band-gap energy of Ag-doped TiO2 nanoparticles in comparison to TiO2 nanoparticles was investigated by UV-vis spectroscopy. The rate of recombination and transfer behaviour of the photoexcited electron-hole pairs in the semiconductors was recorded by photoluminescence. The antimicrobial activity of TiO2 and Ag-doped TiO2 nanoparticles (3% and 7%) was investigated against both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. As a result, the viability of all three microorganisms was reduced to zero at 60 mg/30 mL culture in the case of both (3% and 7% doping) concentrations of Ag-doped TiO2 nanoparticles. Annealed TiO2 showed zero viability at 80 mg/30 mL whereas doped Ag-TiO2 7% showed zero viability at 40 mg/30 mL culture in the case of P. aeruginosa only. PMID:23844339

Gupta, Kiran; Singh, R P; Pandey, Ashutosh; Pandey, Anjana

2013-01-01

242

Photocatalytic antibacterial performance of TiO2 and Ag-doped TiO2 against S. aureus. P. aeruginosa and E. coli  

PubMed Central

Summary This paper reports the structural and optical properties and comparative photocatalytic activity of TiO2 and Ag-doped TiO2 nanoparticles against different bacterial strains under visible-light irradiation. The TiO2 and Ag-doped TiO2 photocatalysts were synthesized by acid catalyzed sol–gel technique and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence (PL). The XRD pattern revealed that the annealed sample of TiO2 has both anatase and rutile phases while only an anatase phase was found in Ag-doped TiO2 nanoparticles. The decreased band-gap energy of Ag-doped TiO2 nanoparticles in comparison to TiO2 nanoparticles was investigated by UV–vis spectroscopy. The rate of recombination and transfer behaviour of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. The antimicrobial activity of TiO2 and Ag-doped TiO2 nanoparticles (3% and 7%) was investigated against both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. As a result, the viability of all three microorganisms was reduced to zero at 60 mg/30 mL culture in the case of both (3% and 7% doping) concentrations of Ag-doped TiO2 nanoparticles. Annealed TiO2 showed zero viability at 80 mg/30 mL whereas doped Ag-TiO2 7% showed zero viability at 40 mg/30 mL culture in the case of P. aeruginosa only. PMID:23844339

Gupta, Kiran; Singh, R P; Pandey, Ashutosh

2013-01-01

243

Aerogel processing of MTi 2O 5 (M = Mg, Mn, Fe, Co, Zn, Sn) compositions using single source precursors: synthesis, characterization and photocatalytic behavior  

Microsoft Academic Search

Oxide semiconductor photocatalysts based on TiO2 (band gap of 3.2eV) are normally used to destroy organics under UV irradiation. Currently we have been focused on the aerogel synthesis of nanocrystalline photocatalysts that will destroy organic compounds such as acetaldehyde using visible and UV radiations. Herein we report the results of our attempts to synthesize mixed metal oxides of the type

P. N. Kapoor; S. Uma; S. Rodriguez; K. J. Klabunde

2005-01-01

244

An on-line measurement and control system for submerged arc spray synthesis of TiO2 nanoparticles.  

PubMed

This article presents the development of an on-line measurement and control system for process characterization and optimization of the nanoparticle manufacturing process, called the submerged arc-spray nanoparticle synthesis system (SANSS). To achieve optimized control of particle uniformity, this research investigates the feasibility of employing optical fiber probe and the dynamic light scattering (DLS) technique to monitor and control particle sizes. According to the theory of DLS, an on-line nanoparticle sampling and measurement system was developed and integrated with the SANSS as an important step to verify the measurement performance of the proposed method. To examine the measurement accuracy of the developed system, calibrated polystyrene latex particles with known accurate sizes were employed to verify the particle sizing accuracy of the proposed system. The data conformity between the measurement results of TiO, nanoparticles obtained by various methods, including TEM, a calibrated commercial particle sizing system and the on-line measurement system, has indicated that the developed method was feasible and effective. PMID:18464363

Chen, Liang-Chia; Ji, Bao-Hong

2008-02-01

245

Sol-gel synthesis, characterization and optical properties of mercury-doped TiO 2 thin films deposited on ITO glass substrates  

NASA Astrophysics Data System (ADS)

The Hg-doped and undoped nano-crystalline TiO 2 films on ITO glass substrates surface and polycrystalline powders were prepared by sol-gel dip coating technique. The crystal structure and surface morphology of TiO 2 were characterized by means of X-ray diffractometer (XRD), atomic force microscope (AFM), spectrophotometer, Fourier-transform infrared (FTIR), and spectroscopic ellipsometry (SE). The results indicated that the powder of TiO 2, doped with 5% Hg in room temperature was only composed of the anatase phase whereas in the undoped powder exhibits an amorphous phase were present. After heat treatments of thin films, titanium oxide starts to crystallize at the annealing temperature 400 °C. The average crystallite size of the undoped TiO 2 films was about 8.17 nm and was increased with Hg-doping in the TiO 2 films. Moreover, the grains distributed more uniform and the surface roughness was greater in the Hg-doped TiO 2 films than in the undoped one. Refractive index and porosity were calculated from the measured transmittance spectrum. The values of the index of refraction are in the range (1.95-2.49) and the porosity is in the range (47-2.8). The coefficient of transmission varies from 60 to 90%. SE study was used to determine the annealing temperature effect on the optical properties in the wavelength range from 0.25 to 2 ?m and the optical gap of the Hg-doped TiO 2 thin films.

Mechiakh, R.; Ben Sedrine, N.; Chtourou, R.

2011-08-01

246

Visible-Light-Driven Oxidation of Primary C-H Bonds over CdS with Dual Co-catalysts Graphene and TiO2  

PubMed Central

Selective activation of primary C–H bonds for fine chemicals synthesis is of crucial importance for the sustainable exploitation of available feedstocks. Here, we report a viable strategy to synthesize ternary GR-CdS-TiO2 composites with an intimate spatial integration and sheet-like structure, which is afforded by assembling two co-catalysts, graphene and TiO2, into the semiconductor CdS matrix with specific morphology as a visible light harvester. The GR-CdS-TiO2 composites are able to serve as a highly selective visible-light-driven photocatalyst for oxidation of saturated primary C–H bonds using benign oxygen as oxidant under ambient conditions. This work demonstrates a wide, promising scope of adopting co-catalyst strategy to design more efficient semiconductor-based photocatalyst toward selective activation of C–H bonds using solar light and molecular oxygen. PMID:24264835

Yang, Min-Quan; Zhang, Yanhui; Zhang, Nan; Tang, Zi-Rong; Xu, Yi-Jun

2013-01-01

247

Room temperature synthesis of nanocrystalline anatase sols and preparation of uniform nanostructured TiO2 thin films: optical and structural properties  

NASA Astrophysics Data System (ADS)

Transparent TiO2 thin films were deposited on soda-lime glass substrates via the sol-gel method using a nanocrystalline TiO2 sol solution prepared at room temperature employing the dip-coating method. The effects of pH on crystallinity, particle size and stability of the synthesized TiO2 sols were investigated, systematically. TiO2 thin films were thickened by means of a sequential dip-coating process. The TiO2 films were transparent and exhibited proper adherence. The effects of thickness and annealing temperature on the structural and optical properties of the thin films were evaluated. The prepared powder was crystalline without any thermal treatment. The crystallite size of the particles (anatase) was in the range 4.2-12.1 nm depending on the initial pH value. Although only the anatase phase was observed at room temperature and 400 °C, a further increase in annealing temperature up to 700 °C resulted in the formation of the rutile phase. Even at high annealing temperatures, fairly smooth and homogeneous surfaces with no cracks and pores were observed. It was demonstrated that the films were transparent in the visible region with characteristic absorption in the UV region. Band gap of the as-deposited film was estimated to be 3.34 eV and was found to decrease with increasing annealing temperature.

Hosseingholi, M.; Pazouki, M.; Hosseinnia, A.; Aboutalebi, S. H.

2011-02-01

248

Synthesis and characterization of photochromic Ag-embedded TiO2 nanocomposite thin films by non-reactive RF-magnetron sputter deposition  

NASA Astrophysics Data System (ADS)

Ag-embedded TiO2 nanocomposite thin film with reversible photochromic properties were prepared by layer-by-layer non-reactive RF-magnetron sputtering. Films were produced in Ar/O2 and pure Ar atmospheres. In the oxidizing regime, a diffusion of Ag from the film volume to the outer film surface was observed. Therefore, pure Ar plasma was applied in the deposition of TiO2. The electronic and optical properties of the TiO2 film were almost not affected by the presence of oxygen. Transmission electron microscopy (TEM) and reflection mode X-ray absorption spectroscopy (XAS) were performed to study the morphology, crystal structure and chemical state of the embedded Ag nanoparticles before and after the annealing step. Annealing of the film led to the crystallization of the TiO2 matrix. Moreover, the Ag nanoparticles in the film underwent Ostwald ripening leading to particle agglomerate. No oxidation of the embedded Ag during the sputter deposition and subsequent annealing process was found as confirmed by XAS measurements. The non-reactive RF-magnetron method is believed to avoid the energetic oxygen ions attack to Ag during the deposition of Ag-embedded TiO2 nanocomposite and thus the films are expected to have better optical properties and long-term stability.

Zuo, J.; Keil, P.; Grundmeier, G.

2012-07-01

249

First-principles study of Cu-doping and oxygen vacancy effects on TiO2 for water splitting  

NASA Astrophysics Data System (ADS)

We investigate the electronic structures and optical properties of Cu-doped TiO2-x using density functional theory (DFT) calculations. We find that Cu doping creates an empty impurity band lying above the valence band of TiO2, which bridges most of the gap between the valence band maximum and conduction band minimum in undoped TiO2. The results also show that oxygen vacancies produce a similar effect and that Cu-doping can increase the stability of oxygen vacancies. We propose that Cu-doped TiO2-x improves light harvesting and could be a promising visible-light photocatalyst.

Zhang, Huamin; Yu, Xiaohui; McLeod, John A.; Sun, Xuhui

2014-09-01

250

Photocatalytic activity of WO x -TiO 2 under visible light irradiation  

Microsoft Academic Search

With an attempt to extend light absorption of the TiO2-based photocatalysts toward the visible light range and eliminate the rapid recombination of excited electrons\\/holes during photoreaction, new photocatalyst (WOx-TiO2) powder was prepared by a sol–gel method. The photooxidation efficiency of WOx-TiO2 catalyst was also evaluated by conducting a set of experiments to photodegrade methylene blue (MB) in aqueous solution. The

X. Z Li; F. B Li; C. L Yang; W. K Ge

2001-01-01

251

Diatom-templated TiO2 with enhanced photocatalytic activity: biomimetics of photonic crystals  

NASA Astrophysics Data System (ADS)

The siliceous frustules with sophisticated optical structure endow diatoms with superior solar light-harvesting abilities for effective photosynthesis. The preserved frustules of diatom ( Cocconeis placentula) cells, as biophotonic crystals, were thus employed as both hard templates and silicon resources to synthesize TiO2 photocatalyst. Characterizations by a combination of physicochemical techniques proved that the bio-inspired sample is TiO2-coated SiO2 with biogenic C self-doped in. It was found that the synthesized composites exhibited similar morphologies to the original diatom templates. In comparison with commercial Degussa P25 TiO2, the C-doped TiO2/SiO2 catalyst exhibited more light absorption in the visible region and higher photocatalytic efficiency for photodegradation of rhodamine B under visible light due to the biomorphic hierarchical structures, TiO2 coating and C-doping.

He, Jiao; Chen, Daomei; Li, Yongli; Shao, Junlong; Xie, Jiao; Sun, Yuejuan; Yan, Zhiying; Wang, Jiaqiang

2013-11-01

252

CCMR: Synthesis of Nanosized Titanium-Chromium nitride Powders by Ammonolysis of Co-precipitated TiO2/Cr2O3 Precursors  

NSDL National Science Digital Library

Nanocrystalline bimetallic metal nitride, Ti0.5Cr0.5N was synthesized by ammonolysis at 800°C for 14 hours of the nanozide TiO2/Cr2O3 precursor powder. TiO2/Cr2O3 nanopowder resulting from the coprecipitation method. The precursor and the resulting nitrides were characterized by X-Ray diffraction analysis and scanning electron microscope (SEM). The corrosion stability was analyzed by the thermal gravimetric analysis (TGA). The results indicated that the precursor solution contains TiO2 and K2CrO7. The final product is TiN and CrN with an average particle size of 30nm.

Hernã¡ndez Rivera, Mayra

2010-08-15

253

Designed synthesis of SiO2/TiO2 core/shell structure as light scattering material for highly efficient dye-sensitized solar cells.  

PubMed

SiO2/TiO2 core/shell nanoparticles (STCS-NPs) with diameters of 110, 240, and 530 nm were fabricated to investigate the influence of the size and refractive index of light-scattering particles on light-scattering properties. The optical properties of STCS-NPs were evaluated and compared with SiO2-NPs and TiO2-NPs. The structure of STCS-NPs, consisting of a low refractive index core and high refractive index shell, provides efficient light scattering. The optimized anode film with STCS-NPs had ca. 20% improved power conversion efficiency (PCE). PMID:23635382

Son, Suim; Hwang, Sun Hye; Kim, Chanhoi; Yun, Ju Young; Jang, Jyongsik

2013-06-12

254

Control of the size and shape of TiO2 nanoparticles in restricted media  

NASA Astrophysics Data System (ADS)

Template-capped TiO2 nanostructures have been synthesized. In certain template conditions, TiO2 hexagons are found to form. These hexagonal structures can be effectively sensitized by fluorescein dye without any change in the protonation state of the dye. Bare TiO2 nanoparticles are not so useful for sensitization with dyes like fluorescein as they alter the dye protonation state. The novelty of this work is twofold—the hitherto elusive hexagonal phase of TiO2 nanoparticles has been stabilized and the synthesis of TiO2 in the rutile phase has been achieved under mild conditions.

Biswas, Abhijit; Corani, Alice; Kathiravan, Arunkumar; Infahsaeng, Yingyot; Yartsev, Arkady; Sundstrom, Villy; De, Swati

2013-05-01

255

Photocatalytic degradation of acetaminophen in modified TiO2 under visible irradiation.  

PubMed

This study investigated the photocatalytic degradation of acetaminophen (ACT) in synthetic titanium dioxide (TiO2) solution under a visible light (? >440 nm). The TiO2 photocatalyst used in this study was synthesized via sol-gel method and doped with potassium aluminum sulfate (KAl(SO4)2) and sodium aluminate (NaAlO2). The influence of some parameters on the degradation of acetaminophen was examined, such as initial pH, photocatalyst dosage, and initial ACT concentration. The optimal operational conditions were also determined. Results showed that synthetic TiO2 catalysts presented mainly as anatase phase and no rutile phase was observed. The results of photocatalytic degradation showed that LED alone degraded negligible amount of ACT but with the presence of TiO2/KAl(SO4)2, 95% removal of 0.10-mM acetaminophen in 540-min irradiation time was achieved. The synthetic TiO2/KAl(SO4)2 presented better photocatalytic degradation of acetaminophen than commercially available Degussa P-25. The weak crystallinity of synthesized TiO2/NaAlO2 photocatalyst showed low photocatalytic degradation than TiO2/KAl(SO4)2. The optimal operational conditions were obtained in pH 6.9 with a dose of 1.0 g/L TiO2/KAl(SO4)2 at 30 °C. Kinetic study illustrated that photocatalytic degradation of acetaminophen fits well in the pseudo-first order model. Competitive reactions from intermediates affected the degradation rate of ACT, and were more obvious as the initial ACT concentration increased. PMID:23888349

Dalida, Maria Lourdes P; Amer, Kristine Marfe S; Su, Chia-Chi; Lu, Ming-Chun

2014-01-01

256

Visible Light-activated TiO2 photocatalytic Films; Synthesis, Characterization and Environmental Application for the Destruction of Microcystin-LR  

EPA Science Inventory

Titanium dioxide (TiO2) photocatalysis has become one of the most effective advanced oxidation technologies (AOTs) for the treatment of persistent organic contaminants. To generate hydroxyl radicals, a non-selective, reactive oxidizing species and responsible for the oxidation of...

257

Ultrasound assisted synthesis of TiO2-WO3 heterostructures for the catalytic degradation of Tergitol (NP-9) in water.  

PubMed

TiO2-WO3 heterostructures were synthesized at room temperature, ambient pressure, and short reaction time via a sonochemical approach. TEM and EDX images show that the prepared TiO2-WO3 heterostructures consist of globular agglomerates (?250 nm in diameter) composed of very small (<5 nm) dense particles (WO3) dispersed inside the globules. The observed less intense monoclinic WO3 diffraction peak (around 2?=22° belonging to (001) plane) and the high intense hexagonal WO3 diffraction peak (around 2?=28° belonging to (200) plane) in XRD indicate that there may be phase transition occurring due to the formation of intimate bond between TiO2 and WO3. In addition, the formation of such new phase was also observed from Raman spectra with a new peak at 955 cm(-1), which is due to the symmetric stretching of W=O terminal. The catalytic activity of TiO2-WO3 heterostructures was tested for the degradation of wastewater pollutant containing Tergitol (NP-9) by a process combined with ozonation and it showed two-fold degradation rate compared with ozone process alone. PMID:24491600

Anandan, Sambandam; Wu, Jerry J

2014-07-01

258

Large scale synthesis of FeS coated Fe nanoparticles as reusable magnetic photocatalysts  

NASA Astrophysics Data System (ADS)

The FeS coated Fe nanoparticles were prepared by using high temperature reactions between the commercial Fe nanoparticles and the S powders in a sealed quartz tube. The simple method developed in this work is effective for large scale synthesis of FeS/Fe nanoparticles with tunable shell/core structures, which can be obtained by controlling the atomic ratio of Fe to S. The structural, magnetic and photocatalytic properties of the nanoparticles were investigated systematically. The good photocatalytic performance originating from the FeS shell in degradation of methylene blue under visible light and the high saturation magnetization originating from the ferromagnetic Fe core make the FeS/Fe nanoparticles a good photocatalyst that can be collected and recycled easily with a magnet. An exchange bias up to 11 mT induced in Fe by FeS was observed in the Fe/FeS nanoparticles with ferro/antiferromagnetic interfaces. The enhanced coercivity up to 32 mT was ascribed to the size effect of Fe core.

Feng, He; Si, Ping-Zhan; Xiao, Xiao-Fei; Jin, Chen-Hao; Yu, Sen-Jiang; Li, Zheng-Fa; Ge, Hong-Liang

2013-09-01

259

Preparation and photocatalytic activity of nanoglued Sn-doped TiO2.  

PubMed

In this paper, Sn-doped TiO(2) photocatalyst was prepared and immobilized on a glass substrate using an about-to-gel SiO(2) sol as a nanoglue. The characterization of the Sn-doped TiO(2) by XRD showed that 5% Sn content is formed by anatase and rutile crystallites. Characterization of the nanoglued photocatalyst by the BET measurement, TEM, and SEM showed that the photocatalyst was a nanoporous material with a high-surface area. The Sn-doped TiO(2) was uniformly dispersed within the three-dimensional network of the silica in the form of nanoparticles. The nanoglued photocatalyst showed high photocatalytic activity during the degradation of penicillin under UV light. The effect of different Sn content on the amount of hydroxyl radical was discussed by using salicylic acid as probe molecules. The results show that an appropriate amount of Sn dopant can greatly increase the amount of hydroxyl radicals generated by TiO(2) nanoparticles, which are responsible for the obvious increase of photocatalytic activity. PMID:18834665

Li, Xiang; Xiong, Rongchun; Wei, Gang

2009-05-30

260

Photochemical activity of TiO2 nanotubes  

NASA Astrophysics Data System (ADS)

TiO2 is well known as a low-cost, highly active photocatalyst showing good environmental compatibility. Recently it was found that TiO2 nanotubes promise to enable for high photocatalytic activity (PCA). In our experiments, we studied the PCA and spectroscopic properties of TiO2 nanotube arrays formed by the anodization of Ti. The PCA efficiency related to the decomposition of methylene-blue was measured. To obtain reliable data, the results were calibrated by comparing with standard materials like Pilkington Activ™ which is a commercially available self cleaning glass. The studies included a search strategy for finding optimum conditions for the nanotube formation and the investigation of the relationship between PCA and annealing temperature. TiO2 nanotubes of different shapes and sizes were prepared by an anodization of Ti foil in different electrolytes, at variable applied voltages and concentrations. The photo-dissociation of methylene-blue was detected spectroscopically. For the optimized material, an enhancement factor of 2 in comparison to the standard reference material was found. Furthermore, femtosecond-laser induced photoluminescence and nonlinear absorption of the material were investigated. Possibilities for further enhancements of the PCA are discussed.

Pfuch, A.; Güell, F.; Toelke, T.; Das, S. K.; Messaoudi, H.; McGlynn, E.; Seeber, W.; Fábrega, C.; Andreu, T.; Morante, J. R.; Grunwald, R.

2013-03-01

261

Synergistic Effect of CdSe Quantum Dot Sensitization and Nitrogen Doping of TiO2  

E-print Network

gap semiconductors such as TiO2, ZnO, and WO3 have been demonstrated as promising candidatesSynergistic Effect of CdSe Quantum Dot Sensitization and Nitrogen Doping of TiO2 Nanostructures the synthesis and photoelectrochemical (PEC) studies of TiO2 nanoparticles and nanowires simultaneously doped

Li, Yat

262

Solar photocatalytic activity of TiO2 modified with WO3 on the degradation of an organophosphorus pesticide.  

PubMed

In this study, the solar photocatalytic activity (SPA) of WO3/TiO2 photocatalysts synthesized by the sol-gel method with two different percentages of WO3 (2 and 5%wt) was evaluated using malathion as a model contaminant. For comparative purpose bare TiO2 was also prepared by sol-gel process. The powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, diffuse reflectance UV-vis spectroscopy (DRUV-vis), specific surface area by the BET method (SSABET), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy with a high annular angle dark field detector (STEM-HAADF). The XRD, Raman, HRTEM and STEM-HAADF analyses indicated that WO3 was present as a monoclinic crystalline phase with nanometric cluster sizes (1.1 ± 0.1 nm for 2% WO3/TiO2 and 1.35 ± 0.3 nm for 5% WO3/TiO2) and uniformly dispersed on the surface of TiO2. The particle size of the materials was 19.4 ± 3.3 nm and 25.6 ± 3 nm for 2% and 5% WO3/TiO2, respectively. The SPA was evaluated on the degradation of commercial malathion pesticide using natural solar light. The 2% WO3/TiO2 photocatalyst exhibited the best photocatalytic activity achieving 76% of total organic carbon (TOC) abatement after 300 min compared to the 5% WO3/TiO2 and bare TiO2 photocatalysts, which achieved 28 and 47% mineralization, respectively. Finally, experiments were performed to assess 2% WO3/TiO2 catalyst activity on repeated uses; after several successive cycles its photocatalytic activity was retained showing long-term stability. PMID:23993423

Ramos-Delgado, N A; Gracia-Pinilla, M A; Maya-Treviño, L; Hinojosa-Reyes, L; Guzman-Mar, J L; Hernández-Ramírez, A

2013-12-15

263

Purification of water by bipolar pulsed discharge plasma combined with TiO2 catalysis  

NASA Astrophysics Data System (ADS)

In the process of water treatment by bipolar pulsed discharge plasma, there are not only the chemical effects such as the cold plasma, but also the physical effects such as the optical radiation. The energy of the optical radiation can be used by photocatalyst. Therefore, the effect of the photocatalyst to the degradation of the organic pollutant was investigated using a packed bed reactor by bipolar pulsed discharge in the air-liquid-solid mixture. The nanoparticle TiO2 photocatalyst was obtained using the sol-gel method and the typical dye solution Indigo Carmine was chosen as the degradation target to test the catalytic effect of the nanoparticle TiO2 photocatalyst. Experiment results proved that the degradation efficiency of the Indigo Carmine solution was increased by a certain extent with the TiO2 photocatalyst. It was totally decolorized within 3 minutes by bipolar pulsed discharge in the condition that the peak voltage was 30 kV and the air flow was 1.0 m3 h-1.

Zhang, Yongrui; Zhang, Ruobing; Ma, Wenchang; Zhang, Xian; Wang, Liming; Guan, Zhicheng

2013-03-01

264

Synthesis and application of hollow magnetic graphitic carbon microspheres with/without TiO2 nanoparticle layer on the surface.  

PubMed

Hollow magnetic graphitic carbon microspheres (HMGSs) with/without a TiO(2) nanoparticle layer on their surfaces are designed and synthesized by combining the bubble-template method, assembly of beta-cyclodextrin and Fe(3)O(4) stabilized by oleic acid and ammonia, and consequent graphitization reaction. HMGSs have potential in adsorption, enrichment, magnetic-assisted separation and drug delivery. PMID:20664877

Feng, Shanshan; Ren, Zhiyu; Wei, Yuanlong; Jiang, Baojiang; Liu, Yang; Zhang, Lingyi; Zhang, Weibing; Fu, Honggang

2010-09-14

265

Synthesis of TiO2-polyaniline core-shell nanofibers and their unique UV photoresponse based on different photoconductive mechanisms in oxygen and non-oxygen environments.  

PubMed

The TiO2-polyaniline (PANI) core-shell nanofibers with unique ultraviolet (UV) photoresponse were designed and fabricated. When the core-shell nanofibers were tested in an oxygen (O2) and a non-oxygen environment under UV illumination, respectively, a decrease and an increase in photoconduction were observed, which suggested different photoconductive mechanisms of the core-shell materials in different environments. PMID:23586074

Yang, Shengxue; Cui, Xiujun; Gong, Jian; Deng, Yulin

2013-05-21

266

Facile synthesis of Fe3O4@mesoporous TiO2 microspheres for selective enrichment of phosphopeptides for phosphoproteomics analysis.  

PubMed

Protein phosphorylation is one of the most important post-translational modifications. Due to the dynamic nature and low stoichiometry of the protein phosphorylation, enrichment of phosphopeptides from proteolytic mixtures is necessary prior to their characterization by mass spectrometry. In this work, we synthesized Fe3O4@mesoporous TiO2 magnetic microspheres with core-shell structure and large surface area for selective enrichment of phosphopeptides. To demonstrate its ability for selective enrichment of phosphopeptides, we applied Fe3O4@mesoporous TiO2 magnetic microspheres to isolation and enrichment of the phosphopeptides from tryptic digestion of standard proteins and real samples, and then the enriched peptides were analyzed by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) or liquid chromatography coupled to electrospray ionization mass spectrometry (LC-ESI-MS). Due to that the as-made Fe3O4@mesoporous TiO2 microspheres have large surface area, good dispersivity and biocompatibility, they have been demonstrated as a powerful tool for phosphoproteomics research. PMID:23597982

Lu, Jin; Wang, Mengyi; Deng, Chunhui; Zhang, Xiangmin

2013-02-15

267

Synthesis of LaVO4/TiO2 heterojunction nanotubes by sol-gel coupled with hydrothermal method for photocatalytic air purification.  

