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1

Combustion synthesis of TiO 2 nanoparticles as photocatalyst  

Microsoft Academic Search

This paper describes a new type of combustion synthesis of metal oxide nanoparticles, in which the adiabatic flame temperature of the solid phase reaction is beyond the boiling point of the product, and its implementation for the synthesis of titanium dioxide as photocatalyst. In this study, raw materials comprising titanium particles of different sizes and sodium perchlorate were intensively mixed

Yasuaki Kitamura; Noriyuki Okinaka; Tamaki Shibayama; Orlando Omar Prieto Mahaney; Daisuke Kusano; Bunsho Ohtani; Tomohiro Akiyama

2007-01-01

2

Hydrothermal synthesis of Cr and Fe co-doped TiO(2) nanoparticle photocatalyst  

Microsoft Academic Search

We report here new findings on the visible light photodecomposition activity of gaseous iso-propyl alcohol over Cr and Fe co-doped TiO(2) nanoparticles. High surface area, doped TiO(2) nanoparticles were synthesized hydrothermally and co-dopant effects are investigated. The physico-chemical properties of the co-doped nanoparticles led to efficient photocatalysts. Cr and Fe co-doped TiO(2) nanoparticles exhibited two times higher photocatalytic activity for

E. D. Jeong; Pramod H. Borse; J. S. Jang; J. S. Lee; Ok-Sang Jung; H. Chang; J. S. Jin; M. S. Won; H. G. Kim

2008-01-01

3

[Synthesis and properties of nano-rutile TiO2 photocatalysts].  

PubMed

Nano-rutile TiO2 photocatalysts with bigger specific surface area were prepared by a hydrolysis method at 323 K, and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), ultraviolet-visible diffuse reflection spectroscopy (UV-Vis DRS), infrared spectroscopy (IR) and photoelectrochemical (PEC). The ultraviolet (UV) and visible light photocatalytic activities of as-prepared rutile and anatase TiO2 nano-photocatalysts with almost same specific surface areas were evaluated by methyl orange (MO) as mode compound to photocatalytic reaction. The results of the photocatalytic experiment shows that when rutile and anatase have the similar specific surface area of approximately 95 m2.g-1, the UV light photocatalytic activity of rutile is comparable to that of anatase, while rutile shows significantly higher visible light photocatalytic activities than anatase. The photoelectrochemical experiment shows that the order of photocurrent densities of the catalysts from weak to strong is in accordance with the order of UV light photocatalytic activities of the catalysts from low to high under UV light irradiation. PMID:23705421

Li, Hui-Quan; Xu, Bo-Lian; Fan, Yi-Ning; Yang, Han-Pei; Hong, Wen-Shan

2013-03-01

4

Synthesis and characterization of V–C 60\\/TiO 2 photocatalysts designed for degradation of methylene blue  

Microsoft Academic Search

C60\\/TiO2 and V–C60\\/TiO2 composite photocatalysts were prepared with titanium (IV) n-butoxide (TNB) by a sol–gel method. Fullerene had absorptive and semiconducting properties, and vanadium could enhance the photogenerated electron transfer. The V–C60\\/TiO2 composite shows a good photo-degradation activity. XRD patterns of the composites showed that the C60\\/TiO2 composite contained a mixture of anatase and rutile phase forms while the V–C60\\/TiO2

Won-Chun Oh; Feng-Jun Zhang; Ming-Liang Chen

2010-01-01

5

Novel TiO2/C nanocomposites: synthesis, characterization, and application as a photocatalyst for the degradation of organic pollutants.  

PubMed

Novel TiO(2)/carbon nanocomposites were prepared through the pyrolysis of TiO(2)/poly(furfuryl alcohol) hybrid materials, which were obtained by the sol-gel method, starting from titanium tetraisopropoxide (TTIP) and furfuryl alcohol (FA) precursors. Six different TiO(2)/C samples were prepared based on different TiO(2) nanoparticle sizes and TiO(2)/FA ratios. All of the samples were characterized using X-ray diffraction, infrared, and Raman spectroscopy. The results indicated effective FA polymerization onto the TiO(2) (anatase) nanoparticles, polymer conversion to disordered carbon following the pyrolysis, and a simultaneous TiO(2) anatase-rutile phase transition. The resulting TiO(2)/carbon composites were used as photocatalysts in the advanced oxidative process (AOP) for the degradation of reactive organic dyes in aqueous solution. The results indicate excellent photocatalytic performance (degradation of 99% of the dye after 60 min) with several advantages over traditional TiO(2)-based photocatalysts. PMID:22056275

da Costa, Elias; Zamora, Patricio P; Zarbin, Aldo J G

2011-10-21

6

One-step synthesis of N- and F-codoped mesoporous TiO2 photocatalysts with high visible light activity.  

PubMed

We report on a novel approach to the synthesis of N- and F-codoped mesoporous TiO2 photocatalysts via a reproducible, rapid and single-step combustion method. TiF4 was used as the precursor to provide the source of Ti and F, while urea was used as the fuel as well as the source of the N dopant. The as-synthesized samples were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The specific surface areas of the samples were determined using a Quantachrome Nova 2200 for the N2 adsorption/desorption under liquid-nitrogen temperature. Our studies show that the fabricated N- and F-codoped TiO2 photocatalysts have mesoporous structure and a very large specific surface area (155.3 m(2) g(-1)) and that the codoping of N and F significantly narrows the TiO2 bandgap energy from 3.2 to 2.45 eV. We further studied the photocatalytic activity of the synthesized N- and F-codoped mesoporous TiO2 through the decomposition of acetic acid, showing that the N- and F-codoped mesoporous TiO2 catalyst fabricated in this study exhibits superb photocatalytic activity and visible light response compared to one of the best commercially available TiO2 photocatalysts, P25. PMID:20097984

Wu, Guosheng; Wen, Jiali; Nigro, Samantha; Chen, Aicheng

2010-01-25

7

Synthesis of N-doped TiO2 Using Guanidine Nitrate: An Excellent Visible Light Photocatalyst  

EPA Science Inventory

An excellent visible light active nitrogen-rich TiO2 photocatalyst have been synthesized by using guanidine nitrate as the doping material. The catalytic efficiency of the catalyst has been demonstrated by the decomposition of the dye, methyl orange (MO), and the pollutant, 2,4 d...

8

Visible-light-driven TiO2 photocatalyst synthesis and photocatalytic properties  

NASA Astrophysics Data System (ADS)

Nano TiO2 was synthesized by hydrothermal method. The sample was modified by doping transition metal ion (V, Cr and Fe) and non metal (N). Doped TiO2 samples were characterized by XRD (X-ray diffraction), FE-SEM (Fieldemission scanning electron microscopy) and UV-Vis (UV-Vis diffuse reflectance spectroscopy). Photocatalytic activity in mineralization of xylene (vapor phase), methylene blue and active dyer PR (liquid phase) were tested. In comparison to non-doped TiO2, V-,Cr-,Fe-doped TiO2 and N-doped TiO2 samples exhibited much higher photocatalytic activity using visible light instead of UV.

Tuan, Vu Anh; Linh, Bui Thi Hai; Yen, Hoang; Thang, Dinh Cao; Cuong, Tran Manh; Phuong, Dang Tuyet; Hoa, Tran Thi Kim; Thang, Hoang Vinh; Hoa, Nguyen Van; Tuan, Nguyen Quoc

2008-12-01

9

Synthesis of nanostructured TiO2/SiO2 as an effective photocatalyst for degradation of acid orange  

NASA Astrophysics Data System (ADS)

TiO2/SiO2 composites were produced as photocatalysts both by hydrolysis of TiCl4 and from TiO2 suspension prepared by hydrolysis of TiCl4. TiO2/SiO2 composites were dried at 70 °C and calcinated at 400 °C and 600 °C to investigate the effect of calcination temperature on the phase transformation of TiO2 structure. Photocatalytic effects of produced TiO2/SiO2 composites were measured against degradation of acid orange 7 (AO7) by UV-vis spectroscopy. The chemical compositions of produced samples were studied by X-ray fluorescence (XRF) technique. The composite structures were analyzed by X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM) facilities to reveal the surface morphology and their phase structures. Energy dispersive X-ray spectroscopy (EDS) was conducted to understand the elemental surface composition of composites. Photocatalytic activity of composites normalized with surface area, and TiO2/SiO2 composite produced by TiO2 suspension prepared by hydrolysis of TiCl4 and calcinated at 600 °C indicated 40% photocatalytic degradation of AO7 after 2 h under UV radiation.

Cetinkaya, Tugrul; Neuwirthová, Lucie; Kutláková, Kate?ina M.; Tomášek, Vladimír; Akbulut, Hatem

2013-08-01

10

Synthesis of rhombic hierarchical YF3 nanocrystals and their use as upconversion photocatalysts after TiO2 coating  

NASA Astrophysics Data System (ADS)

A facile method has been developed to synthesize uniform nanoscale YF3 architectures. Interestingly, the unique YF3 nanostructure exhibits a flat and rhombic appearance which is formulated through the hierarchical assembly of YF3 nanocrystals along a specific crystalline orientation. Investigations on the formation process suggest that an assembly disassembly process is responsible for the construction of this novel structure. Enabled by doping with different lanthanides ions, the products can exhibit various down- or up-conversion luminescences, showing their potentials in serving as versatile host matrixes. The tunable luminescent properties allow designing effective upconversion photocatalysts when the doped YF3 nanostructures are coated with a TiO2 shell on their surface. In particular, the YF3@TiO2 hybrid structures have the porous nature that is partially inherited from the YF3 architectures, whose high surface-to-volume ratio facilitates their use as photocatalysts. In this article, we have demonstrated that the YF3:Yb,Tm@TiO2 structures exhibit satisfactory photocatalytic activities under the irradiation of both UV and near IR light. As compared with the conventional TiO2 catalysts, the hybrid structures here offer better performance in photocatalysis in the full solar spectrum. It is anticipated that this work provides a new approach to designing photocatalysts with responses to a broader spectral range.A facile method has been developed to synthesize uniform nanoscale YF3 architectures. Interestingly, the unique YF3 nanostructure exhibits a flat and rhombic appearance which is formulated through the hierarchical assembly of YF3 nanocrystals along a specific crystalline orientation. Investigations on the formation process suggest that an assembly disassembly process is responsible for the construction of this novel structure. Enabled by doping with different lanthanides ions, the products can exhibit various down- or up-conversion luminescences, showing their potentials in serving as versatile host matrixes. The tunable luminescent properties allow designing effective upconversion photocatalysts when the doped YF3 nanostructures are coated with a TiO2 shell on their surface. In particular, the YF3@TiO2 hybrid structures have the porous nature that is partially inherited from the YF3 architectures, whose high surface-to-volume ratio facilitates their use as photocatalysts. In this article, we have demonstrated that the YF3:Yb,Tm@TiO2 structures exhibit satisfactory photocatalytic activities under the irradiation of both UV and near IR light. As compared with the conventional TiO2 catalysts, the hybrid structures here offer better performance in photocatalysis in the full solar spectrum. It is anticipated that this work provides a new approach to designing photocatalysts with responses to a broader spectral range. Electronic supplementary information (ESI) available: XRD pattern of products, TEM images of intermediate samples, TEM images of samples prepared in control experiments, N2 adsorption-desorption isotherm and EDX spectrum of products. See DOI: 10.1039/c3nr34018j

Li, Zhengquan; Li, Congling; Mei, Yuanyuan; Wang, Limin; Du, Gaohui; Xiong, Yujie

2013-03-01

11

Low-temperature synthesis of mesoporous TiO2 photocatalyst with self-cleaning strategy to remove organic templates  

NASA Astrophysics Data System (ADS)

A novel low-temperature method integrated solvothermal and self-cleaning technique has been developed to prepare mesoporous TiO2 photocatalyst using triblock copolymers P123 as templates. The organic templates could be removed completely by the self-cleaning strategy under simulated sunlight irradiation. The product is characterized by FTIR, TG, XRD, N2 adsorption-desorption isotherms and TEM. The mild condition of the method is advantageous to retain the mesostructure compared with the calcination procedure. Further study indicates that the sample displays a higher photocatalytic activity for MO degradation than that of calcined sample, which could be attributed to its higher surface area, smaller crystal size and larger surface hydroxyl content.

Chu, Sheng; Luo, Leilei; Yang, Juncheng; Kong, Fei; Luo, Si; Wang, Ying; Zou, Zhigang

2012-10-01

12

Synthesis and characterization of the N-doped TiO2 photocatalyst for the photodegradation of methylene blue and phenol.  

PubMed

To extend the light absorption of TiO2-based photocatalysts towards the visible-light range and to eliminate the rapid recombination of excited electrons/holes during photoreaction, a new type of photocatalyst (N-doped TiO2) powder was prepared through a simple sol-gel process. The crystal phase composition, structure, and light absorption of the new photocatalyst were comprehensively examined via X-ray diffraction, ultraviolet-visible (UV-Vis) absorption spectroscopy, and atomic-absorption spectroscopy. The photo-oxidation efficiency of the photocatalyst was also evaluated in the photodegradation of methylene blue (MB) and of phenol in aqueous solutions under visible-light irradiation from a neon lamp (lambda > 400 nm). The results of the analyses that were performed in this study indicated that the N-doped TiO2 could eliminate the electron/holes recombination and could increase the light absorption in the visible range. The results of the analysis of the UV-Vis diffuse reflection and optical-absorption spectra indicated that a new energy level below 3.2 eV generated in the N-doped TiO2 promoted the optical absorption in the visible-light region and made visible-light excitation possible (E < 3.2 eV). The experiment demonstrated that the photo-oxidation efficiency of MB when N-doped TiO2 powder was used was significantly higher than that when the conventional TiO2 powders were used. The development of such photocatalyst may be considered a breakthrough in the large-scale utilization of solar energy to address the current and future environmental needs. PMID:22121743

Khang, Nguyen Cao; Van Minh, Nguyen; Yang, In-Sang

2011-07-01

13

Synthesis and Characterization of Novel N-doped TiO2 Photocatalyst with Visible Light Active  

NASA Astrophysics Data System (ADS)

A novel N-doped TiO2 (N1-N2-TiO2) with substitutional and interstitial N impurities simultaneously was successfully synthesized. The catalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, photoluminescence, and electron paramagnetic resonance. The results demonstrated that the nitrogen was substituted for the lattice oxygen atoms, and was also interstitially doped into the TiO2 lattice. The photocatalytic tests indicated that the N1-N2-TiO2 showed the highest photocatalytic activities of all the N-doped TiO2 under visible light, attributing to the synergetic effect of substitutional and interstitial nitrogen of N-doped TiO2.

Peng, Feng; Liu, Yi; Wang, Hong-juan; Yu, Hao; Yang, Jian

2010-08-01

14

Efficient visible light-active N-doped TiO2 photocatalysts by a reproducible and controllable synthetic route.  

PubMed

A reproducible and controllable method allows the synthesis of practical quantities of efficient, visible light active TiO(2)(N) photocatalysts in which the nitrogen content may be varied to achieve optimum performance. PMID:17031443

In, Suil; Orlov, Alexander; García, Felipe; Tikhov, Mintcho; Wright, Dominic S; Lambert, Richard M

2006-08-31

15

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

16

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

17

Combinatorial synthesis and high-throughput evaluation of doped TiO2 thin films for the development of photocatalysts  

Microsoft Academic Search

TiO2 thin films doped with various transition metals were systematically fabricated by combinatorial laser MBE technique. Alternating KrF excimer laser ((lambda) equals 248 nm) ablation of TiO2 and Ti1-x MxO2 (M equals transition metal) was employed to deposit combinatorial library of 18 samples for each dopant with different concentrations. Anatase films with c-axis orientation were grown epitaxially on SrTiO3(001) substrate

Yuji Matsumoto; Makoto Murakami; Zhengwu Jin; Akira Nakayama; Tetsuo Yamaguchi; Takashi Ohmori; Eiji Suzuki; Satoshi Nomura; Masashi Kawasaki; Hideomi Koinuma

2000-01-01

18

One-step synthesis of visible active CNS-tridoped TiO2 photocatalyst from biomolecule cystine  

NASA Astrophysics Data System (ADS)

CNS-tridoped TiO2 nano-particles were synthesized through simple one-step sol-gel reactions in the presence of biomolecule cystine. This biomolecule could not only serve as the source for C, N and S tridoping, but also could control the light absorption in visible region and separation efficiency of photogenerated charge carriers. The resulting materials were characterized by X-ray diffraction (XRD), Nitrogen adsorption-desorption, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and surface photovoltage spectrum (SPS). It was found that S6+ was incorporated into the lattice of TiO2 through substituting titanium atoms; N might coexist in the forms of substituted N (NOTi) and interstitial N (OTiN) in TiO2; and C could form a mixed layer of carbonate on the surface of TiO2. Further, the addition of cystine greatly improved the light absorption in visible region and the separation efficiency of photogenerated charge carriers. The photocatalytic activities of the as-synthesized samples were evaluated for the degradation of phenol under simulated sunlight irradiation. Results showed that CNS-tridoped TiO2 exhibited higher sunlight photocatalytic degradation efficiency than that of undoped and P25 TiO2 samples. The enhanced photocatalytic activity could be attributed to the small crystallite size, intense light absorption in visible region, large amount of surface hydroxyl groups and high separation efficiency of photogenerated charger carriers.

Cheng, Xiuwen; Yu, Xiujuan; Xing, Zipeng

2012-07-01

19

Synthesis of N-doped nano TiO2 using guanidine nitrate: an excellent visible light photocatalyst.  

PubMed

An excellent visible light active nitrogen-rich TiO2 nanocatalyst has been synthesized by using guanidine nitrate as the nitrogen source. The catalytic efficiency of the catalyst has been demonstrated by the decomposition of the dye, methyl orange (MO), and the pollutant, 2,4 dichlorophenol (DCP), under common household lightbulbs as well as sunlight. The reactions proceed faster on exposure to solar light (less than 1 h for MO and 4 h for DCP) compared with the commercial light bulbs (3 h for MO and 6 h for DCP). The catalyst could be used up to five times without loss of activity and regenerated for further use just by washing and drying at 200 degrees C. PMID:21449345

Baruwati, Babita; Varma, Rajender S

2011-03-01

20

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

2012-11-06

21

Effect of successive incorporation of tungstophosphoric acid into TiO 2 on the activity of photocatalysts for the degradation of methylene blue  

Microsoft Academic Search

The effect of incorporation of different amounts of tungstophosphoric acid (TPA) into TiO2 to alter its photocatalytic activity was studied. Varying amounts of TPA (10%–50% in weight) were introduced into TiO2 synthesis gel for hydrothermal preparation of TPA–TiO2 photocatalysts. The produced photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis (EDX), UV–vis diffuse

A. Ariapad; M. A. Zanjanchi

2011-01-01

22

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

23

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

2013-06-19

24

Characterization and photocatalytic activity of Zn 2+-TiO 2/AC composite photocatalyst  

NASA Astrophysics Data System (ADS)

Activated carbon (AC) supported Zn 2+-TiO 2 photocatalyst was prepared by sol-gel method. The prepared samples were characterized by X-ray diffraction, scanning electron micrograph, nitrogen absorption, diffuse reflectance UV/VIS and X-ray photoelectron spectroscopy. Using toluene as a pollution target, the photocatalytic activity of photocatalyst was evaluated. The results showed that prepared photocatalyst was obviously helpful for the removal of toluene in air. The photocatalytic degradation of toluene by Zn 2+-TiO 2/AC reached 100% for 40 min and remained 75% after 160 min, while degradation by TiO 2 was only 30%. It indicated that the photocatalytic activity of prepared photocatalyst was enhanced. It is due to Zn 2+-doping increased the oxidation and reduction of hole-electron pairs, which was the important factor in heterogeneous photocatalysis.

Lu, Xincheng; Jiang, Jianchun; Sun, Kang; Cui, Dandan

2011-12-01

25

TiO 2\\/polyaniline composites: An efficient photocatalyst for the degradation of methylene blue under natural light  

Microsoft Academic Search

Polyaniline (PAn) sensitized nanocrystalline TiO2 composites (TiO2\\/PAn) were successfully prepared and used as an efficient photocatalyst for the degradation of dye methylene blue (MB). The results showed that PAn was able to sensitize TiO2 efficiently and the composite photocatalyst could be activated by absorbing both the ultraviolet and visible light (?: 190?800nm), whereas pure TiO2 absorbed ultraviolet light only (?<380nm).

Fang Wang; Shi Xiong Min

2007-01-01

26

Remote energy storage in Ni(OH)2 with TiO2 photocatalyst.  