PubMed

With the aim of improving the effective utilization of visible light, the LaVO(4)/TiO(2) heterojunction nanotubes were fabricated by sol-gel coupled with hydrothermal method. The photocatalytic ability was demonstrated through catalytic removal of gaseous toluene species. The nanotube samples were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), surface photovoltage (SPV), Raman spectra and N(2) adsorption-desorption measurements. The characterization results showed that the samples with high specific surface areas were of typical nanotubular morphology, which would lead to the high separation and transfer efficiency of photo induced electron-hole pairs. The as-prepared nanotubes exhibited high photocatalytic activity in decomposing toluene species under visible light irradiation with fine photochemical stability. The enhanced photocatalytic performance of LaVO(4)/TiO(2) nanotubes might be attributed to the matching band potentials, the interconnected heterojunction of LaVO(4) versus TiO(2), and the large specific surface areas of nanotubes. PMID:22795044

Zou, Xuejun; Li, Xinyong; Zhao, Qidong; Liu, Shaomin

2012-10-01

268

A maskless synthesis of TiO2-nanofiber-based hierarchical structures for solid-state dye-sensitized solar cells with improved performance  

PubMed Central

TiO2 hierarchical nanostructures with secondary growth have been successfully synthesized on electrospun nanofibers via surfactant-free hydrothermal route. The effect of hydrothermal reaction time on the secondary nanostructures has been studied. The synthesized nanostructures comprise electrospun nanofibers which are polycrystalline with anatase phase and have single crystalline, rutile TiO2 nanorod-like structures growing on them. These secondary nanostructures have a preferential growth direction [110]. UV–vis spectroscopy measurements point to better dye loading capability and incident photon to current conversion efficiency spectra show enhanced light harvesting of the synthesized hierarchical structures. Concomitantly, the dye molecules act as spacers between the conduction band electrons of TiO2 and holes in the hole transporting medium, i.e., spiro-OMeTAD and thus enhance open circuit voltage. The charge transport and recombination effects are characterized by electrochemical impedance spectroscopy measurements. As a result of improved light harvesting, dye loading, and reduced recombination losses, the hierarchical nanofibers yield 2.14% electrochemical conversion efficiency which is 50% higher than the efficiency obtained by plain nanofibers. PMID:24410851

2014-01-01

269

Photocatalytic degradation of PCP-Na with TiO2 photocatalysis loaded with platinum.  

PubMed

Titanium dioxide (TiO2) samples of different crystal forms were prepared by hydrolysis tetrabutyl titanate in various water to alkoxide ratios and sintering the hydrolysis product at different temperatures. The photocatalysts coated on hollow glass beads and loaded with platinum varying from 0.2% to 2.4% by weight. The photocatalytic degradation rate of sodium pentachlorophenolate (PCP-Na) depends on the preparing conditions such as: sintering temperatures, water to alkoxide ratios (R), platinum content and the size. The proper conditions of preparation photocatalysts are as follows: the ratio of TiO2: sodium silicate: hollow glass beads: platinum is 10:5:20:0.15 (w/w), R is 100, sintering temperature is 650 degrees C, and the size of hollow glass is 0.5-1 mm. Under these conditions, the ratio between acatase and rutile of the photocatalyst is 2:1, and the photocatalytic activity is high. PMID:12211998

Xi, Bei-Dou; Liu, Hong-Liang

2002-07-01

270

Visible light photocatalytic degradation of 4-chlorophenol using vanadium and nitrogen co-doped TiO2  

NASA Astrophysics Data System (ADS)

Vanadium and Nitrogen were codoped in TiO2 photocatalyst by Sol-gel method to utilize visible light more efficiently for photocatalytic reactions. A noticeable shift of absorption edge to visible light region was obtained for the singly-doped namely V-TiO2, N-TiO2 and codoped V-N-TiO2 samples in comparison with undoped TiO2, with smallest band gap obtained with codoped-TiO2. The photocatalytic activities for all TiO2 photocatalysts were tested by 4-chlorophenol (organic pollutant) degradation under visible light irradiation. It was found that codoped TiO2 exhibits the best photocatalytic activity, which could be attributed to the synergistic effect produced by V and N dopants.

Jaiswal, R.; Patel, N.; Kothari, D. C.; Miotello, A.

2013-02-01

271

Photochemical Active of SiO2, WO3 Doping on TiO2 Thin Film in H2S Removal  

Microsoft Academic Search

Recently, photocatalytic oxidation of pollutant in air with semiconductor photocatalyst is a hot spot in environmental science. The feasibility study of photochemical active of degrade H2S by SiO2, WO3 doping on TiO2 thin film has been taken. SiO2\\/TiO2 and WO3\\/TiO2 composite photocatalyst thin films have been made, and its purification capacity of H2S gas has been tested. X-ray diffraction and

Ge Jie; Zhang Cheng-zhong; Liu Tao

2010-01-01

272

Stability and dynamics of carbon and nitrogen dopants in anatase TiO2 : A density functional theory study  

Microsoft Academic Search

The properties of carbon- and nitrogen-doped anatase TiO2 , a renowned photocatalyst, depend strongly on the atomic-scale details of dopant incorporation and dynamics. Here we identify with ab initio calculations stable structures of C dopants in TiO2 that differ from previous theoretical predictions. We also describe the evolution of dopants and point defects in terms of diffusion barriers and defect

L. Tsetseris

2010-01-01

273

Investigation of photocatalytic degradation of phenol by Fe(III)-doped TiO2 and TiO2 nanoparticles  

PubMed Central

In this study Fe (III)-doped TiO2 nanoparticles were synthesized by sol–gel method at two atomic ratio of Fe/Ti, 0.006 and 0.034 percent. Then the photoactivity of them was investigated on degradation of phenol under UV (<380 nm) irradiation and visible light (>380 nm). Results showed that at appropriate atomic ratio of Fe to Ti (% 0.034) photoactivity of Fe(III)–doped TiO2 nanoparticles increased. In addition, the effects of various operational parameters on photocatalytic degradation, such as pH, initial concentration of phenol and amount of photocatalyst were examined and optimized. At all different initial concentration, highest degradation efficiency occurred at pH =?3 and 0.5 g/L Fe(III)–doped TiO2 dosage. With increase in initial concentration of phenol, photocatalytic degradation efficiency decreased. Photoactivity of Fe (III)-doped TiO2 under UV irradiation and visible light at optimal condition (pH =?3 and catalyst dosage =?and 0.5 g/L) was compared with P25 TiO2 nanoparticles. Results showed that photoactivity of Fe(III)-doped TiO2 under visible light was more than P25 TiO2 photoactivity, but it was less than P25 TiO2 photoactivity under UV irradiation. Also efficiency of UV irradiation alone and amount of phenol adsorption on Fe(III)-doped TiO2 at dark condition was investigated. PMID:25105016

2014-01-01

274

Preparation and photocatalytic properties of silica gel-supported TiO 2  

Microsoft Academic Search

Silica gel-supported TiO2 was successfully prepared by post-synthesis hydrolytic restructuring method. The surface morphology and structure were characterized by scanning electron microscopy (SEM) and infrared (IR) spectra, respectively. TiO2 content was determined by the H2TiO2(SO4)2 colorimetric method and the specific surface area of the samples was investigated by BET method. The photocatalytic efficiency and adsorption properties of the samples were

Yan Min Wang; Su Wen Liu; Zhiliang Xiu; Xin Bing Jiao; Xiao Peng Cui; Jie Pan

2006-01-01

275

Influence of some physical parameters on sol-gel-derived TiO2 thin films  

Microsoft Academic Search

We present some physical parameters that affect the deposition of TiO2 films by the sol-gel method. A set of solutions with different TiO2 concentrations has been prepared. After synthesis of a set of TiO2 films by spin coating at different spinning speeds, the films were annealed at different temperatures. The viscosities of the start solutions were measured by a viscometer.

S. M. Attia; Jue Wang; Jun Shen; Guangming Wu; Qinyuan Zhang; Zhenquan Lai; Tianhe Yang

2000-01-01

276

Parameter effect on photocatalytic degradation of phenol using TiO 2 -P25\\/activated carbon (AC)  

Microsoft Academic Search

P25 powder embedded and TiO2 immobilized on activated carbon (TiO2-P25\\/AC) was prepared by P25 powder modified sol-gel and dip-coated method. The photocatalysts were characterized by XRD,\\u000a BET, SEM and their photocatalytic activities were evaluated through phenol degradation in a fluidized bed photoreactor. The\\u000a addition of P25 in the photocatalysts could significantly enhance the photocatalytic activity, and the optimum loading of

Sze-Mun Lam; Jin-Chung Sin; Abdul Rahman Mohamed

2010-01-01

277

Thermodynamically Driven One-Dimensional Evolution of Anatase TiO2 Nanorods: One-Step Hydrothermal Synthesis for Emerging Intrinsic Superiority of Dimensionality.  

PubMed

In photoelectrochemical cells, there exists a competition between transport of electrons through the porous semiconductor electrode toward the conducting substrate and back-reaction of electrons to recombine with oxidized species on the semiconductor-electrolyte interface, which determines the charge collection efficiency and is strongly influenced by the density and distribution of electronic states in band gap and architectures of the semiconductor electrodes. One-dimensional (1D) anatase TiO2 nanostructures are promising to improve charge transport in photoelectrochemical devices. However, the conventional preparation of 1D anatase nanostructures usually steps via a titanic acid intermediate (e.g., H2Ti3O7), which unavoidably introduces electronic defects into the host lattice, resulting in undesired shielding of the intrinsic role of dimensionality. Here, we manage to promote the 1D growth of anatase TiO2 nanostructures by adjusting the growth kinetics, which allows us to grow single-crystalline anatase TiO2 nanorods through a one-step hydrothermal reaction. The synthesized anatase nanorods possess a lower density of trap states and thus can simultaneously facilitate the diffusion-driven charge transport and suppress the electron recombination. Moreover, the electronically boundary free nanostructures significantly enhance the trap-free charge diffusion coefficient of the anatase nanorods, which enables the emergence of the intrinsic superiority of dimensionality. By virtue of these merits, the anatase nanorods synthesized in this work take obvious advantages over the conventional anatase counterparts in photoelectrochemical systems (e.g., dye-sensitized solar cells) by showing more efficient charge transport and collection and higher energy conversion efficiency. PMID:25290360

Chen, Jiazang; Yang, Hong Bin; Miao, Jianwei; Wang, Hsin-Yi; Liu, Bin

2014-10-29

278

Synthesis and characterization of maleimide-functionalized polystyrene-SiO2/TiO2 hybrid nanocomposites by sol-gel process.  

PubMed

Maleimide-functionalized polystyrene (PSMA-SiO2/TiO2) hybrid nanocomposites were prepared by sol-gel reaction starting from tratraethoxysilane (TEOS) and titanium isopropoxide in the solution of polystyrene maleimide in 1,4-dioxane. The hybrid films were obtained by the hydrolysis and polycondensation of TEOS and titanium isopropoxide in maleimide-functionalized polystyrene solution followed by the Michael addition reaction. The transparency of polymer (PSMA-SiO2/TiO2) hybrid was prepared from polystyrene titanium isopropoxide using the ?-aminopropyltriethoxy silane as crosslinking agent by in situ sol-gel process via covalent bonding between the organic-inorganic hybrid nanocomposites. The maleimide-functionalized polystyrene was synthesized by Friedel-Crafts reaction from N-choloromethyl maleimide. The FTIR spectroscopy data conformed the occurrence of Michael addition reaction between the pendant maleimide moieties of the styrene and ?-aminopropyltriethoxysilane. The chemical structure and morphology of PSMA-SiO2/TiO2 hybrid nanocomposites were characterized by FTIR, nuclear magnetic resonance (NMR), 13?C NMR, SEM, XRD, and TEM analyses. The results also indicate that the inorganic particles are much smaller in the ternary systems than in the binary systems; the shape of the inorganic particles and compatibility for maleimide-functionalized polystrene and inorganic moieties are varied with the ratio of the inorganic moieties in the hybrids. Furthermore, TGA and DSC results indicate that the thermal stability of maleimide-functionalized polystyrene was enhanced through the incorporation of the inorganic moieties in the hybrid materials. PMID:22738226

Ramesh, Sivalingam; Sivasamy, Arumugam; Kim, Joo-Hyung

2012-01-01

279

Synthesis and characterization of maleimide-functionalized polystyrene-SiO2/TiO2 hybrid nanocomposites by sol-gel process  

NASA Astrophysics Data System (ADS)

Maleimide-functionalized polystyrene (PSMA-SiO2/TiO2) hybrid nanocomposites were prepared by sol-gel reaction starting from tratraethoxysilane (TEOS) and titanium isopropoxide in the solution of polystyrene maleimide in 1,4-dioxane. The hybrid films were obtained by the hydrolysis and polycondensation of TEOS and titanium isopropoxide in maleimide-functionalized polystyrene solution followed by the Michael addition reaction. The transparency of polymer (PSMA-SiO2/TiO2) hybrid was prepared from polystyrene titanium isopropoxide using the ?-aminopropyltriethoxy silane as crosslinking agent by in situ sol-gel process via covalent bonding between the organic-inorganic hybrid nanocomposites. The maleimide-functionalized polystyrene was synthesized by Friedel-Crafts reaction from N-choloromethyl maleimide. The FTIR spectroscopy data conformed the occurrence of Michael addition reaction between the pendant maleimide moieties of the styrene and ?-aminopropyltriethoxysilane. The chemical structure and morphology of PSMA-SiO2/TiO2 hybrid nanocomposites were characterized by FTIR, nuclear magnetic resonance (NMR), 13 C NMR, SEM, XRD, and TEM analyses. The results also indicate that the inorganic particles are much smaller in the ternary systems than in the binary systems; the shape of the inorganic particles and compatibility for maleimide-functionalized polystrene and inorganic moieties are varied with the ratio of the inorganic moieties in the hybrids. Furthermore, TGA and DSC results indicate that the thermal stability of maleimide-functionalized polystyrene was enhanced through the incorporation of the inorganic moieties in the hybrid materials.

Ramesh, Sivalingam; Sivasamy, Arumugam; Kim, Joo-Hyung

2012-06-01

280

Synthesis and characterization of maleimide-functionalized polystyrene-SiO2/TiO2 hybrid nanocomposites by sol-gel process  

PubMed Central

Maleimide-functionalized polystyrene (PSMA-SiO2/TiO2) hybrid nanocomposites were prepared by sol–gel reaction starting from tratraethoxysilane (TEOS) and titanium isopropoxide in the solution of polystyrene maleimide in 1,4-dioxane. The hybrid films were obtained by the hydrolysis and polycondensation of TEOS and titanium isopropoxide in maleimide-functionalized polystyrene solution followed by the Michael addition reaction. The transparency of polymer (PSMA-SiO2/TiO2) hybrid was prepared from polystyrene titanium isopropoxide using the ?-aminopropyltriethoxy silane as crosslinking agent by in situ sol–gel process via covalent bonding between the organic–inorganic hybrid nanocomposites. The maleimide-functionalized polystyrene was synthesized by Friedel-Crafts reaction from N-choloromethyl maleimide. The FTIR spectroscopy data conformed the occurrence of Michael addition reaction between the pendant maleimide moieties of the styrene and ?-aminopropyltriethoxysilane. The chemical structure and morphology of PSMA-SiO2/TiO2 hybrid nanocomposites were characterized by FTIR, nuclear magnetic resonance (NMR), 13?C NMR, SEM, XRD, and TEM analyses. The results also indicate that the inorganic particles are much smaller in the ternary systems than in the binary systems; the shape of the inorganic particles and compatibility for maleimide-functionalized polystrene and inorganic moieties are varied with the ratio of the inorganic moieties in the hybrids. Furthermore, TGA and DSC results indicate that the thermal stability of maleimide-functionalized polystyrene was enhanced through the incorporation of the inorganic moieties in the hybrid materials. PMID:22738226

2012-01-01

281

Photocatalytic oxidation of chloroform using immobilized-biogenic TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

Although commercial titanium dioxide (TiO2) nanoparticles as a suspension in water are one of the most popular photocatalysts for treatment of chlorinated organic compounds, the reuse and recovery of the nanoscale phtocatalyst is a practical challenge for application in water and groundwater treatment system. As part of efforts to overcome this practical limitation, development of immobilized TiO2 is needed. Diatom Pinnularia sp. were found to be capable of producing nanoscale TiO2 in their microscale silica shells. In order to obtain biogenic TiO2 nanoparticles from Pinnularia sp., soluble Ti was fed to the silicon-starved cells, resulting in deposition of titanium on the microscale features of the silica shells. After thermal treatment at 720 oC for 2 hr, the titanium was eventually converted to nanoscale TiO2. In order to determine the physical and chemical properties of the immobilized TiO2, material characterization such as TEM, STEM-EDS, BET and XRD analysis was carried out. In this study, a novel type of immobilized photocatalytic nanoparticles, biogenic TiO2 on silica shells was used for the mineralization of chloroform in water. Batch tests were conducted to evaluate the chloroform removal efficiency of biogenic and commercial TiO2 nanoparticles. Also, the amount of Cl- ions in water during the mineralization was measured to check mineralization of chloroform by biogenic TiO2 nanoparticles. Kinetic models were used to determine the rate of chloroform mineralization. In addition, the effect of UVA (ultraviolet-A) intensity on chloroform mineralization was investigated. The results obtained from this study could provide useful information for practical application of biogenic TiO2 in the groundwater treatment contaminated with some chlorinated organic compounds.

Kim, Y.; Cho, Y.; Yoo, H.

2011-12-01

282

Study on a novel POM-based magnetic photocatalyst: Photocatalytic degradation and magnetic separation  

Microsoft Academic Search

The photocatalytic performance of a novel polyoxometalate (POM)-based magnetic photocatalyst was studied by photocatalytic degradation of a model compound (formic acid) in an annular fluidized bed photoreactor. Degradation rate, apparent quantum efficiency, and energy efficiency were evaluated and compared with suspended TiO2 fine particles (Degussa P25) and quartz sand supported TiO2 photocatalysts. All degradation experiments were conducted under fully irradiated

Wei Qiu; Ying Zheng; Katy A. Haralampides

2007-01-01

283

Efficient visible light driven photocatalytic removal of NO with aerosol flow synthesized B, N-codoped TiO2 hollow spheres.  

PubMed

In this study, we demonstrate that aerosol assisted flow synthesized B, N-codoped TiO(2) photocatalyst possesses superior photocatalytic activity to pure and single element doped counterparts on the degradation of NO in a flow system under both simulated solar light and visible light irradiation. Characterization results revealed that B, N-codoped TiO(2) photocatalyst was composed of hollow microspheres. Boron and nitrogen were in the form of Ti-O-B and N-Ti-O structures, respectively. The introduction of B and N into the TiO(2) lattice could effectively tune the band gap of TiO(2) and extend its optical response to the visible-light region. The synergistic effect of B and N codoping on visible light driven photocatalytic activity enhancement of TiO(2) was discussed on the basis of experimental results. PMID:21514043

Ding, Xing; Song, Xiao; Li, Pengna; Ai, Zhihui; Zhang, Lizhi

2011-06-15

284

Controllable hydrothermal synthesis of rutile TiO2 hollow nanorod arrays on TiCl4 pretreated Ti foil for DSSC application  

NASA Astrophysics Data System (ADS)

Rutile TiO2 nanorod arrays (TNRs) were achieved by hydrothermal process on TiCl4 pretreated Ti foil. Subsequently, TNRs were hydrothermally etched in HCl solution to form hollow TiO2 nanorod arrays (H-TNRs). The TiCl4 pretreatment plays key roles in enhancement of Ti foil corrosion resistance ability and crystal nucleation introduction for TNRs growth. TNRs with desired morphology can be obtained by controlling TiCl4 concentration and the amount of tetrabutyl titanate (TTB) accordingly. TNRs with the length of ~1.5 ?m and diameter of ~200 nm, obtained on 0.15 M TiCl4 pretreated Ti foil with 0.6 mL TTB, exhibits relatively higher photocurrent. The increased pore volume of the H-TNRs has contributed to the increased surface area which is benefit for Dye-Sensitized Solar Cells (DSSC) application. And the 180 °C-H-TNRs photoanode obtained from the 0.15-TiCl4-TNRs sample demonstrated 128.9% enhancement of photoelectric efficiency of DSSC compared to that of the original TNR photoanode.

Xi, Min; Zhang, Yulan; Long, Lizhen; Li, Xinjun

2014-11-01

285

In-situ synthesis of TiO2 network nanoporous structure on Ti wire substrate and its application in fiber dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

In this paper, we explore a two-step treatment method to modify the Ti wires which are used as anode substrates of fiber dye sensitized solar cells (FDSSCs). A special kind of network nanoporous structure is formed on the surface of Ti wire substrates through sodium hydroxide hydrothermal reaction and titanium tetrachloride (TiCl4) assistant treatment. Nanoporous structures with different sizes are in-situ grown on the Ti wire substrates by changing the hydrothermal reaction condition. Then, TiO2 network nanoporous structures with branch-like nano-structure or 2D nanoflakes are obtained after TiCl4 treatment. The effects of these network nanoporous structures on the FDSSC performances are investigated intensively. It is found that these special network nanoporous structures between TiO2 nanoparticle active layer and Ti wire substrate are beneficial to the connection of the nanoparticle layer and fiber-shaped substrate, thus improving the electron transport rate and prolonging electron lifetime. As a result, the power conversion efficiency of this parallel assembled FDSSC increases to 4.64% from 2.56% after this two-step treatment.

Tao, Hong; Fang, Guo-jia; Ke, Wei-jun; Zeng, Wei; Wang, Jing

2014-01-01

286

Synthesis of TiO(2)/WO(3)/MnO(2) composites and high-throughput screening for their photoelectrical properties.  

PubMed

On the basis of the idea of equilateral ingredient triangle, a material library of the TiO(2)/WO(3)/MnO(2) composite material system was designed, which consisted of 66 ingredient points. Each point in the library corresponded with a device. To fabricate the device, the technology of screen printing was used. The pastes which were suitable for this technology were prepared by ball milling. After we printed the pastes onto the alumina substrate which had been preprinted with Au interdigital electrodes, these printed samples were sintered at 550 degrees C for 2 h in air. The photocurrent of each device under different light sources was measured respectively using a high-throughput screening system. The largest photocurrent was observed when the mole ratio of TiO(2)/WO(3) was 2/8 in the composite system. X-ray diffraction (XRD) was used to investigate the phase structure of the powder which had excellent photoelectric response. PMID:20225882

Zou, Zhijun; Liu, Yuan; Li, Huayao; Liao, Yichuan; Xie, Changsheng

2010-05-10

287

Unique properties of 2?D layered titanate nanosheets as a building block for the optimization of the photocatalytic activity and photostability of TiO2-based nanohybrids.  

PubMed

In comparison with the hybridization with 0D TiO2 nanoparticle, 2D layered TiO2 nanosheets are much more effective in the improvement of the photocatalytic activity and photostability of semiconducting compounds. The 2D TiO2-Ag3PO4 nanohybrid described in this paper shows a greater decrease in the electron-hole recombination upon hybridization and a stronger chemical interaction between the components than the 0D homologue. This result confirms the benefits of 2D layered TiO2 nanosheets as a building block for efficient hybrid-type photocatalyst materials. PMID:25042969

Jo, Yun Kyung; Kim, In Young; Gunjakar, Jayavant L; Lee, Jang Mee; Lee, Nam-Suk; Lee, Sang-Hyup; Hwang, Seong-Ju

2014-08-01

288

Sterilization effect of UV light on Bacillus spores using TiO(2) films depends on wavelength.  

PubMed

UV light and photocatalysts such as titanium dioxide (TiO(2)) and silver (Ag) are useful for disinfection of water and surfaces. However, the effect of UV wavelength on photocatalytic disinfection of spores is not well understood. Inactivation of Bacillus spores has been examined using different UV wavelengths and TiO(2) or TiO(2)/Ag composite materials. The level of UVA disinfection of Bacillus anthracis and Bacillus brevis vegetative cells increased with the presence of the TiO(2) and Ag photocatalysts, but had little effect on their spores. B. brevis spores were slightly more sensitive to UVB and UVC than the spores of B. atrophaeus. Photocatalytic sterilization against spores was strongest in UVC and UVB and weakest in UVA. The rate of inactivation of Bacillus spores was significantly increased by the presence of TiO(2), but was not markedly different from that induced by the presence of Ag. Therefore, TiO(2)/Ag plus UVA can be used for the sterilization of vegetative cells, while TiO(2) and UVC are effective against spores. PMID:22449993

Nhung, Le Thi Tuyet; Nagata, Hirofumi; Takahashi, Akira; Aihara, Mutsumi; Okamoto, Toshihiro; Shimohata, Takaaki; Mawatari, Kazuaki; Akutagawa, Masatake; Kinouchi, Yhosuke; Haraguchi, Masanobu

2012-01-01

289

Enhancing selective decomposition of ibuprofen onto porous TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

Advanced oxidation technologies have gained tremendous attention for water treatment purposes after demonstration of insufficient efficiency of conventional systems for removal of many emerging chemicals of concern. Among AOTs, a TiO2-UV system is one of the most promising approaches due to its green properties and its effectiveness in generation of extremely oxidizing species such as hydroxyl radicals. However it has been demonstrated that non-selectivity of HRs in decomposition of organic compounds results in parallel decomposing of naturally abundant organic matter (NOM) along with toxic target contaminant, which significantly decreases the decomposition rate of target contaminants. Despite a great amount of researches conducted on TiO2 photocatalysts, limited success has been achieved in enhancing selectivity of TiO2 photocatalytic oxidation. In this study, a novel approach for suppressing the adverse effect of co-existing organics such as NOM has been proposed. Physical access of competing compounds was restrained through manipulation of the porous structure of TiO2 photocatalysts. An advanced templating method was employed to create a porous structure across TiO2 nanoparticles. In this study Ibuprofen as a target contaminant was decomposed in the presence of humic acid as competing NOM. Porous particles demonstrated significant improvement in selective decomposition of ibuprofen in the presence of humic acid as competing species. In the second phase of the study, a comprehensive study was conducted through changing the porous structure and size of co-existing organics in competing and non-competing conditions. The photocatalytic results, in correlation with material characterization demonstrated beneficial role of the controlled porous structure on adsorption followed by decomposition of organic species onto TiO2 photocatalysts.

Zakersalehi, Abolfazl

290

Ultrasonically assisted hydrothermal synthesis of nanocrystalline ZrO2, TiO2, NiFe2O4 and Ni0.5Zn0.5Fe2O4 powders.  

PubMed

Ultrasonic-hydrothermal and hydrothermal treatment was used for synthesis of nanocrystalline zirconia, titania, nickel and nickel-zinc ferrites powders from precipitated amorphous zirconyl, titanyl, binary nickel-iron and ternary nickel-zinc-iron hydroxides, respectively. Resulted nanopowders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption (BET), and magnetic susceptibility measurements. It was established that ultrasonically assisted hydrothermal treatment of amorphous zirconyl and titanyl gels results in significant rise of the rate of ZrO2 and TiO2 crystallization and promotes formation of thermodynamically stable monoclinic zirconia, but does not affect the microstructure and mean particles size of resulting nanopowders. Ultrasonic-hydrothermal processing of co-precipitated amorphous nickel, zinc and iron hydroxides favours formation of nanocrystalline ferrite powders with narrower particle size distribution. PMID:16223687

Meskin, Pavel E; Ivanov, Vladimir K; Barantchikov, Alexander E; Churagulov, Bulat R; Tretyakov, Yury D

2006-01-01

291

Facile one-pot hydrothermal synthesis of B/N-codoped TiO2 hollow spheres with enhanced visible-light photocatalytic activity and photoelectrochemical property  

NASA Astrophysics Data System (ADS)

B/N-codoped TiO2 hollow spheres (B/N-THs) were synthesized by facile one-pot hydrothermal method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption isotherms, UV-vis diffuse reflectance spectrum (DRS) and X-ray photoelectron spectroscopy (XPS). The B/N-THs have large surface areas (up to 172.1 m2 g-1). The photocatalytic activities of as-prepared THs were evaluated by degradation of Reactive Brilliant Red dye X-3B solution under visible light irradiation. The results showed that B/N-THs exhibited the highest photocatalytic activity due to their high surface area and synergetic effect of B/N-codoped. A photocurrent-time spectrum was examined by anodic photocurrent response to characterize the electron-transferring efficiency in the process of photocatalysis reaction.