PubMed

Oxidative energy generated by UV-irradiated TiO2 photocatalyst was stored in Ni(OH)2 that was 12.5-50 microm apart from the TiO2. It is likely that active oxygen species generated on TiO2 diffused into the gas phase and oxidized Ni(OH)2. Loading the TiO2 with Pt accelerated the remote energy storage by an order of magnitude. It was revealed that the stored energy could be taken out and used chemically or electrochemically. The oxidized Ni(OH)2 was reduced by gaseous formaldehyde, formate, ethanol and H2O2. PMID:16763703

Takahashi, Yukina; Tatsuma, Tetsu

2006-05-12

27

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

28

TiO2 nanotubes/MWCNTs nanocomposite photocatalysts: synthesis, characterization and photocatalytic hydrogen evolution under UV-vis light illumination.  

PubMed

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 micromol x h(-1) x g(-1). Good photocatalytic stability of the as-synthesized samples was observed as well. PMID:22754984

Li, Haopeng; Zhang, Xiaoyan; Cui, Xiaoli; Lin, Yuehe

2012-03-01

29

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

30

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

31

Structural and surface approach to the enhanced photocatalytic activity of sulfated TiO 2 photocatalyst  

Microsoft Academic Search

TiO2 materials prepared by sol–gel method and then impregnated with sulfuric acid and further calcined at different temperatures show high photon efficiencies for the photocatalytic degradation of phenol under UV-illumination. Best photocatalyst was obtained after calcination around 700°C, giving specific activities (i.e. per m2) significantly higher than those exhibited by similarly prepared non-sulfated TiO2 or by pure Degussa P25. Structural

G. Colón; M. C. Hidalgo; G. Munuera; I. Ferino; M. G. Cutrufello; J. A. Navío

2006-01-01

32

Bactericidal effect of TiO 2 photocatalyst on selected food-borne pathogenic bacteria  

Microsoft Academic Search

Titanium dioxide (TiO2) photocatalysts have attracted great attention as a material for photocatalytic sterilization in the food and environmental industry. This research aimed to design a new photobioreactor and its application to sterilize selected food borne pathogenic bacteria, Salmonella choleraesuis subsp., Vibrio parahaemolyticus, and Listeria monocytogenes. The photocatalytic reaction was carried out with various TiO2 concentrations and Ultraviolet (UV) illumination

Byunghoon Kim; Dohwan Kim; Donglyun Cho; Sungyong Cho

2003-01-01

33

TiO 2 photocatalysts and diamond electrodes  

Microsoft Academic Search

Photocatalysis and electroanalysis are two seemingly disparate research areas, but they are linked by the fact that both involve the use of well-known materials, TiO2 and diamond, respectively, in new ways in the service of both environmental and medical sciences. In the present article, recent developments in the area of TiO2 photocatalysis and diamond electrochemistry are summarized, with emphasis on

A Fujishima; Tata N Rao; D. A Tryk

2000-01-01

34

Dramatic activity of mixed-phase TiO2 photocatalyst synthesized by hydrothermal method  

NASA Astrophysics Data System (ADS)

The mixed-phase TiO2 photocatalysts with different anatase/rutile/brookite ratios and high specific surface area (157-218 m2/g) were prepared by hydrothermal method at 100 °C and the effect of rutile content in TiO2 on the BET surface area, light absorption and separation efficiency of photogenerated charge carriers was studied and correlated to the photocatalytic activity of TiO2. Rutile content increased from 0% to 100% by increasing the amount of TiCl4 in aqueous phase and the initial pH value of reaction solution played an important role in the phase composition of TiO2. The photocatalytic mechanism of mixed-phase TiO2 was discussed.

Li, Huiquan; Xu, Bolian; Fan, Yining

2013-02-01

35

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

36

Preparation of fibrous TiO 2 photocatalyst and its optimization towards the decomposition of indoor ammonia under illumination  

Microsoft Academic Search

Aqueous dispersion containing TiO2 particles was firstly prepared and then mixed with silicone or acrylic additives to establish a treating bath. And the fibrous TiO2 photocatalysts were produced by padding three woven fabrics including cotton, polyester and flax fabrics as support materials with this treating bath and some factors affecting the preparation process were discussed. Moreover, the fibrous TiO2 photocatalysts

Yongchun Dong; Zhipeng Bai; Ruihua Liu; Tan Zhu

2007-01-01

37

Composites of TiO 2-aluminum pillared montmorillonite: Synthesis, characterization and photocatalytic degradation of methylene blue  

Microsoft Academic Search

Aluminum pillared montmorillonite was prepared and used as a porous support for synthesis of TiO2-based photocatalysts with varying TiO2 loading. The physicochemical properties of the TiO2-pillared montmorillonite samples were characterized by X-ray diffraction, N2 adsorption isotherm, UV–visible diffuse reflectance spectroscopy, scanning electron microscopy and transmission electron microscopy. Photocatalytic activity of the materials was evaluated by methylene blue photodegradation in aqueous

Shaobin Wang; Narsito; Karna Wijaya

2010-01-01

38

Enhancement of stability of N-doped TiO2 photocatalysts with Ag loading  

NASA Astrophysics Data System (ADS)

Various contents of Ag nanoparticles were successfully introduced into the N-doped TiO2 photocatalysts via a hydrothermal procedure in the silver-ammonia solutions with different Ag concentrations. Effects of Ag loading on the structure and properties of N-doped TiO2 photocatalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, fluorescence spectroscopy (FL), UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and N2 physical adsorption analysis. The relationship between the stability of N dopants in TiO2 lattice and the Ag loading content was investigated for the first time. The results confirm that Ag nanoparticles loading on TiO2 surfaces significantly restrain the escape of the N dopants from the oxide during the hydrothermal process, and the escape rate of N dopants decreased gradually with the increase of Ag loading amount. The dependence of photocatalytic activity on Ag content was also investigated through degradation of rhodamine B (RhB) under visible light irradiation. It was found that the photocatalytic activity increases gradually with increasing Ag content first, and then decreases after exceeding the optimal Ag content. Therefore, the photocatalytic activity of Ag/N co-modified TiO2 photocatalysts can be adjusted by the Ag content.

Gao, Yuanpeng; Fang, Pengfei; Chen, Feitai; Liu, Yang; Liu, Zhi; Wang, Dahai; Dai, Yiqun

2013-01-01

39

Preparation and application of efficient TiO2 /ACFs photocatalyst.  

PubMed

Activated carbon fibers (ACFs) supported titanium dioxide (TiO2) photocatalyst was developed by sol-gel method. The surface morphology and microstructure of the photocatalyst were characterized with scan electron microscope(SEM), X-ray diffraction patterns and specific surface area analysis. The prepared photocatalyst is specially helpful for the removal of low molecular weight organic pollutants in wastewater. Decomposition efficiency of methylene blue solution by TiO2/ACFs catalyst reached almost 100% under 60 min reaction, while the decomposition efficiency by pure TiO2 was only 25% under 3 h reaction. The mineralization of toluene aqueous solution was measured by total organic carbon instrument, and the evolution of intermediate species was detected by gas chromatograph instrument. The results indicated that the prepared photocatalyst not only enhanced the photoactivity of TiO2, but also suppressed the emergence of intermediate species, which may be more deleterious to human. The enhancement of photocatalysis was due to increased efficiency of adsorption and desorption, which were control steps in heterogeneous photocatalysis. PMID:17278758

Liu, Jian-hua; Yang, Rong; Li, Song-mei

2006-01-01

40

Phenol degradation by TiO2 photocatalysts combined with different pulsed discharge systems.  

PubMed

Films of TiO2 nanotubes distributed over the inner surface of a discharge reactor cylinder (CTD) or adhered to a stainless steel electrode surface (PTD) in a discharge reactor were compared with a single-discharge (SD) system to investigate their efficiencies in phenol degradation. Morphology studies indicated that the TiO2 film was destroyed in the PTD system, but that there was no change in the CTD system after discharge. X-ray diffraction results revealed that the anatase phase of the original sample was preserved in the CTD system, but that an anatase-to-rutile phase transformation occurred in the PTD system after discharge. The highest efficiencies of phenol degradation and total organic carbon (TOC) mineralization were observed in the CTD system, and there was no decrease in phenol degradation efficiency upon reuse of a TiO2 film, indicating high catalysis activity and stability of the TiO2 photocatalysts in the combined treatment. TiO2 photocatalysts favored the formation of hydrogen peroxide and disfavored the formation of ozone. A greater degree of oxidation of intermediates and higher energy efficiency in phenol oxidation were observed with the TiO2-plasma systems, especially in the CTD system, compared to those with the SD system. PMID:23981678

Zhang, Yi; Lu, Jiani; Wang, Xiaoping; Xin, Qing; Cong, Yanqing; Wang, Qi; Li, Chunjuan

2013-08-11

41

Nanostructured TiO2 photocatalysts for the determination of organic pollutants.  

PubMed

Owing to the inherent advantages of nanostructured TiO(2) photocatalysts, including high photocatalytic activity, strong oxidation power, low cost, environmental benignity and excellent stability, TiO(2) photocatalyts have recently attracted extensive attention from scientific researchers, technology developers and investors for use in sensing applications. The TiO(2) sensors can be used for lab-based analyses, on-line and on-site determination of organic pollutants in wastewater. This work reviews the application of TiO(2) nanomaterials in photocatalytic and photoelectrocatalytic monitoring of aggregative organic parameters such as total organic carbon (TOC) and chemical oxygen demand (COD), as well as individual organic compounds in aqueous solution. PMID:22133353

Qiu, Jingxia; Zhang, Shanqing; Zhao, Huijun

2011-11-07

42

Photophysical properties of nanosized metal-doped TiO2 photocatalyst working under visible light  

Microsoft Academic Search

Metal-doped TiO2 nanoparticles were prepared by the sol-gel and hydrothermal synthesis methods. The estimated quantum yields (QYs) of Pt\\/Cr-doped TiO2 nanoparticles was ca. 0.3 %. Cr-, Co- and N-doped TiO2 showed the photocatalytic activity for IPA degradation to CO2, but only Cr-doped TiO2 produced H-2 photocatalytically in the presence of methanol-water aqueous solution under visible light (lambda 420 nm). Thus,

S. W. Bae; P. H. Borse; S. J. Hong; J. S. Jang; J. S. Lee; E. D. Jeong; T. E. Hong; J. H. Yoon; J. S. Jin; H. G. Kim

2007-01-01

43

TiO2/activated carbon fibers photocatalyst: effects of coating procedures on the microstructure, adhesion property, and photocatalytic ability.  

PubMed

In order to more easily separate TiO(2) photocatalyst from the treated wastewater, TiO(2) film was immobilized on the surface of activated carbon fibers (ACFs) by employing two kinds of coating procedures, dip-coating, and hydrothermal treatment. The effects of coating procedures on microstructure of TiO(2)-coated ACFs (TiO(2)/ACFs), such as morphology, porous property, crystal structure, and light absorption characteristics were investigated in detail. The adhesion property between TiO(2) film and ACFs was evaluated by ultrasonic vibration, and the photocatalytic activity of TiO(2)/ACFs was tested by the photocatalytic decoloration of methylene blue solution. The results show that hydrothermal treatment presented many advantages to obtain high-performance TiO(2)/ACFs photocatalyst in comparison with dip-coating. Hydrothermal treatment could improve the binding property between TiO(2) films and ACFs, which endowed the as-obtained TiO(2)/ACFs photocatalyst with improved reusable performance, and TiO(2)/ACFs synthesized by hydrothermal treatment presented higher photocatalytic activity. PMID:23010321

Shi, Jian-Wen; Cui, Hao-Jie; Chen, Jian-Wei; Fu, Ming-Lai; Xu, Bin; Luo, Hong-Yuan; Ye, Zhi-Long

2012-08-29

44

Enhancement of tributyltin degradation under natural light by N-doped TiO2 photocatalyst.  

PubMed

Photo-degradation of tributyltin (TBT) has been enhanced by TiO(2) nanoparticles doped with nitrogen (N-doped TiO(2)). The N-doped catalyst was prepared by a sol-gel reaction of titanium (IV) tetraisopropoxide with 25% ammonia solution and calcined at various temperatures from 300 to 600°C. X-ray diffraction results showed that N-doped TiO(2) remained amorphous at 300°C. At 400°C the anatase phase occurred then transformed to the rutile phase at 600°C. The crystallite size calculated from Scherrer's equation was in the range of 16-51 nm which depended on the calcination temperature. N-doped TiO(2) calcined at 400°C which contained 0.054% nitrogen, demonstrated the highest photocatalytic degradation of TBT at 28% in 3h under natural light when compared with undoped TiO(2) and commercial photocatalyst, P25-TiO(2) which gave 14.8 and 18% conversion, respectively. PMID:20855158

Bangkedphol, S; Keenan, H E; Davidson, C M; Sakultantimetha, A; Sirisaksoontorn, W; Songsasen, A

2010-08-26

45

Parameter Effects and Reaction Pathways of Photoreduction of CO 2 over TiO 2\\/SO 4 2– Photocatalyst  

Microsoft Academic Search

The feasibility of applying a modified acidic photocatalyst (TiO2\\/SO42–) to reduce carbon dioxide was investigated. The photocatalytic reduction of CO2 was conducted in a bench-scale batch photocatalytic reactor. Three near-UV black lamps with a maximal spectrum wavelength of 365 nm were assembled on the top of the reactor to provide an average irradiation intensity of 2.0 mW\\/cm2. The TiO2\\/SO42– photocatalyst

Cho-Ching LO; Chung-Hsuang HUNG; Chung-Shin YUAN; Yu-Li HUNG

2007-01-01

46

Floating photocatalysts based on TiO 2 grafted on expanded polystyrene beads for the solar degradation of dyes  

Microsoft Academic Search

In this work, a highly active, low cost, simple and robust floating photocatalyst based on TiO2 P25 grafted on expanded polystyrene (EPS) beads was developed. SEM and TG analyses showed that ca. 18wt% of TiO2 can be permanently grafted on the surface of EPS particles. This floating photocatalyst showed high efficiency for the degradation of three different dyes, i.e. methylene

F. Magalhães; R. M. Lago

2009-01-01

47

Mesoporous layers of TiO2 as highly efficient photocatalysts for the purification of air  

NASA Astrophysics Data System (ADS)

Mesoporous films of TiO2 prepared by a template-assisted procedure based on the evaporation-induced self-assembly mechanism were shown to be efficient photocatalysts for the oxidation of nitrogen oxide. Their high photocatalytic activity is explained by a local increase in the partial pressure of NO in the nanopores of the porous film close to the photocatalytic active sites. Owing to the strong adsorption of the intermediate products, a high selectivity towards nitric acid is achieved.

Kalousek, Vít; Tschirch, Jessica; Bahnemann, Detlef; Rathouský, Ji?í

2008-10-01

48

Mesoporous layers of TiO 2 as highly efficient photocatalysts for the purification of air  

Microsoft Academic Search

Mesoporous films of TiO2 prepared by a template-assisted procedure based on the evaporation-induced self-assembly mechanism were shown to be efficient photocatalysts for the oxidation of nitrogen oxide. Their high photocatalytic activity is explained by a local increase in the partial pressure of NO in the nanopores of the porous film close to the photocatalytic active sites. Owing to the strong

Vít Kalousek; Jessica Tschirch; Detlef Bahnemann; Jirí Rathouský

2008-01-01

49

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

50

A photocatalytic performance of TiO 2 photocatalyst prepared by the hydrothermal method  

Microsoft Academic Search

Anatase phase nanocrystalline TiO2 powders were prepared by hydrothermal method with the TTIP (titanium tetra isopropoxide) at 200 oC in a stirred autoclave\\u000a system. The effects of synthesis conditions on the physical properties of catalyst were investigated by using XRD, SEM, DLS,\\u000a DSC and BET. The TiO2 powders obtained from the optimum condition showed uniform spherical shape, crystalline structure, submicron

Woo Seok Nam; Gui Young Han

2003-01-01

51

Low-temperature hydrothermal synthesis of S-doped TiO 2 with visible light photocatalytic activity  

Microsoft Academic Search

A one-step low-temperature hydrothermal route was developed for the synthesis of S-doped TiO2 photocatalysts from TiS2 and HCl. Crystalline TiO2 was formed and sulfur could be efficiently doped into the anatase lattice under hydrothermal conditions. When the initial TiS2 concentration is increased, the content of S-dopant and optical absorption in the visible region also increase. The photocatalytic activity of the

Wingkei Ho; Jimmy C.. Yu; Shuncheng Lee

2006-01-01

52

Enhancement of TiO2 photocatalytic activity by structuring the photocatalyst film as photonic sponge.  

PubMed

A TiO2 film having "photonic sponge" architecture (ps-TiO2) has been prepared using titania Degussa P25 nanoparticles that have been infiltrated into a template obtained through the arrangement of a mixture of different size latex spheres. The resulting photonic sponge exhibits 3.3 fold higher initial photocatalytic degradation rate for succinonitrile disappearance than analogous films of the same thickness made of unstructured P25 TiO2 nanoparticles. When corrected for the three fold lower mass of the ps-TiO2 films with respect to more dense P25, the enhancement of the photocatalytic activity by the photonic sponge morphology for the same mass of photocatalyst is about one order of magnitude. It was also observed that films of photonic sponge of 3 microm depth are more efficient than thicker films (5 and 7 microm). PMID:18688500

Carbonell, Esther; Ramiro-Manzano, Fernando; Rodríguez, Isabelle; Corma, Avelino; Meseguer, Francisco; García, Hermenegildo

2008-04-04

53

Photocatalyst TiO 2 supported on glass fiber for indoor air purification: effect of NO on the photodegradation of CO and NO 2  

Microsoft Academic Search

A synthetic photocatalyst TiO2 prepared using the sol–gel method showed a higher activity than commercial photocatalyst TiO2 (P25), for the photodegradation of NO and benzene, toluene, ethylbenzene, o-xylene (BTEX) at typical indoor air parts-per-billion (ppb) levels. The Brunauer–Emmett–Teller (BET) surface area was found to be the vital parameter for the increased activity of the photocatalyst. The photocatalyst was immobilized on

C. H. Ao; S. C. Lee; Jimmy C. Yu

2003-01-01

54

Highly active TiO2N photocatalysts prepared by treating TiO2 precursors in NH3/ethanol fluid under supercritical conditions.  

PubMed

N-doped TiO2 photocatalysts were prepared by pretreating the TiO2 precursor in NH3/ethanol fluid under supercritical conditions, denoted as TiO2N(SC). In contrast to the TiO2N(DC), obtained via direct calcination in which the N dopants were mainly present in the form of surface adsorbed NH3 molecules, most N dopants in the TiO2N(SC) were present in O-Ti-N and N-Ti-N nitrides, as confirmed by either the X-ray photoelectron spectroscopy (XPS) and or the Fourier transform infrared (FTIR) spectra. During liquid-phase oxidative degradation of phenol under irradiation with UV light characteristic of 365 nm, the TiO2N(SC) exhibited much higher activity than either the TiO2N(DC) or the TiO2(SC), i.e., the undoped TiO2 obtained under SCs. According to various characterizations including X-ray diffraction, transmission electron microscopy, FTIR, Brunauer-Emmett-Teller, XPS, and UV-vis diffuse reflectance spectra, the higher activity of the TiO2N(SC) could be attributed to its higher surface area, larger pore volume, well-crystallized anatase, and stronger absorbance of light with longer wavelength. Meanwhile, the OH species resulted from the nitridation of TiO2 could supply more HO* radicals, which were considered as powerful oxidants during phenol degradation. Furthermore, the electron-deficient nitrogen atoms in O-Ti-N nitrides could also account for the higher activity since it could inhibit the recombination between the photoinduced electrons and holes by capturing the photoinduced electrons. The activity of the TiO2N(SC) first increased and then decreased with the increase of the N-content. The TiO2N(SC)-1 with N/Ti molar ratio of 1.73% exhibited maximum activity, which was even much higher than P-25. PMID:16471715

Li, Hexing; Li, Jingxia; Huo, Yuning

2006-02-01

55

Ag/AgCl@helical chiral TiO2 nanofibers as a visible-light driven plasmon photocatalyst.  

PubMed

Ag/AgCl@chiral TiO2 nanofibers are synthesized to tune the angle of the incident visible light through the chiral structure of the TiO2 nanofibers, intensifying the surface plasmon resonance effect of the supported Ag/AgCl materials, which are proven to be a highly active and stable visible light photocatalyst for the degradation of 17-?-ethinylestradiol. PMID:23999692

Wang, Dawei; Li, Yi; Li Puma, Gianluca; Wang, Chao; Wang, Peifang; Zhang, Wenlong; Wang, Qing

2013-10-10

56

Favorable recycling photocatalyst TiO 2\\/CFA: Effects of calcination temperature on the structural property and photocatalytic activity  

Microsoft Academic Search

A batch of TiO2\\/CFA photocatalysts was prepared by using coal fly ash (CFA), waste discharged from coal-fired power plant, as substrate. The effects of calcination temperature on the structural property of TiO2\\/CFA, such as morphology, crystal structure, porous property and light absorption characteristic were investigated in detail. Further more, the effects of calcination temperature on the photocatalytic activity and the

Jian-wen Shi; Shao-hua Chen; Shu-mei Wang; Zhi-long Ye; Peng Wu; Bin Xu

2010-01-01

57

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

58

Visible-light-induced photocatalytic degradation of methylene blue with polyaniline-sensitized TiO 2 composite photocatalysts  

Microsoft Academic Search

A series of polyaniline (PANI)-sensitized TiO2 composite photocatalysts (PANI\\/TiO2) with different mass ratio of polyaniline to nano- TiO2 (P25) (1:200–1:700) were facilely prepared by mixing a tetrahydrofuran (THF) solution of camphorsulfonic acid (CSA)-doped polyaniline (PANI-CSA) and TiO2 nanoparticle suspension in ethanol. Transmission electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet–visible diffuse reflectance spectroscopy (DRS) measurements were used

Fang Wang; Shixiong Min; Yuqi Han; Lei Feng

2010-01-01

59

Development of metal cation compound-loaded S-doped TiO 2 photocatalysts having a rutile phase under visible light  

Microsoft Academic Search

We have synthesized S (S4+)-doped TiO2 photocatalysts having a rutile phase. Rutile S-doped TiO2 photocatalysts loaded with metal ion compounds (Fe3+, Rh3+, Cu2+, Co3+, Ni2+, Cr3+) have also been prepared (S-doped TiO2-Mn+). The metal ions were adsorbed on the surfaces of S-doped TiO2 nanoparticles by impregnation methods (IM) or photodeposition methods (PH). The photocatalytic activities of S-doped TiO2 for oxidation

Teruhisa Ohno; Naoya Murakami; Toshiki Tsubota; Hitoshi Nishimura

2008-01-01

60

Synthesis, characterization and photocatalytic activity of Al2O3-TiO2 based composites.  

PubMed

The synthesis, characterization and photocatalytic performance of non-traditional Al2O3-TiO2-based photocatalysts is reported. Al2O3-TiO2 support was loaded with various fractions of CuO and ZrO2. A sound agreement was observed between the bandgaps of synthesized powders measured by UV-Visible diffuse reflectance spectroscopy (DRS) in the solid phase and UV-Visible spectroscopy in the aqueous medium. X-ray diffraction (XRD) analysis revealed the composite nature of the catalysts with the retention of individual identity of each component. The average crystallite size of the individual component was found to be in the range of 20 to 40 nm. Scanning electron microscopy (SEM) analysis authenticated the presence of CuO and ZrO2 at the surface of Al2O3-TiO2 support, while Rutherford Back Scattering Spectroscopy (RBS) confirmed the quantity of the modifiers as per theoretical calculations. The composites showed an enhanced photocatalytic activity in sunlight compared to Al2O3-TiO2 for the degradation of dyes. Efforts were made to elucidate the enhanced sunlight response of the synthesized composite catalysts compared to Al2O3-TiO2. As monitored by ion chromatography (IC), the synthesized photocatalysts completely mineralized the dyes leaving behind inorganic ions in solution. The kinetics of photocatalytic degradation of dyes was evaluated for optimum correlation with the existing models. The stability of the photocatalysts against the photo-corrosion was monitored by analyzing the samples for respective metals in solution after sunlight exposure. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Environmental Science and Health, Part A, to view the supplemental file. PMID:24117092

Ali, Zulfiqar; Aslam, M; Ismail, Iqbal M I; Hameed, A; Hussain, Syed Tajammul; Chaudhry, Muhammad Nawaz; Gondal, M A

2014-01-01

61

Visible light responsive N-F-codoped TiO2 photocatalysts for the degradation of 4-chlorophenol.  

PubMed

N-F-codoped TiO2 (NFTO) photocatalysts were synthesized by a simple sol-gel process with tetrabutyl titanate (Ti(OBu)4) as the precursor of TiO2 and ammonium fluoride (NH4F) as the source of N and F. The synthesized photocatalysts were investigated by Xray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and photodegradation reaction tests of 4-chlorophenol under visible light irradiation to understand the relationship between the structure of NFTO catalyst and corresponding photocatalytic activity. The crystal phase and particle size of catalysts were found to be largely affected by the calcination temperature. In addition, N-F-codoping could inhibit phase transition of TiO2 from anatase to rutile. The presence of N and F atoms in the lattice of TiO2 is responsible for the visible light catalytic activity. In UV-Vis DRS tests, the spectrum of NFTO exhibited red shift compared with Degussa P25 and the band gap was reduced to around 2.92 eV. Under optimal calcination temperature and dopant concentration conditions, the NFTO photocatalyst exhibited the highest activity in the photodegradation reaction tests of 4-chlorophenol under visible light irradiation with a degradation rate of 75.84%. Besides, the 5-recycle test showed that NFTO photocatalyst could be reused and its activity kept stable under visible light irradiation. PMID:22432319

Li, Xiaohong; Zhang, Haidong; Zheng, Xuxu; Yin, Zhongyi; Wei, Le

2011-01-01

62

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

63

TiO2-V2O5 nanocomposites as alternative energy storage substances for photocatalysts.  

PubMed

TiO2-V2O5 was prepared and evaluated as an energy storage material for photocatalysts with high capacity and initial charging rate. The compound was successfully obtained by sol-gel technique and effects of compound composition and calcination temperature on the energy storage ability were investigated. The synthesized compounds were characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray analysis (SEM-EDX) and transmission electron microscopy (TEM). The results reveals that the compound of Ti:V molar ratio equal to 1:0.11 calcined at 550 degrees C exhibited superior energy storage ability than parent substances and 1.7-times higher capacity and 2.3-times higher initial charging rate compared to WO3, indicating that the compound is a remarkable alternative to conventional energy storage substances. PMID:22524065

Ngaotrakanwiwat, Pailin; Meeyoo, Vissanu

2012-01-01

64

Synthesis of titanium dioxide (TiO2) nanomaterials.  

PubMed

Titanium dioxide (TiO2) is a promising material for many emerging applications. Even more promising are the benefits offered by the material when its length scale is reduced to the nanometer range. Nanomaterials usually exhibit unique properties resulting from either the extremely large surface area-to-volume ratio or the quantum confinement effect of energy carriers. In this article we present an overview of recent progress in the synthesis of TiO2 nanomaterials. The topics include synthesis of TiO2 nanoparticles, nanorods, nanowires, nanotubes, and mesoporous/nanoporous materials using different preparation approaches such as sol-gel, sol, hydrothermal, solvothermal, and vapor deposition. The applications of TiO2 nanomaterials are also briefly summarized. PMID:16736747

Chen, Xiaobo; Mao, Samuel S

2006-04-01

65

Anchoring a uniform TiO2 layer on graphene oxide sheets as an efficient visible light photocatalyst  

NASA Astrophysics Data System (ADS)

TiO2-graphene oxide (GO) was successfully prepared by a two-step approach including the in situ growth of a uniform TiC layer on graphene oxide sheets and subsequently oxidation conversion of TiC to anatase TiO2. The as-prepared composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic activity was evaluated by degradation of methylene blue (MB) under visible light irradiation. The results suggest that TiO2-GO keep the similar morphology with the pristine GO sheets and the nanosize anatase TiO2 particles distribute uniformly and densely on the surface of GO sheets. TiO2 particles contact closely with GO via TiOC bonds. The presence of GO provides a good support substrate and enhances the adsorption capacity and photo-degradation ability of the composite photocatalyst. And by adjusting the molar ratio of GO and titanium powder in the molten salt process, TiO2-GO nanocomposites with controllable contents of GO and TiO2, good adsorption capacity and excellent photo-degradation ability can be obtained.

Cong, Ye; Long, Mei; Cui, Zhengwei; Li, Xuanke; Dong, Zhijun; Yuan, Guanming; Zhang, Jiang

2013-10-01

66

Microwave Hydrothermal Synthesis of Rutile TiO2 Nanorods  

Microsoft Academic Search

We present in this paper the synthesis of rutile TiO2 nanorods using an efficient microwave hydrothermal method. The product was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, and the results indicated the growth of high quality rutile nanorods along the c-axis of rutile TiO2 and the radial aggregation of them into spherical secondary nanoparticles.

Guobin Ma; Xiaoning Zhao; Jianmin Zhu

2005-01-01

67

Microwave Hydrothermal Synthesis of Rutile TiO2 Nanorods  

NASA Astrophysics Data System (ADS)

We present in this paper the synthesis of rutile TiO2 nanorods using an efficient microwave hydrothermal method. The product was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, and the results indicated the growth of high quality rutile nanorods along the c-axis of rutile TiO2 and the radial aggregation of them into spherical secondary nanoparticles.

Ma, Guobin; Zhao, Xiaoning; Zhu, Jianmin

68

Morphologically-tunable TiO2 nanorod film with high energy facets: green synthesis, growth mechanism and photocatalytic activity.  

PubMed

A novel green synthesis strategy was developed to synthesize a film photocatalyst containing anatase TiO(2) nanorods wholly dominated with {100} and {101} facets by employing a simple hydrothermal reaction in the presence of NaCl solution and hydrogen titanate nanosheet array film. The formation mechanism of the anatase TiO(2) nanorods was deduced from X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations, which revealed that the highly reactive {100} facets were derived from the enhanced structural stability of hydrogen titanate induced by Na(+) and selective adsorption of Cl(-) on the {100} facets of anatase TiO(2) crystals. Photocatalytic performance has indicated that the TiO(2) nanorods with {100} facet exposure exhibit much higher activities than that of rhombic nanoparticles with {101} facet exposure for the degradation of organic contaminants, which may be primarily ascribed to the high surface energy of {100} facets. PMID:22767389

Wang, Changhua; Zhang, Xintong; Zhang, Yanli; Jia, Yan; Yuan, Bo; Yang, Jikai; Sun, Panpan; Liu, Yichun

2012-07-06

69

A highly efficient TiO2@ZnO n-p-n heterojunction nanorod photocatalyst  

NASA Astrophysics Data System (ADS)

Shell@core-nanostructured TiO2@ZnO n-p-n heterojunction nanorods with diameter of 30 nm were successfully fabricated via a hydrothermal method. The photodegradation rate of the TiO2@ZnO n-p-n nanorods evaluated by photodegrading methyl orange has been demonstrated to increase three times compared to that of wurtzite hexagonal ZnO. Anatase TiO2 and Ti2O3 grow along ZnO crystal lattices, which forms p-type Zn2+ doped Ti2O3 in the interface of TiO2/ZnO and therefore numerous n-p-n heterojunctions owing to the substitution of Ti3+ by Zn2+. Under the drive of inner electric field, the photogenerated electrons are both injected to the conduction band of Zn2+ doped Ti2O3 from conduction bands of ZnO and TiO2, which efficiently enhances the separation of photogenerated electron-hole pairs and accelerates the transport of charges. The results suggest that TiO2@ZnO n-p-n heterojunction nanorods are very promising for enhancing the photocatalytic activity of photocatalysts.

Lin, Lin; Yang, Yingchao; Men, Long; Wang, Xin; He, Dannong; Chai, Yuchao; Zhao, Bin; Ghoshroy, Soumitra; Tang, Qunwei

2012-12-01

70

Fabrication and comparison of highly efficient Cu incorporated TiO 2 photocatalyst for hydrogen generation from water  

Microsoft Academic Search

Efficient Cu incorporated TiO2 (Cu–TiO2) photocatalysts for hydrogen generation were fabricated by four methods: in situ sol–gel, wet impregnation, chemical reduction of Cu salt, and in situ photo-deposition. All prepared samples are characterized by good dispersion of Cu components, and excellent light absorption ability. Depending on the preparation process, hydrogen generation rates of the as-prepared Cu–TiO2 were recorded in the

Shiping Xu; Jiawei Ng; Xiwang Zhang; Hongwei Bai; Darren Delai Sun

2010-01-01

71

Fe 3+-TiO 2 photocatalysts prepared by combining sol–gel method with hydrothermal treatment and their characterization  

Microsoft Academic Search

Fe3+-doped anatase nanosized TiO2 photocatalysts have been prepared by combining sol–gel method with hydrothermal treatment. The samples were characterized by UV–vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET)-specific surface area (SBET), transmission electron microscopy (TEM), atomic absorption flame emission spectroscopy (AAS), electron paramagnetic resonance (EPR) spectroscopy and X-ray photoelectron spectroscopy (XPS). From results of UV–vis diffuse reflectance spectroscopy, Fe3+-doped

Jiefang Zhu; Feng Chen; Jinlong Zhang; Haijun Chen; Masakazu Anpo

2006-01-01

72

Grinding of Si 3N 4 Ceramic Balls with the Aid of PhotoCatalyst of TiO 2  

Microsoft Academic Search

There are big needs from industry that the polishing process using loose abrasive be replaced by grinding process. This paper explores the possibility of replacement by investigating effects of the free radical reaction on the precision grinding performance. Free radicals were generated with the aid of TiO2, a kind of photo-catalyst. Experiments were conducted on Si3N4 ceramic ball grinding with

Bo ZHANG; Akira NAKAJIMA; M. Kiuchi

2002-01-01

73

A facile one-step synthesis of TiO 2 \\/graphene composites for photodegradation of methyl orange  

Microsoft Academic Search

TiO2\\/graphene composite photocatalysts have been prepared by a simple liquid phase deposition method using titanium tetrafluoride\\u000a and electron beam (EB) irradiation-pretreated graphene as the raw materials. The products were characterized by X-ray diffraction,\\u000a transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of varying\\u000a the synthesis parameters such as graphene content, concentration of titanium tetrafluoride solution and irradiation

Haijiao Zhang; Panpan Xu; Guidong Du; Zhiwen Chen; Kokyo Oh; Dengyu Pan; Zheng Jiao

2011-01-01

74

Synthetic trends for BiVO4 photocatalysts: Molybdenum substitution vs. TiO2 and SnO2 heterojunctions  

NASA Astrophysics Data System (ADS)

The influence of hydrothermal synthesis, thermal post-treatment at 500 °C and Mo content on a series of Bi1-x/3V1-xMoxO4 (0.02photocatalysts was investigated for methylene blue (MB) degradation and O2 evolution. Mo incorporation stabilizes the tetragonal scheelite phase of BiVO4, thereby inducing a small blue shift of the band gap. This adverse effect can be partially compensated by incorporation of lower Mo amounts (up to ca. 4%), which stabilizes the particle morphology upon calcination. Both BiVO4@TiO2 and BiVO4:Mo@TiO2 heterojunction composites with TiO2 particle coatings in the 10 nm range were newly synthesized and displayed promising photocatalytic performance in MB degradation. Comparative studies with SnO2 heterojunctions revealed a superior influence of TiO2 deposition over SnO2 coating on both BiVO4 and Bi1-x/3V1-xMoxO4 oxide substrates. Different synthetic guidelines for BiVO4-based solid solutions and heterojunctions in photocatalytic wastewater treatment and water oxidation are discussed.

Kontic, Roman; Patzke, Greta R.

2012-05-01

75

Incident light dependence for photocatalytic degradation of acetaldehyde and acetic acid on S-doped and N-doped TiO2 photocatalysts  

NASA Astrophysics Data System (ADS)

We have synthesized S (S4+)-doped and N (N3-)-doped TiO2 photocatalysts. S-doped and N-doped TiO2 loaded with Fe2O3 nanoparticles have also been prepared. These photocatalysts showed activity under a wide range of wavelengths of irradiation. Action spectra of photochemical reaction rate as a function of the incident light wavelength for oxidation of acetic acid on S-doped TiO2 was studied.The photocatalytic activities of S-doped and N-doped TiO2 photocatalysts loaded with Fe2O3 nanoparticles for oxidation of acetic acid in aqueous phase and acetaldehyde in gas phase are markedly improved compared to those of doped TiO2 without loading of Fe2O3 nanoparticles under a wide range of incident light wavelengths. The optimum amount of Fe2O3 nanoparticles loaded on S-doped TiO2 particles was different from that on N-doped TiO2 for oxidation of organic compounds. The relationship between reaction rate of photocatalytic oxidation of acetaldehyde on doped TiO2 loaded with Fe2O3 nanoparticles and amount of Fe2O3 nanoparticles is discussed.

Nishijima, Kazumoto; Ohtani, Bunsho; Yan, Xiaoli; Kamai, Taka-Aki; Chiyoya, Tetsuo; Tsubota, Toshiki; Murakami, Naoya; Ohno, Teruhisa

2007-10-01

76

Fluorinated semiconductor photocatalysts: tunable synthesis and unique properties.  

PubMed

Semiconductor photocatalysts are of great significance in solar energy conversion and environmental remediation. To overcome serious drawbacks of these materials with respect to narrow light-response range and low quantum efficiency, a variety of strategies have been developed in the past decades to enhance the light harvesting and excitation as well as the charge transfer against recombination. In particular, fluorination of semiconductor photocatalysts can be employed to modify their surface and bulk properties, and consequently, to enhance their photocatalytic performance. This review presents a comprehensive description of the F-mediated synthesis and unique properties of fluorinated semiconductor photocatalysts, in particular titanium dioxide (TiO(2)). The available strategies for the synthesis of fluorinated photocatalysts include post-synthesis fluorination and in-situ fluorination. Depending on the synthesis route and conditions, it is possible to control the chemical nature of incorporated fluorine (such as adsorbed fluoride and lattice-doped fluorine) and the fluoride-mediated crystal modification and organization, which often results in exceptional surface and bulk physicochemical properties, giving rise to unique photocatalytic properties. Significantly, the surface fluorination induces unusual adsorption behavior and interfacial charge transfer dynamics, directly affecting photocatalytic redox properties of the surface-fluorinated photocatalysts. The lattice fluorine-doping, sole or cooperative with other complementary co-dopants, introduces special localized electronic structures and surface defect states, accounting for the exceptional visible-light photoactivity of the fluorine-doped photocatalysts. Finally, recent advances in the synthesis and properties of fluorinated photocatalysts are summarized along with perspectives on further developments in this area of research. PMID:22425280

Liu, Shengwei; Yu, Jiaguo; Cheng, Bei; Jaroniec, Mietek

2012-02-28

77

A new type of water splitting system composed of two different TiO 2 photocatalysts (anatase, rutile) and a IO 3 ?\\/I ? shuttle redox mediator  

Microsoft Academic Search

A new photocatalytic reaction that splits water into H2 and O2 was designed by a two-step photoexcitation system composed of a IO3?\\/I? shuttle redox mediator and two different TiO2 photocatalysts, Pt-loaded TiO2-anatase for H2 evolution and TiO2-rutile for O2 evolution. Simultaneous gas evolution of H2(180?mol\\/h) and O2(90?mol\\/h) was observed from a basic (pH=11) NaI aqueous suspension of two different TiO2

Ryu Abe; Kazuhiro Sayama; Kazunari Domen; Hironori Arakawa

2001-01-01

78

Characterization and mechanism analysis of Mo-N-co-doped TiO2 nano-photocatalyst and its enhanced visible activity.  

PubMed

In this study, Mo-N-co-doped TiO(2) nano-photocatalysts have been synthesized through hydrolysis-precipitation method, combined with sonication posttreatment. The resulting materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). XRD showed that co-doping with Mo and N favored the formation of anatase and retarded the growth of crystallite size. XPS revealed that N was incorporated into the lattice of TiO(2) through substituting oxygen atoms and coexisted in the forms of ?-N and ?-N in co-doped TiO(2). Meanwhile, Mo was also incorporated into the lattice of TiO(2) through substituting titanium atoms and existed in the form of Mo(6+). DRS indicated that the light absorbance in visible region was improved by co-doping with Mo and N, leading to a narrower band gap and higher visible light photocatalytic activity for the degradation of phenol than that of pure and N-doped TiO(2). The enhanced visible light photocatalytic activity of Mo-N-co-doped TiO(2) nano-photocatalyst was attributed to the small crystallite size, narrow band gap and intense light absorbance in visible region. This study provides a new method to synthesize visible light active TiO(2)-based photocatalyst. PMID:22326229

Cheng, Xiuwen; Yu, Xiujuan; Xing, Zipeng

2011-12-06

79

Photodegradation of phenanthrene by N-doped TiO2 photocatalyst.  