Lin, Xiaoxia; Fu, Degang

2014-08-01

292

Hydrogenated TiO2 nanotube arrays for supercapacitors.  

PubMed

We report a new and general strategy for improving the capacitive properties of TiO(2) materials for supercapacitors, involving the synthesis of hydrogenated TiO(2) nanotube arrays (NTAs). The hydrogenated TiO(2) (denoted as H-TiO(2)) were obtained by calcination of anodized TiO(2) NTAs in hydrogen atmosphere in a range of temperatures between 300 to 600 °C. The H-TiO(2) NTAs prepared at 400 °C yields the largest specific capacitance of 3.24 mF cm(-2) at a scan rate of 100 mV s(-1), which is 40 times higher than the capacitance obtained from air-annealed TiO(2) NTAs at the same conditions. Importantly, H-TiO(2) NTAs also show remarkable rate capability with 68% areal capacitance retained when the scan rate increase from 10 to 1000 mV s(-1), as well as outstanding long-term cycling stability with only 3.1% reduction of initial specific capacitance after 10,000 cycles. The prominent electrochemical capacitive properties of H-TiO(2) are attributed to the enhanced carrier density and increased density of hydroxyl group on TiO(2) surface, as a result of hydrogenation. Furthermore, we demonstrate that H-TiO(2) NTAs is a good scaffold to support MnO(2) nanoparticles. The capacitor electrodes made by electrochemical deposition of MnO(2) nanoparticles on H-TiO(2) NTAs achieve a remarkable specific capacitance of 912 F g(-1) at a scan rate of 10 mV s(-1) (based on the mass of MnO(2)). The ability to improve the capacitive properties of TiO(2) electrode materials should open up new opportunities for high-performance supercapacitors. PMID:22364294

Lu, Xihong; Wang, Gongming; Zhai, Teng; Yu, Minghao; Gan, Jiayong; Tong, Yexiang; Li, Yat

2012-03-14

293

Synthesis, characterization and photocatalytic activity of new photocatalyst CdBiYO4  

NASA Astrophysics Data System (ADS)

CdBiYO4 was synthesized by a solid-state reaction method for the first time. The structural and photocatalytic properties of CdBiYO4 had been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray spectrometry. CdBiYO4 crystallized with a tetragonal spinel structure by space group I41/amd. The lattice parameters for CdBiYO4 were a = b = 14.519 Å and c = 9.442 Å. The band gap of CdBiYO4 was estimated to be 2.41 eV. The photocatalytic degradation of methylene blue (MB) was realized under visible light irradiation with CdBiYO4 as catalyst. The results showed that CdBiYO4 owned higher photocatalytic activity compared with pure TiO2 or N-doped TiO2 for photocatalytic degradation of MB under visible light irradiation. The photocatalytic degradation of MB with CdBiYO4 or N-doped TiO2 as catalyst followed the first-order reaction kinetics, and the first-order rate constant was 0.0137 or 0.0033 min-1. After visible light irradiation for 225 min with CdBiYO4 as catalyst, complete removal and mineralization of MB were observed. The reduction of the total organic carbon, the formation of inorganic products, SO42- and NO3-, and the evolution of CO2 revealed the continuous mineralization of MB during the photocatalytic process. The possible photocatalytic degradation pathway of MB was obtained under visible light irradiation. CdBiYO4/(visible light) photocatalysis system was found to be suitable for textile industry wastewater treatment and could be utilized to resolve other environmental chemical pollution problems.

Du, Huiyang; Luan, Jingfei

2012-09-01

294

Characterization of Pure and Modified TiO2 Layer on Glass and Aluminum Support by Beam Deflection Spectrometry  

NASA Astrophysics Data System (ADS)

{TiO}2 thin films used as photocatalysts in environmental applications were studied by beam deflection spectroscopy (BDS) and by atomic force microscopy. A novel multiparameter theoretical model was developed in order to explain BDS experimental data. The fundamental parameters of examined films: thermal diffusivity, thermal conductivity, and charge transport properties such as the value of the energy bandgap, carrier lifetime, concentration, and type of dopants, were obtained as results of the modeling of BDS data. With BDS, we observed that the material's thermal conductivity and thermal diffusivity depend also on the porosity and the surface roughness of films. Consequently, the photocatalytic performance can be estimated by measuring the thermal diffusivity of films. Furthermore, we found that surface roughness is prone to changes when the film is used as photocatalysts in water purification processes. During the purification process, the roughness decreases and the photocatalytical performance drops. Moreover, it was discovered that the thermal, electrical, and morphological properties of photocatalysts films depend on the support to which the {TiO}2 layer is deposited. These complex relations demonstrate that knowledge of fundamental physical parameters is required in order to improve the photocatalytic performance of {TiO}2 films. In this view, the BDS measurements offer a tool for noncontact and nondestructive evaluation of thermal and electronic parameters of thin film {TiO}2 photocatalysts as demonstrated in this work.

Korte, Dorota; Pavlica, Egon; Bratina, Gvido; Franko, Mladen

2013-12-01

295

CORONA DISCHARGE REACTOR FOR SELECTIVE OXIDATION OF ALCOHOLS AND HYDROCARBONS USING OZONATION AND PHOTOXIDATION OF OVER TIO2  

EPA Science Inventory

We have developed a process that combines the use of surface corona for the production of ozone by passing air or oxygen through a high voltage electrical discharge and the emitted UV is being used to activate a photocatalyst. A thin film of nanostructured TiO2 with primary part...

296

Doping mode, band structure and photocatalytic mechanism of B-N-codoped TiO 2  

NASA Astrophysics Data System (ADS)

The photocatalyst B and N codoped TiO 2 (B-N-TiO 2) was prepared via the sol-gel method by using boric acid and ammonia as B and N precursors. The doping mode, band structure and photocatalytic mechanism of B-N-TiO 2 were investigated well and elucidated in detail. B-N-TiO 2 showed the narrowed band gap and thus extended the optical absorption due to interstitial N and [NOB] species in the TiO 2 crystal lattice. The coexistence of interstitial N and [NOB] species in the TiO 2 crystal lattice and surface NO x species allowed the more efficient utilization of visible light. Simultaneously, interstitial [NOB] and N species and surface B 2O 3 and NO x species facilitated the separation of photo generated electrons and holes and suppress their recombination effectively. Hence, B-N-TiO 2 showed a higher photocatalytic activity than pure TiO 2, N-doped TiO 2 (N-TiO 2) and B-doped TiO 2 (B-TiO 2) under both UV and visible light irradiation.

Yuan, Jixiang; Wang, Enjun; Chen, Yongmei; Yang, Wensheng; Yao, Jianghong; Cao, Yaan

2011-06-01

297

First-principles study on transition metal-doped anatase TiO2  

NASA Astrophysics Data System (ADS)

The electronic structures, formation energies, and band edge positions of anatase TiO2 doped with transition metals have been analyzed by ab initio band calculations based on the density functional theory with the planewave ultrasoft pseudopotential method. The model structures of transition metal-doped TiO2 were constructed by using the 24-atom 2 × 1 × 1 supercell of anatase TiO2 with one Ti atom replaced by a transition metal atom. The results indicate that most transition metal doping can narrow the band gap of TiO2, lead to the improvement in the photoreactivity of TiO2, and simultaneously maintain strong redox potential. Under O-rich growth condition, the preparation of Co-, Cr-, and Ni-doped TiO2 becomes relatively easy in the experiment due to their negative impurity formation energies, which suggests that these doping systems are easy to obtain and with good stability. The theoretical calculations could provide meaningful guides to develop more active photocatalysts with visible light response.

Wang, Yaqin; Zhang, Ruirui; Li, Jianbao; Li, Liangliang; Lin, Shiwei

2014-01-01

298

Improvement of solar energy conversion with Nb-incorporated TiO2 hierarchical microspheres.  

PubMed

Niobium-modified TiO2 hierarchical spherical micrometer-size particles, which consist of many nanowires, are synthesized by solvothermal synthesis and studied as photoelectrodes for water photo-oxidation and dye-sensitized solar cell (DSSC) applications. Incorporation of Nb leads to a rutile-to-anatase TiO2 phase transition in the TiO2 hierarchical spheres (HSs), with the anatase percentage increasing from 0% for the pristine TiO2 HSs to 47.6% for the 1.82 at.% Nb-incorporated TiO2 sample. Incorporation of Nb leads to significant improvements in water photo-oxidation with the photocurrents reaching 70.5 ?A cm(-2) at 1.23 V versus the reversible hydrogen electrode, compared with 28.3 ?A cm(-2) for the pristine TiO2 sample. The photoconversion efficiency of Nb:TiO2 HS-based DSSCs reaches 6.09±0.15% at 0.25 at.% Nb, significantly higher than that for the pristine TiO2 HS cells (3.99±0.02%). In addition, the incident-photon-to-current efficiency spectra for DSSCs show that employing TiO2 and Nb:TiO2 HSs provides better light harvesting, especially of long-wavelength photons, than anatase TiO2 nanoparticle-based DSSCs. PMID:23512241

Hoang, Son; Ngo, Thong Q; Berglund, Sean P; Fullon, Raymond R; Ekerdt, John G; Mullins, C Buddie

2013-07-22

299

A Novel Method for Synthesis of TiO2 Nanoparticles-coated Plastic Fibers Using a Vibration Method and the Use of Coated Fibers as Photocatalitic Materials for Decomposing of Organic Pollutant in Water under Sunlight Illumination  

NASA Astrophysics Data System (ADS)

Photocatalytic is a catalyst process that requires light energy in process of converting material in a chemical reaction. TiO2 is one of the most suitable materials in photocatalytic process. In this study, TiO2 nanoparticles-coated plastic fibers made by using vibrating method. TiO2 nanoparticles-coated plastic fibers products used for wastewater purification using photocatalytic process. Speed of water purification is influenced by TiO2 nanoparticles-coated plastic fibers position on container. TiO2 nanoparticles-coated plastic fibers with horizontal position on container has a faster photocatalytic process compared to TiO2 nanoparticles-coated plastic fibers with vertical position on container.

Isnaini, Vandri Ahmad; Amalia, Irma Fitria; Aliah, Hasniah; Arutanti, Osi; Masturi, Nuryadin, Bebeh Wahid; Abdullah, Mikrajuddin; Khairurrijal

2010-10-01

300

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts.  

PubMed

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol-gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate. PMID:24647187

Chen, C; Xie, Q; Hu, B Q; Zhao, X L

2014-01-01

301

Bactericidal Performance of Visible-Light Responsive Titania Photocatalyst with Silver Nanostructures  

PubMed Central

Background Titania dioxide (TiO2) photocatalyst is primarily induced by ultraviolet light irradiation. Visible-light responsive anion-doped TiO2 photocatalysts contain higher quantum efficiency under sunlight and can be used safely in indoor settings without exposing to biohazardous ultraviolet light. The antibacterial efficiency, however, remains to be further improved. Methodology/Principal Findings Using thermal reduction method, here we synthesized silver-nanostructures coated TiO2 thin films that contain a high visible-light responsive antibacterial property. Among our tested titania substrates including TiO2, carbon-doped TiO2 [TiO2 (C)] and nitrogen-doped TiO2 [TiO2 (N)], TiO2 (N) showed the best performance after silver coating. The synergistic antibacterial effect results approximately 5 log reductions of surviving bacteria of Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus and Acinetobacter baumannii. Scanning electron microscope analysis indicated that crystalline silver formed unique wire-like nanostructures on TiO2 (N) substrates, while formed relatively straight and thicker rod-shaped precipitates on the other two titania materials. Conclusion/Significance Our results suggested that proper forms of silver on various titania materials could further influence the bactericidal property. PMID:20454454

Chang, Hsin-Hou

2010-01-01

302

[Photocatalytic degradation of low level formaldehyde on TiO2 porous film].  

PubMed

Photocatalytic degradation of low level formaldehyde in the gas phase was studied in a intermittent recirculation photocatalytic reaction system with TiO2 porous film photocatalyst coated on stainless steel mesh. The effects of carrier of the photocatalyst, coating cycle of the photocatalyst, the initial concentration of formaldehyde and the illumination source were investigated respectively. The study of the aging stability of the photocatalyst was carried out as well. Results show that the degradation efficiency of formaldehyde increased with the increase of mesh number. The degradation efficiency also increased with the increase of carrier number, but the influence of carrier number on the degradation efficiexcy was gradually weakened with increasing carrier number. The activity of the photocatalyst firstly increased and then decreased when coating cycle increased from 1 cycle to 6 cycles. When initial concentration was in the range of 1.34 - 10.72 mg/m3, the change of formaldehyde concentration markedly increased with the increase of initial concentration, but the degradation efficiency increased and subsequently decreased with increasing initial concentration. The degradation efficiency with germicidal light was approximately 19.0% higher than that with black light holding same power, and the enhancement in light intensity could approximately increase the degradation efficiency by 20.5%. Finally, the experiment on the longevity of the photocatalyst indicated that the photocatalyst had the good photocatalytic activity after being used for 4 cycles. PMID:16212164

Yang, Qing; Guo, Fen; Xing, Ying; Xian, Cai-Jun; Guo, Bao-Wen

2005-07-01

303

Photocatalytic process of simultaneous desulfurization and denitrification of flue gas by TiO2-polyacrylonitrile nanofibers.  

PubMed

TiO2 nanoparticles were successfully fabricated on electrospun polyacrylonitrile (PAN) nanofibers via the coupling of electrospinning and hydrothermal pathway. A straightforward photocatalysis oxidation process has been developed for simultaneous desulfurization and denitrification of flue gas using the TiO2-PAN photocatalyst. Also, the influences of some important operating parameters, such as titanium loading content of catalyst, flue gas humidity, flue gas flow, and inlet flue gas temperature on removal efficiencies of SO2 and NO were investigated. The results demonstrated that removal efficiencies of 99.3% for SO2 and 71.2% for NO were attained under the following optimal experiment conditions: titanium loading content, 6.78 At %; gas flow rate, 200 mL/min; flue gas humidity, 5%; inlet flue gas temperature, 40 °C. Furthermore, the presumed reaction mechanism of SO2 and NO removal using TiO2-PAN photocatalyst under UV light was proposed. PMID:24024677

Su, Chunyan; Ran, Xu; Hu, Jianglei; Shao, Changlu

2013-10-15

304

Sol-gel synthesis and characterization of pure and manganese doped TiO2 nanoparticles--a new NLO active material.  

PubMed

Pure and Manganese (4%, 8%, 12% and 16%) doped titanium di-oxide (Mn-TiO2) nanoparticles were synthesized by sol-gel technique. The preparation of pure and Mn doped TiO2 nanoparticles were achieved by tetra-isopropyl orthotitanate and 2-propanol as common starting materials and the products were annealed at 450°C and 750°C to get anatase and rutile phases, respectively. The prepared materials were characterized by X-ray diffraction analysis (XRD), Fourier transform infra-red spectroscopy (FT-IR), UV-VIS-Diffuse reflectance spectroscopy (DRS), Photoluminescence (PL) spectroscopy, Scanning electron microscopy (SEM) with Energy dispersive X-ray analysis (EDX) and Kurtz powder second harmonic generation (SHG) test. XRD patterns confirmed the crystalline nature and tetragonal structure of synthesized materials. The functional groups present in the samples were identified by FTIR study. The allowed direct and indirect band gap energies, as well as the crystallite sizes of obtained nanoparticles were calculated from DRS analysis. Microstructures and elemental identification were done by SEM with EDX analysis. The existence of SHG signals was observed using Nd: YAG laser with fundamental wavelength of 1064 nm. The products were found to be transparent in the entire visible region with cut-off wavelengths within the UV region confirms its suitability for device fabrications. PMID:24374482

Praveen, P; Viruthagiri, G; Mugundan, S; Shanmugam, N

2014-01-01

305

Synthesis and growth mechanism of thin-film TiO2 nanotube arrays on focused-ion-beam micropatterned 3D isolated regions of titanium on silicon.  

PubMed

In this paper, the fabrication and growth mechanism of net-shaped micropatterned self-organized thin-film TiO2 nanotube (TFTN) arrays on a silicon substrate are reported. Electrochemical anodization is used to grow the nanotubes from thin-film titanium sputtered on a silicon substrate with an average diameter of ~30 nm and a length of ~1.5 ?m using aqueous and organic-based types of electrolytes. The fabrication and growth mechanism of TFTN arrays from micropatterned three-dimensional isolated islands of sputtered titanium on a silicon substrate is demonstrated for the first time using focused-ion-beam (FIB) technique. This work demonstrates the use of the FIB technique as a simple, high-resolution, and maskless method for high-aspect-ratio etching for the creation of isolated islands and shows great promise toward the use of the proposed approach for the development of metal oxide nanostructured devices and their integration with micro- and nanosystems within silicon-based integrated-circuit devices. PMID:23957211

Hamedani, Hoda Amani; Lee, Simon W; Al-Sammarraie, Abdulkareem; Hesabi, Zohreh R; Bhatti, Asim; Alamgir, Faisal M; Garmestani, Hamid; Khaleel, Mohammad A

2013-09-25

306

TiO2 promoted by two different non-noble metal cocatalysts for enhanced photocatalytic H2 evolution  

NASA Astrophysics Data System (ADS)

TiO2 photocatalysts modified by cobalt and nickel cocatalysts were prepared via polymerized complex method (PCM) and evaluated by photocatalytic hydrogen evolution. Hydrogen generation in 6 h for the TiO2 promoted by cobalt and nickel (0.1%Co + 0.2%Ni/TiO2) is about two times (2456 ?mol H2) compared to that of TiO2 promoted only by cobalt (1180 ?mol H2 for 0.1%Co/TiO2) or nickel (1127 ?mol H2 for 0.2%Ni/TiO2), and mechanically mixed TiO2 promoted by cobalt and TiO2 promoted by nickel (0.1%Co/TiO2:0.2%Ni/TiO2 = 1:1 (m/m), 1282 ?mol H2). The high photocatalytic H2 evolution activity over TiO2 promoted by cobalt and nickel is ascribed to enhanced photo response due to the presence of cobalt and nickel impurity level, and effective separation of photogenerated electrons and holes due to the synergistic effect of cobalt and nickel, which serve as active sites for H2 evolution reaction (HER) and oxidation reaction (OR) respectively. This study demonstrates a viable strategy to design more active photocatalysts for photocatalytic H2 evolution by substituting noble metals with more abundant elements using as HER and OR cocatalysts, respectively.

Lin, Jing-Dong; Yan, Shi; Huang, Qin-Dong; Fan, Mei-Ting; Yuan, You-Zhu; Tan, Timothy Thatt-Yang; Liao, Dai-Wei

2014-08-01

307

Ag3PO4/TiO2 composite for efficient photodegradation of organic pollutants under visible light  

NASA Astrophysics Data System (ADS)

Photocatalytic degradation of organic pollutants attracts much attention in environment remediation, and it is still a challenge to develop highly efficient and stable visible-light-response photocatalyst. Herein, we synthesized Ag3PO4/TiO2 (P-25) composite via a facile in situ precipitation method to enhance the activity and stability of Ag3PO4. SEM and TEM characterizations indicate TiO2 particles are dispersed on Ag3PO4 surface, resulting in heterojunction interfaces. UV-vis DRS spectra show that TiO2 in the composite does not interfere the absorption of visible light, while the photoluminescence spectra confirm TiO2 inhibits the recombination of photo-induced charges. Therefore, during the photodegradation of organic pollutants under visible light, the composites are much more active than pure Ag3PO4. Moreover, XPS and XRD analysis show the reduction of Ag3PO4 to Ag0 is retarded during the photoreaction. Furthermore, the effect of TiO2 amount in the composites was studied, and AP12 is the most active with the reaction rate being 1.43 times higher than pure Ag3PO4. The strategy of using TiO2 as activity and stability promoter to construct the composite may be useful in developing highly active and stable visible-light photocatalyst for pollutants removal.

Zhao, Feng-Min; Pan, Lun; Wang, Siwen; Deng, Qinyi; Zou, Ji-Jun; Wang, Li; Zhang, Xiangwen

2014-10-01

308

Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts.  

PubMed

The photocatalytic activity and the promoting effect of titania (TiO2) by commercial activated carbon (CAC) for removing the pollutant in wastewater were investigated. The TiO2/CAC composite photocatalysts with various ratios of CAC to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of TiO2/CAC was investigated for the degradation of Sunset Yellow (SY) in aqueous solution using UV-A light. The TiO2/CAC is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The synergism between TiO2 and CAC may increase the catalytic activity. 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 mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable. PMID:24662758

Rajamanickam, D; Shanthi, M

2014-07-15

309

Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts  

NASA Astrophysics Data System (ADS)

The photocatalytic activity and the promoting effect of titania (TiO2) by commercial activated carbon (CAC) for removing the pollutant in wastewater were investigated. The TiO2/CAC composite photocatalysts with various ratios of CAC to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of TiO2/CAC was investigated for the degradation of Sunset Yellow (SY) in aqueous solution using UV-A light. The TiO2/CAC is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The synergism between TiO2 and CAC may increase the catalytic activity. 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 mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable.

Rajamanickam, D.; Shanthi, M.

2014-07-01

310

Ultraslow recombination in AOT-capped TiO2 nanoparticles sensitized by protoporphyrin IX.  

PubMed

Aerosol OT (AOT) capped TiO2 nanoparticles have been prepared by a phase transfer mechanism. The TiO2 nanoparticles have a diameter of 5-10 nm, are highly crystalline (anatase) and show high photoluminescence. They are effectively sensitized by protoporphyrin IX (PPIX) and show high electron injection rates while the rate of back recombination is much slower than those reported previously. Thus the AOT capped TiO2 nanoparticles synthesized in this work are highly effective not only in promoting ultrafast electron injection from PPIX to TiO2 but more importantly they lead to extremely slow back recombination rates. The significance of this work is in the synthesis of highly photoluminescent TiO2 nanoparticles which can be easily sensitized by a porphyrin dye, whereby ultraslow recombination is observed. PMID:25142514

Biswas, Sudipta; De, Swati; Kathiravan, Arunkumar

2014-10-28

311

Using TiO 2 supported on Clinoptilolite as a catalyst for photocatalytic degradation of azo dye Disperse yellow 23 in water  

Microsoft Academic Search

In this investigation photocatalytic degradation of azo dye Disperse yellow 23 in water was studied. Titanium (IV) oxide was\\u000a supported on Clinoptilolite (CP) (Iranian Natural Zeolite) using the solid-state dispersion (SSD) method. The results show\\u000a that the TiO2\\/Clinoptilolite (SSD) is an active photocatalyst. The maximum effect of photo degradation was observed at 10 wt % TiO2, 90 wt % Clinoptilolite.

M. Nikazara; K. Gholivand; K. Mahanpoor

2007-01-01

312

Preparation of photocatalytic TiO 2 transparent thin film by thermal decomposition of Ti-alkoxide with ?-terpineol as a solvent  

Microsoft Academic Search

TiO2 thin film photocatalysts coated onto glass plates were prepared by thermal decomposition of tetraisopropyl orthotitanate with a dip coating process using ?-terpineol as a highly viscous solvent. Two types of ligands, polyethylene glycol 600 and (ethoxyethoxy)ethanol were added to the dip-coating solution as the stabilizer of titanium alkoxide. TiO2 thin films were obtained after calcination at 450°C for 1

Nobuaki Negishi; Koji Takeuchi

2001-01-01

313

Enhanced photocatalytic hydrogen evolution over Pt supported on mesoporous TiO 2 prepared by single-step sol–gel process with surfactant template  

Microsoft Academic Search

Nanocrystalline mesoporous TiO2 photocatalyst with narrow pore size distribution was synthesized by a surfactant-assisted templating sol–gel technique and used as a support for Pt towards photocatalytic H2 evolution. Single-step sol–gel (SSSG) method, in which Pt precursor was introduced into the completely hydrolyzed TiO2 sol prepared with a mesopore-directing surfactant template, was utilized to load the Pt cocatalyst onto the synthesized

Thammanoon Sreethawong; Susumu Yoshikawa

2006-01-01

314

The synthesis of nitrogen/sulfur co-doped TiO2 nanocrystals with a high specific surface area and a high percentage of {001} facets and their enhanced visible-light photocatalytic performance  

PubMed Central

Nitrogen/sulfur co-doped anatase TiO2 nanocrystals with a high specific surface area and a high percentage of {001} facets were synthesized by a solvent-thermal process followed by the calcination with thiourea at an optimum heat treatment temperature. Under current experimental conditions, the optimum heat treatment temperature was found at 300°C, which successfully introduced nitrogen and sulfur dopants into the anatase lattice to replace a small portion of oxygen atoms while preserving the geometry of these anatase TiO2 nanocrystals to maintain a high percentage of {001} facets. These nitrogen/sulfur co-doped anatase TiO2 nanocrystals demonstrated a largely enhanced light absorption in the whole visible-light range and exhibited much higher photocatalytic performance than both P25 TiO2 nanoparticles and anatase TiO2 nanocrystals with a high percentage of {001} facets under visible-light illumination. PMID:23095371

2012-01-01

315

TiO2 Hollow Spheres Composed of Highly Crystalline Nanocrystals Exhibit Superior Lithium Storage Properties.  

PubMed

While the synthesis of TiO2 hollow structures is well-established, in most cases it is particularly difficult to control the crystallization of TiO2 in solution or by calcination. As a result, TiO2 hollow structures do not really exhibit enhanced lithium storage properties. Herein, we report a simple and cost-effective template-assisted method to synthesize anatase TiO2 hollow spheres composed of highly crystalline nanocrystals, in which carbonaceous (C)?spheres are chosen as the removable template. The release of gaseous species from the combustion of C?spheres may inhibit the growth of TiO2 crystallites so that instead small TiO2 nanocrystals are generated. The small size and high crystallinity of primary TiO2 nanoparticles and the high structural integrity of the hollow spheres gives rise to significant improvements in the cycling stability and rate performance of the TiO2 hollow spheres. PMID:25124735

Zhang, Genqiang; Wu, Hao Bin; Song, Taeseup; Paik, Ungyu; Lou, Xiong Wen David

2014-11-10

316

Novel hollow mesoporous 1D TiO2 nanofibers as photovoltaic and photocatalytic materials.  

PubMed

Hollow mesoporous one dimensional (1D) TiO(2) nanofibers are successfully prepared by co-axial electrospinning of a titanium tetraisopropoxide (TTIP) solution with two immiscible polymers; polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) using a core-shell spinneret, followed by annealing at 450 °C. The annealed mesoporous TiO(2) nanofibers are found to having a hollow structure with an average diameter of 130 nm. Measurements using the Brunauer-Emmett-Teller (BET) method reveal that hollow mesoporous TiO(2) nanofibers possess a high surface area of 118 m(2) g(-1) with two types of mesopores; 3.2 nm and 5.4 nm that resulted from gaseous removal of PEO and PVP respectively during annealing. With hollow mesoporous TiO(2) nanofibers as the photoelectrode in dye sensitized solar cells (DSSC), the solar-to-current conversion efficiency (?) and short circuit current (J(sc)) are measured as 5.6% and 10.38 mA cm(-2) respectively, which are higher than those of DSSC made using regular TiO(2) nanofibers under identical conditions (? = 4.2%, J(sc) = 8.99 mA cm(-2)). The improvement in the conversion efficiency is mainly attributed to the higher surface area and mesoporous TiO(2) nanostructure. It facilitates the adsorption of more dye molecules and also promotes the incident photon to electron conversion. Hollow mesoporous TiO(2) nanofibers with close packing of grains and crystals intergrown with each other demonstrate faster electron diffusion, and longer electron recombination time than regular TiO(2) nanofibers as well as P25 nanoparticles. The surface effect of hollow mesoporous TiO(2) nanofibers as a photocatalyst for the degradation of rhodamine dye was also investigated. The kinetic study shows that the hollow mesoporous surface of the TiO(2) nanofibers influenced its interactions with the dye, and resulted in an increased catalytic activity over P25 TiO(2) nanocatalysts. PMID:22315140

Zhang, Xiang; Thavasi, Velmurugan; Mhaisalkar, S G; Ramakrishna, Seeram

2012-03-01

317

Visible light-degradation of azo dye methyl orange using TiO2/?-FeOOH as a heterogeneous photo-Fenton-like catalyst.  