PubMed

The photodegradation of phenanthrene has been catalyzed by nanostructures of TiO2 doped with nitrogen, N-doped TiO2. The N-doped TiO2 was prepared from the sol-gel reaction of Titanium(IV) bis(ethyl acetoacetato)diisopropoxide with 25% ammonia solution. The N-doped TiO2 was calcined at various temperatures from 300 to 700 degrees C. X-ray diffraction (XRD) results showed that N-doped TiO2 remained amorphous at 300 degrees C but anatase-to-rutile transformation started at 400 degrees C and was complete at 700 degrees C. The average particle size calculated from Scherrer's equation was in the range of 9-51 nm with surface area (S(BET)) of 253.7-4.8 m2/g. X-ray photoelectron spectroscopy (XPS) results confirmed the incorporation of nitrogen atoms (Ti-N bond) in the N-doped catalyst. Moreover, the percentage of nitrogen determined by Elemental analysis was 0.236% of N-doped calcined at 400 degrees C. UV-Vis reflection spectra indicated that N-doped TiO2 calcined at 400 degrees C shifted to the higher absorption edge in the range of visible light. N-doped TiO2 calcined at 400 degrees C successfully catalyzed the photodegradation of phenanthrene (80% conversion) whereas N-doped TiO2 calcined at 500 degrees C and P25 TiO2 failed as catalysts. PMID:19799052

Sirisaksoontorn, Weekit; Thachepan, Surachai; Songsasen, Apisit

2009-07-15

80

Significant photocatalytic enhancement in methylene blue degradation of TiO 2 photocatalysts via graphene-like carbon in situ hybridization  

Microsoft Academic Search

Graphene-like carbon\\/TiO2 photocatalysts were prepared via a facile in situ graphitization approach. The introduction of graphene-like carbon to TiO2 effectively enhanced its photocatalytic activity. A graphene-like carbon\\/TiO2 photocatalyst with a monolayer carbon shell (0.468nm) showed the highest photocatalytic activity which is about 2.5 times as high as that of pristine TiO2 (P25) under UV light irradiation. The mechanism of the

Yajun Wang; Rui Shi; Jie Lin; Yongfa Zhu

2010-01-01

81

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...

82

[Visible-light responding BiVO4/TiO2 nanocomposite photocatalyst].  

PubMed

The two kinds of new nanocomposites BiVO4/TiO2 nanowires were synthesized by hydrothermal process. Their crystal structure, morphology and photocatalytic activities for degradation of methylene blue solution were characterized using various measurement techniques. The XRD results indicate that they are made up of monoclinic BiVO4 and anatase TiO2 phases. The SEM, TEM and HRTEM images show that the two samples include BiVO4 nanoparticles supported onto TiO2 nanowires. The UV-Vis absorption spectra reveal that the absorption edges of the samples exhibit red-shift in comparison with that of the pure TiO2 nanowires. The measurement results for the visible-light photodegradation of methylene blue show that the nanocomposite sample prepared from the layered titanate nanowires with Bi3+ has the highest photocatalytic activity. PMID:20828005

Ji, Tian-hao; Yang, Fang; Zhou, Jiao-yan; Du, Hai-yan; Sun, Jia-yue

2010-07-01

83

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...

84

Comparison of the substrate dependent performance of Pt, Au and Ag-doped TiO 2 photocatalysts in H 2 -production and in decomposition of various organics  

Microsoft Academic Search

Pt-, Au- and Ag-deposited Degussa P25 photocatalysts [at 1% (m\\/m) noble metal loading] were prepared in which the noble metals\\u000a are most likely to be very finely dispersed on the surface of the TiO2 nanocrystals. Deposition of noble metals increased the photocatalytic efficiency (relative to the bare photocatalyst) in\\u000a the decomposition of oxalic- and formic acid, while decreased it in

Károly Mogyorósi; Ákos Kmetykó; Nóra Czirbus; Gábor Veréb; Pál Sipos; András Dombi

2009-01-01

85

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

86

Synthesis of hybrid zeolite materials with TiO2 nanocrystals using solid-solid method  

NASA Astrophysics Data System (ADS)

Zeolite seems to be a promising support for TiO2 photocatalyst because of its regular pores and good adsorption ability. TiO2 supported on zeolite integrates the photocatalytic activity of TiO2 with the adsorption properties of zeolites. The aim of this paper was the syntheses and characterizations of functionalized zeolite materials with undoped, Fe-doped and N-doped TiO2 nanocrystals. The zeolite hybrid materials impregnation with titanium dioxide was achieved through solid-solid method. TiO2 doped with metallic (Fe) and non-metallic (N) ions was obtained directly from precursors by sol-gel and hydrothermal methods. The hybrid materials were characterized by XRD, SEM with EDAX, IR and AFM.

Orha, Corina; Lazau, Carmen; Ratiu, Cornelia; Sfirloaga, Paula; Vlazan, Paulina; Ioitescu, Alexandra; Manea, Florica; Barvinschi, Paul; Muscutariu, Ioan; Grozescu, Ioan

2009-03-01

87

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

PubMed Central

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.

2010-01-01

88

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

2009-12-24

89

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

90

Study of Visible Light Reactive Photocatalyst TIO2 Prepared with Thiourea  

NASA Astrophysics Data System (ADS)

Visible light reactive N-doped TiO2 samples were prepared with thiourea in the sol-gel method. They had the single anatase-type crystal structure. N-doped TiO2 synthesized with thiourea (T-TiO2) had a higher catalytic activity than that synthesized with urea (U-TiO2). The S2p peak observed on the surface of T-TiO2 was assigned to S6+ by XPS measurement. It was estimated that sulfuric acid species exist on the surface of T-TiO2. However, it was concluded that sulfuric acid species do not have the catalytic activity directly, but depress the crystallinity, the decrease of specific surface area and the decrease of visible light absorption.

Murai, Kei-Ichiro; Endo, Kazuki; Nakagawa, Taisuke; Yamahata, Akiko; Moriga, Toshihiro

91

Highly efficient visible light TiO2 photocatalyst prepared by sol-gel method at temperatures lower than 300°C.  

PubMed

Highly efficient visible light TiO(2) photocatalyst was prepared by the sol-gel method at lower temperature (? 300°C), and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and differential scanning calorimetry-thermogravimetric analysis (DSC-TGA). The effects of the heat treatment temperature and time of the as-prepared TiO(2) on its visible light photocatalytic activity were investigated by monitoring the degradation of methyl orange solution under visible light irradiation (wavelength ? 400 nm). Results show that the as-prepared TiO(2) nanoparticles possess an anatase phase and mesoporous structure with carbon self-doping and visible photosensitive organic groups. The visible light photocatalytic activity of the as-prepared TiO(2) is greatly higher than those of the commercial TiO(2) (P-25) and other visible photocatalysts reported in literature (such as PPy/TiO(2), P3HT/TiO(2), PANI/TiO(2), N-TiO(2) and Fe(3+)-TiO(2)) and its photocatalytic stability is excellent. The reasons for improving the visible light photocatalytic activity of the as-prepared TiO(2) can be explained by carbon self-doping and a large amount of visible photosensitive groups existing in the as-prepared TiO(2). The apparent optical thickness (?(app)), local volumetric rate of photo absorption (LVRPA) and kinetic constant (k(T)) of the photodegradation system were calculated. PMID:21616590

Wang, Desong; Xiao, Libin; Luo, Qingzhi; Li, Xueyan; An, Jing; Duan, Yandong

2011-05-10

92

Thin film TiO 2 photocatalyst deposited by reactive magnetron sputtering  

Microsoft Academic Search

TiO2 films were deposited by r.f. reactive magnetron sputtering on non-alkali glass at 200 °C under total gas pressure of 0.3, 1.0 and 3.0 Pa with oxygen flow ratio [O2\\/(O2+Ar)] of 30%. All films showed polycrystalline anatase structure, in which a small portion of rutile phase was observed only for the films deposited at 0.3 Pa. The films deposited at

Makiko Yamagishi; Shna Kuriki; P. K. Song; Yuzo Shigesato

2003-01-01

93

Visible-light sensitization of TiO 2 photocatalysts by wet-method N doping  

Microsoft Academic Search

Titanium dioxide powders prepared by a wet method, i.e., the hydrolysis of titanium tetra-isopropoxide or titanium tetrachloride with an aqueous ammonia solution, followed by calcination at temperatures above 330°C, exhibit photocatalytic activity in the visible-light region owing to N doping. The maximum absorption of visible light by the N-doped TiO2 was about 50% at around 440nm. Thermal analysis revealed that

Shinri Sato; Ryuhei Nakamura; Shinji Abe

2005-01-01

94

Self-organized TiO2 nanotube layers as highly efficient photocatalysts  

Microsoft Academic Search

Self-organized high-aspect-ratio TiO2 nanotubular layers exhibit excellent photocatalytic properties that are significantly enhanced compared to nanoparticulate layers. These tubular layers have showed remarkable photocatalytic activity for the decomposition of organic azo dyes namely, Acid Organge 7 (AO7) and Methylene Blue (MB), which are non-biodegradable dyes used in the textile industry and often considered as standard dyes for testing photocatalytic activity.

Martin Zlamal; Josef Krysa; Patrik Schmuki

2007-01-01

95

Quantum yields of active oxidative species formed on TiO 2 photocatalyst  

Microsoft Academic Search

The quantum yield of hydroxyl radical (?OH) production during TiO2 photocatalysis was estimated to be 7×10?5 in aqueous solution by means of a method using terephthalic acid as a fluorescence probe. This value is much lower than the quantum yield of ordinary photocatalytic reactions (?10?2). Conversely, the quantum yield of hole generation estimated by iodide ion oxidation was equivalent (5.7×10?2)

Ken-ichi Ishibashi; Akira Fujishima; Toshiya Watanabe; Kazuhito Hashimoto

2000-01-01

96

Heterogeneous photocatalytic treatment of simulated dyehouse effluents using novel TiO 2-photocatalysts  

Microsoft Academic Search

Heterogeneous photocatalytic treatment of two different synthetic dyehouse effluents called RI and RII, that were simulating textile wastewater from an integrated plant and a dyehouse mill and containing various reactive dyestuffs and associated auxiliary chemicals, was investigated by using different TiO2 types and reaction conditions. The effect of initial pH and effluent dilution ratio on treatment efficiency was examined and

Idil Arslan; Isil Akmehmet Balcioglu; Detlef W. Bahnemann

2000-01-01

97

Kinetic studies of oxidation of ethylene over a TiO 2 photocatalyst  

Microsoft Academic Search

The photo-assisted catalytic degradation of ethylene was studied in the tubular photoreactor packed with TiO2 pellets prepared by sol–gel method. The dependence of the reaction rate on the light intensity, feed composition (ethylene, oxygen and water vapor) and temperature were investigated. More than 95% ethylene was always completely mineralized irrespective of the reaction conditions. The reaction rate for ethylene conversion

Suzuko Yamazaki; Satoru Tanaka; Hidekazu Tsukamoto

1999-01-01

98

Gel-hydrothermal synthesis of carbon and boron co-doped TiO 2 and evaluating its photocatalytic activity  

Microsoft Academic Search

Carbon and boron co-doped TiO2 photocatalysts were prepared firstly by the gel-hydrothermal method, that is, synthesized through sol–gel process followed by hydrothermal in the glucose solution. The prepared photocatalysts were characterized by XRD, Raman spectra, TEM, N2 physical adsorption, XPS, and UV–vis absorption spectra. It was found that the co-doped TiO2 has a larger BET surface areas and a narrower

Yongmei Wu; Mingyang Xing; Jinlong Zhang

2011-01-01

99

Preparation and characterization of visible-light-active nitrogen-doped TiO2 photocatalyst.  

PubMed

A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO4)2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wavelength. The crystal structure of anatase was characterized by XRD. The structure analysis result of X-ray fluorescence (XRF) shows that doped-nitrogen was presented in the sample. The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants. The photocatalytic activities of samples were increasing gradually with calcination temperature from 400 degrees C to 700 degrees C under UV irradiation. It can be seen that the degradation of methyl orange follows zero-order kinetics. However, the calcination temperatures have no significant influence on the degradation of phenol under sunlight. The N-doped catalyst shows higher activity than the bare one under solar irradiation. PMID:16158579

Huang, Xian-Huai; Tang, Yu-Chao; Hu, Chun; Yu, Han-Qing; Chen, Chu-Sheng

2005-01-01

100

Synthesis of natural cellulose-templated TiO2/Ag nanosponge composites and photocatalytic properties.  

PubMed

In this paper, TiO(2)/Ag sponge-like nanostructure composites have been prepared by the surface sol-gel method with the template of natural cellulose, which is relatively simple, low-cost, and environmentally friendly. The Ag nanoparticles are deposited on the TiO(2) nanosponges through UV irradiation photoreduction of silver nitrate solutions. The physicochemical properties of as-prepared composites are characterized by XRD, BET, SEM, TEM, XPS and UV-vis DRS techniques. The UV-light photocatalytic activities of the composites are evaluated through the photodegradation of two model organic molecules including RhB and salicylic acid. The experimental results show that the photocatalytic activities of TiO(2)/Ag nanosponge composites are superior to that of P25, pure TiO(2) nanoparticle aggregates synthesized by the hydrothermal method and pure TiO(2) nanosponge. The superior activities of TiO(2)/Ag nanosponge composite photocatalysts can be attributed to the unique nanosponge morphology, uniform dispersion of Ag nanoparticles, and strong interaction between Ag and TiO(2) nanosponges. PMID:22548498

Yu, Dong-Hui; Yu, Xiaodan; Wang, Changhua; Liu, Xian-Chun; Xing, Yan

2012-05-08

101

Synthesis and characterisation of TiO2-derived nanotubes  

Microsoft Academic Search

TiO2-based nanotubes were synthesised via hydrothermal and reflux methods in a 10 N NaOH solution at 403 K under stirring for 20–72 h from nano TiO2 and industrial TiO2 powders. The results show that the yield of nanotube formed through the hydrothermal method is higher than that of the reflux method. The samples were characterised by means of scanning electron

Shahrara Afshar; Moones Hakamizadeh

2009-01-01

102

Preparation Complex Photocatalyst of Modified TiO2\\/K2Ti6O13 by Tungstosilicic Acid and Study its Degradation of Methyl Orange  

Microsoft Academic Search

With potassium titanate (VI) whisker as carrier, and silicotungstic acid (H4SiW12O40) as modified reagent, the compound photocatalyst H4SiW12O40\\/TiO2\\/K2Ti6O13 was prepared by sol-gel-dipping method. UV-vis spectra showed that the compound photocatalyst had strongly responded to UV light and had some absorbency of visible light. The photocatalytic activity was evaluated by degradation of methyl orange under UV light. The photocatalytic influences of

Songtian Li; Weichun Yang; Changhao Li

2010-01-01

103

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

2013-05-07

104

Hydrothermal synthesis of flower-like TiO2 nanocrystals/graphene oxide nanocomposites  

NASA Astrophysics Data System (ADS)

A facile hydrothermal method has been developed to be capable of decorating graphene oxide (GO) with flower-like TiO2 nanocrystals without using any bridging species. The flower-like TiO2 nanocrystals were uniformly self-assembled on the surface of GO nanosheets. The photocatalytic activity experiment indicated that the prepared TiO2/GO nanocomposites exhibited a higher photocatalytic activity for the photocatalytic degradation of rhodamine B (RB) aqueous solution under the UV illumination, this methodology made the synthesis of TiO2/GO nanocomposites possible and may be further extended to prepare more complicated nanocomposites based on GO for technological applications.

Jia, Xiao-Hua; Song, Hao-Jie; Min, Chun-Ying

2013-06-01

105

Environment-friendly biomimetic synthesis of TiO2 nanomaterials for photocatalytic application  

NASA Astrophysics Data System (ADS)

We have demonstrated an environment-friendly biomimetic synthesis method for the preparation of TiO2 nanomaterials with different crystal phases and morphologies. This is the first time that it has been found that the crystal phase of TiO2 can be controlled just by using different biotemplates, and cannot be changed by calcination up to 750?°C. In our experiment, anatase TiO2 was obtained by using yeast and albumen templates, while rutile TiO2 was formed by using dandelion pollen as the template.

Bao, Shu-Juan; Lei, Chao; Xu, Mao-Wen; Cai, Chang-Jun; Jia, Dian-Zeng

2012-05-01

106

Preparation of high quality nitrogen doped TiO 2 thin film as a photocatalyst using a pulsed laser deposition method  

Microsoft Academic Search

Nitrogen doped titanium oxide (TiO2?xNx) photocatalysts, which were reported to be activated by visible light irradiation as well as ultraviolet irradiation, have been prepared by pulsed laser deposition (PLD) method using TiN target in nitrogen\\/oxygen gas mixture. Crystalline structure, nitrogen states in the lattice, composition and surface morphology were analyzed by using X-ray diffraction, X-ray photoelectron spectroscopy and atomic force

Yoshiaki Suda; Hiroharu Kawasaki; Tsuyoshi Ueda; Tamiko Ohshima

2004-01-01

107

Self-sterilizing and self-cleaning of silicone catheters coated with TiO(2) photocatalyst thin films: a preclinical work.  

PubMed

TiO(2) photocatalysts were successfully coated on silicone catheters or medical tubes by pretreatment of the silicone surface with a sulfuric acid solution (5 M) for 3 h. The TiO(2) film adhered to the silicone substrate strongly against tensile and bending stresses. On the TiO(2)-coated silicone-catheters under UV illumination, both the bleaching of methylene blue dye and the photocatalytic bactericidal effect on Escherichia coli (E. coli) cells were confirmed. Thus, this type of catheter can be sterilized and cleaned simply by irradiation with low-intensity UV light and can, therefore, be useful in the protection from catheter-related bacterial infections. PMID:11153004

Ohko, Y; Utsumi, Y; Niwa, C; Tatsuma, T; Kobayakawa, K; Satoh, Y; Kubota, Y; Fujishima, A

2001-01-01

108

N-doped TiO2 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 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 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 TiO2 showed superior photo-catalytic activity compared to that for pure TiO2. TiO2 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 CO2 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

109

Preparation, characterization and performance of a novel visible light responsive spherical activated carbon-supported and Er3+:YFeO3-doped TiO2 photocatalyst.  

PubMed

A novel spherical activated carbon (SAC) supported and Er(3+):YFeO(3)-doped TiO(2) visible-light responsive photocatalyst (Er(3+):YFeO(3)/TiO(2)-SAC) was synthesized by a modified sol-gel method with ultrasonic dispersion. It was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDS), powder X-ray diffractometer (XRD) and UV-vis diffuse reflectance spectrophotometer (DRS). The photocatalytic activity of Er(3+):YFeO(3)/TiO(2)-SAC was evaluated for degradation of methyl orange (MO) under visible light irradiation. The effects of calcination temperature and irradiation time on its photocatalytic activity were examined. The experimental results indicated that Er(3+):YFeO(3) could function as an upconversion luminescence agent, enabling photocatalytic degradation of MO by TiO(2) under visible light. The Er(3+):YFeO(3)/TiO(2) calcinated at 700°C showed the highest photocatalytic capability compared to those calcinated at other temperatures. The photocatalytic degradation of MO followed the Langmuir-Hinshelwood kinetic model. Although the photocatalyst showed a good physical stability and could tolerate a shear force up to 25 × 10(-3)N/g, its photocatalytic activity decreased over a four-cycle of reuse in concentrated MO solution, indicating that the decreased activity was ascribed to the fouling of catalyst surface by MO during the degradation process. However, the fouled Er(3+):YFeO(3)/TiO(2)-SAC could be regenerated through water rinsing-calcination or acid rinsing-calcination treatment. PMID:22119303

Hou, Dianxun; Feng, Liang; Zhang, Jianbin; Dong, Shuangshi; Zhou, Dandan; Lim, Teik-Thye

2011-11-09

110

Defective TiO2 with oxygen vacancies: synthesis, properties and photocatalytic applications  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the synthesis of defective TiO2 with oxygen vacancies, and the defect related properties of TiO2 including structural, electronic, optical, dissociative adsorption and reductive properties, which are intimately related to the photocatalytic performance of TiO2. In particular, photocatalytic applications with regard to defective TiO2 are outlined. In addition, we offer some perspectives on the challenge and new direction for future research in this field. We hope that this tutorial minireview would provide some useful contribution to the future design and fabrication of defective semiconductor-based nanomaterials for diverse photocatalytic applications.Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the synthesis of defective TiO2 with oxygen vacancies, and the defect related properties of TiO2 including structural, electronic, optical, dissociative adsorption and reductive properties, which are intimately related to the photocatalytic performance of TiO2. In particular, photocatalytic applications with regard to defective TiO2 are outlined. In addition, we offer some perspectives on the challenge and new direction for future research in this field. We hope that this tutorial minireview would provide some useful contribution to the future design and fabrication of defective semiconductor-based nanomaterials for diverse photocatalytic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00476g

Pan, Xiaoyang; Yang, Min-Quan; Fu, Xianzhi; Zhang, Nan; Xu, Yi-Jun

2013-04-01

111

Fabrication of a TiO2-BDD heterojunction and its application as a photocatalyst for the simultaneous oxidation of an azo dye and reduction of Cr(VI).  