PubMed

In this study, a novel TiO2/?-FeOOH composite photocatalyst was synthesized by a hydrothermal method. X-ray diffraction, Fourier transform infrared spectrum, UV-vis diffuse reflectance spectra and scanning electron microscopy (SEM) were used to characterize the composite photocatalyst. The photocatalytic activity of the prepared composite photocatalyst was evaluated in a heterogeneous photo-Fenton-like process using methyl orange (MO) as target pollutant. The TiO2/?-FeOOH composites exhibited higher photocatalytic activity than pure ?-FeOOH and TiO2 under visible-light irradiation. The enhanced photocatalytic activity can be ascribed to the formation of TiO2/?-FeOOH heterostructure, which plays an important role in expanding the photoactivity to the visible light region and in effectively prolonging the lifetime of photoinduced electrons and holes. Further investigation revealed that the 25TiO2/?-FeOOH composite synthesized with the TiO2/Fe(3+) in a mole ratio of 25:75 showed the highest catalytic activity. PMID:24292465

Xu, Zhihui; Zhang, Ming; Wu, Jingyu; Liang, Jianru; Zhou, Lixiang; L, Bo

2013-01-01

318

InVO4/TiO2 composite for visible-light photocatalytic degradation of 2-chlorophenol in wastewater.  

PubMed

InVO4/TiO2 composite was synthesized via amalgamation of InVO4 with TiO2 (Degussa P-25) powders. Application of the produced composite was evaluated as a catalyst for visible-light photocatalytic degradation of 2-chlorophenol (2-CP) in synthetic wastewater solutions. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy energy dispersive X-ray microanalyses and nitrogen physisorption. The degradation of 2-CP was affected by solution pH, light intensity, photocatalyst dosage and 2-CP initial concentration. InVO4/TiO2 showed higher photocatalytic degradation of 2-CP as compared with Degussa P-25 TiO2. Complete degradation of 2-CP was achieved with the InVO4/TiO2 catalyst under optimized conditions (1 g/L catalyst with a pollutant concentration of 50 mg/L at solution pH 5 and irradiation time of 180 min). Comparatively, 2-CP degradation efficiency of 50.5% was achieved with the TiO2 (Degussa P-25) at the same experimental conditions. The study confirmed that InVO4/TiO2 has high potential for degradation of 2-CP from wastewater under visible-light irradiation. PMID:25145167

Rashid, J; Barakat, M A; Pettit, S L; Kuhn, J N

2014-01-01

319

Predictable and controllable dual-phase interfaces in TiO2(B)/anatase nanofibers.  

PubMed

The TiO2(B)/anatase dual-phase nanofiber exhibits enhanced photocatalytic activity when interfaces form during phase transformation of TiO2. To precisely control the formation of coherent interfaces between TiO2(B) and anatase, a thorough knowledge of phase transformation particularly from TiO2(B) to anatase (TA) is required. In our study, a crystallographic model in conjunction with transmission electron microscopy (TEM) was employed to investigate the phase transformation. The coherent interface with a crystallographic orientation relationship of [001]TB//[100]TA, (200)TB//(002)TA, and (020)TB//(020)TA predicted by the crystallography model was also observed by TEM experimentally. In addition, two types of incoherent interfaces that may deteriorate photocatalytic activity were examined and can be eliminated via an accurate tuning of calcination. The fundamental knowledge acquired from this work, therefore, provides a new insight to synthesize more efficient dual-phase TiO2 photocatalysts. PMID:25355278

Lei, Yimin; Sun, Jie; Liu, Hongwei; Cheng, Xuan; Chen, Fuyi; Liu, Zongwen

2014-11-01

320

Controlling Surface Defects and Photophysics in TiO2 Nanoparticles.  

PubMed

Titanium dioxide (TiO2) is widely used for photocatalysis and solar cell applications, and the electronic structure of bulk TiO2 is well understood. However, the surface structure of nanoparticulate TiO2, which has a key role in properties such as solubility and catalytic activity, still remains controversial. Detailed understanding of surface defect structures may help explain reactivity and overall materials performance in a wide range of applications. In this work we address the solubility problem and surface defects control on TiO2 nanoparticles. We report the synthesis and characterization of ?4 nm TiO2 anatase spherical nanoparticles that are soluble and stable in a wide range of organic solvents and water. By controlling the temperature during the synthesis, we are able to tailor the density of defect states on the surface of the TiO2 nanoparticles without affecting parameters such as size, shape, core crystallinity, and solubility. The morphology of both kinds of nanoparticles was determined by TEM. EPR experiments were used to characterize the surface defects, and transient absorption measurements demonstrate the influence of the TiO2 defect states on photoinduced electron transfer dynamics. PMID:25109403

Llansola-Portoles, Manuel J; Bergkamp, Jesse J; Finkelstein-Shapiro, Daniel; Sherman, Benjamin D; Kodis, Gerdenis; Dimitrijevic, Nada M; Gust, Devens; Moore, Thomas A; Moore, Ana L

2014-11-13

321

Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications  

PubMed Central

Summary A biomolecule-assisted pyrolysis method has been developed to synthesize sulfur-doped graphitic carbon nitride (CNS) nanosheets. During the synthesis, sulfur could be introduced as a dopant into the lattice of carbon nitride (CN). Sulfur doping changed the texture as well as relative band positions of CN. By growing CN on preformed sulfur-doped CN nanosheets, composite CN/CNS heterojunction nanosheets were constructed, which significantly enhanced the photoelectrochemical performance as compared with various control counterparts including CN, CNS and physically mixed CN and CNS (CN+CNS). The enhanced photoelectrochemical performance of CN/CNS heterojunction nanosheets could be ascribed to the efficient separation of photoexcited charge carriers across the heterojunction interface. The strategy of designing and preparing CN/CNS heterojunction photocatalysts in this work can open up new directions for the construction of all CN-based heterojunction photocatalysts. PMID:24991514

Tao, Hua Bing; Chen, Jiazang; Miao, Jianwei

2014-01-01

322

Nanoporous TiO2 nanoparticle assemblies with mesoscale morphologies: nano-cabbage versus sea-anemone.  

PubMed

We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation. PMID:24760418

Darbandi, Masih; Gebre, Tesfaye; Mitchell, Lucas; Erwin, William; Bardhan, Rizia; Levan, M Douglas; Mochena, Mogus D; Dickerson, James H

2014-06-01

323

Photocatalytic degradation of an azo-dye on TiO2/activated carbon composite material.  

PubMed

A sequential adsorption/photocatalytic regeneration process to remove tartrazine, an azo-dye in aqueous solution, has been investigated. The aim ofthis work was to compare the effectiveness of an adsorbent/photocatalyst composite-TiO2 deposited onto activated carbon (AC) - and a simple mixture of powders of TiO2 and AC in same proportion. The composite was an innovative material as the photocatalyst, TiO2, was deposited on the porous surface ofa microporous-AC using metal-organic chemical vapour deposition in fluidized bed. The sequential process was composed of two-batch step cycles: every cycle alternated a step of adsorption and a step of photocatalytic oxidation under ultra-violet (365 nm), at 25 degreeC and atmospheric pressure. Both steps, adsorption and photocatalytic oxidation, have been investigated during four cycles. For both materials, the cumulated amounts adsorbed during four cycles corresponded to nearly twice the maximum adsorption capacities qmax proving the photocatalytic oxidation to regenerate the adsorbent. Concerning photocatalytic oxidation, the degree of mineralization was higher with the TiO2/AC composite: for each cycle, the value of the total organic carbon removal was 25% higher than that obtained with the mixture powder. These better photocatalytic performances involved better regeneration than higher adsorbed amounts for cycles 2, 3 and 4. Better performances with this promising material - TiO2 deposited onto AC - compared with TiO2 powder could be explained by the vicinity of photocatalytic and AC adsorption sites. PMID:24600875

Andriantsiferana, C; Mohamed, E F; Delmas, H

2014-01-01

324

High-aspect ratio titania three-dimensional (TiO2) nanostructures: fabrication and applications  

NASA Astrophysics Data System (ADS)

In this paper, the fabrication of high aspect ratio 3-dimensional titania (TiO2) nanostructures based on costeffectively hydrothermal synthesis method is presented. A novel patterning method to overcome the tradeoff between tall trunks (nanorods) and large spacing is addressed. Polydimethylsiloxane (PDMS) was adopted to restrain the growth of the trunks (nanorods) of nanoforests to well control the morphology and surface area of TiO2 nanoforests.

Lin, Chih-Min; Yin, Shizhuo

2012-10-01

325

Room temperature one-step synthesis of microarrays of N-doped flower-like anatase TiO2 composed of well-defined multilayer nanoflakes by Ti anodization  

NASA Astrophysics Data System (ADS)

Microarrays of N-doped flower-like TiO2 composed of well-defined multilayer nanoflakes were synthesized at room temperature by electrochemical anodization of Ti in NH4F aqueous solution. The TiO2 flowers were of good anatase crystallinity. The effects of anodizing time, applied voltage and NH4F concentration on the flower-like morphology were systematically examined. It was found that the morphologies of the anodized Ti were related to the anodizing time and NH4F concentration. The size and density of the TiO2 flowers could be tuned by changing the applied voltage. The obtained N-doped flower-like TiO2 microarrays exhibited intense absorption in wavelengths ranging from 320 to 800 nm. Under both UV and visible light irradiation, the photocatalytic activity of the N-doped flower-like TiO2 microarrays in the oxidation of methyl orange showed a significant increase compared with that of commercial P25 TiO2 film.

Wang, Chenglin; Wang, Mengye; Xie, Kunpeng; Wu, Qi; Sun, Lan; Lin, Zhiqun; Lin, Changjian

2011-07-01

326

Room temperature one-step synthesis of microarrays of N-doped flower-like anatase TiO2 composed of well-defined multilayer nanoflakes by Ti anodization.  

PubMed

Microarrays of N-doped flower-like TiO(2) composed of well-defined multilayer nanoflakes were synthesized at room temperature by electrochemical anodization of Ti in NH(4)F aqueous solution. The TiO(2) flowers were of good anatase crystallinity. The effects of anodizing time, applied voltage and NH(4)F concentration on the flower-like morphology were systematically examined. It was found that the morphologies of the anodized Ti were related to the anodizing time and NH(4)F concentration. The size and density of the TiO(2) flowers could be tuned by changing the applied voltage. The obtained N-doped flower-like TiO(2) microarrays exhibited intense absorption in wavelengths ranging from 320 to 800 nm. Under both UV and visible light irradiation, the photocatalytic activity of the N-doped flower-like TiO(2) microarrays in the oxidation of methyl orange showed a significant increase compared with that of commercial P25 TiO(2) film. PMID:21719961

Wang, Chenglin; Wang, Mengye; Xie, Kunpeng; Wu, Qi; Sun, Lan; Lin, Zhiqun; Lin, Changjian

2011-07-29

327

Novel hollow mesoporous 1D TiO2 nanofibers as photovoltaic and photocatalytic materials  

NASA Astrophysics Data System (ADS)

Hollow mesoporous one dimensional (1D) TiO2 nanofibers are successfully prepared by co-axial electrospinning of a titanium tetraisopropoxide (TTIP) solution with two immiscible polymers; polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) using a core-shell spinneret, followed by annealing at 450 °C. The annealed mesoporous TiO2 nanofibers are found to having a hollow structure with an average diameter of 130 nm. Measurements using the Brunauer-Emmett-Teller (BET) method reveal that hollow mesoporous TiO2 nanofibers possess a high surface area of 118 m2 g-1 with two types of mesopores; 3.2 nm and 5.4 nm that resulted from gaseous removal of PEO and PVP respectively during annealing. With hollow mesoporous TiO2 nanofibers as the photoelectrode in dye sensitized solar cells (DSSC), the solar-to-current conversion efficiency (?) and short circuit current (Jsc) are measured as 5.6% and 10.38 mA cm-2 respectively, which are higher than those of DSSC made using regular TiO2 nanofibers under identical conditions (? = 4.2%, Jsc = 8.99 mA cm-2). The improvement in the conversion efficiency is mainly attributed to the higher surface area and mesoporous TiO2 nanostructure. It facilitates the adsorption of more dye molecules and also promotes the incident photon to electron conversion. Hollow mesoporous TiO2 nanofibers with close packing of grains and crystals intergrown with each other demonstrate faster electron diffusion, and longer electron recombination time than regular TiO2 nanofibers as well as P25 nanoparticles. The surface effect of hollow mesoporous TiO2 nanofibers as a photocatalyst for the degradation of rhodamine dye was also investigated. The kinetic study shows that the hollow mesoporous surface of the TiO2 nanofibers influenced its interactions with the dye, and resulted in an increased catalytic activity over P25 TiO2 nanocatalysts.Hollow mesoporous one dimensional (1D) TiO2 nanofibers are successfully prepared by co-axial electrospinning of a titanium tetraisopropoxide (TTIP) solution with two immiscible polymers; polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) using a core-shell spinneret, followed by annealing at 450 °C. The annealed mesoporous TiO2 nanofibers are found to having a hollow structure with an average diameter of 130 nm. Measurements using the Brunauer-Emmett-Teller (BET) method reveal that hollow mesoporous TiO2 nanofibers possess a high surface area of 118 m2 g-1 with two types of mesopores; 3.2 nm and 5.4 nm that resulted from gaseous removal of PEO and PVP respectively during annealing. With hollow mesoporous TiO2 nanofibers as the photoelectrode in dye sensitized solar cells (DSSC), the solar-to-current conversion efficiency (?) and short circuit current (Jsc) are measured as 5.6% and 10.38 mA cm-2 respectively, which are higher than those of DSSC made using regular TiO2 nanofibers under identical conditions (? = 4.2%, Jsc = 8.99 mA cm-2). The improvement in the conversion efficiency is mainly attributed to the higher surface area and mesoporous TiO2 nanostructure. It facilitates the adsorption of more dye molecules and also promotes the incident photon to electron conversion. Hollow mesoporous TiO2 nanofibers with close packing of grains and crystals intergrown with each other demonstrate faster electron diffusion, and longer electron recombination time than regular TiO2 nanofibers as well as P25 nanoparticles. The surface effect of hollow mesoporous TiO2 nanofibers as a photocatalyst for the degradation of rhodamine dye was also investigated. The kinetic study shows that the hollow mesoporous surface of the TiO2 nanofibers influenced its interactions with the dye, and resulted in an increased catalytic activity over P25 TiO2 nanocatalysts. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11251e

Zhang, Xiang; Thavasi, Velmurugan; Mhaisalkar, S. G.; Ramakrishna, Seeram

2012-02-01

328

Water-dispersible TiO2 nanoparticles via a biphasic solvothermal reaction method  

PubMed Central

A biphasic solvothermal reaction method has been used for the synthesis of TiO2 nanoparticles (NPs). In this method, hydrolysis and nucleation occur at the interface of organic phase (titanium (IV) n-propoxide and stearic acid dissolved in toluene) and water phase (tert-butylamine dissolved in water) resulting in the nucleation of the stearic acid-capped TiO2 NPs. These NPs are hydrophilic due to hydrophobic stearic acid ligands and could be dispersed in toluene, but not in water. These stearic acid-capped TiO2 NPs were surface-modified with 2,3-dimercaptosuccinic acid (DMSA) in order to make them water soluble. The resultant TiO2 NPs were easily redispersed in water without any noticeable aggregation. The Rietveld profile fitting of X-ray diffraction (XRD) pattern of the TiO2 NPs revealed highly crystalline anatase structure. The average crystallite size of TiO2 NPs was calculated to be 6.89 nm, which agrees with TEM results. These results have important implications for the use of TiO2 in biomedical, environmental, and industrial applications. PMID:24289214

2013-01-01

329

TiO2-graphene oxide nanocomposite as advanced photocatalytic materials  

PubMed Central

Background Graphene oxide composites with photocatalysts may exhibit better properties than pure photocatalysts via improvement of their textural and electronic properties. Results TiO2-Graphene Oxide (TiO2 - GO) nanocomposite was prepared by thermal hydrolysis of suspension with graphene oxide (GO) nanosheets and titania peroxo-complex. The characterization of graphene oxide nanosheets was provided by using an atomic force microscope and Raman spectroscopy. The prepared nanocomposites samples were characterized by Brunauer–Emmett–Teller surface area and Barrett–Joiner–Halenda porosity, X-ray Diffraction, Infrared Spectroscopy, Raman Spectroscopy and Transmission Electron Microscopy. UV/VIS diffuse reflectance spectroscopy was employed to estimate band-gap energies. From the TiO2 - GO samples, a 300??m thin layer on a piece of glass 10×15 cm was created. The photocatalytic activity of the prepared layers was assessed from the kinetics of the photocatalytic degradation of butane in the gas phase. Conclusions The best photocatalytic activity under UV was observed for sample denoted TiGO_100 (k?=?0.03012?h-1), while sample labeled TiGO_075 (k?=?0.00774?h-1) demonstrated the best activity under visible light. PMID:23445868

2013-01-01

330

LC/MS/MS structure elucidation of reaction intermediates formed during the TiO2 photocatalysis of microcystin-LR  

EPA Science Inventory

Microcystin-LR (MC-LR), a cyanotoxin and emerging drinking water contaminant, was treated with TiO(2) photocatalysts immobilized on stainless steel plates as an alternative to nanoparticles in slurry. The reaction intermediates of MC-LR were identified with mass spectrometry (MS)...

331

The doping mechanism of Cr into TiO2 and its influence on the photocatalytic performance.  

PubMed

The chromium doped titanium dioxide (Cr-TiO2) has been synthesized using a hydrothermal method. The as-prepared samples have been characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HR-TEM), XPS valence band spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-vis DR), photoluminescence (PL) spectroscopy and time resolved PL (TR-PL) spectroscopy. The doping mechanism and related influence on the photocatalytic performance of TiO2 are thus proposed. The doped Cr(3+) ions can replace the Ti atoms in the lattice with oxygen vacancy compensation, distribute homogeneously in the framework of TiO2 crystals, and may make the n-type TiO2 less n-type or more p-type due to the resultant formation of oxygen vacancies, resulting in absorption of visible light, decrease of the intensity of PL emission and prolonged lifetime of photogenerated charge carriers. Compared with TiO2, the doped samples exhibit an improved visible-light photocatalytic activity. The influence of nitrogen modification has also been studied. We envision that these results would afford a better understanding of the doping mechanism of TiO2 using metal ions and, therefore, may provide a feasible way to prepare the TiO2-based photocatalysts for real applications. PMID:24154550

Li, Xuemin; Guo, Zhengkai; He, Tao

2013-12-14

332

Photocatalytic and antibacterial properties of a TiO2/nylon-6 electrospun nanocomposite mat containing silver nanoparticles.  

PubMed

Silver-impregnated TiO(2)/nylon-6 nanocomposite mats exhibit excellent characteristics as a filter media with good photocatalytic and antibacterial properties and durability for repeated use. Silver nanoparticles (NPs) were successfully embedded in electrospun TiO(2)/nylon-6 composite nanofibers through the photocatalytic reduction of silver nitrate solution under UV-light irradiation. TiO(2) NPs present in nylon-6 solution were able to cause the formation of a high aspect ratio spider-wave-like structure during electrospinning and facilitated the UV photoreduction of AgNO(3) to Ag. TEM images, UV-visible and XRD spectra confirmed that monodisperse Ag NPs (approximately 4 nm in size) were deposited selectively upon the TiO(2) NPs of the prepared nanocomposite mat. The antibacterial property of a TiO(2)/nylon-6 composite mat loaded with Ag NPs was tested against Escherichia coli, and the photoactive property was tested against methylene blue. All of the results showed that TiO(2)/nylon-6 nanocomposite mats loaded with Ag NPs are more effective than composite mats without Ag NPs. The prepared material has potential as an economically friendly photocatalyst and water filter media because it allows the NPs to be reused. PMID:21429663

Pant, Hem Raj; Pandeya, Dipendra Raj; Nam, Ki Taek; Baek, Woo-Il; Hong, Seong Tshool; Kim, Hak Yong

2011-05-15

333

Treatment on Low NOx Concentration and DEP Collection with Barrier Discharge System Superposing TiO2  

NASA Astrophysics Data System (ADS)

The automobiles exhaust carbon particles and NOx into the air, and then gases accumulate in expressway tunnels. DC corona discharge is used widely in electrostatic precipitator (ESP). However, the ESP with DC corona discharge can little remove NOx. Therefore, we proposed a new barrier discharge type precharger to replace corona discharge type prechargers to remove NOx. When discharge is generated in the air, NOx necessarily is generated. Then, we need to grasp the lower limit NOx concentration to remove NOx from the gas. We focus attention on photocatalyst because it is effective in NOx removal. However, photocatalyst needs ultraviolet ray. Therefore, TiO2 is painted on barrier discharge electrodes, an ultraviolet ray included in discharge luminescence was irradiated to TiO2. Furthermore, the relationship between initial NOx concentration and removal characteristic is investigated in detail.

Takagi, Yasuhiro; Hosoi, Katsuhiko; Ehara, Yoshiyasu; Takahashi, Takeo; Ito, Tairo; Zukeran, Akinori; Kawada, Yoshihiro; Kono, Yoshihiro; Yasumoto, Koji

334

Development of stable pollution free TiO2/Au nanoparticle immobilized green photo catalyst for degradation of methyl orange.  

PubMed

Two types of heterogeneous nanoparticle immobilized photocatalysts viz., PSP4VP-TiO2 and PSP4VP-TiO2-Au were synthesized by immobilization of TiO2 and TiO2-Au nanoparticles individually onto the insoluble cross-linked poly(styrene)-co-poly(4-vinylpyridine) as a common matrix. These two different green photocatalysts were characterized by FT-IR, SEM, HRTEM and EDS analyses and proves that the respective nanoparticles were found to immobilize onto the matrix. The photocatalytic efficiency of these catalysts was examined using degradation of methyl orange as a model reaction and found they are excellent in UV and sunlight. The stability and recycle/reusability of the catalysts were also observed to be good. PMID:21485879

Murugan, Eagambaram; Rangasamy, Rajmohan

2011-02-01

335

New TiO2/MgAl-LDH nanocomposites for the photocatalytic degradation of dyes.  

PubMed

In this study we report the synthesis of a series of composite nanostructures comprising LDH and TiO2 phases. The materials characterization showed that the LDH crystallites are encapsulated inside the TiO2 matrix after the anatase seeds are deposited on MgxAl-LDHs. The structure in which LDH phase is embedded into anatase matrix is unique bringing important advantages to the photocatalytic performances of the nanocomposites. The photocatalytic activity of the prepared nanocomposites was tested on the degradation of the methylene blue (MB) in aqueous solution. The photocatalytic activities of the nanocomposites were compared with commercial TiO2 nanoparticles Degussa P25. The nanocomposites exhibited superior photocatalytic activity in basic environment because the negatively charged surface of TiO2 nanoparticles at high pH attracts the positively charged methylene blue species. PMID:21121320

Seftel, E M; Popovici, E; Beyers, E; Mertens, M; Zhu, H Y; Vansant, E F; Cool, P

2010-12-01

336

Origin of the visible-light photoactivity of NH3-treated TiO2: Effect of nitrogen doping and oxygen vacancies  

NASA Astrophysics Data System (ADS)

N-doped and oxygen-deficient TiO2 photocatalysts were obtained by heating commercial TiO2 in NH3 atmosphere, followed by a postcalcination process. Catalysts were characterized by X-ray diffraction (XRD), N2-sorption BET surface area, X-ray photoelectron spectroscopy (XPS), Elemental analysis (EA), UV/vis diffuse reflectance spectroscopy (DRS), Electron spin resonance (ESR) and Photoluminescence (PL). It shows that the NH3-heat-treatment of TiO2 resulted in not only nitrogen doping but also creation of oxygen vacancies with optical absorption in visible-light region. The postcalcination achieved several beneficial effects including dramatic removal of surface amino species, a rapid decrease in surface Ti3+ species, and a low recombination rate of photogenerated carriers on the co-doped TiO2. The photocatalytic measurement was carried out by the degradation of gas-phase benzene under visible light irradiation. At steady state, the photocatalytic conversion rate of benzene over the postannealed catalyst was 35.8%, accompanied by the yield of 115 ppmv CO2, which was much higher than that on the NH3-treated TiO2 before postcalcination or the H2-treated TiO2 catalysts. Results show that the visible-light activity of the NH3-treated TiO2 is attributed to a synergistic effect of substitutional nitrogen species and oxygen vacancies in TiO2.

Chen, Yilin; Cao, Xiaoxin; Lin, Bizhou; Gao, Bifen

2013-01-01

337

Disorder in TiO2-x  

Microsoft Academic Search

We present a theoretical survey, based on reliable computer simulation methods, of defect energetics in TiO2-x. A lattice potential for TiO_2 is developed and used in calculations of the formation energies of point and extended defects. We predict vacancies to be the most stable point defects. We show that they will exist in equilibrium with the shear planes that microscopy

C. R. A. Catlow; R. James

1982-01-01

338

Bactericidal activity of photocatalytic TiO(2) reaction: toward an understanding of its killing mechanism.  

PubMed

When titanium dioxide (TiO(2)) is irradiated with near-UV light, this semiconductor exhibits strong bactericidal activity. In this paper, we present the first evidence that the lipid peroxidation reaction is the underlying mechanism of death of Escherichia coli K-12 cells that are irradiated in the presence of the TiO(2) photocatalyst. Using production of malondialdehyde (MDA) as an index to assess cell membrane damage by lipid peroxidation, we observed that there was an exponential increase in the production of MDA, whose concentration reached 1.1 to 2.4 nmol. mg (dry weight) of cells(-1) after 30 min of illumination, and that the kinetics of this process paralleled cell death. Under these conditions, concomitant losses of 77 to 93% of the cell respiratory activity were also detected, as measured by both oxygen uptake and reduction of 2,3,5-triphenyltetrazolium chloride from succinate as the electron donor. The occurrence of lipid peroxidation and the simultaneous losses of both membrane-dependent respiratory activity and cell viability depended strictly on the presence of both light and TiO(2). We concluded that TiO(2) photocatalysis promoted peroxidation of the polyunsaturated phospholipid component of the lipid membrane initially and induced major disorder in the E. coli cell membrane. Subsequently, essential functions that rely on intact cell membrane architecture, such as respiratory activity, were lost, and cell death was inevitable. PMID:10473421

Maness, P C; Smolinski, S; Blake, D M; Huang, Z; Wolfrum, E J; Jacoby, W A

1999-09-01

339

Noble-metal-free plasmonic photocatalyst: hydrogen doped semiconductors  

PubMed Central

The unique capacity of localized surface plasmon resonance (LSPR) offers a new opportunity to overcome the limited efficiency of semiconductor photocatalyst. Here we unravel that LSPR, which usually occurs in noble metal nanoparticles, can be realized by hydrogen doping in noble-metal-free semiconductor using TiO2 as a model photocatalyst. Moreover, its LSPR is located in infrared region, which supplements that of noble metal whose LSPR is generally in the visible region, making it possible to extend the light response of photocatalyst to infrared region. The near field enhancement is shown to be comparable with that of noble-metal nanoparticles, indicating that highly enhanced light absorption rate can be expected. The present work can provide a key guideline for the creation of highly efficient noble-metal-free plasmonic photocatalysts and have a much wider impact in infrared bioimaging and spectroscopy where infrared LSPR is essential. PMID:24496400

Ma, Xiangchao; Dai, Ying; Yu, Lin; Huang, Baibiao

2014-01-01

340

Fabrication of In2S3 nanoparticle decorated TiO2 nanotube arrays by successive ionic layer adsorption and reaction technique and their photocatalytic application.  

PubMed

In2S3 nanoparticle (NP) decorated self-organized TiO2 nanotube array (In2S3/TiO2 NT) hybrids were fabricated via simple successive ionic layer adsorption and reaction (SILAR) technique. The In2S3 NPs in a size of about 15 nm were found to deposit on the top surface of the highly oriented TiO2 NT while without clogging the tube entrances. The loading amount of In2S3 NPs on the TiO2 NT was controlled by the cycle number of SILAR deposition. Compared with the bare TiO2 NT, the In2S3/TiO2 NT hybrids showed stronger absorption in the visible light region and significantly enhanced photocurrent density. The photocatalytic activity of the In2S3/TiO2 NT photocatalyst far exceeds that of bare TiO2 NT in the degradation of typical herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) under simulated solar light. After 160-min irradiation, almost 100% 2,4-D removal is obtained on the 7-In2S3/TiO2 NT prepared through seven SILAR deposition cycles, much higher than 26% on the bare TiO2 NT. After 10 successive cycles of photocatalytic process with total 1,600 min of irradiation, In2S3/TiO2 NT maintained as high 2,4-D removal efficiency as 95.1% with good stability and easy recovery, which justifies the potential of the photocatalytic system in application for the photocatalytic removal of organic pollutants such as herbicides or pesticides from water. PMID:24738366

Zhang, Zhenrong; Tang, Yanhong; Liu, Chengbin; Wan, Long

2014-06-01

341

Stability and dynamics of carbon and nitrogen dopants in anatase TiO2 : A density functional theory study  

NASA Astrophysics Data System (ADS)

The properties of carbon- and nitrogen-doped anatase TiO2 , a renowned photocatalyst, depend strongly on the atomic-scale details of dopant incorporation and dynamics. Here we identify with ab initio calculations stable structures of C dopants in TiO2 that differ from previous theoretical predictions. We also describe the evolution of dopants and point defects in terms of diffusion barriers and defect complex formation. In particular, we study processes that allow dopants and oxygen native defects to migrate and initiate dopant transformations. The results reveal a range of growth and annealing conditions that can create, shift, or annihilate levels in the TiO2 band gap, altering significantly its catalytic activity.

Tsetseris, L.

2010-04-01

342

A new dielectric ta-C film coating of Ag-nanoparticle hybrids to enhance TiO2 photocatalysis  

NASA Astrophysics Data System (ADS)

We have demonstrated a novel method to enhance TiO2 photocatalysis by adopting a new ultrathin tetrahedral-amorphous-carbon (ta-C) film coating on Ag nanoparticles to create strong plasmonic near-field enhancement. The result shows that the decomposition rate of methylene blue on the Ag/10 Å ta-C/TiO2 composite photocatalyst is ten times faster than that on a TiO2 photocatalyst and three times faster than that on a Ag/TiO2 photocatalyst. This can be ascribed to the simultaneous realization of two competitive processes: one that excites the surface plasmons (SPs) of the ta-C-film/Ag-nanoparticle hybrid and provides a higher electric field near the ta-C/TiO2 interface compared to Ag nanoparticles alone, while the other takes advantage of the dense diamond-like ta-C layer to help reduce the transfer of photogenerated electrons from the conduction band of TiO2 to the metallic surface, since any electron transfer will suppress the excitation of SP modes in the metal nanoparticles.

Liu, Fanxin; Tang, Chaojun; Wang, Zhenlin; Sui, Chenghua; Ma, Hongtao

2014-03-01

343

Photocatalytic Degradation of DIPA Using Bimetallic Cu-Ni/TiO2 Photocatalyst under Visible Light Irradiation  

PubMed Central

Bimetallic Cu-Ni/TiO2 photocatalysts were synthesized using wet impregnation (WI) method with TiO2 (Degussa-P25) as support and calcined at different temperatures (180, 200, and 300°C) for the photodegradation of DIPA under visible light. The photocatalysts were characterized using TGA, FESEM, UV-Vis diffuse reflectance spectroscopy, fourier transform infrared spectroscopy (FTIR) and temperature programmed reduction (TPR). The results from the photodegradation experiments revealed that the Cu-Ni/TiO2 photocatalysts exhibited much higher photocatalytic activities compared to bare TiO2. It was found that photocatalyst calcined at 200°C had the highest photocatalyst activities with highest chemical oxygen demand (COD) removal (86.82%). According to the structural and surface analysis, the enhanced photocatalytic activity could be attributed to its strong absorption into the visible region and high metal dispersion. PMID:25105158

Bustam, Mohamad Azmi; Chong, Fai Kait; Man, Zakaria B.; Khan, Muhammad Saqib; Shariff, Azmi M.

2014-01-01

344

Photocatalytic degradation of DIPA using bimetallic Cu-Ni/TiO2 photocatalyst under visible light irradiation.  

PubMed

Bimetallic Cu-Ni/TiO2 photocatalysts were synthesized using wet impregnation (WI) method with TiO2 (Degussa-P25) as support and calcined at different temperatures (180, 200, and 300°C) for the photodegradation of DIPA under visible light. The photocatalysts were characterized using TGA, FESEM, UV-Vis diffuse reflectance spectroscopy, fourier transform infrared spectroscopy (FTIR) and temperature programmed reduction (TPR). The results from the photodegradation experiments revealed that the Cu-Ni/TiO2 photocatalysts exhibited much higher photocatalytic activities compared to bare TiO2. It was found that photocatalyst calcined at 200°C had the highest photocatalyst activities with highest chemical oxygen demand (COD) removal (86.82%). According to the structural and surface analysis, the enhanced photocatalytic activity could be attributed to its strong absorption into the visible region and high metal dispersion. PMID:25105158

Riaz, Nadia; Bustam, Mohamad Azmi; Chong, Fai Kait; Man, Zakaria B; Khan, Muhammad Saqib; Shariff, Azmi M

2014-01-01

345

Development of mesoporous TiO(2) microspheres with high specific surface area for selective enrichment of phosphopeptides by mass spectrometric analysis.  

PubMed

In this study, mesoporous TiO(2) microspheres were synthesized by simple hydrothermal reaction, and successfully developed for phosphopeptides enrichment from both standard protein digestion and real biological sample such as rat brain tissue extract. The mesoporous TiO(2) microspheres (the diameter size of about 1.0 microm) obtained by simple hydrothermal method were found to have a specific surface area of 84.98 m(2)/g, which is much larger than smooth TiO(2) microspheres with same size. The surface area of mesoporous TiO(2) microspheres is almost two times of commercial TiO(2) nanoparticle (a diameter of 90 nm). Using standard proteins digestion and real biological samples, the superior selectivity and capacity of mesoporous TiO(2) microspheres for the enrichment of phosphorylated peptides than that of commercial TiO(2) nanoparticles and TiO(2) microspheres was also observed. It has been demonstrated that mesoporous TiO(2) microspheres have powerful potential for selective enrichment of phosphorylated peptides. Moreover, the preparation of the mesoporous TiO(2) microspheres obtained by the hydrothermal reaction is easy, simple and low-cost. These mesoporous TiO(2) microspheres with the ability of large scale synthesis can widely be applied for phosphorylated proteomic research. PMID:20219200

Tang, Jia; Yin, Peng; Lu, Xiaohui; Qi, Dawei; Mao, Yu; Deng, Chunhui; Yang, Pengyuan; Zhang, Xiangmin

2010-04-01

346

Large enhancement of photocatalytic activity by chemical etching of TiO2 crystallized glass  

NASA Astrophysics Data System (ADS)

The authors aim to report the largest enhancement of photocatalytic activity by chemical etching in anatase-type TiO2 crystallized glass. Optimization of several conditions for crystallization behavior and chemical etching to realize the nano-structured ceramics (NSC) has been performed in the crystallized glass. NSC-fabrication by chemical etching in the crystallized glass is one of the most effective solutions to provide bulk materials with high specific surface area. We have found that the best condition for the NSC fabrication as a novel bulk photocatalyst in our glass system, and have obtained 16 times higher catalytic activity than that of non-etched one.

Yoshida, Kazuki; Takahashi, Yoshihiro; Ihara, Rie; Terakado, Nobuaki; Fujiwara, Takumi; Kato, Hideki; Kakihana, Masato

2014-10-01

347

WO 3 Coupled P-TiO 2 Photocatalysts with Mesoporous Structure  

Microsoft Academic Search

\\u000a Abstract  A series of WO3 coupled P-doped TiO2 photocatalysts with mesoporous structure were synthesized by the decomposition of the doped H3PW12O40 precursor in the framework of TiO2. The effects of P doping and WO3 coupling on the structures, surface acidity, and optical properties of TiO2 were investigated by TGA, DSC, FT-IR, XRD, NH3-TPD, SEM, TEM, XPS, UV–Vis DRS, PL, and BET

Changlin Yu; Jimmy C. Yu; Wanqin Zhou; Kai Yang

2010-01-01

348

Metal oxide semiconductors as visible light photocatalysts  

NASA Astrophysics Data System (ADS)

Mn-, Co-, and Mn-Co doped TiO2 ternary and quaternary semiconducting powder materials prepared by using the co-precipitation method and fully characterized by using x-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM — EDS) and UV- visible diffuse reflection spectroscopy were utilized for the photocatalytic degradation of methylene blue under visible light irradiation. These materials show a red shift and absorption in the visible region depending on the dopant type and concentration. These materials have proven to be effective as visible light photocatalysts.

Kiriakidis, George; Binas, Vassilios

2014-08-01

349

Nanoporous TiO2 nanoparticle assemblies with mesoscale morphologies: nano-cabbage versus sea-anemone  

NASA Astrophysics Data System (ADS)

We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation.We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation. Electronic supplementary information (ESI) available: Synthesis and characterization procedures, TEM/XRD of samples prepared at different temperature and water content, table of nitrogen adsorption-desorption values of different samples. See DOI: 10.1039/c3nr06154j

Darbandi, Masih; Gebre, Tesfaye; Mitchell, Lucas; Erwin, William; Bardhan, Rizia; Levan, M. Douglas; Mochena, Mogus D.; Dickerson, James H.

2014-05-01

350

TiO2\\/AC Composites for Synergistic Adsorption-Photocatalysis Processes: Present Challenges and Further Developments for Water Treatment and Reclamation  

Microsoft Academic Search

Titanium dioxide supported on activated carbon, or TiO2\\/AC composite, exhibits bifunctionality of adsorption and photocatalysis in synergism. The authors review the TiO2\\/AC synthesis techniques, characteristics, and performances in removing organic pollutants in water. Practical issues pertinent to applications of the TiO2\\/AC composite in water treatment and reclamation are discussed. These include dispersing the particles and recovering from the product water,

Teik-Thye Lim; Pow-Seng Yap; Madhavi Srinivasan; Anthony G. Fane

2011-01-01

351

Preparation, characterization and activity evaluation of TiN/F-TiO2 photocatalyst.  

PubMed

In this paper, F-TiO(2) and TiN/F-TiO(2) nanoparticle photocatalysts were prepared by ball milling. The photocatalysts were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), terephthalic acid photoluminescence probing technique (TA-PL), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflection spectroscopy (DRS). The photocatalytic activity of the photocatalysts was evaluated by photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The results showed that the photocatalytic activity of the F-TiO(2) was much higher than that of TiO(2), and the photocatalytic activity of the TiN/F-TiO(2) was much higher than that of TiO(2) and F-TiO(2) under UV light irradiation. The optimum percentage of doped TiN is 0.2 wt.%. Compared with pure TiO(2), the photoabsorption wavelength range of the TiN/F-TiO(2) and F-TiO(2) photocatalysts red shifts and improves the utilization of the total spectrum. The effect of ball milling time on the photocatalytic activity of the photocatalysts was also investigated. The optimum ball milling time is 12 h. The mechanisms of influence on the photocatalytic activity of the photocatalysts were also discussed. PMID:21215517

Shifu, Chen; Yunguang, Yang; Wei, Liu

2011-02-28

352

Facile aerosol synthesis and characterization of ternary crumpled graphene-TiO?-magnetite nanocomposites for advanced water treatment.  

PubMed

In this work, the synthesis and characterization of multifunctional crumpled graphene-based ternary nanocomposite photocatalysts for advanced water treatment applications is described. Currently, a major hurdle for the scale-up and optimization of aqueous, graphene-based photocatalysts is restacking of graphene nanosheets due to strong ?-? interactions. To overcome this hurdle, a fast and facile aerosol technique to synthesize monomeric, aggregation-resistant, crumpled graphene-based photocatalysts was developed. The aerosol route utilizes water evaporation-induced confinement forces to effectively crumple graphene oxide and subsequently encapsulate commercially available TiO2 and magnetite nanoparticles. The as-synthesized crumpled graphene-TiO2-magnetite (GOTIM) ternary core-shell nanostructures are shown to possess superior aqueous-based photocatalytic properties (over a 20-fold enhancement in some cases) compared to TiO2 alone. Total GOTIM photocatalytic reactivity is confirmed to also include efficient photoreduction reaction pathways, in addition to expected oxidation routes typical of TiO2-based photocatalysts, significantly expanding photocatalytic application potential compared to TiO2 alone. Reaction kinetics and proposed mechanisms (both oxidative and reductive) are described for a model organic compound, here as methyl orange. Further, with the addition of hole scavengers such as EDTA, and/or lowering the O2 concentration, we demonstrate enhancement of photocatalyzed reduction reactions, suggesting potential for directed, controlled reduction applications. In addition to robust aqueous stability, low-field magnetic susceptibility is demonstrated, allowing for low-energy, in situ material separations, which are critical for material recycling and reuse. PMID:24983817

Jiang, Yi; Wang, Wei-Ning; Biswas, Pratim; Fortner, John D

2014-07-23

353

Synthesis and characterization of F-N-W-codoped TiO{sub 2} photocatalyst with enhanced visible light response  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? Anatase F-N-W-codoped TiO{sub 2} was prepared by a sol–gel-hydrothermal method. ? Under visible illumination, carbon removal rate of RB reached 94% using F-7NW-TiO{sub 2}. ? F, N and W dopants narrowed band gap and lowed charge pairs recombination rate. ? There were W{sub x}Ti{sub 1?x}O{sub 2}, O-Ti-N and valence variation of W ions existing. -- Abstract: Anatase F-N-W-codoped TiO{sub 2} photocatalyst was successfully prepared by a method combining sol–gel with hydrothermal treatment. Effects of F, N and W ion dosage concentration on the crystallinity, morphology, grain size and chemical status of the photocatalyst were investigated. The results showed that the F-7NW-TiO{sub 2} photocatalyst composed of uniform ellipsoidal particles around 20 nm in length and 10 nm in width, and the photocatalyst displayed enhanced visible-light absorption and photocatalytic activities. Using the photocatalyst and under visible irradiation for 1.5 h, the decoloration percent of RB and carbon removal rate were about 98% and 94% respectively, which were much higher than that of commercial P25, TiO{sub 2}, N-W-TiO{sub 2} and F-TiO{sub 2}. The high visible-light photocatalytic activity of F-7NW-TiO{sub 2} might result from narrowing the band gap and lowing charge pairs recombination rate for the W{sub x}Ti{sub 1?x}O{sub 2}, O-Ti-N and valence variation of W ions existing.

Shi, Xiaoliang, E-mail: sxl071932@126.com [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China) [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Qin, Haibo; Yang, Xingyong [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China)] [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Zhang, Qiaoxin [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China) [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China)

2012-12-15

354

Cationic (V, Y)-codoped TiO2 with enhanced visible light induced photocatalytic activity: A combined experimental and theoretical study  

NASA Astrophysics Data System (ADS)

To employ TiO2 as an efficient photocatalyst, high reactivity under visible light and improved separation of photoexcited carriers are required. An effective co-doping approach is applied to modify the photocatalytic properties of TiO2 by doping vanadium (transition metal) and yttrium (rare earth element). V and/or Y codoped TiO2 was prepared using hydrothermal method without any post calcination for crystallization. Based on density functional theory, compensated and noncompensated V, Y codoped TiO2 models were constructed and their structural, electronic, and optical properties were calculated. Through combined experimental characterization and theoretical modeling, V, Y codoped TiO2 exhibited high absorption coefficient with enhanced visible light absorption. All the prepared samples showed pure anatase phase and spherical morphology with uniform particle distribution. Electronic band structure demonstrates that V, Y codoping drastically reduced the band gap of TiO2. It is found that both the doped V and Y exist in the form of substitutional point defects replacing Ti atom in the lattice. The photocatalytic activity, evaluated by the degradation of methyl orange, displays that the codoped TiO2 sample exhibits enhanced visible light photocatalytic activity. The synergistic effects of V and Y drastically improved the Brunauer-Emmett-Teller specific surface area, visible light absorption, and electron-hole pair's separation leading to the enhanced visible light catalytic activity.

Khan, Matiullah; Cao, Wenbin

2013-11-01

355

Photocatalytic degradation of dyestuff wastewater with Zn(2+)-TiO2-SiO2 nanocomposite.  

PubMed

A novel photocatalyst of Zn(2+)-TiO2-SiO2 nanocomposite has been prepared by a sol-gel method, which is used for the degradation of Rhodamine B (RhB) and Congo red (CR) as the probe dyestuff that are notorious organic compounds present in dyes wastewater. The prepared samples are characterized by low temperature N2 adsorption (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS) and Fourier transformed infrared spectroscopy (FT-IR). It is found that the nanocomposite of Zn(2+)-TiO2-SiO2 exhibits much higher photocatalytic activity under both UV light and visible light irradiation as compared with Degussa P25, Zn(2+)-TiO2 and SiO2-TiO2. The photodegradation efficiencies of RhB (5 mg/L) and CR (10 mg/L) can reach above 90% and 83% for 1.5 h visible light irradiation, respectively. Synergetic effect between Zn(2+)-SiO2-doping not only inhibit the crystal growth and anatase-to-rutile transformation of TiO2 nanocatalyst, but also extend the light response to the visible region, which provides a good way and material in the degradation field of dyes wastewater. PMID:23862435

Sui, Guozhe; Liu, Tao; Li, Jinlong; Jia, Lihua; Lv, Jun

2013-06-01

356

Preparation and characterization of amine-functionalized SiO 2/TiO 2 films for formaldehyde degradation  

NASA Astrophysics Data System (ADS)

This paper investigated the gaseous formaldehyde degradation by the amine-functionalized SiO 2/TiO 2 photocatalytic films for improving indoor air quality. The films were synthesized via the co-condensation reaction of methyltrimethoxysilane (MTMOS) and 3-aminopropyltrimethoxysilane (APTMS). The physicochemical properties of prepared photocatalysts were characterized with N 2 adsorption/desorption isotherms measurement, X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FT/IR). The effect of amine-functional groups and the ratio of MTMOS/APTMS precursors on the formaldehyde adsorption and photocatalytic degradation were investigated. The results showed that the formaldehyde adsorption and photocatalytic degradation of the APTMS-functionalized SiO 2/TiO 2 film was higher than that of SiO 2/TiO 2 film due to the surface adsorption on amine sites and the relatively high of the specific surface area of the APTMS-functionalized SiO 2/TiO 2 film (˜15 times higher than SiO 2/TiO 2). The enhancement of the formaldehyde degradation of the film can be attributed to the synergetic effect of adsorption and subsequent photocatalytic decomposition. The repeatability of photocatalytic film was also tested and the degradation efficiency was 91.0% of initial efficiency after seven cycles.

Photong, Somjate; Boonamnuayvitaya, Virote

2009-09-01

357

nanocrystallites condensed in vapor-phase for photocatalyst applications  

NASA Astrophysics Data System (ADS)

We have synthesized titanium dioxide (TiO2) nanocrystallites by pulsed laser ablation (PLA) in oxygen (O2) background gas for photocatalyst applications. Varying O2 background gas pressure or substrate target distance ( D TS), it was possible to change weight fraction of anatase phase in the anatase/rutile mixture from 0.2 to 1.0. Porosity of the deposited TiO2 films increased with increasing and D TS. Relation between the process parameters and the formed crystal phases was explained from the point of cooling process in vapor-phase. Furthermore, rapid thermal annealing (RTA) was performed as post-annealing, suppressing sintering of the nanocrystallites. Photocatalytic activities of the TiO2 nanocrystallites depended on the RTA temperature and following crystallinity restoring as well as the crystal phase: anatase or rutile.

Yoshida, Takehito; Yagi, Nobuyasu; Nakagou, Riki; Sugimura, Akira; Umezu, Ikurou

2014-10-01

358

composite photocatalyst  

NASA Astrophysics Data System (ADS)

A novel composite photocatalyst Ag/AgBr/MoO3 was successfully synthesized via a simple precipitation method at room temperature. The obtained products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy in detail. The photocatalytic activity of the samples was evaluated by monitoring the degradation of rhodamine B (RhB) solution under visible-light irradiation. The results showed that the photocatalytic activity of Ag/AgBr/MoO3 composite significantly enhanced and the degradation ratio of RhB reached 97.7 % after 15 min only. The excellent photocatalytic activity might be closely related to the large surface area, porosity structure and efficient separation of photoinduced electron-hole pairs. The possible reaction mechanism was also discussed.

Song, Jimei; Shi, Yali; Ren, Mingsong; Hu, Gang

2014-09-01

359

Formation of TiO 2 nano-fiber doped with Gd 3+ and its photocatalytic activity  

Microsoft Academic Search

Titanium dioxide (TiO2) nano-fibers doped with Gd3+ were synthesized by two-step synthesis method. The formed fibers were visualized from transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results showed that the average diameter of the TiO2 nano-fibers was 60–80 nm and the length of fibers was in the range of 6–7 ?m. The TiO2 nano-fibers doped with Gd3+ heat

Wuyi Zhou; Yi Zhou; Shaoqiu Tang

2005-01-01

360

Synthesis of monodisperse mesoporous TiO2 spheres with tunable sizes between 0.6 and 3.1 ?m and effects of reaction temperature, Ti source purity, and type of alkylamine on size and monodispersity.  

PubMed

We report a novel method for synthesizing monodisperse mesoporous TiO(2) spheres (sizes = 0.6-3.1 ?m) by hydrolysis of titanium isopropoxide (TIP) in a mixture of C(8)-C(16)n-alkylamine, water, and ethanol. The size increases with decreasing temperature, TIP concentration, and water concentration, and upon purifying TIP. n-Dodecylamine gives the highest monodispersity. PMID:22441100

Hong, Myun Pyo; Kim, Jang Yong; Vemula, Koteswararao; Kim, Hyun Sung; Yoon, Kyung Byung

2012-05-01

361

Nonmetal species in the carbon modified TiO2 and its visible light photocatalytic activity  

NASA Astrophysics Data System (ADS)

A carbon modified TiO2 (CT) was synthesized by hydrolyzing titanium tetrachloride with diethylamine and calcination at 400 °C. CT was then handled with a NaOH aqueous solution elution and a subsequent re-assembling treatment. X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), thermogravimetric and differential thermal analysis (TG-DTA), chemical oxygen demand (COD) and UV-vis diffuse reflectance spectroscopy (DRS) were then used to assess the changes of CT during the whole process. It is revealed that carbon in the CT should mostly be presented as surface deposited organic matters but not likely doped into the TiO2 lattice. CT exhibits obvious visible absorption and high photocatalytic activity for the degradation of 2,4-dichlorophenol (DCP) under visible light irradiation. Meanwhile, CT photocatalyst possesses excellent stability and reusability. NaOH solution elution washes off a large amount of surface deposited organics and worsens the visible absorbance and photocatalytic activity of CT, which can be well recovered by the re-assembling treatment. The re-assembled photocatalyst, CTSL, exhibits exhibits a very similar photocataytic activity with CT for degradation of DCP under the visible light irradiation, but is much higher than that of CTS.

Shi, Yanfen; Chen, Feng; Zhang, Jinlong

2013-01-01

362

High-surface-area mesoporous TiO2 microspheres via one-step nanoparticle self-assembly for enhanced lithium-ion storage.  

PubMed

Mesoporous TiO2 microspheres assembled from TiO2 nanoparticles with specific surface areas as high as 150 m(2) g(-1) were synthesized via a facile one-step solvothermal reaction of titanium isopropoxide and anhydrous acetone. Aldol condensation of acetone gradually releases structural H2O, which hydrolyzes and condenses titanium isopropoxide, forming TiO2 nanocrystals. Simultaneous growth and aggregation of TiO2 nanocrystals leads to the formation of high-surface-area TiO2 microspheres under solvothermal conditions. After a low-temperature post-synthesis calcination, carbonate could be incorporated into TiO2 as a dopant with the carbon source coming from the organic byproducts during the synthesis. Carbonate doping modifies the electronic structure of TiO2 (e.g., Fermi level, Ef), and thus influences its electrochemical properties. Solid electrolyte interface (SEI) formation, which is not common for titania, could be initiated in carbonate-doped TiO2 due to elevated Ef. After removing carbonate dopants by high-temperature calcination, the mesoporous TiO2 microspheres showed much improved performance in lithium insertion and stability at various current rates, attributed to a synergistic effect of high surface area, large pore size and good anatase crystallinity. PMID:25363569

Wang, Hsin-Yi; Chen, Jiazang; Hy, Sunny; Yu, Linghui; Xu, Zhichuan; Liu, Bin

2014-12-21

363

Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water.  

EPA Science Inventory

Hybrid TiO2/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl4. The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV?vis DRS and TGA. Surfac...

364

Effects of F doping on TiO 2 acidic sites and their application in QCM based gas sensors  

Microsoft Academic Search

Titanium dioxide (TiO2) and fluorine doped titanium dioxide (F-TiO2) particles were prepared by a one-pot hydrothermal synthesis, and applied on quartz crystal microbalance (QCM) resonators to detect trace levels of nerve agent stimulant, dimethyl methylphosphonate (DMMP). DMMP sensing measurements exhibited that TiO2 functionalized QCM resonators had fast response and recovery as well as satisfactory sensitivity. F-TiO2 functionalized QCM resonators showed

Yingqiang Zhao; Xin Du; Xiaoying Wang; Junhui He; Yunbo Yu; Hong He

2010-01-01

365

Hierarchically organized nanostructured TiO2 for photocatalysis applications  

NASA Astrophysics Data System (ADS)

A template-free process for the synthesis of nanocrystalline TiO2 hierarchical microstructures by reactive pulsed laser deposition (PLD) is here presented. By a proper choice of deposition parameters a fine control over the morphology of TiO2 microstructures is demonstrated, going from classical compact/columnar films to a dense forest of distinct hierarchical assemblies of ultrafine nanoparticles (<10 nm), up to a more disordered, aerogel-type structure. Correspondingly, the film density varies with respect to bulk TiO2 anatase, with a degree of porosity going from 48% to over 90%. These structures are stable with respect to heat treatment at 400 °C, which results in crystalline ordering but not in morphological changes down to the nanoscale. Both as deposited and annealed films exhibit very promising photocatalytic properties, even superior to standard Degussa-P25 powder, as demonstrated by the degradation of stearic acid as a model molecule. The observed kinetics are correlated to the peculiar morphology of the PLD grown material. We show that the 3D multiscale hierarchical morphology enhances reaction kinetics and creates an ideal environment for mass transport and photon absorption, maximizing the surface area-to-volume ratio while at the same time providing readily accessible porosity through the large inter-tree spaces that act as distributing channels. The reported strategy provides a versatile technique to fabricate high aspect ratio 3D titania microstructures through a hierarchical assembly of ultrafine nanoparticles. Beyond photocatalytic and catalytic applications, this kind of material could be of interest for those applications where high surface-to-volume and efficient mass transport are required at the same time.