PubMed

A TiO2-boron doped diamond (TiO2-BDD) heterojunction was employed as a photocatalyst to simultaneously oxidize an azo dye C.I. reactive yellow 15 (RY15) and reduce hexavalent chromium (Cr(VI)). This heterojunction was fabricated first by depositing a BDD film on a Ti sheet in a hot filament chemical vapor deposition reactor, followed by covering a layer of TiO2 in a metal-organic chemical vapor deposition system. The morphology of this heterojunction was characterized by using a scanning electron microscope (SEM). X-ray diffraction (XRD), Raman spectroscopy, and current-voltage (I-V) measurement were used to characterize its structures. Additionally, the characterization of surface photovoltage showed that the TiO2-BDD heterojunction exhibited a higher photovoltage response and a better ability for charge separation than the photocatalyst of TiO2 directly deposited on a Ti sheet (TiO2-Ti). The photocatalytic experiments revealed that the kinetic constants for the oxidation of RY15 and the reduction of Cr(VI) were, respectively, increased by 85 and 71% when the photocatalyst of TiO2-Ti was replaced by the TiO2-BDD heterojunction. Meanwhile, a significant synergy was confirmed in the simultaneous oxidation of RY15 and reduction of Cr(VI). The enhanced photocatalytic ability of the TiO2-BDD composite could be attributed to the heterojunction. The possible photocatalytic mechanism was also discussed. PMID:18546724

Yu, Hongbin; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

2008-05-15

112

Enhanced photocatalytic performance of direct Z-scheme g-C3N4-TiO2 photocatalysts for the decomposition of formaldehyde in air.  

PubMed

Formaldehyde (HCHO) is a major indoor pollutant and long-term exposure to HCHO may cause health problems such as nasal tumors and skin irritation. Photocatalytic oxidation is considered as the most promising strategy for the decomposition of HCHO. Herein, for the first time, a direct g-C3N4-TiO2 Z-scheme photocatalyst without an electron mediator was prepared by a facile calcination route utilizing affordable P25 and urea as the feedstocks. Photocatalytic activities of the as-prepared samples were evaluated by the photocatalytic oxidation decomposition of HCHO in air. It was shown that the photocatalytic activity of the prepared Z-scheme photocatalysts was highly dependent on the g-C3N4 content. At the optimal g-C3N4 content (sample U100 in this study), the apparent reaction rate constant was 7.36 × 10(-2) min(-1) for HCHO decomposition, which exceeded that of pure P25 (3.53 × 10(-2) min(-1)) by a factor of 2.1. The enhanced photocatalytic activity could be ascribed to the formation of a g-C3N4-TiO2 Z-scheme photocatalyst, which results in the efficient space separation of photo-induced charge carriers. Considering the ease of the preparation method, this work will provide new insights into the design of high-performance Z-scheme photocatalysts for indoor air purification. PMID:23999576

Yu, Jiaguo; Wang, Shuhan; Low, Jingxiang; Xiao, Wei

2013-09-03

113

Synthesis and characterization of Ag deposited TiO2 particles by laser ablation in water  

NASA Astrophysics Data System (ADS)

Ag deposited TiO2 (Ag/TiO2) particles were synthesized by laser ablation of silver and titanium targets in de-ionized (DI) water. Post-annealing makes the structure stable and the materials change to crystalline state. It is a new approach to form Ag/TiO2 particles with a simple system and non-toxic materials. TiO2 particles with size from 20 to 30 nm coated with silver nano-clusters were observed. The silver nano-clusters can enhance the absorption capability of TiO2 photocatalysts. UV-vis spectrum analysis shows that there is a strong absorption peak at around 400 nm. It is attributed to Ag nanoparticles surface plasmon resonance (SPR) effect. This effect helps to improve the spectral characteristics of TiO2 nanoparticles with its absorption spectra shifted to a longer wavelength region. From the above properties, Ag/TiO2 nanoparticles would have new potential applications in photocatalyst and photo-anode.

Liu, C. H.; Hong, M. H.; Zhou, Y.; Chen, G. X.; Saw, M. M.; Hor, A. T. S.

2007-12-01

114

Mechanistic studies of the photocatalytic oxidation of trichloroethylene with visible-light-driven N-doped TiO2 photocatalysts.  

PubMed

Visible-light-driven TiO2 photocatalysts doped with nitrogen have been prepared as powders and thin films in a cylindrical tubular furnace under a stream of ammonia gas. The photocatalysts thus obtained were found to have a band-gap energy of 2.95 eV. Electron spin resonance (ESR) under irradiation with visible light (lambda > or = 430 nm) afforded the increase in intensity in the visible-light region. The concentration of trapped holes was about fourfold higher than that of trapped electrons. Nitrogen-doped TiO2 has been used to investigate mechanistically the photocatalytic oxidation of trichloroethylene (TCE) under irradiation with visible light (lambda > or = 420 nm). Cl and O radicals, which contribute significantly to the generation of dichloroacetyl chloride (DCAC) in the photocatalytic oxidation of TCE under UV irradiation, were found to be deactivated under irradiation with visible light. As the main by-product, only phosgene was detected in the photocatalytic oxidation of TCE under irradiation with visible light. Thus, the reaction mechanism of TCE photooxidation under irradiation with visible light clearly differs markedly from that under UV irradiation. Based on the results of the present study, we propose a new reaction mechanism and adsorbed species for the photocatalytic oxidation of TCE under irradiation with visible light. The energy band for TiO2 by doping with nitrogen may involve an isolated band above the valence band. PMID:16548017

Joung, Soon-Kil; Amemiya, Takashi; Murabayashi, Masayuki; Itoh, Kiminori

2006-07-17

115

Synthesis of Fe2O3\\/TiO2 nanorod nanotube arrays by filling TiO2 nanotubes with Fe  

Microsoft Academic Search

Synthesis of hematite (alpha-Fe2O3) nanostructures on a titania (TiO2) nanotubular template is carried out using a pulsed electrodeposition technique. The TiO2 nanotubes are prepared by the sonoelectrochemical anodization method and are filled with iron (Fe) by pulsed electrodeposition. The Fe\\/TiO2 composite is then annealed in an O2 atmosphere to convert it to Fe2O3\\/TiO2 nanorod-nanotube arrays. The length of the Fe2O3

Susanta K. Mohapatra; Subarna Banerjee; Mano Misra

2008-01-01

116

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).

2011-01-01

117

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

PubMed

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

Velmurugan, Rengasamy; Sreedhar, Bojja; Swaminathan, Meenakshisundaram

2011-07-30

118

Facile synthesis of V 2 O 5 \\/TiO 2 core–shell nanobelts  

Microsoft Academic Search

We report a facile chemical approach for the synthesis of one-dimensional V2O5\\/TiO2 core–shell nanobelts. The coated V2O5 nanobelts are synthesized by a hydrothermal method which is feasible for large-scale production. V2O5 nanobelts coated with a thin layer of TiO2 sol are formed before sintering, and after sintering one-dimensional V2O5\\/TiO2 core–shell nanobelts, composed of single-crystalline V2O5 nanobelts cores uniformly coated with

Shasha Lv; Jie Ding; Hongrui Peng; Guicun Li

2010-01-01

119

The Synthesis of Cadmium Doped Mesoporous TiO2  

SciTech Connect

Cd doped mesoporous titanium oxide was prepared using non-ionic surfactants and easily handled titanium precursors. The Cd doping was found to be able to significantly inhibit the growth of anatase crystal size, stabilize the mesoporous structure, and retard the densification of nanoporous TiO2 at elevated temperatures.

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

2007-06-01

120

Preparation of nanostructured TiO2-based photocatalyst by controlling the calcining temperature and pH  

NASA Astrophysics Data System (ADS)

Nanostructured TiO2 has been synthesized using one-step sol-gel method and characterized by different characterization techniques (SEM, EDS, XRD, and UV-vis spectroscopy). The photocatalytic degradation of methylene blue (MB) and Congo red (CR) is studied with the synthesized TiO2. The photocatalytic degradation data has been validated using several kinetic models. The TiO2 showed efficient photocatalytic degradation performance on MB and CR. In addition to this, the effect of pH on the photocatalytic degradation has been investigated. The TiO2 showed enhanced photocatalytic performance in basic media than that in neutral or acidic ones.

Uddin, Mohammed Jasim; Islam, Md Akhtarul; Haque, Sheikh Ariful; Hasan, Saidul; Amin, Mohammad Shaiful Alam; Rahman, Mohammed Mastabur

2012-08-01

121

Low temperature synthesis of N-doped TiO2 nanocatalysts for photodegradation of methyl orange.  

PubMed

N-doped TiO2 nanoparticles were synthesized using a hydrazine-assisted liquid method at low temperatures, owing to the additional heat provided by the decomposition of hydrazine nitrate, which was formed by reaction of hydrazine with nitric acid. Different crystal phases of N-doped TiO2 were studied by varying the nitric acid concentration, and calcination temperature and time. These photocatalysts were characterized using a transmission electron microscope, UV-vis photometer, X-ray diffractometer, and nitrogen adsorption. Photocatalytic performance of the N-doped TiO2 was studied by testing the degradation of methyl orange under visible irradiation. It was observed that N-doped TiO2 demonstrated much higher photocatalytic performance than commercial TiO2 (P-25) and exhibited excellent reusability. PMID:23755694

Namkhang, Pornpan; An, Woo-Jin; Wang, Wei-Ning; Rane, Koyar S; Kongkachuichay, Paisan; Biswas, Pratim

2013-03-01

122

Supercritical preparation of a highly active S-doped TiO2 photocatalyst for methylene blue mineralization.  

PubMed

Sulfur-modification of the TiO2 was achieved by treating the TiO2 precursor (xerogel) under supercritical conditions in CS2/ethanol fluid. Nuclear magnetic resonance, X-ray photoelectron spectroscopy and Fourier transform infrared spectra demonstrated that the TiO2 was modified by the S-species incorporated into the TiO2 network by forming S-Ti-O bonds rather than by the adsorbed CS2. During liquid-phase photocatalytic degradation of methylene blue (MB) under visible light irradiation (> 420 nm), the as-prepared S-doped TiO2 exhibited much higher activity than the undoped TiO2 obtained via either supercritical treatment or direct calcinations and even the N-doped TiO2 obtained via supercritical treatment. The promoting effects of both the supercritical treatment and S-modification on the photocatalytic activity were discussed by considering the high surface, large porous channels, well crystallized anatase phase, excellent thermal stability, and strong absorbance for visible lights, corresponding to the high quantum efficiency. The maximum activity was obtained at 1.8% S/Ti molar ratio, nearly 8 times higher than that of the commercially available P25 TiO2. PMID:17626444

Li, Hexing; Zhang, Xinyu; Huo, Yuning; Zhu, Jian

2007-06-15

123

Amine functionalized TiO2-carbon nanotube composite: synthesis, characterization and application to glucose biosensing  

NASA Astrophysics Data System (ADS)

The synthesis of amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2-TiO2-CNTs) using sol-gel method was investigated. The synthesized nanocomposite was characterized with XRD, FTIR spectroscopy, BET test and SEM imaging. The results demonstrated a unique nanostructure with no destruction of the CNTs' shape. In addition, the presence of amine groups on the composite surface was confirmed by FTIR. This nanocomposite was used for one-step immobilization of glucose oxidase (GOx) to sense glucose. The result of cyclic voltammetry showed a pair of well-defined and quasi-reversible peaks for direct electron transfer of GOx in the absence of glucose. Also, the result of electrochemical impedance spectroscopy indicated that GOx was successfully immobilized on the surface of NH2-TiO2-CNTs. Furthermore, good amperometric response showed that immobilized GOx on the NH2-TiO2-CNTs exhibits exceptional bioelectrocatalytic activity toward glucose oxidation.

Tasviri, Mahboubeh; Rafiee-Pour, Hossain-Ali; Ghourchian, Hedayatollah; Gholami, Mohammad Reza

2011-12-01

124

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

2011-04-13

125

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

126

Synthesis and characterisation of biologically compatible TiO2 nanoparticles  

PubMed Central

We describe for the first time the synthesis of biocompatible TiO2 nanoparticles containing a functional NH2 group which are easily dispersible in water. The synthesis of water dispersible TiO2 nanoparticles coated with mercaptosuccinic acid is also reported. We show that it is possible to exchange the stearic acid from pre-synthesised fatty acid-coated anatase 5-nm nanoparticles with a range of organic ligands with no change in the size or morphology. With further organic functionalisation, these nanoparticles could be used for medical imaging or to carry cytotoxic radionuclides for radioimmunotherapy where ultrasmall nanoparticles will be essential for rapid renal clearance.

2011-01-01

127

Synthesis and characterisation of biologically compatible TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

We describe for the first time the synthesis of biocompatible TiO2 nanoparticles containing a functional NH2 group which are easily dispersible in water. The synthesis of water dispersible TiO2 nanoparticles coated with mercaptosuccinic acid is also reported. We show that it is possible to exchange the stearic acid from pre-synthesised fatty acid-coated anatase 5-nm nanoparticles with a range of organic ligands with no change in the size or morphology. With further organic functionalisation, these nanoparticles could be used for medical imaging or to carry cytotoxic radionuclides for radioimmunotherapy where ultrasmall nanoparticles will be essential for rapid renal clearance.

Cheyne, Richard W.; Smith, Tim Ad; Trembleau, Laurent; McLaughlin, Abbie C.

2011-06-01

128

Nanostructured AgBr loaded TiO 2 : An efficient sunlight active photocatalyst for degradation of Reactive Red 120  

Microsoft Academic Search

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\\u000a (SEM), energy dispersive spectra (EDS), X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscope\\u000a (AFM) analysis. The results of characterization reveal that AgBr loaded TiO2 has a nanostructure.

Rengasamy Velmurugan; Bojja Sreedhar; Meenakshisundaram Swaminathan

2011-01-01

129

Preparation of S-doped TiO 2 photocatalysts and their photocatalytic activities under visible light  

Microsoft Academic Search

Although titanium dioxide photocatalysts having anatase phase are a promising substrate for photodegradation of pollutants in water and air, their photocatalytic activities show only under ultraviolet (UV) light. For us to utilized a wide range of incident light such as solar light, development of the photocatalysts whose activities show under visible light is one of the most important strategies. We

Teruhisa Ohno; Miyako Akiyoshi; Tsutomu Umebayashi; Keisuke Asai; Takahiro Mitsui; Michio Matsumura

2004-01-01

130

Preparation of visible light active S-doped TiO2 photocatalysts and their photocatalytic activities  

Microsoft Academic Search

Although titanium dioxide photocatalysts having an anatase phase are a promising substrate for photodegradation of pollutants in water and air, their photocatalytic activities show only under UV light. To utilize solar light which has a large amount of visible light, the development of the photocatalysts whose activities show under visible light is one of the most important strategies. We have

T. Ohno

2004-01-01

131

Effects of organic acids on the size-controlled synthesis of rutile TiO 2 nanorods  

Microsoft Academic Search

Size-controlled synthesis of pure rutile-phase TiO2 nanorods was carried out by a hydrothermal method using different organic acids as modifiers, and metatitanic acid and concentrated sulfuric acid as raw materials. The synthesized rutile TiO2 nanorods were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of organic acid modifiers on the sizes of rutile TiO2 nanorods were

Yinhua Jiang; Hengbo Yin; Yueming Sun; Hui Liu; Lixu Lei; Kangmin Chen; Yuji Wada

2007-01-01

132

Effect of transition metal elements addition on the properties of nitrogen-doped TiO2 photocatalysts  

NASA Astrophysics Data System (ADS)

Nitrogen-doped TiO2 (TiO2-xNy) nanoparticles with and without adding the transition metal ions, such as Co+ and Ni+, were synthesized by thermohydrolysis of TiCl3. The samples were characterized by X-ray diffraction, specific surface area determination, UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of the sample was investigated by employing the oxidative destruction of nitric oxide as a probe reaction using a continuously flowing gases-solid system. Although the doping of transition metal ion in the lattice of titania was not useful to improve the photocatlytic activity, loading of transition metal oxides on the surface of titania resulted in an improvement of the photoreactivity of the nitrogen-doped TiO2. The beneficial effect was explained by an increased separation efficiency of the photogenerated electron-hole pairs.

Li, H.; Zhang, P.; Yin, S.; Wang, Y.; Dong, Q.; Guo, C.; Sato, T.

2012-01-01

133

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

134

Synthesis of TiO2 nanoparticles by hydrolysis and peptization of titanium isopropoxide solution  

NASA Astrophysics Data System (ADS)

Here we report the synthesis and characterization of a stable suspension of modified titania nanoparticles. Phase-pure TiO2 nanocrystallites with narrow particle-size distributions were selectively prepared by hydrolysis-peptization of modified alkoxide followed by hydrothermal treatment. Autoclaving modified TiO2 in the presence of HNO3 as cooperative catalysts led to the formation of crystalline TiO2 with narrow-sized distribution. Following the hydrothermal treatment at 150°C, X-ray diffraction shows the particles to be exclusively anatase. Synthesized powder is characterized by FT-IR, scanning electron microscopy (FESEM) and transmission electron microscopy (HRTEM). The photocatalytic activity in the degradation of orange-II is quite comparable to good anatase and rutile nanocrystallites.

Mahata, S.; Mahato, S. S.; Nandi, M. M.; Mondal, B.

2012-07-01

135

Boron and nitrogen-codoped TiO2 nanorods: Synthesis, characterization, and photoelectrochemical properties  

NASA Astrophysics Data System (ADS)

Boron and nitrogen codoped TiO2 nanorods (BNTRs) were synthesized via two-step hydrothermal reactions using TiN as a starting material. The as-prepared samples were characterized by X-ray diffraction, field-emission scanning electron microscope (SEM), transmission electron microscopy and X-ray photoelectron spectroscopy techniques. The results showed that TiO2 nanorods with the diameter of approximately 50-100 nm and the length of several micrometers were doped by the interstitial N and B. The nanorods were firstly formed in the hydrothermal synthesis of nitrogen doped TiO2. The growing process of nanorods was observed by SEM and a most probable formation mechanism of the trititanate nanorods was proposed. The BNTRs showed a higher photocatalytic activity and a bigger photocurrent response than N-TiO2 nanorods under visible light irradiation.

Zhou, Xiaosong; Peng, Feng; Wang, Hongjuan; Yu, Hao

2011-11-01

136

Ionic-liquid-assisted synthesis of uniform fluorinated B/C-codoped TiO2 nanocrystals and their enhanced visible-light photocatalytic activity.  