Di Fonzo, F.; Casari, C. S.; Russo, V.; Brunella, M. F.; Bassi, A. Li; Bottani, C. E.

2009-01-01

366

[Simultaneous desulfurization and denitrification by TiO2/ACF under different irradiation].  

PubMed

The supported TiO2 photocatalysts were prepared in laboratory, and the experiments of simultaneous desulfurization and denitrification were carried out by self-designed photocatalysis reactor. The optimal experimental conditions were achieved, and the efficiencies of simultaneous desulfurization and denitrification under two different light sources were compared. The results show that the oxygen content of flue gas, reaction temperature, flue gas humidity and irradiation intensity are most essential factors to photocatalysis. For TiO2/ACF, the removal efficiencies of 99.7% for SO2 and 64.3% for NO are obtained respectively at optimal experimental conditions under UV irradiation. For TiO2/ACF, the removal efficiencies of 97.5% for SO2 and 49.6% for NO are achieved respectively at optimal experimental conditions under the visible light irradiation. The results of five times parallel experiments indicate standard deviation S of parallel data is little. The mechanism of removal for SO2 and NO is proposed under two light sources by ion chromatography analysis of the absorption liquid. PMID:19544996

Han, Jing; Zhao, Yi

2009-04-15

367

TiO2/CdSe core-shell nanofiber film for photoelectrochemical hydrogen generation.  

PubMed

We report on a novel core-shell TiO2/CdSe nanofiber photoanode for photoelectrochemical hydrogen generation. The core-shell nanofiber films, with a hierarchical network structure, are prepared on fluorine-doped tin oxide coated substrates via electrospinning pyrolysis and chemical bath deposition. The hierarchical network structure shows significantly improved photoelectrochemical properties due, we believe, to possessing more active sites for the oxidation reaction and a larger TiO2/CdSe interface area for photogenerated charges' separation. The synthesis details are discussed to provide a generic route for preparing other similar photoanodes with hierarchical network structures. PMID:24876070

Liu, Ya; Zhao, Liang; Li, Mingtao; Guo, Liejin

2014-07-01

368

Enhancing the surface properties of the immobilized Degussa P-25 TiO2 for the efficient photocatalytic removal of methylene blue from aqueous solution  

NASA Astrophysics Data System (ADS)

A method has been developed for enhancing the surface properties of immobilized Degussa P-25 TiO2 nanoparticles on glass plate supports with excellent photocatalytic activity. The immobilization technique utilized a dip-coating method involving a coating solution containing Degussa P-25 TiO2 particles, epoxidized natural rubber (ENR-50) and poly vinyl chloride (PVC) in a mixture of toluene and dichloromethane. The optimum ratio of ENR/PVC blend was found to be 1:2. Immobilization process of the composite appeared to reduce the specific surface area by at least half of the pristine P-25 TiO2 particles. However, a systematic removal of ENR-50 additive via a 5 h photocatalytic process enabled the immobilized photocatalyst (P-25TiO2/ENR/PVC/5 h) to regenerate the surface area to within 86% of the pristine P-25 TiO2 particles, produce bigger pore volume and smaller particle size. The enhanced surface properties of the immobilized P-25/ENR/PVC/5 h photocatalyst system generated a photocatalytic performance as good as the slurry method of the P-25 TiO2 nanoparticles for the photocatalytic degradation of MB dye in aqueous solution. The immobilized P-25TiO2/ENR/PVC/5 h catalyst plate was also found to be highly reusable up to at least 10 runs without losing its photocatalytic efficiency. Above all, the system could avoid tedious filtration step of the treated water as normally observed with the aqueous slurry system.

Nawi, M. A.; Zain, Salmiah Md.

2012-06-01

369

Efficient dechlorination of chlorinated solvent pollutants under UV irradiation by using the synthesized TiO2 nano-sheets in aqueous phase.  

PubMed

Titanium dioxide (TiO2), which is the widely used photo-catalyst, has been synthesized by simple hydrothermal solution containing tetrabutyl titanate and hydrofluoric acid. The synthesized product has been applied to photo-degradation in aqueous phase of chlorinated solvents, namely tetrachloroethene (PCE), trichloroethene (TCE) and 1,1,1-trichloroethane (TCA). The photo-degradation results revealed that the degradation of these harmful chemicals was better in UV/synthesized TiO2 system compared to UV/commercial P25 system and UV only system. The photo-catalytic efficiency of the synthesized TiO2 was 1.4, 1.8 and 3.0 folds higher compared to the commercial P25 for TCA, TCE and PCE degradation, respectively. Moreover, using nitrobenzene (NB) as a probe of hydroxyl radical (·OH), the degradation rate was better over UV/synthesized TiO2, suggesting the high concentration of ·OH generated in UV/synthesized TiO2 system. In addition, ·OH concentration was confirmed by the strong peak displayed in EPR analysis over UV/synthesized TiO2 system. The characterization result using XRD and TEM showed that the synthesized TiO2 was in anatase form and consisted of well-defined sheet-shaped structures having a rectangular outline with a thickness of 4 nm, side length of 50 nm and width of 33 nm and a surface 90.3 m(2)/g. XPS analysis revealed that ?Ti-F bond was formed on the surface of the synthesized TiO2. The above results on both photocatalytic activity and the surface analysis demonstrated the good applicability of the synthesized TiO2 nano-sheets for the remediation of chlorinated solvent contaminated groundwater. PMID:25079650

Ndong, Landry Biyoghe Bi; Ibondou, Murielle Primaelle; Miao, Zhouwei; Gu, Xiaogang; Lu, Shuguang; Qiu, Zhaofu; Sui, Qian; Mbadinga, Serge Maurice

2014-05-01

370

Degradation of glyphosate in soil photocatalyzed by Fe3O4/SiO2/TiO2 under solar light.  

PubMed

In this study, Fe(3)O(4)/SiO(2)/TiO(2) photocatalyst was prepared via a sol-gel method, and Fe(3)O(4) particles were used as the core of the colloid. Diffraction peaks of Fe(3)O(4) crystals are not found by XRD characterization, indicating that Fe(3)O(4) particles are well encapsulated by SiO(2). FTIR characterization shows that diffraction peaks of Ti-O-Si chemical bonds become obvious when the Fe(3)O(4) loading is more than 0.5%. SEM characterization indicates that agglomeration occurs in the Fe(3)O(4)/SiO(2)/TiO(2) photocatalyst, whereas photocatalysts modified by Fe(3)O(4)/SiO(2) present excellent visible light absorption performance and photocatalytic activity, especially when the Fe(3)O(4) loading is 0.5%. Photocatalytic degradation of glyphosate in soil by these photocatalysts under solar irradiation was investigated. Results show that 0.5% Fe(3)O(4)/SiO(2)/TiO(2) has the best photocatalytic activity. The best moisture content of soil is 30%~50%. Degradation efficiency of glyphosate reaches 89% in 2 h when the dosage of photocatalyst is 0.4 g/100 g (soil), and it increased slowly when more photocatalyst was used. Soil thickness is a very important factor for the photocatalytic rate. The thinner the soil is, the better the glyphosate degradation is. Degradation of glyphosate is not obviously affected by sunlight intensity when the intensity is below 6 mW/cm(2) or above 10 mW/cm(2), but it is accelerated significantly when the sunlight intensity increases from 6 mW/cm(2) to 10 mW/cm(2). PMID:21695039

Xu, Xuan; Ji, Fangying; Fan, Zihong; He, Li

2011-04-01

371

High-performance self-powered UV photodetectors based on TiO2 nano-branched arrays  

NASA Astrophysics Data System (ADS)

Nano-branched TiO2 arrays were fabricated on fluorine-doped tin oxide (FTO) glass by a facile two-step chemical synthesis process. Self-powered UV photodetectors based on photoelectrochemical cells (PECs) were assembled using these TiO2 nano-branched arrays as photoanodes. These visible-blind self-powered UV photodetectors exhibit high sensitivity and high-speed photoresponse. Compared with photodetectors based on bare TiO2 nanorod arrays, TiO2 nano-branched arrays show drastically improved photodetecting performance as photoanodes. The photosensitivity increases from 0.03 to 0.22 A W-1 when optimized nano-branched TiO2 arrays are used, corresponding to an incident photon-to-current conversion efficiency higher than 77%. The UV photodetectors also exhibit excellent spectral selectivity and fast response (0.05 s decay time). The improved performance is attributed to a markedly enlarged TiO2/electrolyte contact area and good electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunk.

Xie, Yanru; Wei, Lin; Li, Qinghao; Chen, Yanxue; Yan, Shishen; Jiao, Jun; Liu, Guolei; Mei, Liangmo

2014-02-01

372

Nanoscale anatase TiO2 with dominant {1 1 1} facets shows high photocatalytic activity  

NASA Astrophysics Data System (ADS)

In this work, we report a novel synthesis of nanoscale anatase TiO2 with dominant highly active {1 1 1} facets by a simple one-step hydrothermal route with the assistance of NH4F and HF. In this progress, the exposed crystal facets of TiO2 can been directly tuned by controlling the mole ratio of NH4+ and F-. When the mole ratio of NH4+ and F-reach 1:2, nanoscale anatase TiO2 with dominant {1 1 1} facets can be obtained. Nanoscale anatase TiO2 with exposed {1 0 1} or {0 0 1} facets will be prepared when there is only ammonia or HF added respectively. Such nano-TiO2 with exposed highly active {1 1 1} facets has large specific surface area and shows excellent photocatalytic activity: as much as 2-3 times than that of TiO2 nanosheets with exposed {0 0 1} facets and commercial Degussa P25 which confirms the {1 1 1} facets have higher photocatalytic activity than {0 0 1} and {1 0 1} facets. The higher photocatalytic activity of {1 1 1} facets can be ascribed to the fact that all Ti and O atoms on the surface are unsaturated Ti5c, Ti3c and O2c modes which produces a higher adsorption and degradation ability. The present work demonstrates a explore of hydrothermal synthetic method for controlling preparation of nano-materials.

Zhang, Jun; Qian, Lisha; Yang, Lingxia; Tao, Xi; Su, Kunpeng; Wang, Hongbo; Xi, Junhua; Ji, Zhenguo

2014-08-01

373

Highly efficient TiO2-based microreactor for photocatalytic applications.  

PubMed

A photocatalytic, TiO2-based microreactor is designed and fabricated on a metal-titanium foil. The microchannel is mechanically engraved in the substrate foil, and a double-layered TiO2 anatase film is immobilized on its inner walls with a two-step synthesis, which included anodization and a hydrothermal treatment. X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirm the presence of an approximately 10-?m-thick layer of titania nanotubes and anatase nanoparticles. The SEM and transmission electron microscopy (TEM) of the cross sections show a dense interface between the titanium substrate and the TiO2 nanotubes. An additional layer of TiO2-anatase nanoparticles on the top of the film provides a large, photocatalytic surface area. The metal-titanium substrate with a functionalized serpentine channel is sealed with UV-transparent Plexiglas, and four 0.8-mW UV LEDs combined with a power controller on a small printed-circuit board are fixed over the substrate. The photocatalytic activity and the kinetic properties for the degradation of caffeine are provided, and the longer-term stability of the TiO2 film is evaluated. The results show that after 6 months of use and 3600 working cycles the microreactor still exhibits 60% of its initial efficiency. PMID:23978202

Krivec, Matic; Žagar, Kristina; Suhadolnik, Luka; ?eh, Miran; Draži?, Goran

2013-09-25

374

Photoconductivity and stabilization of dopamine embedded in sol-gel TiO2 matrix  

NASA Astrophysics Data System (ADS)

This work reports the synthesis of amorphous TiO2 matrix by sol-gel method at atmospheric conditions. DA was encapsulated in a TiO2 matrix to reduce its chemical instability. To TiO2/DA sample was added the 15C5 to diminish the oxidation process. The stabilization process was followed by absorption spectra, colour change and infrared spectroscopy. Oxidation processes of the DA were identified by the presence of DA-quinone and DA-chrome. The TiO2/DA complex retarded the oxidation process for 30 days, while the TiO2/DA/15C5 complex this period was extended for 47 days. Photoconductivity studies were performed on both kinds of samples to analyze their charge transports. The experimental data were fitted with straight lines at darkness and under illumination at 320 nm, 400 nm, and 515 nm. This indicates an ohmic behavior. Transport parameters were calculated. The conductive effect is stronger under darkness than under illumination at 320 nm because the oxidation process in the darkness is less intense than under illumination.

Prado-Prone, Gina; Valverde-Aguilar, Guadalupe; García-Macedo, Jorge; Vergara-Aragón, P.

2012-09-01

375

Comparison of Photocatalytic Activity of TiO2 Anatase Prepared by the Sol-Gel Technique and Chemical Vapour Deposition on Naphthalene in the Gas Phase  

NASA Astrophysics Data System (ADS)

In this study the gas phase photocatalytic oxidation of naphthalene in the presence of TiO2-based photocatalysts prepared by chemical vapor deposition (CVD) and the sol-gel method is examined. As precursors for the photocatalyst preparation TiCl4 was used for chemical vapor deposition (CVD), while for the sol-gel technique the precursor was titanium tetra-isopropoxide. The level of naphthalene degradation was examined with FTIR spectroscopy; the identification of the products obtained was performed by GC-MS measurements. The kinetics of the photooxidation reaction of naphthalene in excess of oxygen was investigated. It was found that the kinetics of naphthalene oxidation follow a first-order law; the rate constants were determined by means of mathematical modeling. Also, it was found that the rate limiting steps for naphthalene oxidation are diffusion of the components on the catalyst surface and transport through the films of the photocatalyst particles. The photocatalytic activity of TiO2-based photocatalysts prepared by CVD as a gas phase method and the sol-gel technique as a liquid method are compared. The photocatalysts showed an excellent efficiency for naphthalene degradation in the presence of oxygen; a complete mineralization of the aromatic toxic compound to CO2 and water was achieved.

Marinkovski, Mirko; Nacevski, Goran; Tomovska, Radmila; Paunovi?, Perica; Fajgar, Radek

376

Two novel hierarchical homogeneous nanoarchitectures of TiO2 nanorods branched and P25-coated TiO2 nanotube arrays and their photocurrent performances  

PubMed Central

We report here for the first time the synthesis of two novel hierarchical homogeneous nanoarchitectures of TiO2 nanorods branched TiO2 nanotube arrays (BTs) and P25-coated TiO2 nanotube arrays (PCTs) using two-step method including electrochemical anodization and hydrothermal modification process. Then the photocurrent densities versus applied potentials of BTs, PCTs, and pure TiO2 nanotube arrays (TNTAs) were investigated as well. Interestingly, at -0.11 V and under the same illumination condition, the photocurrent densities of BTs and PCTs show more than 1.5 and 1 times higher than that of pure TNTAs, respectively, which can be mainly attributed to significant improvement of the light-absorbing and charge-harvesting efficiency resulting from both larger and rougher surface areas of BTs and PCTs. Furthermore, these dramatic improvements suggest that BTs and PCTs will achieve better photoelectric conversion efficiency and become the promising candidates for applications in DSSCs, sensors, and photocatalysis. PMID:21711607

2011-01-01

377

Preparation and characterization of iodine-doped mesoporous TiO2 by hydrothermal method  

NASA Astrophysics Data System (ADS)

Iodine-doped mesoporous TiO2 (I/TiO2) was prepared by hydrothermal method, using tetrabutyl titanate as precursor, potassium iodate as iodine sources. The as-prepared I/TiO2 catalysts were characterized by UV-vis, XRD, TEM, BET, TG/DTA, XPS and photoluminescence (PL) spectroscopy. Production of rad OH radicals on the I/TiO2 surface was detected by the PL technique using terephthalic acid as a probe molecule. The effects of hydrothermal reaction temperature, calcination temperature and iodine doping content on the structure and properties of the catalysts were investigated. The results showed that iodine-doped TiO2 calcinated at 300 °C have good anatase crystal. The optimal hydrothermal conditions have been determined to be that reaction temperature 120 °C, calcinated temperature 300 °C and added 1.16 mmol iodine dopants. The average particle size of I/TiO2 synthesized under optimal condition (I-3 sample) is about 3.9 nm. The I-3 photocatalyst contains 100% anatase crystalline phase of TiO2. BET specific surface area of I-3 sample is184.8 m2 g-1 and is 3.67 times that of pure TiO2 (50.37 m2 g-1). Iodine in I/TiO2 catalyst mainly exists in the form of I2, and photoactivity of I/TiO2 catalyst in visible light comes from photosensitize of I2. I/TiO2 catalysis shows very high efficiency for the degradation of phenol under visible light.

Wang, Wei-an; Shi, Qian; Wang, Yu-ping; Cao, Jin-li; Liu, Guo-qing; Peng, Pan-ying

2011-02-01

378

[Tetrabutyl titanate hydrolysis prepared TiO2 photocatalysis loaded with platinum technology].  

PubMed

Photocatalysts Pt/TiO2 coated on hollow glass beads were prepared by tetrabutyl titanate hydrolysis with Sodium silicate on hollow glass beads at various condition and loaded with platinum varying from 0.2% to 2.4% by weight. Sodium pentachlorophenolate (PCP-Na) solution were used to examined for their photoactivity and characterized by X-ray and BET. The results indicated that the optimization condition to prepare photocatalysts: Water to titanium alkoxides was 100, Sintering temperature was 650 degrees C, Diameter of hollow glass beads was 0.5 mm, TiO2: sodium silicate: hollow glass beads was 10:2.5:20, Platinum content of photocatalysts was about 1.4%-1.6%. When the experiments were carried out in such conditions, the initial concentration of PCP-Na was 100 mg/L, initial pH was 6.5, oxygen flux was 1.6 mL/s, illumination intensity was 30 kW.m-2, catalysts was 2 g/L, illumination time was 2 hours, respectively. Then the rates removals of PCP-Na could reach 92.0%. PMID:11987410

Xi, Beidou; Liu, Hongliang

2002-01-30

379

Visible light photoactivity of TiO2 loaded with monometallic (Au or Pt) and bimetallic (Au/Pt) nanoparticles  

NASA Astrophysics Data System (ADS)

TiO2 modified with monometallic (Au or Pt) and bimetallic (Au/Pt) nanoparticles have been prepared using a water-in-oil microemulsion system (water/AOT/cyclohexane) followed by calcination step. The effect of metal ratio, reducing agent type (NaBH4 or N2H4), TiO2 matrix type (P-25, ST-01, TiO-5, TiO2 nanotubes or TiO2 obtained by TIP hydrolysis) as well as calcination temperature (from 350 to 650 °C) were systematically investigated. Obtained photocatalysts were characterized by UV-vis diffuse-reflectance spectroscopy (DRS), BET surface area measurements, scanning transmission microscopy (STEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity under visible light (? > 420 nm) has been estimated in phenol degradation reaction in aqueous phase. The results showed that phenol degradation rate under visible light in the presence of TiO2 loaded with Au/Pt nanoparticles differed from 0.7 to 2.2 ?mol dm-3 min-1 for samples prepared using different reducing agent. Sodium borohydride (NaBH4) favors formation of smaller Au/Pt nanoparticles and higher amount gold in Au/Pt is in the form of electronegative species (Au?-) resulted in higher photoactivity. TiO2 obtained by TIP hydrolysis in microemulsion system seems to be the best support for Au/Pt nanoparticles from all among investigated matrix. It was also observed that enhancement of calcination temperature from 450 to 650 °C resulted in rapid drop of Au/Pt-TiO2 photoactivity under visible light due to surface area shrinkage, crystal structure change and probably change in Au/Pt nanoparticles morphology.

Go??biewska, Anna; Lisowski, Wojciech; Jarek, Marcin; Nowaczyk, Grzegorz; Zieli?ska-Jurek, Anna; Zaleska, Adriana

2014-10-01

380

[Photocatalytic removing of a mustard gas analogue 2-CEES vapor over SO4(2-)/TiO2].  

PubMed

Disinfection with photocatalysis, compared to with the conventional cleanout, is both high efficient and non contaminative, but the simple TiO2 photocatalyst is showing to be of low activity and low active stability so to be hardly practical application. In the paper, SO4(2-)/TiO2 were papered by surface modification of TiO2 with dilute H2SO4, and the photocatalytic degradation of 2-chloroethyl ethyl sulfide (2-CEES) on the samples was examined in a fixed-bed microreactor. The examination show that the acidic modification enhanced both the activity and the active stability of TiO2, and the sample ST200 prepared by calcination at 200 degrees C was better than ST400 by calcination at 400 degrees C. The effect of water vapor content and reaction temperature on the photocatalytic degradation of 2-CEES was also tested, showing that the sample ST200 had high activity and stability at 90 degrees C, and kept a constant activity when adding 30.5 mL/L water vapor into the reactive system in which 2-CEES initial concentration was low to < 61 microL x L(-1). In addition, it was found that supporting SO4(2-)/TiO2 on gamma-Al2O3, SiO2 and active carbon could improve on the activity and stability of SO4(2-)/TiO2, and on supports SiO2 is the best one. PMID:16124485

Han, Shi-tong; Xi, Hai-ling; Wang, Xu-xu; Fu, Xian-zhi

2005-05-01

381

Ultrathin (0 0 1) and (1 0 0) TiO2(B) sheets: Surface reactivity and structural properties  

NASA Astrophysics Data System (ADS)

B polymorph of titanium dioxide (TiO2(B)) appears as a metastable phase during thermal annealing of low content sodium layered titanate nanostructures obtained via the widely used hydrothermal synthesis. In addition, the computed formation energy for the TiO2(B) (0 0 1) slabs in the order of the one calculated for anatase (1 0 1) which represents one of the most stable TiO2 surfaces. This encourages the study of this polymorph which could gain prominence in TiO2 applications at the nanoscale. In a first instance ultrathin TiO2(B) sheets, parallel to crystallographic planes (0 0 1) and (1 0 0), are investigated and compared to other well know TiO2 polymorphs, such as rutile and anatase surfaces. Then the adsorption of formic acid on (0 0 1) and (1 0 0) - less stable - TiO2(B) dry ultrathin sheets was studied as the first step for further evaluation of TiO2(B) nanostructures for dye sensitized solar cells (DSSC) applications. The results show that the monodentate through the carbonyl group configuration is the most stable for (0 0 1) sheet while bidentate dissociated configuration is the most stable for (1 0 0) sheet being the computed adsorption energies 0.51 eV and 1.49 eV, respectively. The evaluated reactivity of TiO2(B) slabs is comparable with anatase and indicates that it could be a good adsorbent for common dyes used for dye sensitized solar cells purposes.

Fernández-Werner, Luciana; Faccio, Ricardo; Juan, Alfredo; Pardo, Helena; Montenegro, Benjamín; Mombrú, Álvaro W.

2014-01-01

382

Zirconium and silver co-doped TiO2 nanoparticles as visible light catalyst for reduction of 4-nitrophenol, degradation of methyl orange and methylene blue.  

PubMed

Catalytic activity of Zr and Ag co-doped TiO2 nanoparticles on the reduction of 4-nitrophenol, degradation of methylene blue and methyl orange was studied using sodium borohydride as reducing agent. The nanoparticles were characterized using X-ray diffraction, energy dispersive X-ray, high resolution transmission electron microscopy, selected area electron diffraction and UV-Vis spectroscopy. The rate of the reduction/degradation was found to increase with increasing amount of the photocatalyst which could be attributed to higher dispersity and small size of the nanoparticles. The catalytic activity of Zr and Ag co-doped TiO2 nanoparticles showed no significant difference even after recycling the catalyst four times indicating a promising potential for industrial application of the prepared photocatalyst. PMID:25150432

Naraginti, Saraschandra; Stephen, Finian Bernard; Radhakrishnan, Adhithya; Sivakumar, A

2015-01-25

383

Pt deposited TiO2 catalyst fabricated by thermal decomposition of titanium complex for solar hydrogen production  

NASA Astrophysics Data System (ADS)

C, N codoped TiO2 catalyst has been synthesized by thermal decomposition of a novel water-soluble titanium complex. The structure, morphology, and optical properties of the synthesized TiO2 catalyst were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of the Pt deposited TiO2 catalysts synthesized at different temperatures was evaluated by means of hydrogen evolution reaction under both UV-vis and visible light irradiation. The investigation results reveal that the photocatalytic H2 evolution rate strongly depended on the crystalline grain size as well as specific surface area of the synthesized catalyst. Our studies successfully demonstrate a simple method for the synthesis of visible-light responsive Pt deposited TiO2 catalyst for solar hydrogen production.

Truong, Quang Duc; Le, Thanh Son; Ling, Yong-Chien

2014-12-01

384

Effects of calcination on the photocatalytic properties of nanosized TiO 2 powders prepared by TiCl 4 hydrolysis  

Microsoft Academic Search

The ultra fine nanosized TiO2 photocatalysts in the anatase, rutile, and both phases were prepared by the hydrolysis of TiCl4 solution. The resulting materials have been characterized by HREM, XRD, BET and UV–VIS absorption spectroscopy. The photoactivity, effective degradation, and the selectivity for complete mineralization of these catalysts were tested in the photocatalytic degradation of phenol. For this reaction, the

Qinghong Zhang; Lian Gao; Jingkun Guo

2000-01-01

385

Enhanced photocatalytic activity of S-doped TiO2-ZrO2 nanoparticles under visible-light irradiation.  

PubMed

Porous nanocrystalline S-doped TiO2-ZrO2 visible-light photocatalysts were prepared through a one-step method. The resulting materials were characterized by X-ray diffraction (XRD), N(2) adsorption-desorption measurements, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS), Fourier transform infrared spectra (FT-IR) and electron paramagnetic resonance (ESR). It was found that modification by ZrO2 could effectively inhibit phase transformation, enhance visible-light absorption, and possess more surface hydroxyl groups. The photocatalytic activity of S-doped TiO2-ZrO2 was higher than that of unmodified S-doped TiO2 and Degussa P25. The enhanced photocatalytic activity could be attributed to the higher specific area, smaller crystal size, porous structure and more surface hydroxyl groups in the catalyst. PMID:19144462

Tian, Guohui; Pan, Kai; Fu, Honggang; Jing, Liqiang; Zhou, Wei

2009-07-30

386

Preparation of new magnetic nanocatalysts based on TiO2 and ZnO and their application in improved photocatalytic degradation of dye pollutant under visible light.  

PubMed

Photocatalytic degradation of methyl orange (MO) as a model of an organic pollution was accomplished with magnetic and porous TiO(2)/ZnO/Fe(3)O(4)/PANI and ZnO/Fe(3)O(4)/PANI nanocomposites under visible light irradiation. The structures of nanocomposites were characterized by various techniques including UV-Vis absorption spectroscopy, XRD, SEM, EDS, BET and TGA. Optical absorption investigations show two ?(max) at 450 and 590 nm for TiO(2)/ZnO/Fe(3)O(4)/PANI nanocomposites respectively possessing optical band gaps about 2.75 and 2.1 eV smaller than that of the neat TiO(2) and ZnO nanoparticles. Due to these optical absorptions, the nanocomposites can be considered promising candidates as visible light photocatalysts to produce more electron-hole pairs. The degradation of MO, extremely increased using polymeric photocatalysts and decolorization in the presence of visible light achieved up to 90% in less than 20 min in comparison with the neat nanoparticles (about 10%). All these advantages promise a bright future for these composites as useful photocatalysts. The degradation efficiency of MO using stable nanocomposites was still over 70% after ten times reusing. The highest decolorizing efficiencies were achieved with 0.75 g L(-1) of catalyst and 10 mg L(-1) of MO at natural pH under visible light irradiation in less than 20 min. PMID:22817280

Nabid, Mohammad Reza; Sedghi, Roya; Gholami, Saeede; Oskooie, Hossein Abdi; Heravi, Majid M

2013-01-01

387

Anatase TiO2 nanocrystals with exposed {001} facets on graphene sheets via molecular grafting for enhanced photocatalytic activity  

NASA Astrophysics Data System (ADS)

Owing to their extensive practical applications and fundamental importance, the controllable synthesis of well-faceted anatase TiO2 crystal with high percentage of reactive facets has attracted increasing attention. Here, nano-sized anatase TiO2 sheets mainly dominated by {001} facets had been prepared on graphene sheets by using a facile solvothermal synthetic route. The percentage of {001} facets in TiO2 nanosheets was calculated to be ca. 64%. The morphologies, structural properties, growth procedures and photocatalytic activities of the resultant TiO2/graphene nanocomposites were investigated. In comparison with commercial P25 and pure TiO2 nanosheets, the composite exhibited significant improvement in photocatalytic degradation of the azo dye Rhodamine B under visible light irradiation. The enhancement of photocatalytic activity and stability was attributed to the effective charge anti-recombination of graphene and the high catalytic activity of {001} facets.Owing to their extensive practical applications and fundamental importance, the controllable synthesis of well-faceted anatase TiO2 crystal with high percentage of reactive facets has attracted increasing attention. Here, nano-sized anatase TiO2 sheets mainly dominated by {001} facets had been prepared on graphene sheets by using a facile solvothermal synthetic route. The percentage of {001} facets in TiO2 nanosheets was calculated to be ca. 64%. The morphologies, structural properties, growth procedures and photocatalytic activities of the resultant TiO2/graphene nanocomposites were investigated. In comparison with commercial P25 and pure TiO2 nanosheets, the composite exhibited significant improvement in photocatalytic degradation of the azo dye Rhodamine B under visible light irradiation. The enhancement of photocatalytic activity and stability was attributed to the effective charge anti-recombination of graphene and the high catalytic activity of {001} facets. Electronic supplementary information (ESI) available: Calculational details; UV-vis diffuse reflectance spectra; photocatalytic decomposition data; and detailed data of pure TiO2 nanosheets. See DOI: 10.1039/c1nr11411e

Sun, Lei; Zhao, Zhenlu; Zhou, Yunchun; Liu, Li

2012-01-01

388

Adsorption and degradation of model volatile organic compounds by a combined titania-montmorillonite-silica photocatalyst.  

PubMed

A series of adsorptive photocatalysts, combined titania-montmorillonite-silica were synthesized. The resultant photocatalysts consisted of more and more spherically agglomerated TiO(2) particles with increasing of TiO(2) content, and anatase was the only crystalline phase with nano-scale TiO(2) particles. With increasing of the cation exchange capacity to TiO(2) molar ratio, specific surface area and pore volume increased very slightly. In a fluidized bed photocatalytic reactor by choosing toluene, ethyl acetate and ethanethiol as model pollutants, all catalysts had relatively high adsorption capacities and preferred to adsorb higher polarity pollutants. Langmuir isotherm model better described equilibrium data compared to Freundlich model. Competitive adsorptions were observed for the mixed pollutants on the catalysts, leading to decrease adsorption capacity for each pollutant. The combined titania-montmorillonite-silica photocatalyst exhibited excellent photocatalytic removal ability to model pollutants of various components. Almost 100% of degradation efficiency was achieved within 120 min for each pollutant with about 500 ppb initial concentration, though the efficiencies of multi-component compounds slightly decreased. All photocatalytic reactions followed the Langmuir-Hinshelwood model. Degradation rate constants of multi-component systems were lower than those for single systems, following the order of toluene

Chen, Jiangyao; Li, Guiying; He, Zhigui; An, Taicheng

2011-06-15

389

In situ synthesis of water-soluble magnetic graphitic carbon nitride photocatalyst and its synergistic catalytic performance.  

PubMed

Water-soluble magnetic-functionalized graphitic carbon nitride (g-C3N4) composites were synthesized successfully by in situ decorating spinel ZnFe2O4 nanoparticles on g-C3N4 sheets (CN-ZnFe) through a one-step solvothermal method. The magnetic properties of CN-ZnFe can be effectively controlled via tuning the coverage density and the size of ZnFe2O4 nanoparticles. The results indicate that the CN-ZnFe exhibits excellent photocatalytic efficiency for methyl orange (MO) and fast separation from aqueous solution by magnet. Interestingly, the catalytic performance of the CN-ZnFe is strongly dependent on the loading of ZnFe2O4. The optimum activity of 160CN-ZnFe photocatalyst is almost 6.4 and 5.6 times higher than those of individual g-C3N4 and ZnFe2O4 toward MO degradation, respectively. By carefully investigating the influence factors, a possible mechanism is proposed and it is believed that the synergistic effect of g-C3N4 and ZnFe2O4, the smaller particle size, and the high solubility in water contribute to the effective electron-hole pairs separation and excellent photocatalytic efficiency. This work could provide new insights that g-C3N4 sheets function as good support to develop highly efficient g-C3N4-based magnetic photocatalysts in environmental pollution cleanup. PMID:24251865

Zhang, Shouwei; Li, Jiaxing; Zeng, Meiyi; Zhao, Guixia; Xu, Jinzhang; Hu, Wenping; Wang, Xiangke

2013-12-11

390

Synthesis of a new type of echinus-like Fe3O4@TiO2 core-shell-structured microspheres and their applications in selectively enriching phosphopeptides and removing phospholipids.  

PubMed

Some compounds of low abundance in biological samples play important roles in bioprocesses. However, the detection of these compounds at inherently trace concentrations with interference from a complex matrix is difficult. New materials for sample pretreatment are essential for the removal of interferences and for selective enrichment. In this study, echinus-like Fe(3)O(4)@TiO(2) core-shell-structured microspheres (echinus-like microspheres) have been synthesized for the first time. Rutile phase TiO(2) nanorods with a length of approximately 300 nm and width of approximately 60 nm are arranged regularly on the surface of the microspheres. This novel type of material exhibited good selectivity and adsorption capacity toward phosphate-containing compounds. In proteomics research, the echinus-like microspheres were used to selectively enrich phosphopeptides from complex peptide mixtures. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) analysis showed that fourteen phosphopeptides were detected from ?-casein tryptic digests after enrichment. Even in peptide mixtures that contained highly abundant nonphosphorylated peptides with interference from bovine serum albumin, these phospopeptides could still be selectively trapped with little nonspecific adsorption. In metabolomics studies, the echinus-like microspheres were further used to selectively remove phosphocholines (PCs) and lysophosphocholines (LPCs), which are the main matrix interferences for the detection of metabolites of low abundance in plasma. Liquid chromatography-quadrupole time-of-flight mass spectrometry was used to perform the metabolic profiling of plasma. The high concentrations of PCs and LPCs were effectively eliminated, and many endogenous metabolites of low abundance were enhanced or even observed for the first time. All of the results suggest that echinus-like microspheres have potential applications in proteomics and metabolomics to improve the detection sensitivity of important compounds. PMID:23294993

Li, Hua; Shi, Xianzhe; Qiao, Lizhen; Lu, Xin; Xu, Guowang

2013-02-01

391

Hydrogen production by Tuning the Photonic Band Gap with the Electronic Band Gap of TiO2  

PubMed Central

Tuning the photonic band gap (PBG) to the electronic band gap (EBG) of Au/TiO2 catalysts resulted in considerable enhancement of the photocatalytic water splitting to hydrogen under direct sunlight. Au/TiO2 (PBG-357?nm) photocatalyst exhibited superior photocatalytic performance under both UV and sunlight compared to the Au/TiO2 (PBG-585?nm) photocatalyst and both are higher than Au/TiO2 without the 3 dimensionally ordered macro-porous structure materials. The very high photocatalytic activity is attributed to suppression of a fraction of electron-hole recombination route due to the co-incidence of the PBG with the EBG of TiO2 These materials that maintain their activity with very small amount of sacrificial agents (down to 0.5 vol.% of ethanol) are poised to find direct applications because of their high activity, low cost of the process, simplicity and stability. PMID:24108361

Waterhouse, G. I. N.; Wahab, A. K.; Al-Oufi, M.; Jovic, V.; Anjum, D. H.; Sun-Waterhouse, D.; Llorca, J.; Idriss, H.

2013-01-01

392

Solid-state dye-sensitized solar cells fabricated with nanoporous TiO 2 and TPD dyes: Analysis of penetration behavior and I-V characteristics  

NASA Astrophysics Data System (ADS)

We present the synthesis, electrochemical properties and device-based investigation of triphenylene diamine (TPD) sensitizer with an extended ? system consisting of donor, electron conducting and anchoring group for solid-state dye-sensitized solar cells. Solid-state dye-sensitized solar cells were fabricated using blocking TiO2 electrodes, nanoporous TiO2 electrodes and the organic hole-transporting medium, HTM (spiro-OMeTAD) in a fluorine doped tin oxide/blocking TiO2/nanoporous TiO2/TPDs/hole transport material/Au configuration. Solid state dye sensitized solar cell consisting of TPD_2 as sensitizer on mesoporous TiO2 shows the best results with a short-circuit current of 2.8 mA/cm2, an open circuit voltage of 835 mV and an overall conversion efficiency of 0.97%.

Erten-Ela, Sule; Brendel, Johannes; Thelakkat, Mukundan

2011-06-01

393

Assessing Photocatalytic Oxidation Using Modified TiO 2 Nanomaterials for Virus Inactivation in Drinking Water: Mechanisms and Application  

NASA Astrophysics Data System (ADS)

Photocatalytic oxidation is an alternative water treatment method under consideration for disinfecting water. Chlorine disinfection can form harmful byproducts, and some viruses (e.g. adenoviruses) are resistant to other alternative disinfection methods. Photocatalytic oxidation using nano-sized photocatalytic particles (e.g. TiO2, fullerene) holds promise; however, it is limited by its low efficiency and long required treatment times. This research focuses on improving virus inactivation by photocatalytic oxidation by modifying catalysts for improved activity, by analyzing virus inactivation kinetics, and by elucidating the inactivation mechanisms of adenovirus serotype 2 (AdV2) and bacteriophage MS2. Modifying TiO2 with silver (nAg/TiO2) or silica (SiO2-TiO2) improves the inactivation kinetics of bacteriophage MS2 by a factor of 3-10. nAg/ TiO2 increases hydroxyl radical (HO·) production while SiO2 increases the adsorption of MS2 to TiO 2. These results suggest that modifying the photocatalyst surface to increase contaminant adsorption is an important improvement strategy along with increasing HO· production. The inactivation kinetics of AdV2 by P25 TiO2 is much slower than the MS2 inactivation kinetics and displays a strong shoulder, which is not present in the MS2 kinetics. nAg/TiO2 initially improves the inactivation rate of AdV2. SiO2-TiO2 reduces the AdV2 inactivation kinetics since adsorption is not significantly enhanced, as it is with MS2. Amino-C60 is highly effective for AdV2 inactivation under visible light irradiation, making it a good material for use in solar disinfection systems. The efficacy of amino-fullerene also demonstrates that singlet oxygen is effective for AdV2 inactivation. When exposed to irradiated TiO2, AdV2 hexon proteins are heavily damaged resulting in the release of DNA. DNA damage is also present but may occur after capsids break. With MS2, the host interaction protein is rapidly damaged, but not the coat protein. The kinetics of MS2 inactivation are rapid since it may quickly lose its ability to attach to host cells, while AdV2 kinetics are slower since the entire capsid must undergo heavy oxidation before inactivation occurs. Adenovirus inactivation likely occurs through breaching the capsid followed by radical attack of DNA and core proteins.

Liga, Michael Vincent

394

Preparation and characterization of tungsten-loaded titanium dioxide photocatalyst for enhanced dye degradation.  

PubMed

Tungsten-loaded TiO(2) photocatalyst has been successfully prepared and characterized. TEM analysis showed that the photocatalysts were nanosize with the tungsten species forming layers of coverage on the surface of TiO(2), but not in clustered form. This was confirmed by XRD and FT-Raman analyses where tungsten species were well dispersed at lower loading (<6.5 mol%), but were in crystalline WO(3) at higher loadings (>12 mol%). In addition, loading with tungsten could stabilize the anatase phase from transforming into inactive rutile phase and did not shift the optical absorption to the visible region as shown by DRUV-vis analysis. PZC value of TiO(2) was found at 6.4, but the presence of tungsten at 6.5 mol% WO(3), decreased the PZC value to 3. Tungsten-loaded TiO(2) was superior to unmodified TiO(2) with 2-fold increase in degradation rate of methylene blue, and equally effective for the degradation of different class of dyes such as methyl violet and methyl orange at 1 mol% WO(3) loading. PMID:19969415

Saepurahman; Abdullah, M A; Chong, F K

2010-04-15

395

Synthesis, Characterization and Photocatalytic Activity of New Photocatalyst ZnBiSbO4 under Visible Light Irradiation  

PubMed Central

In this paper, ZnBiSbO4 was synthesized by a solid-state reaction method for the first time. The structural and photocatalytic properties of ZnBiSbO4 had been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscope and UV-visible spectrometer. ZnBiSbO4 crystallized with a pyrochlore-type structure and a tetragonal crystal system. The band gap of ZnBiSbO4 was estimated to be 2.49 eV. The photocatalytic degradation of indigo carmine was realized under visible light irradiation with ZnBiSbO4 as a catalyst compared with nitrogen-doped TiO2 (N-TiO2) and CdBiYO4. The results showed that ZnBiSbO4 owned higher photocatalytic activity compared with N-TiO2 or CdBiYO4 for the photocatalytic degradation of indigo carmine under visible light irradiation. The reduction of the total organic carbon, the formation of inorganic products, SO42? and NO3?, and the evolution of CO2 revealed the continuous mineralization of indigo carmine during the photocatalytic process. One possible photocatalytic degradation pathway of indigo carmine was obtained. The phytotoxicity of the photocatalytic-treated indigo carmine (IC) wastewater was detected by examining its effect on seed germination and growth. PMID:24879521

Luan, Jingfei; Chen, Mengjing; Hu, Wenhua

2014-01-01

396

Dual cure photocatalyst systems  

SciTech Connect

A family of dual cure photocatalyst systems is being developed to be used in the solventless processing of organic coatings. The photocatalyst systems consist of organometallic compounds often in combination with other agents. Upon photolysis, the photocatalyst system generates a Lewis acid and a free radical. The Lewis acid can initiate the polymerization of epoxies or the addition of isocyanates and polyols to form polyurethanes while the free radical can initiate the polymerization of acrylates. The performance of the various photocatalyst systems will be compared on the basis of the physical properties of the cured compositions they produce. 17 figs.

DeVoe, R.J.; Brown-Wensley, K.A.; Holmes, G.L.; Mathis, M.D.; McCormick, F.B.; Palazzotto, M.C.; Spurgeon, K.M. (Minnesota Mining and Mfg. Co., St. Paul, MN (USA). Corporate Research Labs.)

1990-01-01

397

CdS quantum dot-sensitized solar cells based on nano-branched TiO2 arrays  

PubMed Central

Nano-branched rutile TiO2 nanorod arrays were grown on F:SnO2 conductive glass (FTO) by a facile, two-step wet chemical synthesis process at low temperature. The length of the nanobranches was tailored by controlling the growth time, after which CdS quantum dots were deposited on the nano-branched TiO2 arrays using the successive ionic layer adsorption and reaction method to make a photoanode for quantum dot-sensitized solar cells (QDSCs). The photovoltaic properties of the CdS-sensitized nano-branched TiO2 solar cells were studied systematically. A short-circuit current intensity of approximately 7 mA/cm2 and a light-to-electricity conversion efficiency of 0.95% were recorded for cells based on optimized nano-branched TiO2 arrays, indicating an increase of 138% compared to those based on unbranched TiO2 nanorod arrays. The improved performance is attributed to a markedly enlarged surface area provided by the nanobranches and better electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunks. PMID:24597830

2014-01-01

398

CdS quantum dot-sensitized solar cells based on nano-branched TiO2 arrays.  

PubMed

Nano-branched rutile TiO2 nanorod arrays were grown on F:SnO2 conductive glass (FTO) by a facile, two-step wet chemical synthesis process at low temperature. The length of the nanobranches was tailored by controlling the growth time, after which CdS quantum dots were deposited on the nano-branched TiO2 arrays using the successive ionic layer adsorption and reaction method to make a photoanode for quantum dot-sensitized solar cells (QDSCs). The photovoltaic properties of the CdS-sensitized nano-branched TiO2 solar cells were studied systematically. A short-circuit current intensity of approximately 7 mA/cm2 and a light-to-electricity conversion efficiency of 0.95% were recorded for cells based on optimized nano-branched TiO2 arrays, indicating an increase of 138% compared to those based on unbranched TiO2 nanorod arrays. The improved performance is attributed to a markedly enlarged surface area provided by the nanobranches and better electron conductivity in the one-dimensional, well-aligned TiO2 nanorod trunks. PMID:24597830

Liu, Chang; Li, Yitan; Wei, Lin; Wu, Cuncun; Chen, Yanxue; Mei, Liangmo; Jiao, Jun

2014-01-01

399

Photodegradation of acetaminophen in TiO 2 suspended solution  

Microsoft Academic Search

This study investigated the photocatalytic degradation of acetaminophen (APAP) in TiO2 suspended solution under a 250W metal halide lamp. The influence of some parameters on the degradation of acetaminophen was studied and described in details, such as initial APAP concentration, initial pH value and TiO2 dosage. After 100min irradiation, about 95% of APAP is decomposed in the 1.0gL?1 TiO2 aqueous

Xu Zhang; Feng Wu; XuWei Wu; Pengyu Chen; Nansheng Deng

2008-01-01

400

Effect of TiO2 on the photocatalytic properties of bismuth oxide.  

PubMed

Bi2-xTixO3+x/2 (x = 0.05, 0.10 and 0.15) photocatalysts are prepared by solid-state technique. The band gap of the prepared sample was estimated from the onset of UV-Vis absorption spectra. The photocatalytic activities of as prepared samples are investigated under UV light irradiation for the decomposition of methyl orange (MO). It has been observed that the rate of decomposition of MO increased with increasing Ti4+ content in the present samples. Moreover, it shows better photocatalytic activity than undoped Bi2O3 and TiO2. The lowest band gap is observed for x = 0.15 sample, i.e. 2.55 eV, which also showed the highest photocatalytic activity in the present sample. PMID:24701951

Singla, Gourav; Singh, K

2014-01-01

401

Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water.  

PubMed

Hybrid TiO(2)/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl(4). The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV-vis DRS and TGA. Surface morphology was assessed by the means of SEM and HR-TEM. Statistics-based factorial design (FD) was adopted to investigate the effect of precursors concentrations and therefore to optimize the nanocomposite synthesis through catalytic adsorption of methylene blue (MB) from aqueous solutions. The results indicated that TiO(2)/MC nanocomposites were photocatalytically active in diminishing 40-90% of MB in 4h. PMID:22284756

Virkutyte, Jurate; Jegatheesan, Veeriah; Varma, Rajender S

2012-06-01

402

In situ sonosynthesis of nano TiO2 on cotton fabric.  

PubMed

Here, titanium dioxide nanoparticles (NPs) were sonosynthesized and loaded simultaneously onto the cotton fabric. Titanium tetra isopropoxide (TTIP) was used as precursor and ultrasonic irradiation was utilized as a tool for synthesis of TiO2 in low temperature with anatase structure and loading nanoparticles onto the cotton fabric. TiO2 loaded cotton fabric was characterized by XRD, FE-SEM, EDS, and XRF. Moreover, several properties of the treated cotton fabrics such as self-cleaning, UV protection, washing durability, and tensile strength were studied. The effect of variables, including TTIP concentration and sonication time, was investigated based on central composite design (CCD) and response surface methodology (RSM). The results confirmed formation of anatase TiO2 nanoparticles with 3-6 nm crystalline size loaded onto the cotton fabric at low temperature (75 °C) that led to good self-cleaning and UV-protection properties. The excellent UV-protection rating of the treated fabric maintained even after 25 home launderings indicating an excellent washing durability. Interestingly, sonochemical method had no negative influence on the cotton fabric structure. The statistical analysis indicated significant effect of both TTIP concentration and sonication time on the content of the loaded TiO2 on the fiber and self-cleaning properties of the fabric. PMID:24152573

Akhavan Sadr, Farid; Montazer, Majid

2014-03-01

403

Easily manufactured TiO2 hollow fibers for quantum dot sensitized solar cells.  

PubMed

TiO(2) hollow fibers with high surface area were manufactured by a simple synthesis method, using natural cellulose fibers as template. The effective light scattering properties of the hollow fibers, originating from their micron size, were observed by diffuse reflectance spectroscopy. In spite of the micrometric length of the TiO(2) hollow fibers, the walls were highly porous and high surface area (78.2 m(2) g(-1)) was obtained by the BET method. TiO(2) hollow fibers alone and mixed with other TiO(2) pastes were sensitized with CdSe quantum dots (QDs) by Successive Ionic Layer Adsorption and Reaction (SILAR) and integrated as a photoanode in quantum dot sensitized solar cells (QDSCs). High power conversion efficiency was obtained, 3.24% (V(oc) = 503 mV, J(sc) = 11.92 mA cm(-2), FF = 0.54), and a clear correspondence of the cell performance with the photoanode structure was observed. The unique properties of these fibers: high surface area, effective light scattering, hollow structure to facile electrolyte diffusion and the rather high efficiencies obtained here suggest that hollow fibers can be introduced as promising nanostructures to make highly efficient quantum dot sensitized solar cells. PMID:22108763

Samadpour, Mahmoud; Giménez, Sixto; Zad, Azam Iraji; Taghavinia, Nima; Mora-Seró, Iván

2012-01-14

404

[Preparation and spectral characterisation of TiO2/polyaniline nanocomposites with 2D lamellar morphology].  

PubMed

Nanostructured polyanilines (PANIs) are selected quite often as the matrix for the synthesis of inorganic/conductive polymer composites due to their excellent optical, electrical and magnetic properties. Herein both 2D lamellar PANI and the cor responding composite loading TiO2 species were successfully prepared from a microemulsion system, as composed by dodecyl benzenesulfonic acid (DBSA) and water. The composite was achieved through a simultaneous polymerization of aniline in the presence of ammonium persulfate and hydrolysis of tetrabutyl titanate. Scanning electron microscopy (SEM) images indicate clearly that 2D PANI lamella are formed through organization of small PANI sheets. The inter-lamellar distance of PANI and that of TiO2/polyaniline composite, as derived from X-ray diffraction (XRD), is about 3.4 nm (nearly twice the length of one DBS molecule), suggesting that PANI and double-layered DBSA species are arranged in an alternated way. FTIR spectrum displays that PANI chains exhibit quinonoid and benzenoid strutures while both Raman and X-ray photoelectron spectroscopy (XPS) indicate that rutile TiO2 is produced upon hydrolyzation of tetrabutyl titanate in the microemulsion system. Moreover, UV-Vis spectrum suggests that the electronic absorption behaviour of PANI species is influenced upon loading TiO2. PMID:21510404

Shi, Li; Luo, Zhi-Yuan; Wu, Xiao-Dong; Yang, Xu-Jie; Lu, Lu-De; Wang, Xin

2011-02-01

405

Surfactant free most probable TiO2 nanostructures via hydrothermal and its dye sensitized solar cell properties  

PubMed Central

Tailoring the nano-morphology and nano-architecture of titanium dioxide (TiO2) is the most important task in the third generation solar cells (Dye sensitized solar cells/Quantum dot sensitized solar cells) (DSSCs/QDSSCs). In this article we present complete study of surfactant free synthesis of TiO2 nanostructures by a simple and promising hydrothermal route. The plethora of nanostructures like nanoparticles clusters, 1D tetragonal nanorods, 3D dendrites containing nanorods having <30?nm diameter and 3D hollow urchin like have been synthesized. These nanostructures possess effective large surface area and thus useful in DSSCs. In the present work, 7.16% power conversion efficiency has been demonstrated for 3D dendritic hollow urchin like morphology. Our synthetic strategy provides an effective solution for surfactant free synthesis of efficient TiO2 nanoarchitectures. PMID:24141599

Mali, Sawanta S.; Kim, Hyungjin; Shim, Chang Su; Patil, Pramod S.; Kim, Jin Hyeok; Hong, Chang Kook

2013-01-01

406

Synthesis and characterization of the ZnO/mpg-C?N? heterojunction photocatalyst with enhanced visible light photoactivity.  

PubMed

The ZnO/mpg-C3N4 composite photocatalyst with high visible light activity was successfully synthesized by a facile solvothermal method and characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffuse reflectance spectroscopy (DRS). The results indicated that ZnO particles dispersed uniformly on the mpg-C3N4 sheet. The photocatalytic activity of ZnO/mpg-C3N4 for photodegradation of MB was much higher than that of pure mpg-C3N4 both under the visible light and simulated solar irradiation. The optimal ZnO content for the photocatalytic activity of the ZnO/mpg-C3N4 composites is 24.9%, which is almost 2.3 times as high as that of pure mpg-C3N4 under visible light, and 1.9 times higher than that under simulated solar irradiation. The enhancement in photocatalytic activity should be assigned to the effective separation and transfer of photogenerated charges coming from the well-matched overlapping band-structure between mpg-C3N4 and ZnO. Radical trap experiments show that both ZnO/mpg-C3N4 composites and mpg-C3N4 have the same photodegradation mechanism, and the holes are their main oxidative species for MB degradation. PMID:25043592

Chen, Daimei; Wang, Kewei; Ren, Tiezhen; Ding, Hao; Zhu, Yongfa

2014-09-14

407

A twice liquid arc discharge approach for synthesis of visible-light-active nanocrystalline Ag:ZnO photocatalyst  

NASA Astrophysics Data System (ADS)

Ag:ZnO hybrid nanostructures were successfully prepared by a twice arc discharge method in liquid. The visible light photocatalytic activities were successfully demonstrated for the degradation of Rhodamine B (Rh. B), Methyl orange (MO), and Methylene blue (MB) as standard organic compounds under the irradiation of 90 W halogen light for 2 h. The Ag:ZnO nanostructures were characterized by X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible absorption spectroscopy (UV-Vis). The results revealed that the Ag:ZnO nanostructures extended the light absorption spectrum toward the visible region and significantly enhanced the Rh. B photodegradation under visible light irradiation. 3 mM Ag:ZnO nanostructures exhibited highest photocatalytic efficiency. It has been confirmed that the Ag:ZnO nanostructures could be excited by visible light ( E<3.3 eV). The significant enhancement in the Ag:ZnO nanostructures photocatalytic activity under visible light irradiation can be ascribed to the effect of physisorbed noble metal Ag by acting as electron traps in ZnO band gap. A mechanism for photocatalytic degradation of organic pollutant over Ag:ZnO photocatalyst was proposed based on our observations.