PubMed

Exploiting advanced photocatalysts under visible light is of primary significance for the development of environmentally relevant photocatalytic decontamination processes. In this study, the ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate, was employed for the first time as both a structure-directing agent and a dopant for the synthesis of novel fluorinated B/C-codoped anatase TiO(2) nanocrystals (T(IL)) through hydrothermal hydrolysis of tetrabutyl titanate. These T(IL) nanocrystals feature uniform crystallite and pore sizes and are stable with respect to phase transitions, crystal ripening, and pore collapse upon calcination treatment. More significantly, these nanocrystals possess abundant localized states and strong visible-light absorption in a wide range of wavelengths. Because of synergic interactions between titania and codopants, the calcined T(IL) samples exhibited high visible-light photocatalytic activity in the presence of oxidizing Rhodamine?B (RhB). In particular, 300?°C-calcined T(IL) was most photocatalytically active; its activity was much higher than that of TiO(1.98)N(0.02) and reference samples (T(W)) obtained under identical conditions in the absence of ionic liquid. Furthermore, the possible photocatalytic oxidation mechanism and the active species involved in the RhB degradation photocatalyzed by the T(IL) samples were primarily investigated experimentally by using different scavengers. It was found that both holes and electrons, as well as their derived active species, such as (·)OH, contributed to the RhB degradation occurring on the fluorinated B/C-codoped TiO(2) photocatalyst, in terms of both the photocatalytic reaction dynamics and the reaction pathway. The synthesis of the aforementioned novel photocatalyst and the identification of specific active species involved in the photodegradation of dyes could shed new light on the design and synthesis of semiconductor materials with enhanced photocatalytic activity towards organic pollutants. PMID:23297253

Yu, Jiaguo; Li, Qin; Liu, Shengwei; Jaroniec, Mietek

2013-01-07

137

Synergistic effects of sulfation and co-doping on the visible light photocatalysis of TiO 2  

Microsoft Academic Search

Sol–gel synthesis and sulfation process has been carried out to prepare Fe3+\\/Zn2+ co-doped and SO42? impregnated TiO2 photocatalysts. The aim of the present investigation is to improve the visible light photocatalytic activity of TiO2 using (i) co-doping with transition metal species, Fe3+\\/Zn2+ and (ii) sulfur impregnation procedures. Structural (XRD) characteristics of SO42? impregnated TiO2 reveals the presence of anatase nanoparticles

Sesha S. Srinivasan; Jeremy Wade; Elias K. Stefanakos; Yogi Goswami

2006-01-01

138

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

139

Preparation, characterization and visible-light-driven photocatalytic activity of Fe-incorporated TiO2 microspheres photocatalysts  

NASA Astrophysics Data System (ADS)

Fe incorporated TiO2 microspheres (Fe-TiO2) were prepared by integrating the sol-gel method and impregnating-calcination method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy indicated that ?-Fe2O3 nanoparticles were deposited onto the TiO2 microspheres, and in the mean time, some Fe3+ ions were doped into TiO2 lattice. The absorption of Fe-TiO2 microspheres in the visible light region increased with the increasing of Fe content. Photoluminescence (PL) analyses further confirmed that Fe-incorporation effectively promoted the separation and transfer of photogenerated charge carriers, which can improve the photocatalytic activity of the samples. The photocatalytic activity of Fe-TiO2 microspheres was evaluated by the degradation of methylene blue aqueous solution under visible light irradiation. The results demonstrated that the Fe-TiO2 microspheres exhibited significantly enhanced photocatalytic activity compared with pure TiO2 microspheres. What is more, the charge-transfer processes in Fe-TiO2 were also discussed.

Li, Jun-Qi; Wang, De-Fang; Guo, Zhan-Yun; Zhu, Zhen-Feng

2012-12-01

140

Morphology of a TiO 2 Photocatalyst (Degussa, P-25) Consisting of Anatase and Rutile Crystalline Phases  

Microsoft Academic Search

The TiO2 powder (Degussa, P-25), which is a standard material in the field of photocatalytic reactions, contains anatase and rutile phases in a ratio of about 3 : 1. Transmission electron microscopy showed that the anatase and rutile particles separately form their agglomerates. The average sizes of the anatase and rutile elementary particles are 85 and 25 nm, respectively. Diffuse

Teruhisa Ohno; Koji Sarukawa; Kojiro Tokieda; Michio Matsumura

2001-01-01

141

Photocatalytic activity of N-doped TiO 2 : photocatalytic synthesis of o -aminophenol at room temperature  

Microsoft Academic Search

The photocatalytic synthesis of o-aminophenol in methanol was investigated with N-doped TiO2 nanoparticles under UV-light irradiation. The catalytic quantities of N-doped TiO2 prepared by a simple modified sol–gel process with urea as nitrogen source rapidly reduced o-nitrophenol to the corresponding amine at room temperature.

Hu-qun Wang; Jun-ping Yan; Zhi-min Zhang; Wen-fu Chang

2009-01-01

142

Synthesis of anatase TiO2 nanocrystals with exposed {001} facets.  

PubMed

This paper reports a facile synthesis of anatase TiO(2) nanocrystals with exposed, chemically active {001} facets. The nanocrystals were prepared by digesting electrospun nanofibers consisting of amorphous TiO(2) and poly(vinyl pyrrolidone) with an aqueous acetic acid solution (pH = 1.6), followed by hydrothermal treatment at 150 degrees C for 20 h. The as-obtained nanocrystals exhibited a truncated tetragonal bipyramidal shape with 9.6% of the surface being enclosed by {001} facets. The use of electrospinning is critical to the success of this synthesis as it allows for the generation of very small particles of amorphous TiO(2) to facilitate hydrothermal crystallization, an Ostwald ripening process. The morphology of the nanocrystals had a strong dependence on the pH value of the solution used for hydrothermal treatment. Low pH values tended to eliminate the {001} facets by forming sharp corners while high pH values favored the formation of a rodlike morphology through an oriented attachment mechanism. When acetic acid was replaced by inorganic acids, the TiO(2) nanocrystals further aggregated into larger structures with various morphologies. PMID:19438191

Dai, Yunqian; Cobley, Claire M; Zeng, Jie; Sun, Yueming; Xia, Younan

2009-06-01

143

Design of N-doped anatase TiO2 photocatalyst with visible-light-response based on Ti-O bond weakening  

NASA Astrophysics Data System (ADS)

Nitrogen bulk doping is an effective strategy to change the electronic structures of anatase TiO2 photocatalyst for visible light response improvement. Unfortunately, it is hard to achieve nitrogen bulk doping in practice, due to both limited thermodynamic solubility of substitutional nitrogen and N-induced recombination centers. It remains challenging yet highly desirable to develop new doping approach to increase nitrogen solubility in bulk. This challenge is originally stemmed from both strong Ti-O bond and charge difference (O^2- versus N^3-) between lattice oxygen and nitrogen dopant. In this work, we propose a new doping approach to promote the bulk substitution of lattice oxygen with nitrogen in bulk anatase TiO2, based on the Ti-O bond weakening by pre-implanted interstitial boron.^1 By using the first-principles calculations, we study the interstitial boron induced Ti-O bonding weakening and the thermodynamics/kinetics changes for nitrogen bulk doping.^2 In experiment, we realize to synthesize a bulk gradient B-N co-doping red anatase TiO2 microsphere which has an extended absorption edge up to ca. 700 nm covering the full visible light spectrum and has a bandgap varying from 1.94 eV on its surface to 3.22 eV in its core by gradually elevating VBM. This approach could be extended to modify other electronic materials that demand bulk substitutional doping. 1. G. Liu, J. Pan, L. C. Yin et al., Adv. Funct. Mater., 2012, 22, 3233. 2. G. Liu, L. C. Yin, J. Q. Wang et al., Energy Environ. Sci. 2012, 5, 9603.

Yin, L.-C.; Liu, G.; Cheng, H.-M.

2013-03-01

144

A multifunctional biocide/sporocide and photocatalyst based on titanium dioxide (TiO2) codoped with silver, carbon, and sulfur.  

PubMed

Composite nanostructured samples of Ag (0.5-20%)/(C, S)-TiO(2) were synthesized and characterized by EDX, XRD, FT-IR, UV-vis, BET, XPS, and zeta potential measurements. Photocatalytic and biocidal tests revealed that the amount of the codoped silver (Ag(+)) in (C, S)-TiO(2) played a crucial, distinctive role in the photodegradation of gas-phase acetaldehyde as well as in the inactivation of Escherichia coli cells and Bacillus subtilis spores. Very interestingly, Ag/(C, S)-TiO(2) nanoparticles (crystallite size <10 nm) have shown very strong antimicrobial properties without light activation against both E. coli (log kill >8) and B. subtilis spores (log kill >5) for 30 min exposures, compared with P25-TiO(2). Thus, for the first time, we have demonstrated that titanium dioxide (an environmentally friendly photocatalyst) codoped with silver, carbon, and sulfur can serve as a multifunctional generic biocide as well as a visible light activated photocatalyst. PMID:20141214

Hamal, Dambar B; Haggstrom, Johanna A; Marchin, George L; Ikenberry, Myles A; Hohn, Keith; Klabunde, Kenneth J

2010-02-16

145

Synthesis and Li-ion Insertion Properties of Highly Crystalline Mesoporous Rutile TiO2  

SciTech Connect

Mesoporous TiO2 has attracted great attention as a promising Li insertion electrode material with improved cycling life, rate capability and high power density. Up to date, mesoporous anatase TiO2 has been investigated for Li insertion. Recent studies have shown that nanosized rutile could be an excellent candidate for anode materials for higher Li insertion capacity and improved stability. However, synthesis of highly crystalline mesoporous rutile has met with limited success so far. There has been no report on Li insertion of mesoporous rutile TiO2. In this paper, we report a new low-temperature solution growth of TiO2 nanocrystals within an anionic surfactant matrix to produce highly crystalline mesoporous rutile and investigate Li insertion properties of the mesoporous crystalline rutile. X-ray diffraction (XRD) patterns and N2 sorption isotherms reveal mesoporous structure in the highly crystalline mesoporous TiO2 directly results from the anionic surfactant templating effects with high surface area (245~300 m2/g) and tunable mesopore diameter ranging from 2.2 to 3.8 nm after calcination. Transmission electron microscopy (TEM) measurements show that framework of the highly crystalline mesoporous TiO2 are composed of aligned rutile nanorod building blocks grown along [001] direction. The new mesoporous crystalline rutile can accommodate more than 0.7 Li (Li0.7TiO2, 235 mAh/g) during the first discharge at C/5 rate between 1–3 V versus Li+/Li, with a reversible capacity of 0.55 Li (Li0.55TiO2, 185 mAh/g). The mesoporous crystalline rutile shows excellent capacity retention with less than 10% capacity loss after over 100 cycles. XRD and TEM characterization on electrochemically lithiated sample show that the rutile nanorods were transformed into cubic rocksalt LiTiO2 nanorods, but the mesostructures remained stable after the phase transformation and cycling. Furthermore, the crystalline mesoporous rutile may also have good potentials for other applications such as stable catalyst supports.

Wang, Donghai; Choi, Daiwon; Yang, Zhenguo; Viswanathan, Vilayanur V.; Nie, Zimin; Wang, Chong M.; Song, Yujiang; Zhang, Jiguang; Liu, Jun

2008-05-27

146

Sol–gel-derived super-hydrophilic nickel doped TiO 2 film as active photo-catalyst  

Microsoft Academic Search

Pure and nickel doped TiO2 thin films on soda glass substrates were prepared by sol–gel dip coating process. The resulting films were annealed at 500°C for 1h and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and UV–vis-near IR techniques. AFM reveals that doping of Ni ions suppresses the grain growth of crystal in the

Sunil Dutta Sharma; Davinder Singh; K. K. Saini; Chander Kant; Vikash Sharma; S. C. Jain; C. P. Sharma

2006-01-01

147

Photocatalytic degradation of volatile organic compounds at the gas–solid interface of a TiO 2 photocatalyst  

Microsoft Academic Search

In the present work, photocatalytic degradation of volatile organic compounds including gas-phase trichloroethylene (TCE), acetone, methanol and toluene over illuminated TiO2 was closely examined in a batch photoreactor as a function of water vapor, molecular oxygen and reaction temperature. Water vapor enhanced the photocatalytic degradation rate of toluene, but was inhibitive for acetone, and, there was an optimum water vapor

Sang Bum Kim; Hyun Tae Hwang; Sung Chang Hong

2002-01-01

148

Combined photooxidation/photoreduction using TiO2 photocatalysts to treat organic/inorganic metal-laden wastewaters.  

National Technical Information Service (NTIS)

Titanium dioxide (TiO(sub 2)) colloids prepared from titanium chloride (TiCl(sub 4)) were used as photocatalysts in the experiments. Cysteine was selected as the model derivative for the surface modification of the TiO(sub 2) nanoparticles. Testing of TiO...

R. W. Peters J. M. Wu N. Meshkov M. C. Thurnauer A. E. Ostafin

1995-01-01

149

Degradation of phenol and benzoic acid in the presence of a TiO 2-based heterogeneous photocatalyst  

Microsoft Academic Search

This paper reports the results of a study on the titanium dioxide Wackherr's “Oxyde de titane standard”, which shows very interesting photocatalytic activity. Produced for cosmetic purposes as a white pigment, its features make it very interesting in the field of heterogeneous photocatalysis. The results obtained with this photocatalyst are compared with the behaviour of the well-studied and widely used

Davide Vione; Claudio Minero; Valter Maurino; M. Eugenia Carlotti; Tatiana Picatonotto; Ezio Pelizzetti

2005-01-01

150

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

151

Synthesis of TiO2 Nanoparticle and its phase Transition  

NASA Astrophysics Data System (ADS)

Here we report the synthesis of titanium dioxide (TiO2) nanoparticles and study of its phase transition from anataze to rutile. Titanium dioxide (TiO2) nanoparticles have been prepared by hydrolysis of Titanium isopropoxide an aqueous solution with constant value of pH 2 and peptizing the resultant suspension gel(white-Blue) and calcinate gel at different temperature. Structures of synthetic samples of TiO2 have been examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). The anatase-rutile transition has been a popular topic due to its interest to scientific and engineering fields. . Here we have seen that the 100 °C calcinate powder consist of anatase fine crystalline phase with a particle size 14 to 15 nm. The prepared TiO2 nanoparticles have uniform size and morphology, and the phase transformation kinetics of obtained material was studied by interpretation of the X-ray diffraction patterns peaks. The phase transform occurred from anatase to rutile at calcinate temperature up to 600 °C. A very fine network texture made from uniform nanoparticles was revealed by scanning electron microscopy (SEM) analyses.

Mangrola, M. H.; Joshi, V. G.; Parmar, B. H.

2011-12-01

152

Ultrasonically Activated Hydrothermal Synthesis of Fine TiO 2 and ZrO 2 Powders  

Microsoft Academic Search

Fine TiO2 and ZrO2 powders were prepared by hydrothermal synthesis at 150 and 250°C (10 min, 1 h, 3 h) from aqueous titanyl and zirconyl salts and amorphous titanyl and zirconyl hydroxide gels with and without ultrasonic activation. The synthesized materials were characterized by x-ray diffraction, scanning and transmission electron-microscopic techniques, and nitrogen capillary adsorption measurements. The results demonstrate that

P. E. Meskin; A. E. Baranchikov; V. K. Ivanov; D. R. Afanas'ev; A. I. Gavrilov; B. R. Churagulov; N. N. Oleinikov

2004-01-01

153

Ultrasound with low intensity assisted the synthesis of nanocrystalline TiO 2 without calcination  

Microsoft Academic Search

A novel method has been developed for the preparation of nano-sized TiO2 with anatase phase. Nanoparticles with diameter about 6nm were prepared at a relatively low temperature (75°C) and short time. The synthesis was carried out by the hydrolysis of titanium tetra-isopropoxide (TTIP) in the presence of water, ethanol, and dispersant under ultrasonic irradiation (500kHz) at low intensity. The results

Narjes Ghows; Mohamad H. Entezari

2010-01-01

154

Combustion synthesis and EIS characterization of TiO 2–SnO 2 system  

Microsoft Academic Search

TiO2 is an insulator, but using specific dopants, can modify sharply its electronic structure towards semiconducting behavior. This type of response is widely applied in many electrochemical and electrocatalytical devices, namely chlorine production, hydrocarbon oxidation, CO and CO2 hydrogenation and as electroactive substrata for biological cell growth.Combustion synthesis is a very simple, rapid and clean method for material preparation, which

E. Chinarro; B. Moreno; J. R. Jurado

2007-01-01

155

Solvothermal synthesis of carbon coated N-doped TiO2 nanostructures with enhanced visible light catalytic activity  

NASA Astrophysics Data System (ADS)

Visible light-active carbon coated N-doped TiO2 nanostructures(CTS-TiO2) were prepared by a facile one-step solvothermal method with chitosan as carbon and nitrogen resource at 180 °C. The as-prepared samples were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. The CTS-TiO2 nanocomposites possess anatase phase of nanocrystalline structure with average particle size of about 5-7 nm. A wormhole mesostructure can be observed in the CTS-TiO2 nanocomposites due to the constituent agglomerated of nanoparticles. It has been evidenced that the nitrogen was doped into the anatase titania lattice and the carbon species were modified on the surface of TiO2. The photocatalytic activities of the as-prepared photocatalysts were measured by the degradation of methylene blue (MB) under visible light irradiation at ? ? 400 nm. The results show that CTS-TiO2 nanostructures display a higher visible light photocatalytic activity than pure TiO2, commercial P25 and C-coated TiO2 (C-TiO2) photocatalysts. The higher photocatalytic activity could be attributed to the band-gap narrowed by N-doping and the accelerated separation of the photo-generated electrons and holes by carbon modification.

Yan, Xue-Min; Kang, Jialing; Gao, Lin; Xiong, Lin; Mei, Ping

2013-01-01

156

Synthesis and characterisation of Gd 3+-doped mesoporous TiO 2 materials  

NASA Astrophysics Data System (ADS)

Using multi-walled carbon nano-tubes (MWNTs) as the template, Gd 3+-doped mesoporous TiO 2 (M-TiO 2) material was prepared by the homogeneous precipitation-assisted template method. The as-prepared photo-catalysts were characterised using X-ray diffraction, scanning electron microscopy, nitrogen adsorption/desorption and ultraviolet-visible (UV-vis) diffuse-reflection spectroscopy analyses. The photo-catalytic properties of Gd 3+-doped M-TiO 2 were primarily investigated by the photo-degradation of methyl orange under Xe-lamp irradiation and compared with those of pure M-TiO 2 and the commercial photo-catalyst Degussa P25. The results showed that the as-synthesised samples were of anatase crystalline phase and had red shifts in their UV-vis patterns with different Gd 3+-doping concentrations. Gd 3+-adding at 0.12 mol% could significantly enhance the photo-catalytic properties of the M-TiO 2 material and the rate of photo-degradation of methyl orange reached 97.3% under Xe-lamp irradiation for 150 min.

Lv, Caixia; Zhou, Yi; Li, Hong; Dang, Mingming; Guo, Changchun; Ou, Yancong; Xiao, Bin

2011-03-01

157

Hydrothermal doping method for preparation of Cr 3+-TiO 2 photocatalysts with concentration gradient distribution of Cr 3+  

Microsoft Academic Search

Cr3+-doped anatase titanium dioxide photocatalysts were prepared by the combination of sol–gel process with hydrothermal treatment. The samples were characterized by UV–vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area (SBET), transmission electron microscopy (TEM), atomic absorption flame emission spectroscopy (AAS), electron paramagnetic resonance (EPR) spectroscopy and X-ray photoelectron spectroscopy (XPS). It was confirmed that Cr substitutes

Jiefang Zhu; Zhigang Deng; Feng Chen; Jinlong Zhang; Haijun Chen; Masakazu Anpo; Jiazhen Huang; Lizhong Zhang

2006-01-01

158

Recent advances in visible-light-responsive photocatalysts for hydrogen production and solar energy conversion--from semiconducting TiO2 to MOF/PCP photocatalysts.  

PubMed

The present perspective describes recent advances in visible-light-responsive photocatalysts intended to develop novel and efficient solar energy conversion technologies, including water splitting and photofuel cells. Water splitting is recognized as one of the most promising techniques to convert solar energy as a clean and abundant energy resource into chemical energy in the form of hydrogen. In recent years, increasing concern is directed to not only the development of new photocatalytic materials but also the importance of technologies to produce hydrogen and oxygen separately. Photofuel cells can convert solar energy into electrical energy by decomposing bio-related compounds and livestock waste as fuels. The advances of photocatalysts enabling these solar energy conversion technologies have been going on since the discovery of semiconducting titanium dioxide materials and have extended to organic-inorganic hybrid materials, such as metal-organic frameworks and porous coordination polymers (MOF/PCP). PMID:23760469

Horiuchi, Yu; Toyao, Takashi; Takeuchi, Masato; Matsuoka, Masaya; Anpo, Masakazu

2013-08-28

159

Graphite-like carbon deposited anatase TiO 2 single crystals as efficient visible-light photocatalysts  

Microsoft Academic Search

Graphite-like carbon deposited single-crystal anatase TiO2 with exposed {001} facets was fabricated through a two-step solvothermal process by using glucose as carbon source. The physicochemical\\u000a properties of the as-prepared samples were investigated by X-ray diffraction, Brunauer-Emmett-Teller, transmission electron\\u000a microscopy, Raman, UV–vis diffuse reflectance spectra, electrochemical impedance spectroscopy and surface photovoltage spectroscopy.\\u000a These results demonstrated that graphite-like carbon layers were deposited

Dieqing ZhangXiaolei; Xiaolei Yang; Jian Zhu; Ya Zhang; Peng Zhang; Guisheng Li

2011-01-01

160

Characteristics of doped TiO 2 photocatalysts for the degradation of methylene blue waste water under visible light  

Microsoft Academic Search

Fe-doped, N-doped, (Fe,N)-codoped and undoped TiO2 were prepared by a hydrothermal treatment, followed by a calcination process, using TiOSO4, CO(NH2)2 and Fe(NO3)3 as raw materials. The samples were characterized by XRD, XPS, TEM, PL, FT-IR and UV-Vis diffuse reflectance spectra. Photocatalytic experiments were carried out by decomposition of methylene blue aqueous solution under visible light. It was found that as-prepared

Zhongqing Liu; Yicao Wang; Wei Chu; Zhenhua Li; Changchun Ge

2010-01-01

161

Simultaneous amination of TiO2 nanoparticles in the gas phase synthesis for bio-medical applications  

Microsoft Academic Search

A simultaneous synthesis and surface amination method to effectively modify the surface of inorganic nanoparticles is discussed in this study. As a target material system and surface functional group, TiO2 nanoparticles and amine were selected. APTES (3-aminopropyltriethoxysilane), the source of amine group, was mixed with TTIP (titanium tetraisopropoxide) and used for the synthesis of aminated TiO2 nanoparticles. XRD (X-ray diffractometry)

Kyoung-No Lee; Yangeon Kim; Chang-Woo Lee; Jai-Sung Lee

2011-01-01

162

Synthesis Of Silver Sulfide Stratified Photocatalyst  

SciTech Connect

In this report, silver sulfide (Ag{sub 2}S) was selected as a new H{sub 2}S splitting photocatalyst material, and considered the synthesis method of Ag{sub 2}S photocatalyst particles with stratified structure. Previous stratified particles were synthesized by using metal oxide (hydroxide) as the precursor. Ag{sub 2}O particles as the precursor of Ag{sub 2}S were synthesized by mixing AgNO{sub 3} solution and NaOH, and their particle sizes could be controlled by the solutions' concentration. Then, Ag{sub 2}S particles were obtained by adding Na{sub 2}S solution into suspending solution of Ag{sub 2}O particles with optimum sizes. Particle sizes of Ag{sub 2}S were changed by Na{sub 2}S concentration control, and remaining Ag{sub 2}O precursor could be dissolved by adding NH{sub 3} solution. The photocatalytic H{sub 2}S splitting could be realized by UV-light irradiation on the Ag{sub 2}S particles without co-catalyst like Pt.

Baba, Y.; Yokoyama, S.; Takahashi, H.; Tohji, K. [Graduate School of Environmental Studies Tohoku University, 6-6-20 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi-ken 980-8579 (Japan)

2008-02-25

163

A rapid method for the synthesis of nitrogen doped TiO2 nanoparticles for photocatalytic hydrogen generation.  

PubMed

A facile, fast, and economic method of doping TiO2, synthesized by conventional precipitation route with N has been developed. By this method, stable N doped TiO2 can be prepared within a short duration of time. The method adopted was to treat the TiO2 powder synthesized by simple precipitation with trioctyl amine (TOA) at 320 degrees C for 2 hours followed by calcination at 400 degrees C for 2 hours to obtain the N-doped TiO2. The sample along with NiO as co-catalyst showed significant photocatalytic activity for hydrogen generation from aqueous methanol solution under sunlight type irradiation. This synthesis method opens up a fast and easy route for doping the existing TiO2 or other wide band gap oxide semiconductors with nitrogen so that they can exhibit enhanced photocatalytic activity under solar irradiation. PMID:19928131

Jayakumar, Onattu Damodaran; Sasikala, Rajamma; Betty, Chirayath Antony; Tyagi, Avesh Kumar; Bharadwaj, Shyamala Rajkumar; Gautam, Ujjal Kumar; Srinivasu, Pavuluri; Vinu, Ajayan

2009-08-01

164

Effects of organic acids on the size-controlled synthesis of rutile TiO2 nanorods  

NASA Astrophysics Data System (ADS)

Size-controlled synthesis of pure rutile-phase TiO2 nanorods was carried out by a hydrothermal method using different organic acids as modifiers, and metatitanic acid and concentrated sulfuric acid as raw materials. The synthesized rutile TiO2 nanorods were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of organic acid modifiers on the sizes of rutile TiO2 nanorods were investigated. It was found that the steric effect occurred by the organic modifiers and non-polarity of organic acids were beneficial to the formation of small-sized rutile TiO2 nanorods. The strongly coordinative interaction between the carboxyl (or hydroxyl) group of the modifier and the surface of TiO2 nanoparticles effectively inhibited the crystal growth.

Jiang, Yinhua; Yin, Hengbo; Sun, Yueming; Liu, Hui; Lei, Lixu; Chen, Kangmin; Wada, Yuji

2007-09-01

165

Hierarchical TiO2 nanospheres with dominant {001} facets: facile synthesis, growth mechanism, and photocatalytic activity.  

PubMed

Hierarchical TiO(2) nanospheres with controlled surface morphologies and dominant {001} facets were directly synthesized from Ti powder by a facile, one-pot, hydrothermal method. The obtained hierarchical TiO(2) nanospheres have a uniform size of 400-500?nm and remarkable 78?% fraction of {001} facets. The influence of the reaction temperature, amount of HF, and reaction time on the morphology and the exposed facets was systematically studied. A possible growth mechanism speculates that Ti powder first dissolves in HF solution, and then flowerlike TiO(2) nanostructures are formed by assembly of TiO(2) nanocrystals. Because of the high concentration of HF in the early stage, these TiO(2) nanostructures were etched, and hollow structures formed on the surface. After the F(-) ions were effectively absorbed on the crystal surfaces, {001} facets appear and grow steadily. At the same time, the {101} facets also grow and meet the {101} facets from adjacent truncated tetragonal pyramids, causing coalescence of these facets and formation of nanospheres with dominant {001} facets. With further extension of the reaction time, single-crystal {001} facets of hierarchical TiO(2) nanospheres are dissolved and TiO(2) nanospheres with dominant {101} facets are obtained. The photocatalytic activities of the hierarchical TiO(2) nanospheres were evaluated and found to be closely related to the exposed {001} facets. Owing to the special hierarchical architecture and high percentage of exposed {001} facets, the TiO(2) nanospheres exhibit much enhanced photocatalytic efficiency (almost fourfold) compared to P25 TiO(2) as a benchmark material. This study provides new insight into crystal-facet engineering of anatase TiO(2) nanostructures with high percentage of {001} facets as well as opportunities for controllable synthesis of 3D hierarchical nanostructures. PMID:22499525

Li, Hongmei; Zeng, Yangsu; Huang, Tongcheng; Piao, Lingyu; Yan, Zijie; Liu, Min

2012-04-12

166

Low-temperature solvothermal synthesis of visible-light-responsive S-doped TiO2 nanocrystal  

NASA Astrophysics Data System (ADS)

In this work, a low-temperature solvothermal method has been developed to synthesize visible-light-responsive S-doped TiO2 nanocrystal photocatalyst, using thiourea as the sulfur source to enhance sulfur incorporation into TiO2 lattice. The effects of different S:Ti molar ratio on the crystal structure, chemical composition, surface property and catalytic performance have been studied. X-ray photoelectron spectroscopy (XPS) analysis and Fourier transform infrared (FT-IR) spectra displayed that the TiO2 was modified by the S element incorporated into the TiO2 network to form TiOS bond, which therefore led to the formation of intermediate energy level just above the O 2p valance band, and caused the absorption edge of TiO2 to shift into the visible light region up to 500 nm. Characterization results show that the pure nanocrystal anatase structure, with both the degree of S doping and oxygen vacancies makes contribution to the exceptional photocatalytic activity of TONS in visible-light degradation of Methylene Blue (MB) and phenol molecules.

Yang, Guidong; Yan, Zifeng; Xiao, Tiancun

2012-02-01

167

Synthesis and Characterization of Filtered-cathodic-vacuum-arc-deposited TiO2 Films for Photovoltaic Applications  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) is well-known as a photovoltaic and photocatalytic material. For improvement in the dye-sensitized solar cell (DSSC) performance efficiency, the photocatalyst TiO2 layer would be desired in nanoporous anatase. In this research, TiO2 films were synthesized on glass or p-type silicon substrate using our in-house Filtered Cathodic Vacuum Arc Deposition (FCVAD) system. The deposition was operated at varied oxygen (O2) partial pressures of 10-4, 10-3, 10-2 to 10-1 torr with fixed 0 or 250-V bias and 600-V arc for 10 or 20 minutes. The film transparency increased with increasing of the O2 pressure, indicating increase in the structure required for applications in dye-sensitized solar cells. The films were characterized using the Energy-Dispersive X-ray spectroscopy (EDS) and Raman spectroscopy techniques. The EDS confirmed that the transparent deposited films contained stoichiometric titanium and oxygen under the medium O2 pressure. Raman spectra confirmed that the films were TiO2 containing some rutile but no anatase which needed annealing to form. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used for evaluation of the film's surface morphology and thickness. The result showed that increasing of the O2 pressure decreased the thickness to a nanoscale but increased the amount of TiO2.

Aramwit, C.; Intarasiri, S.; Bootkul, D.; Tippawan, U.; Supsermpol, B.; Seanphinit, N.; Ruangkul, W.; Yu, L. D.

2013-04-01

168

Characterization and activity of visible-light-driven TiO 2 photocatalyst codoped with lanthanum and iodine  

Microsoft Academic Search

The novel visible-light-activated La\\/I\\/TiO2 nanocomposition photocatalyst was successfully synthesized using precipitation-dipping method, and characterized by X-ray powder diffraction (XRD), the Brunauer–Emmett–Teller (BET) method, transmission electron microscopy (TEM), thermogravimetry-differential scanning calorimetry (TG–DSC) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The photocatalytic activity of La\\/I\\/TiO2 was evaluated by studying photodegradation of reactive blue 19 as a probe reaction under simulated sunlight irradiation.

Ling Li; Huisheng Zhuang; Dan Bu

2011-01-01

169

A facile one-step solvothermal synthesis of graphene/rod-shaped TiO2 nanocomposite and its improved photocatalytic activity  

NASA Astrophysics Data System (ADS)

Graphene sheets were obtained through solvothermal reduction of colloidal dispersion of graphene oxide in benzyl alcohol. The graphene/rod-shaped TiO2 nanocomposite was synthesized by this novel and facile solvothermal method. During the solvothermal reaction, both the reduction of graphene oxide and the growth of rod-shaped TiO2 nanocrystals as well as its deposition on graphene occur simultaneously. The photocatalytic activity of graphene/rod-shaped TiO2 and graphene/spherical TiO2 nanocomposites was compared. In the photocatalytic degradation of methyl orange (MO), the graphene/rod-shaped TiO2 nanocomposite with the optimized graphene content of 0.48 wt% shows good stability and exhibits a significant enhancement of photocatalytic activity compared to the bare commercial TiO2 (P25) and graphene/spherical TiO2 nanocomposite with the same graphene content. Photocurrent experiments were performed, which demonstrate that the photocurrent of the graphene/rod-shaped TiO2 nanocomposite electrode is about 1.2 times as high as that of the graphene/spherical TiO2 nanocomposite electrode. The photocatalytic mechanism of graphene/rod-shaped TiO2 nanocomposite was also discussed on the basis of the experimental results. This work is anticipated to open a possibility in the integration of graphene and TiO2 with various morphologies for obtaining high-performance photocatalysts in addressing environmental protection issues.Graphene sheets were obtained through solvothermal reduction of colloidal dispersion of graphene oxide in benzyl alcohol. The graphene/rod-shaped TiO2 nanocomposite was synthesized by this novel and facile solvothermal method. During the solvothermal reaction, both the reduction of graphene oxide and the growth of rod-shaped TiO2 nanocrystals as well as its deposition on graphene occur simultaneously. The photocatalytic activity of graphene/rod-shaped TiO2 and graphene/spherical TiO2 nanocomposites was compared. In the photocatalytic degradation of methyl orange (MO), the graphene/rod-shaped TiO2 nanocomposite with the optimized graphene content of 0.48 wt% shows good stability and exhibits a significant enhancement of photocatalytic activity compared to the bare commercial TiO2 (P25) and graphene/spherical TiO2 nanocomposite with the same graphene content. Photocurrent experiments were performed, which demonstrate that the photocurrent of the graphene/rod-shaped TiO2 nanocomposite electrode is about 1.2 times as high as that of the graphene/spherical TiO2 nanocomposite electrode. The photocatalytic mechanism of graphene/rod-shaped TiO2 nanocomposite was also discussed on the basis of the experimental results. This work is anticipated to open a possibility in the integration of graphene and TiO2 with various morphologies for obtaining high-performance photocatalysts in addressing environmental protection issues. Electronic supplementary information (ESI) available: The TEM images of as-prepared pure rod-shaped TiO2 nanocrystals and the other graphene/rod-shaped TiO2 nanocomposites, the MO adsorption isotherms, the XRD pattern, TEM image and UV-vis diffuse reflectance spectrum of graphene/spherical TiO2 nanocomposite with the graphene content of 0.48 wt%, photocatalytic degradation of MO solution over graphene/spherical TiO2 nanocomposites, and plots of ln(C0/C) versus irradiation time for graphene/rod-shaped TiO2 and graphene/spherical TiO2 nanocomposites. See DOI: 10.1039/c2nr31231j

Dong, Pengyu; Wang, Yuhua; Guo, Linna; Liu, Bin; Xin, Shuangyu; Zhang, Jia; Shi, Yurong; Zeng, Wei; Yin, Shu

2012-07-01

170

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

171

Hydrothermal synthesis of ordered single-crystalline rutile TiO2 nanorod arrays on different substrates  

NASA Astrophysics Data System (ADS)

We report the mild hydrothermal synthesis of single-crystalline rutile TiO2 nanorod arrays (NRAs). The method reported here shows great versatility and can be used to grow TiO2 NRAs on a large diversity of substrates including Si, Si/SiO2, sapphire, Si pillars, and fluorine doped tin oxide (FTO)-covered glass. The average diameter and length of the nanorods prepared at typical conditions are ~60 nm and 400 nm, respectively. Dye-sensitized solar cells assembled with the TiO2 NRAs grown on the FTO-covered glass as photoanode were prepared with a photoconversion efficiency of ~1.10%.

Wang, Hong-En; Chen, Zhenhua; Leung, Yu Hang; Luan, Chunyan; Liu, Chaoping; Tang, Yongbing; Yan, Ce; Zhang, Wenjun; Zapien, Juan Antonio; Bello, Igor; Lee, Shuit-Tong

2010-06-01

172

Synthesis of TiO 2 via hydrolysis of titanium tetraisopropoxide and its photocatalytic activity on a suspended mixture with activated carbon in the degradation of 2-naphthol  

Microsoft Academic Search

Titania (TiO2) photocatalysts are produced using hydrolysis of titanium tetraisopropoxide (TTIP) at 100–600°C. The powders are characterized by thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Anatase phase was obtained after calcination at 200°C. The anatase-rutile transformation takes place at temperatures higher than 400°C. Adding TiO2 powders prepared at 600°C to activated carbon (AC), exhibits much higher photocatalytic activity than commercial

S Qourzal; A Assabbane; Y Ait-Ichou

2004-01-01

173

Hydrothermal synthesis of ordered single-crystalline rutile TiO2 nanorod arrays on different substrates  

Microsoft Academic Search

We report the mild hydrothermal synthesis of single-crystalline rutile TiO2 nanorod arrays (NRAs). The method reported here shows great versatility and can be used to grow TiO2 NRAs on a large diversity of substrates including Si, Si\\/SiO2, sapphire, Si pillars, and fluorine doped tin oxide (FTO)-covered glass. The average diameter and length of the nanorods prepared at typical conditions are

Hong-En Wang; Zhenhua Chen; Yu Hang Leung; Chunyan Luan; Chaoping Liu; Yongbing Tang; Ce Yan; Wenjun Zhang; Juan Antonio Zapien; Igor Bello; Shuit-Tong Lee

2010-01-01

174

Development of solar-driven electrochemical and photocatalytic water treatment system using a boron-doped diamond electrode and TiO2 photocatalyst.  

PubMed

A high-performance, environmentally friendly water treatment system was developed. The system consists mainly of an electrochemical and a photocatalytic oxidation unit, with a boron-doped diamond (BDD) electrode and TiO(2) photocatalyst, respectively. All electric power for the mechanical systems and the electrolysis was able to be provided by photovoltaic cells. Thus, this system is totally driven by solar energy. The treatment ability of the electrolysis and photocatalysis units was investigated by phenol degradation kinetics. An observed rate constant of 5.1 x 10(-3)dm(3)cm(-2)h(-1) was calculated by pseudo-first-order kinetic analysis for the electrolysis, and a Langmuir-Hinshelwood rate constant of 5.6 microM(-1)min(-1) was calculated by kinetic analysis of the photocatalysis. According to previous reports, these values are sufficient for the mineralization of phenol. In a treatment test of river water samples, large amounts of chemical and biological contaminants were totally wet-incinerated by the system. This system could provide 12L/day of drinking water from the Tama River using only solar energy. Therefore, this system may be useful for supplying drinking water during a disaster. PMID:19863989

Ochiai, Tsuyoshi; Nakata, Kazuya; Murakami, Taketoshi; Fujishima, Akira; Yao, Yanyan; Tryk, Donald A; Kubota, Yoshinobu

2009-10-01

175

Disinfection of drinking water contaminated with Cryptosporidium parvum oocysts under natural sunlight and using the photocatalyst TiO2.  

PubMed

The results of a batch-process solar disinfection (SODIS) and solar photocatalytic disinfection (SPCDIS) on drinking water contaminated with Cryptosporidium are reported. Cryptosporidium parvum oocyst suspensions were exposed to natural sunlight in Southern Spain and the oocyst viability was evaluated using two vital dyes [4',6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI)]. SODIS exposures (strong sunlight) of 8 and 12h reduced oocyst viability from 98% (+/-1.3%) to 11.7% (+/-0.9%) and 0.3% (+/-0.33%), respectively. SODIS reactors fitted with flexible plastic inserts coated with TiO2 powder (SPCDIS) were found to be more effective than those which were not. After 8 and 16 h of overcast and cloudy solar irradiance conditions, SPCDIS reduced oocyst viability from 98.3% (+/-0.3%) to 37.7% (+/-2.6%) and 11.7% (+/-0.7%), respectively, versus to that achieved using SODIS of 81.3% (+/-1.6%) and 36.0% (+/-1.0%), respectively. These results confirm that solar disinfection of drinking water can be an effective household intervention against Cryptosporidium contamination. PMID:17624798

Méndez-Hermida, Fernando; Ares-Mazás, Elvira; McGuigan, Kevin G; Boyle, Maria; Sichel, Cosima; Fernández-Ibáñez, Pilar

2007-05-29

176

Preparation and characterization of visible-light-driven N-F-Ta tri-doped TiO2 photocatalysts  

NASA Astrophysics Data System (ADS)

A new strategy to synthesize visible-light-driven N doped and N-F-Ta tri-doped TiO2 nanocatalysts via a hydrothermal combined with heat treatment method applied in Rhodamine B (RhB) and phenol decomposition was reported. The tri-doped sample gave the highest visible-light photocatalytic activity when the molar ratio of Ta to Ti was 1%. At a low tri-doping level, physicochemical analysis indicated that the synergistic effects of N, F and Ta could effectively increase not only the crystallite surface area but also the light absorption and OH generation ability, which contributed to the enhancement of visible-light photocatalytic activities. EPR and XPS analysis demonstrated that N-Ta interaction induced the charge compensation to form N 2p-Ta 5d hybridized states which improved the separation ability of the photoexcited electron-hole pairs. Still, F incorporation facilitated the incorporation of N which further promoted the N 2p-Ta 5d hybridized states. The N 2p, ?*N-O, oxygen vacancy, Ti3+ and Ta 5d states were also responsible for the band gap narrowing. However, a high tri-doping level would affect the crystal growth and introduce too many defects into the lattice, reducing the visible-light photoactivity.

Wang, Wei; Lu, Chunhua; Ni, Yaru; Su, Mingxing; Huang, Wenjuan; Xu, Zhongzi

2012-09-01

177

Enhanced photocatalytic activity of nitrogen doped TiO2 photocatalysts sensitized by metallo Co, Ni-porphyrins  

NASA Astrophysics Data System (ADS)

Nitrogen doped anatase TiO2 powders (N-TiO2) were sensitized by four kinds of metalloporphyrins (CoTHPP, CoTPP, NiTHPP, and NiTPP). The resulting materials were characterized by XRD, TEM, XPS, DRS and N2 adsorption. The results showed that the crystal structure and morphology of N-TiO2 were not affected by the existence of porphyrin on its surface, but the surface area increased after the N-TiO2 sensitized by metalloporphyrins. The photocatalytic degradation of methyl blue (MB) experiments showed that the metalporphyrins sensitized N-TiO2 composite catalysts, especially the CoTHPP/N-TiO2 and CoTPP/N-TiO2, exhibited higher degradation efficiency than the unsentisized N-TiO2 powders. In addition, the photocatalytic degradations of MB using the composite catalysts were all demonstrated to follow first-order kinetic model. The composite catalysts can be recycled four times without significant loss of photocatalytic activity.