Ashkarran, Ali Akbar

2012-05-01

408

Core-shell VO2@TiO2 nanorods that combine thermochromic and photocatalytic properties for application as energy-saving smart coatings  

NASA Astrophysics Data System (ADS)

Vanadium dioxide (VO2) is a Mott phase transition compound that can be applied as a thermochromic smart material for energy saving and comfort, and titanium dioxide (TiO2) is a well-known photocatalyst for self-cleaning coatings. In this paper, we report a VO2@TiO2 core-shell structure, in which the VO2 nanorod core exhibits a remarkable modulation ability for solar infrared light, and the TiO2 anatase shell exhibits significant photocatalytic degradation of organic dye. In addition, the TiO2 overcoating not only increased the luminous transmittance of VO2 based on an antireflection effect, but also modified the intrinsic colour of VO2 films from yellow to light blue. The TiO2 also enhanced the chemical stability of VO2 against oxidation. This is the first report of such a single nanoparticle structure with both thermochromic and photocatalytic properties that offer significant potential for creating a multifunctional smart coating.

Li, Yamei; Ji, Shidong; Gao, Yanfeng; Luo, Hongjie; Kanehira, Minoru

2013-04-01

409

One-pot self-assembled three-dimensional TiO2-graphene hydrogel with improved adsorption capacities and photocatalytic and electrochemical activities.  

PubMed

We reported the development of a new type of multifunctional titanium dioxide (TiO2)-graphene nanocomposite hydrogel (TGH) by a facile one-pot hydrothermal approach and explored its environmental and energy applications as photocatalyst, reusable adsorbents, and supercapacitor. During the hydrothermal reaction, the graphene nanosheets and TiO2 nanoparticles self-assembled into three-dimensional (3D) interconnected networks, in which the spherical nanostructured TiO2 nanoparticles with uniform size were densely anchored onto the graphene nanosheets. We have shown that the resultant TGH displayed the synergistic effects of the assembled graphene nanosheets and TiO2 nanoparticles and therefore exhibited a unique collection of physical and chemical properties such as increased adsorption capacities, enhanced photocatalytic activities, and improved electrochemical capacitive performance in comparison with pristine graphene hydrogel and TiO2 nanoparticles. These features collectively demonstrated the potential of 3D TGH as an attractive macroscopic device for versatile applications in environmental and energy storage issues. PMID:23429833

Zhang, Zheye; Xiao, Fei; Guo, Yunlong; Wang, Shuai; Liu, Yunqi

2013-03-01

410

Morphological control of anodic crystalline TiO2 nanochannel films for use in size-selective photocatalytic decomposition of organic molecules  

NASA Astrophysics Data System (ADS)

We report the size-selective photocatalytic decomposition of organic molecules using crystalline anodic TiO2 nanochannel films as the photocatalyst. The porous TiO2 films were formed by anodizing titanium at 20 V in glycerol electrolyte containing various amounts of K3PO4, K2HPO4, and KH2PO4 at 433 K. Regardless of the electrolyte composition, the as-formed TiO2 films had a crystalline anatase structure. The basicity of the electrolyte markedly influenced the morphology of the TiO2 nanochannel films; more regular nanochannels developed with increasing basicity of the electrolyte. Because the diameter of the nanochannels in the films formed in a basic electrolyte was as small as ˜10 nm, the anodic TiO2 nanochannel films with a thickness of 5 ?m revealed a selective photocatalytic decomposition of methylene blue (MB) in a mixture of MB and direct red 80 (DR) kept under UV irradiation. The importance of the diameter of the nanochannels and their uniformity for size-selective decomposition of organic molecules were investigated.

Tsuji, E.; Taguchi, Y.; Aoki, Y.; Hashimoto, T.; Skeldon, P.; Thompson, G. E.; Habazaki, H.

2014-05-01

411

Core-shell VO2@TiO2 nanorods that combine thermochromic and photocatalytic properties for application as energy-saving smart coatings  

PubMed Central

Vanadium dioxide (VO2) is a Mott phase transition compound that can be applied as a thermochromic smart material for energy saving and comfort, and titanium dioxide (TiO2) is a well-known photocatalyst for self-cleaning coatings. In this paper, we report a VO2@TiO2 core-shell structure, in which the VO2 nanorod core exhibits a remarkable modulation ability for solar infrared light, and the TiO2 anatase shell exhibits significant photocatalytic degradation of organic dye. In addition, the TiO2 overcoating not only increased the luminous transmittance of VO2 based on an antireflection effect, but also modified the intrinsic colour of VO2 films from yellow to light blue. The TiO2 also enhanced the chemical stability of VO2 against oxidation. This is the first report of such a single nanoparticle structure with both thermochromic and photocatalytic properties that offer significant potential for creating a multifunctional smart coating. PMID:23546301

Li, Yamei; Ji, Shidong; Gao, Yanfeng; Luo, Hongjie; Kanehira, Minoru

2013-01-01

412

Graphene TiO2 nanocomposites with high photocatalytic activity for the degradation of sodium pentachlorophenol.  

PubMed

A series of graphene-TiO2 photocatalysts was synthesized by doping TiO2 with graphene oxide via hydrothermal treatment. The photocatalytic capability of the catalysts under ultraviolet irradiation was evaluated in terms of sodium pentachlorophenol (PCP-Na) decomposition and mineralization. The structural and physicochemical properties of these nanocomposites were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy, scanning electron microscopy, Ultraviolet-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectra, and Fourier-transform infrared spectroscopy. The graphene-TiO2 nanocomposites exhibited higher photocatalytic efficiency than commercial P25 for the degradation of PCP-Na, and 63.4% to 82.9% of the total organic carbon was fully mineralized. The improved photocatalytic activity may be attributed to the accelerated interfacial electron-transfer process and the significantly prolonged lifetime of electron-hole pairs imparted by graphene sheets in the nanocomposites. However, excessive graphene and the inhomogeneous aggregation of TiO2 nanoparticles may decrease photodegradation efficiency. PMID:25288556

Zhang, Yaxin; Zhou, Zeyu; Chen, Tan; Wang, Hongtao; Lu, Wenjing

2014-10-01

413

Effect of substrate on evaluation of the photocatalytic activity of TiO2 nanocrystals with exposed {0 0 1} facets  

NASA Astrophysics Data System (ADS)

There are increasing debates on the high photocatalytic activity of TiO2 nanocrystals with exposed high-energy facets. In this paper, the effect of substrate on evaluation of the photocatalytic activity of anatase TiO2 nanocrystals with exposed {0 0 1} facets was studied. Surface-clean anatase TiO2 nanocrystals with exposed {0 0 1} facets were prepared by a microwave-assisted hydrothermal route in a Ti(OC4H9)4-HF-H2O mixed solution (both the amount of Ti(OC4H9)4 and HF were 60 mmol). It was found that the percentage of exposed {0 0 1} facets is negatively correlated with the molar ratio of water to titanium/or fluoride (x). With increasing x from 0 to 21, the percentage of exposed {0 0 1} facets steadily decreases from 81% to 36%. Anionic dye Brilliant Red X-3B (X3B) and cationic dye Methylene Blue (MB) were used as probes to evaluate the relative photocatalytic activity of the prepared TiO2 samples. TiO2 nanocrystals with exposed 40% {0 0 1} facets at x = 15 shows the highest photocatalytic activity in degradation of MB. However, an overwhelmingly better performance of TiO2 sample with exposed 49% {0 0 1} facets at x = 9 was found among all the photocatalysts in photocatalytic degradation of X3B, reflecting the importance of substrate on evaluation the photocatalytic activity of high-energy TiO2 nanocrystals.

Ye, Hengpeng; Lu, Shaoming

2013-04-01

414

UV-visible light-activated Ag-decorated, monodisperse TiO2 aggregates for treatment of the pharmaceutical oxytetracycline.  

PubMed

Noble metal Ag-decorated, monodisperse TiO2 aggregates were successfully synthesized by an ionic strength-assisted, simple sol-gel method and were used for the photocatalytic degradation of the antibiotic oxytetracycline (OTC) under both UV and visible light (UV-visible light) irradiation. The synthesized samples were characterized by X-ray diffraction analysis (XRD); UV-vis diffuse reflectance spectroscopy; environmental scanning electron microscopy (ESEM); transmission electron microscopy (TEM); high-resolution TEM (HR-TEM); micro-Raman, energy-dispersive X-ray spectroscopy (EDS); and inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the uniformity of TiO2 aggregates was finely tuned by the sol-gel method, and Ag was well decorated on the monodisperse TiO2 aggregates. The absorption of the samples in the visible light region increased with increasing Ag loading that was proportional to the amount of Ag precursor added in the solution over the tested concentration range. The Brunauer, Emmett, and Teller (The BET) surface area slightly decreased with increasing Ag loading on the TiO2 aggregates. Ag-decorated TiO2 samples demonstrated enhanced photocatalytic activity for the degradation of OTC under UV-visible light illumination compared to that of pure TiO2. The sample containing 1.9 wt% Ag showed the highest photocatalytic activity for the degradation of OTC under both UV-visible light and visible light illumination. During the experiments, the detected Ag leaching for the best TiO2-Ag photocatalyst was much lower than the National Secondary Drinking Water Regulation for Ag limit (0.1 mg L(-1)) issued by the US Environmental Protection Agency. PMID:24217967

Han, Changseok; Likodimos, Vlassis; Khan, Javed Ali; Nadagouda, Mallikarjuna N; Andersen, Joel; Falaras, Polycarpos; Rosales-Lombardi, Pablo; Dionysiou, Dionysios D

2014-10-01

415

High photoactive and visible-light responsive graphene/titanate nanotubes photocatalysts: preparation and characterization.  

PubMed

A series of graphene/titanate nanotubes (TNTs) photocatalysts using graphene and nanoscale TiO(2) or P25 as original materials were fabricated by hydrothermal method. Both low hydrothermal temperature and proper amount of graphene are propitious to better photoactivity. The photocatalytic activities of these nanocomposites far exceed that of P25, pure TNTs and reported TiO(2)-based nanocomposites for the degradation of Rhodamine-B under visible-light irradiation. These prepared photocatalysts were characterized by TEM, XRD, XPS, BET, FTIR and UV-vis diffuse reflection spectra, and the results indicate that the outstanding photoactivities in visible-light region result from sensitization effect of graphene rather than impurity level in the band gap of TNTs. Furthermore, large BET surface areas of these photocatalysts (almost 10 times larger than that of previously reported graphene/TiO(2) nanoparticles) evidently enhance their absorption abilities and photocatalytic performances (the rate constants of degrading Rhodamine-B are at least 5 times higher than that of previously reported photocatalysts). These photocatalysts show good stability, and their photoactivities do not obviously decrease after four times of repeated uses. A detailed photocatalytic mechanism is suggested, as well. PMID:22019056

Qianqian, Zhai; Tang, Bo; Guoxin, Hu

2011-12-30

416

Photocatalytic degradation of dimethyl phthalate in an aqueous solution with Pt-doped TiO2-coated magnetic PMMA microspheres.  

PubMed

This study investigates the photocatalytic degradation of dimethyl phthalate (DMP) with both the titanium dioxide-coated magnetic poly(methyl methacrylate) (TiO2/mPMMA) and platinum-doped TiO2/mPMMA (Pt-TiO2/mPMMA) microspheres. The TiO2/mPMMA and Pt-TiO2/mPMMA microspheres are employed as novel photocatalysts that offer high photocatalytic activity, magnetic separability and good durability. The photocatalytic experiments of DMP under various conditions are conducted to examine the effects of the initial DMP concentration, photocatalyst dosage, UV radiation intensity and Pt doping content on the degradation of DMP. In addition, the correlations of the photocatalytic kinetics and quantum yield for DMP removal are proposed associated with the system parameters. According to the experimental results, there exists a distinct relationship between the reduction percentages of total organic carbons and DMP. Furthermore, the photodegradation mechanism of DMP in the photocatalytic process is established based on the identification of the intermediates. Moreover, the good repeatability of the photocatalytic performance with the use of the Pt-TiO2/mPMMA microspheres has also been demonstrated in the multi-run experiments. Therefore the Pt-TiO2/mPMMA microspheres are considered as a practical and promising photocatalyst in a suspension reaction system and they can be effectively recovered after use. This study provides useful information about the applications of the TiO2/mPMMA and Pt-TiO2/mPMMA microspheres for the photodegradation of DMP. PMID:19632042

Chen, Yi-Hung; Chen, Li-Lin; Shang, Neng-Chou

2009-12-15

417

Synthesis and photocatalytic activity of mesoporous cerium doped TiO{sub 2} as visible light sensitive photocatalyst  

SciTech Connect

Graphical abstract: Cerium doped titania having optimum 5 wt% of cerium can decompose methylene blue and reduce selenium (IV) efficiently under visible light. Highlights: Black-Right-Pointing-Pointer Effect of cerium doping on the surface properties and visible light mediated photocatalytic reaction is studied. Black-Right-Pointing-Pointer Cerium doping increases the anatase phase stability, surface area (up to 137 m{sup 2}/g) and visible light absorption. Black-Right-Pointing-Pointer Importance of Ce{sup 3+}/Ce{sup 4+}, oxygen vacancy, surface area and crystallinity is correlated with improved catalytic activity. Black-Right-Pointing-Pointer Material with 5 wt% Ce is found to be most active photocatalyst for methylene blue decomposition and Se (IV) reduction. -- Abstract: Cerium doped titania materials were synthesized varying the cerium concentration from 0 to 10 wt%. Materials are characterised by XRD, TEM, XPS and N{sub 2} adsorption desorption method. Surface area and visible light absorption substantially increases and crystallite size decreases with the increasing cerium content. Cerium doping stabilizes the anatase phase and surface area even at 600 Degree-Sign C calcination. Photocatalytic activity towards methylene blue decomposition and selenium (IV) reduction is found to increase with the cerium content up to 5 wt% and then decreases. Materials calcined at 600 Degree-Sign C shows better activity than that calcined at 400 Degree-Sign C, even though surface area decreases. Anatase crystallinity mostly decides the photocatalytic activity rather than only surface area. It can be concluded that the optimum visible light absorption and oxygen vacancy with 5% cerium doping enhances the photocatalytic activity. In addition photocatalytic performance is found to depend on the presence of Ce{sup 4+}/Ce{sup 3+} rather than only visible light absorption.

Aman, Noor [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India)] [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Satapathy, P.K. [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India)] [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India); Mishra, T., E-mail: drtmishra@yahoo.com [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Mahato, M. [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India)] [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Das, N.N. [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India)] [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India)

2012-02-15

418

Graphene oxide as a promising photocatalyst for CO2 to methanol conversion.  

PubMed

Photocatalytic conversion of carbon dioxide (CO(2)) to hydrocarbons such as methanol makes possible simultaneous solar energy harvesting and CO(2) reduction, two birds with one stone for the energy and environmental issues. This work describes a high photocatalytic conversion of CO(2) to methanol using graphene oxides (GOs) as a promising photocatalyst. The modified Hummer's method has been applied to synthesize the GO based photocatalyst for the enhanced catalytic activity. The photocatalytic CO(2) to methanol conversion rate on modified graphene oxide (GO-3) is 0.172 ?mol g cat(-1) h(-1) under visible light, which is six-fold higher than the pure TiO(2). PMID:23160369

Hsu, Hsin-Cheng; Shown, Indrajit; Wei, Hsieh-Yu; Chang, Yu-Chung; Du, He-Yun; Lin, Yan-Gu; Tseng, Chi-Ang; Wang, Chen-Hao; Chen, Li-Chyong; Lin, Yu-Chuan; Chen, Kuei-Hsien

2013-01-01

419

Acetaldehyde photochemistry on TiO2(110)  

SciTech Connect

The ultraviolet (UV) photon induced decomposition of acetaldehyde absorbed on the oxidized retile TIO2(110) surface was studied with photon stimulated desorption (PSD) and theral programmed desorption (TPD). Acetaldehyde desorbs molecularly from TiO2(110) with minor decomposition channels yielding butene on the reduced TiO2 surface and acetate on the oxidized TiO2 surface. Acetaldehyde absorbed on oxidized TiO2(110) undergoes a facile thermal reaction to form a photoactive acetaldehyde-oxygen complex. UV irradiation of the acetaldehyde-oxygen complex resulting in the ejection of methyl radical into gas phase and conversion of the surface bound fragment to formate.

Zehr, Robert T.; Henderson, Michael A.

2008-07-01

420

Enhancing the photocatalytic activity of TiO2 co-doping of graphene-Fe3+ ions for formaldehyde removal.  

PubMed

In the present work, graphene and Fe(3+) ions were doped to enhance the photocatalytic activity of a TiO2 photocatalyst with the expectation of synergistic effects on the specific surface area and electronic conductivity due to the formation of Ti-O-C bonds preventing charge recombination contributed by graphene and band gap energy narrowing by doping with Fe(3+) ions. GR/Fe(3+)-TiO2 was successfully synthesized by the refluxed peroxo titanic acid (PTA) method and was tested for gaseous formaldehyde removal. The results show that graphene contributed to formaldehyde adsorption since the equilibrium adsorption capacity increased with an increasing weight ratio of graphene. The GR/Fe(3+)-TiO2 photocatalyst with a weight ratio of graphene to TiO2 (PTA) of 1:50 and the Fe(3+) dopant at 0.12 wt% was optimal. An equilibrium formaldehyde adsorption capacity of 10.2 mg(HCHO) g(-1)catalyst and photodegradation efficiency of about 50.3% and 25.5% under UV and visible light irradiation for 90 min, respectively, were obtained. It was observed that the adsorption property of the catalyst was increased by adding graphene and the extendable absorption edge of light to longer wavelengths was attributed to the synergistic effect of graphene and Fe(3+) dopants on the band gap energy of the catalyst. The greater photocatalytic activity of GR/Fe(3+)-TiO2 compared to GR-TiO2 resulted from more hydroxyl (OH) and superoxide [Formula: see text] radicals produced via redox reactions with Fe ions. PMID:23694821

Low, Wasu; Boonamnuayvitaya, Virote

2013-09-30

421

Anatase TiO2 nanobelts with plasmonic Au decoration exhibiting efficient charge separation and enhanced activity  

E-print Network

the photoresponse range of TiO2. For example, the photoactivity of Ag�TiO2 nanocom- posite thin film was enhanced TNBs were obtained via a stirring-assisted hydrothermal synthesis and then decorated with Au energy states in the band gap to allow optical absorption of visible light. For example, both N

Liu, Fuqiang

422

Photocatalytic degradation of organic pollutants diluted in water using TiO 2 loaded on fluoride-modified hydrophobic mesoporous silica  

Microsoft Academic Search

The synthesis of the hydrophobic mesoporous silica (denoted as HMS(F)) was performed using tetraethyl orthosilicate (TEOS), tetraethylammonium fluoride (TEAF) as the source of the fluoride and dodecylamine (DDA) as templates. The TiO2 loaded on the hydrophobic HMS(F) (TiO2\\/HMS(F)) exhibited the efficient photocatalytic performance for the degradation of alcohols (2-propanol and 2-hexanol) diluted in water. The amount of adsorption of alcohols

Kazuhiro Maekawa; Osamu Chiyoda; Satoshi Ohshiro; Shusuke Okada; Masakazu Anpo; Hiromi Yamashita

2006-01-01

423

Treatment of emerging contaminants in wastewater treatment plants (WWTP) effluents by solar photocatalysis using low TiO2 concentrations.  

PubMed

The optimal photocatalyst concentration for industrial wastewater treatment in current photoreactor designs is several hundreds of milligrams per liter. However, the elimination of emerging contaminants (ECs), which are present at extremely low concentrations in waste water treatment plants (WWTP) effluents might be accomplished at much lower catalyst (TiO(2)) concentrations. One of the main drawbacks of reducing catalyst loading below the optimum is the loss of useful photons which instead are transmitted through the TiO(2) suspension without being absorbed by the catalyst. Accordingly, in this work, laboratory and solar pilot-scale experiments were performed with real WWTP effluents to evaluate the kinetics of photocatalytic degradation of 52 emerging contaminants under realistic (ppb) concentrations. The analysis of the samples was accomplished by solid phase extraction (SPE) followed by liquid chromatography-mass spectrometry (LC-MS). In view of the results, low concentrations of TiO(2) of the order of tens of milligrams per liter were found to be insufficient for the degradation of the ECs in photoreactors with a short light-path length (29 cm). However, it was established that solar reactors of diameters of several hundreds of millimetres could be used for the efficient removal of ECs from WWTP effluents. The results presented show a general methodology for selecting the most efficient reactor diameter on the basis of the desired catalyst concentration. PMID:21943922

Prieto-Rodriguez, L; Miralles-Cuevas, S; Oller, I; Agüera, A; Li Puma, G; Malato, S

2012-04-15

424

Photocatalytic degradation of 17?-ethinylestradiol (EE2) in the presence of TiO2-doped zeolite.  

PubMed

Current design limitations and ineffective remediation techniques in wastewater treatment plants have led to concerns about the prevalence of pharmaceutical and personal care products (PPCPs) in receiving waters. A novel photocatalyst, TiO2-doped low-silica X zeolite (TiO2-LSX), was used to study the degradation of the pharmaceutical compound, 17?-ethinylestradiol (EE2). The catalyst was synthesized and characterized using XRD, BET surface analysis, SEM-EDAX, and ICP-OES. The effects of different UV light intensities, initial EE2 concentrations, and catalyst dosages on the EE2 removal efficiency were studied. A higher EE2 removal efficiency was attained with UV-TiO2-LSX when compared with UV-TiO2 or UV alone. The EE2 degradation process followed pseudo-first-order kinetics. A comprehensive empirical model was developed to describe the EE2 degradation kinetics under different conditions using multiple linear regression analysis. The EE2 degradation mechanism was proposed based on molecular calculations, identification of photoproducts using HPLC-MS/MS, and reactive species quenching experiments; the results showed that oxidative degradation pathways initiated by hydroxyl radicals were predominant. This novel TiO2-doped zeolite system provides a promising application for the UV disinfection process in wastewater treatment plants. PMID:25036996

Pan, Zhong; Stemmler, Elizabeth A; Cho, Hong Je; Fan, Wei; LeBlanc, Lawrence A; Patterson, Howard H; Amirbahman, Aria

2014-08-30

425

Preparation and characterization of PVA-I complex doped mesoporous TiO2 by hydrothermal method  

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol [PVA]-iodine complex doped mesoporous TiO2 (PIT) and iodine doped (IT) catalysts were prepared by hydrothermal method, using tetrabutyl titanate as precursor, potassium iodate and iodine as iodine sources. The as-prepared PIT and IT catalysts were characterized by UV-vis, XRD, FESEM, BET, TG/DTA, XPS and photoluminescence (PL) spectroscopy. Production of rad OH radicals on the surface of photocatalyst was detected by the PL technique using terephthalic acid as a probe molecule. The influences of calcinated temperature on the structure and properties of the catalysts were investigated. The photocatalytic activity of catalysts was evaluated through photocatalytic decolorization of methylene blue (MB) aqueous solution. The results showed that PIT samples were anatase mesoporous TiO2 and their iodine content and mesoporous structure were influenced by calcinated temperature. Particle size of PIT samples was smaller than that of IT as a result of the PVA skeleton and regular structure. Because of the complexation of iodine and PVA, thermostability of iodine is improved and the amount of iodine in PIT calcinated at 200 °C (PIT-200) is higher than that of IT calcinated at same temperature. Light absorption range and intensity of PIT-200 has been greatly improved due to the synergy of iodine and carbon. The efficiency of photocatalysis for MB is greatly improved with TiO2 modified by PVA-I complex under simulated sun light irradiation.

Shi, Qian; Jiang, Caiyun; Wang, Yuping; Yang, Weiben; Yang, Chun

2013-05-01

426

Aggregated TiO2 Based Nanotubes for Dye Sensitized Solar Cells  

SciTech Connect

One-dimensional (1D) semiconducting oxides have attracted great attention for dye sensitized solar cells (DSCs), but the overall performance is still quite limited as compared to TiO2 nanocrystalline DSCs. Here, we report the synthesis of aggregated TiO2 based nanotubes with controlled morphologies and crystalline structures to obtain an overall power conversion efficiency of 9.9% using conventional dye without any additional chemical treatment steps. The high efficiency is attributed to the unique aggregate structure for light harvesting, optimized high surface area, and good crystallinity of the nanotube aggregates obtained through proper thermal annealing. This study demonstrates that high efficiency DSCs can be obtained with 1D nanomaterials, and provides lessons on the importance of optimizing both the nanocrystalline structure and the overall microscale morphology.

Nie, Zimin; Zhou, Xiaoyuan; Zhang, Qifeng; Cao, Guozhong; Liu, Jun

2013-11-01

427

Fabrication and investigation of gas sensing properties of Nb-doped TiO2 nanotubular arrays  

NASA Astrophysics Data System (ADS)

Synthesis of Nb-containing titania nanotubular arrays at room temperature by electrochemical anodization is reported. Crystallization of pure and Nb-doped TiO2 nanotubes was carried out by post-growth annealing at 400?°C. The morphology of the tubes obtained was characterized by scanning electron microscopy (SEM). Crystal structure and composition of tubes were investigated by glancing incidence x-ray diffraction (GIXRD) and total reflection x-ray fluorescence (TXRF). For the first time gas sensing characteristics of Nb-doped TiO2 nanotubes were investigated and compared to those of undoped nanotubes. The functional properties of nanotubular arrays towards CO, H2, NO2, ethanol and acetone were tested in a wide range of operating temperature. The introduction of Nb largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes.

Galstyan, Vardan; Comini, Elisabetta; Faglia, Guido; Vomiero, Alberto; Borgese, Laura; Bontempi, Elza; Sberveglieri, Giorgio

2012-06-01

428

Fabrication and investigation of gas sensing properties of Nb-doped TiO(2) nanotubular arrays.  

PubMed

Synthesis of Nb-containing titania nanotubular arrays at room temperature by electrochemical anodization is reported. Crystallization of pure and Nb-doped TiO(2) nanotubes was carried out by post-growth annealing at 400°C. The morphology of the tubes obtained was characterized by scanning electron microscopy (SEM). Crystal structure and composition of tubes were investigated by glancing incidence x-ray diffraction (GIXRD) and total reflection x-ray fluorescence (TXRF). For the first time gas sensing characteristics of Nb-doped TiO(2) nanotubes were investigated and compared to those of undoped nanotubes. The functional properties of nanotubular arrays towards CO, H(2), NO(2), ethanol and acetone were tested in a wide range of operating temperature. The introduction of Nb largely improves conductivity and enhances gas sensing performances of TiO(2) nanotubes. PMID:22595952

Galstyan, Vardan; Comini, Elisabetta; Faglia, Guido; Vomiero, Alberto; Borgese, Laura; Bontempi, Elza; Sberveglieri, Giorgio

2012-06-15

429

Control of TiO2 structures from robust hollow microspheres to highly dispersible nanoparticles in a tetrabutylammonium hydroxide solution.  

PubMed

A new process for controlling the structure of TiO2 from hollow microspheres to highly dispersible nanoparticles has been developed by altering the concentration of tetrabutylammonium hydroxide (TBAH) in the solvothermal reaction of titanium isopropoxide. Robust and size-controllable hollow TiO2 microspheres, constructed by the assembly of 18 nm TiO2 nanoparticles, were synthesized at relatively high TBAH concentration. The diameters of hollow spheres, with a shell thickness of approximately 250 nm, were controlled to 1.5-4 microm by varying the concentration of TBAH in the range of 0.1-0.5 M. After calcination at 450 degrees C, the hollow microspheres were not appreciably deformed and were still floating on the surface of the water. However, highly dispersible TiO2 nanoparticles with an average diameter of 13 nm were obtained at a low TBAH concentration such as 9.2 mM. The colloidal particle size of TiO2 in an aqueous suspension at pH 2 was 12.5-13.5 nm, which indicates that the each nanoparticle is completely separated. The overall procedure is simple and highly reproducible, and large-scale synthesis is available at low cost. PMID:17696368

Kim, Yong Joo; Chai, Seung Yong; Lee, Wan In

2007-09-11