Niu, Jinfen; Yao, Binghua; Chen, Yuanqing; Peng, Chao; Yu, Xiaojiao; Zhang, Jian; Bai, Guanghai

2013-04-01

178

Hydrothermal synthesis of TiO2 nanorod arrays on transparent conducting substrates  

Microsoft Academic Search

In this research, we compare hydrothermally synthesized TiO2 nanorods in an unsealed and a sealed system, respectively. Due to the variation of hydrothermal concentration, the morphology is very different. Then we further pre-fabricate a TiO2 seed layer by the sol-gel method and then hydrothermally synthesize TiO2 nanorods. The TiO2 nanorods can also be grown on the TiO2 seed layer successfully.

Jiun-Jie Chao; Jyun-Jie Wang; Shu-Chia Shiu; Shih-Che Hung; Ching-Fuh Lin

2011-01-01

179

Efficient phyto-synthesis and structural characterization of rutile TiO2 nanoparticles using Annona squamosa peel extract.  

PubMed

In the present study, the biosynthesis of rutile TiO(2) nanoparticles (TiO(2) NPs) was achieved by a novel, biodegradable and convenient procedure using fruit peel Annona squamosa aqueous extract. This is the first report on the new, simple, rapid, eco-friendly and cheaper methods for the synthesis of rutile TiO(2) NPs at lower temperature using agricultural waste. Rutile TiO(2) NPs were characterized by UV, XRD, SEM, TEM and EDS studies. The UV-Vis spectrophotometer results were promising and showed a rapid production of TiO(2) NPs with a surface plasmon resonance occurring at 284 nm. The formation of the TiO(2) NPs as observed from the XRD spectrum is confirmed to be TiO(2) particles in the rutile form as evidenced by the peaks at 2?=27.42°, 36.10°, 41.30° and 54.33° when compared with the literature. The TEM images showed polydisperse nanoparticles with spherical shapes and size 23±2 nm ranges. PMID:22983203

Roopan, Selvaraj Mohana; Bharathi, A; Prabhakarn, A; Rahuman, A Abdul; Velayutham, K; Rajakumar, G; Padmaja, R D; Lekshmi, Mohan; Madhumitha, G

2012-08-27

180

Synthesis of TiO2 nanostructured reservoir with temozolomide: Structural evolution of the occluded drug  

NASA Astrophysics Data System (ADS)

Sol gel synthesized nanostructured TiO2 matrix were produced with different channel sizes, where drug are immersed, producing a reservoir with Temozolomide (TMZ). This drug is particularly important for the treatment of cancer tumors, which are fundamentally a consequence of the uncontrolled reproduction of human cell. In this way the chemotherapy plays an important role in the treatment of both recurrent and newly diagnosed patients. In the handling of brain tumors TMZ has been discovered as a recent and efficient second generation drug employed in the control of advanced brain gliomas, and it is a welcome addition. Its active component binds to the cancerous DNA cells, thus preventing their disordered growth, destroying them. In this work, we report the synthesis of TiO2 nanostructured reservoir with TMZ, focusing the effort to the understanding of structural effects on the TMZ configuration by using nuclear magnetic resonance, Raman and IR spectroscopy methods. Our results establish that TMZ molecules are quite sensible to chemical processes and it produces the activation of the molecule, which is followed and understood with help of quantum molecular simulation methods. The study of the molecules allows determining the conditions that produce the activation and chemical selectivity of the molecules, which determines the conditions of synthesis. This information gives parameters for the reservoir structural and chemical optimization.

López, T.; Sotelo, J.; Navarrete, J.; Ascencio, J. A.

2006-10-01

181

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...

182

Synthesis and In Vitro Bioactivity of TiO2 Nanorods  

Microsoft Academic Search

Titanium dioxide (TiO2) powders were synthesized by the hydrothermal method. The TiO2 powders were composed of nanorods with dimensions of 10–18 nm and 60–180 nm in diameter and length, respectively. The in vitro bioactivity of the TiO2 powders was examined by evaluation of hydroxyapatite (HAp) formation ability in simulated body fluid (SBF). The results showed that TiO2 nanorods induced the formation of

Qingshan Zhang

2010-01-01

183

Sucrose monolaurate synthesis with Protex 6L immobilized on electrospun TiO2 nanofiber.  

PubMed

TiO(2) nanofibers with uniform diameter about 125 nm were prepared based on sol-gel process and electrospinning technology. Protex 6L, an industrial alkaline protease, was covalently immobilized on TiO(2) nanofiber through ?-aminopropyltriethoxysilane modification and glutaraldehyde crosslinking. With 2 (v/v)% glutaraldehyde as crosslinker, the enzyme loading is about 201 mg (g nanofiber membrane)(-1), and the specific activity of the immobilized Protex 6L is 2.45 ?mol h(-1) ml(-1) mg(-1) protein for synthesis of sucrose monolaurate from sucrose and vinyl laurate. The optimal condition for sucrose monolaurate production is 5% (v/v) water content in DMSO/2-methyl-2-butanol solvent mixture and 50 °C. Under this condition, 97% conversion was achieved within 36 h by nanofibrous Protex 6L, which is corresponding to a productivity 34 times higher than that of most widely used Novozym 435. After 10 cycles reuse, nanofibrous Protex 6L retained 52.4% of its original activity. PMID:21544616

Wang, Xin-Ran; Zhang, Song-Ping; Wang, Ping

2011-05-05

184

Formation of appropriate sites on nanofiltration membrane surface for binding TiO 2 photo-catalyst: Performance, characterization and fouling-resistant capability  

Microsoft Academic Search

Titanium dioxide (TiO2) nanoparticles were assembled on the surface of nanofiltration blend membrane. For settling TiO2 on the membrane surface, two membrane categories were used: (i) unmodified polyethersulfone (PES)\\/polyimide (PI) blend membrane, and (ii) –OH functionalized PES\\/PI blend membrane with different concentrations of diethanolamine (DEA). These membranes were radiated by UV light after TiO2 depositing with different concentrations. 15min immersion

Y. Mansourpanah; S. S. Madaeni; A. Rahimpour; A. Farhadian; A. H. Taheri

2009-01-01

185

Hydrogen production by photocatalytic water-splitting using Cr or Fe-doped TiO 2 composite thin films photocatalyst  

Microsoft Academic Search

Cr- or Fe-ion-doped TiO2 thin films have been synthesized by radio-frequency magnetron sputtering and a sol–gel method to study hydrogen generation by photocatalytic water-splitting under visible light irradiation. The doping method, dopant concentration, charge transfer from metal dopants to TiO2, and type of dopants used for modification of TiO2 were investigated for their ability to enhance photocatalytic activity. UV–Visible spectra

R. Dholam; N. Patel; M. Adami; A. Miotello

2009-01-01

186

BiFeO3\\/TiO2 core-shell structured nanocomposites as visible-active photocatalysts and their optical response mechanism  

Microsoft Academic Search

Anatase titania-coated bismuth ferrite nanocomposites (BiFeO3\\/TiO2) have been fabricated via a hydrothermal approach combined with a hydrolysis precipitation processing. Analysis of the microstructure and phase composition reveals that a core-shell BiFeO3\\/TiO2 structure can be formed, which results in a significant redshift in the UV-vis absorption spectra as compared to a simple mechanical mixture of BiFeO3-TiO2 nanopowders. The core-shell structured BiFeO3\\/TiO2

Shun Li; Yuan-Hua Lin; Bo-Ping Zhang; Jing-Feng Li; Ce-Wen Nan

2009-01-01

187

Improved Nonaqueous Synthesis of TiO2 for Dye-Sensitized Solar Cells.  

PubMed

Nonaqueous synthesis routes have emerged as a powerful platform for directly obtaining diverse metal oxide nanoparticles with high crystallinity and tunable compositions. The benzyl alcohol (BA) route, for example, has been applied toward dozens of oxides including binary, ternary, and even more complex multimetal systems. Here we compare anatase nanoparticles made from the BA route with the traditional hydrothermal route. XPS measurements indicated that the BA route resulted in more reduced Ti states, corresponding to additional oxygen vacancies. These defects resulted in additional trap states, slower recombination, and slower charge transport. The performance of BA anatase was improved by incorporating niobium intended to suppress oxygen vacancies. The higher performance Nb-containing films were post-treated to yield a 7.96% power conversion efficiency (AM 1.5), similar to the state-of-the-art hydrolytic TiO2 in the same configuration. PMID:24015772

Stefik, Morgan; Heiligtag, Florian J; Niederberger, Markus; Grätzel, Michael

2013-09-16

188

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...

189

Metal-organic framework templated synthesis of Fe2O3/TiO2 nanocomposite for hydrogen production.  

PubMed

A new metal-organic framework (MOF)-templated method has been developed for the synthesis of a metal oxide nanocomposite with interesting photophysical properties. Fe-containing nanoscale MOFs are coated with amorphous titania, then calcined to produce crystalline Fe(2)O(3)/TiO(2) composite nanoparticles. This material enables photocatalytic hydrogen production from water using visible light, which cannot be achieved by either Fe(2)O(3) or TiO(2) alone or a mixture of the two. PMID:22431011

deKrafft, Kathryn E; Wang, Cheng; Lin, Wenbin

2012-03-19

190

Study on the effects of complex ligands in the synthesis of TiO2 nanorod arrays using the sol gel template method  

Microsoft Academic Search

This work reports the effects of complex ligands on the synthesis of TiO2 nanorod arrays prepared by the improved sol-gel template method. In this method, the obtained TiO2 sols from the sol-gel process were injected by a syringe into the templates and then the samples were immediately immersed into boiling TiO2-sol solutions. Densely and directionally aligned anatase nanorods of about

A. Sadeghzadeh Attar; M. Sasani Ghamsari; F. Hajiesmaeilbaigi; Sh Mirdamadi; K. Katagiri; K. Koumoto

2008-01-01

191

Green synthesis of TiO2 nanocrystals with improved photocatalytic activity by ionic-liquid assisted hydrothermal method.  

PubMed

Owing to potential industrial applications and fundamental significance, tailored synthesis of well-defined anatase TiO2 nanocrystals with exposed highly reactive {001} facets has stimulated great research interest. In this work, surface-fluorinated anatase TiO2 nanocrystals have been successfully prepared by using an ionic liquid (IL) assisted hydrothermal synthetic route. TiCl4 is used as precursor, and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim](+)[BF4](-)) as morphology-controlling agent. The anion of the IL plays a key role in controlling the crystallization process via a dissolution-recrystallization process. Compared with the benchmark material Degussa P25, the fluorinated anatase TiO2 nanocrystals exhibit superior photocatalytic activity. PMID:23670586

Wang, Bin; Guo, Lingju; He, Meng; He, Tao

2013-05-14

192

Synthesis and characterization of TiO2 and Ag/TiO2 nanostructure  

NASA Astrophysics Data System (ADS)

Single phase anatase TiO2 nanoparticles were prepared using Titanium tertachloride (TiCl4) as precursor through an inexpensive method. Well dispersed nanocomposites of silver at TiO2 were synthesized successfully by photochemical route. Both TiO2 and Ag/TiO2 were characterized using X-Ray Diffraction (XRD) and transmission electron microscopy (TEM). The particle size of TiO2 is found to be ~ 11 nm and ~ 22 nm for Ag/TiO2, by XRD and confirmed by TEM. TEM micrographs also show the single phase crystal of TiO2 and confirm the deposition of silver among TiO2.

Gahlot, Swati; Thakur, Amit Kumar; Kulshrestha, Vaibhav; Shahi, V. K.

2013-02-01

193

Synthesis, characterization of TiO 2 nanotubes-supported MS (TiO 2NTs@ MS, M=Cd, Zn) and their photocatalytic activity  

Microsoft Academic Search

TiO2 nanotubes-supported MS (TiO2NTs@MS, M=Cd, Zn) are synthesized by a simple wet chemical method at room temperature. The products are characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–vis absorption spectrum and photoluminescence (PL) spectrum. Their optical and morphological properties indicate the interaction between the TiO2 nanotube and MS nanoparticle. The photocatalytic activities of the TiO2NTs@MS are evaluated upon

Hong Li; Baolin Zhu; Yunfeng Feng; Shurong Wang; Shoumin Zhang; Weiping Huang

2007-01-01

194

TiO2-graphene composites with exposed {001} facets produced by a one-pot solvothermal approach for high performance photocatalyst.  

PubMed

TiO2-graphene (TOG) composites with exposed TiO2 {001} facets were prepared by a solvothermal approach without any addition of surfactants or capping agents, only using titanium isopropoxide and graphene oxide ethanol suspension as the precursors. Graphene was covered uniformly and densely with anatase TiO2 nanoparticles, exposing the {001} facets. The X-ray photoelectron spectroscopy, photoluminescence spectroscopy and photocurrent measurements show the presence of electron transfer between TiO2 and graphene. The electron transfer between TiO2 and graphene will greatly retard the recombination of photoinduced charge carriers and prolong electron lifetime, which will contribute to the enhancement of photocatalytic performance. Accordingly, the TOG composites show high photocatalytic activity of methyl orange under UV light, likely due to the effective separation of photoinduced charge, exposure of highly reactive {001} facets and great adsorptivity of dyes. PMID:23817326

Lu, Tiewen; Zhang, Rongbin; Hu, Changyuan; Chen, Fei; Duo, Shuwang; Hu, Quanhong

2013-08-21

195

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

Microsoft Academic Search

A magnetically separable photocatalyst TiO2\\/SiO2\\/NiFe2O4 (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

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

2008-01-01

196

Conduction-Band Tailing of Ce-Doped TiO2 Visible-Light-Driven Photocatalyst: The Essential Role of Oxygen Vacancy  

NASA Astrophysics Data System (ADS)

The varied electronic structure of Ce-doped TiO2 was probed with x-ray absorption spectra at O K-, Ce L-, Ti L-edge, and Ti K-edges. We expose the essential role of existed oxygen vacancies in band gap narrowing of Ce-doped TiO2 and deduce the mechanism in detail by charge transfer and covalent hybridization. Oxygen vacancies would release electrons behind the Ce 4f state, inducing the mixing valence characteristic of the Ce ions (Ce3+/Ce4+) doped in TiO2. Oxygen defect state thus hybridizes with Ce 4f state (Ce3+/Ce4+) constructing an impurity band below the conduction band, causing a tailing of the conduction band minimum and narrowing of band gap of TiO2. As Ce-doped TiO2 annealed in an oxidized atmosphere, filling up oxygen vacancies, the absorption edge in the O K-edge x-ray absorption spectrum is shifted to higher energy as compared with that for the un-treated sample, indicating the drastic diminution of band-gap-narrowing effect. This study evidences the existed oxygen vacancy is critical to mediate the impurity band formation and band gap narrowing of Ce-doped TiO2. The phenomenon should also be emphasized in TiO2 doped with other elements.

Chen, Shi Wei; Lee, Jenn Min; Chiang, Sunny; Haw, Shu Chih; Liang, Yu Chia; Lu, Kueih Tzu; Pao, Chih Wen; Lee, Jyh Fu; Tang, Mau Tsu; Chen, Jin Ming

2011-11-01

197

Synthesis of poly(3-hexylthiophene) grafted TiO2 nanotube composite.  

PubMed

A composite of poly(3-hexylthiophene) (P3HT) grafted on TiO(2) nanotubes was synthesized. It was characterized using XRD, TEM, TGA, FTIR and XPS. Cyclic voltammetry (CV) was used to elucidate the electrochemical behavior and evaluate the HOMO and LUMO energy levels. Photoluminescence (PL) measurements show that the emission intensity of P3HT mixed with TiO(2) nanotubes was one third of that of random P3HT, while that of P3HT grafted onto TiO(2) nanotubes was 10% of random P3HT. The results show that the P3HT grafted onto TiO(2) nanotubes is more efficient in photoinduced charge transfer than a physical mixture of P3HT and TiO(2) nanotubes, indicating this composite has potential for the fabricating hybrid organic-inorganic solid state solar cells. PMID:19246046

Lu, Ming-De; Yang, Sze-Ming

2009-02-06

198

Preparation of TiO 2 \\/activated carbon with Fe ions doping photocatalyst and its application to photocatalytic degradation of reactive brilliant red K2G  

Microsoft Academic Search

Titanium dioxide coated on activated carbon (AC) with Fe ions doping (Fe-TiO2\\/AC) composite was prepared by an improved sol-gel method. The photocatalytic activities were tested by photocatalytic degradation\\u000a of reactive brilliant red K2G in solution. The results show that in comparison with the agglomeration of pure TiO2, the TiO2 nanoparticles are well dispersed in the AC matrix, of which sizes

YouJi Li; Jing Li; MingYuan Ma; YuZhu Ouyang; WenBin Yan

2009-01-01

199

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

200

The vacuum thermal treatment effect on the optical absorption spectra of the TiO2 coated by NiB nano-clasters photocatalyst powders  

Microsoft Academic Search

The thermal vacuum treatment effect on the optical absorption spectra of the TiO2 nanopowders, both pure and coated by the Ni-B clasters with the original electroless method was investigated. It was observed that the thermal treatment of pure TiO2 nanopowders does not change their optical absorption spectrum while after the coating of these powder particles by the Ni-B clasters the

M. M. Nadareishvili; K. A. Kvavadze; G. I. Mamniashvili; T. N. Khoperia; T. I. Zedgenidze

2009-01-01

201

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

202

Enhanced Photocatalytic Performances of CeO2 /TiO2 Nanobelt Heterostructures.  

PubMed

CeO2 /TiO2 nanobelt heterostructures are synthesized via a cost-effective hydrothermal method. The as-prepared nanocomposites consist of CeO2 nanoparticles assembled on the rough surface of TiO2 nanobelts. In comparison with P25 TiO2 colloids, surface-coarsened TiO2 nanobelts, and CeO2 nanoparticles, the CeO2 /TiO2 nanobelt heterostructures exhibit a markedly enhanced photocatalytic activity in the degradation of organic pollutants such as methyl orange (MO) under either UV or visible light irradiation. The enhanced photocatalytic performance is attributed to a novel capture-photodegradation-release mechanism. During the photocatalytic process, MO molecules are captured by CeO2 nanoparticles, degraded by photogenerated free radicals, and then released to the solution. With its high degradation efficiency, broad active light wavelength, and good stability, the CeO2 /TiO2 nanobelt heterostructures represent a new effective photocatalyst that is low-cost, recyclable, and will have wide application in photodegradation of various organic pollutants. The new capture-photodegradation-release mechanism for improved photocatalysis properties is of importance in the rational design and synthesis of new photocatalysts. PMID:23681828

Tian, Jian; Sang, Yuanhua; Zhao, Zhenhuan; Zhou, Weijia; Wang, Dongzhou; Kang, Xueliang; Liu, Hong; Wang, Jiyang; Chen, Shaowei; Cai, Huaqiang; Huang, Hui

2013-05-17

203

Chemical and electrochemical synthesis of nanosized TiO 2 anatase for large-area photon conversion  

Microsoft Academic Search

We report on the synthesis of nanocrystalline titanium dioxide thin films and powders by chemical and electrochemical deposition methods. Both methods are simple, inexpensive and suitable for large-scale production. Air-annealing of the films and powders at T=500 °C leads to densely packed nanometer sized anatase TiO2 particles. The obtained layers are characterized by different methods such as: X-ray diffraction (XRD), transmission

Babasaheb Raghunath Sankapal; Shrikrishna Dattatraya Sartale; Martha Christina Lux-Steiner; Ahmed Ennaoui

2006-01-01

204

Large-scale synthesis of TiO2 nanorods via nonhydrolytic sol-gel ester elimination reaction and their application to photocatalytic inactivation of E. coli.  

PubMed

A simple method of synthesizing a large quantity of TiO(2) nanorods was developed. A nonhydrolytic sol-gel reaction between titanium(IV) isopropoxide and oleic acid at 270 degrees C generated 3.4 nm (diameter) x 38 nm (length) sized TiO(2) nanocrystals. The transmission electron microscopic image showed that the particles have a uniform diameter distribution. X-ray diffraction and selected-area electron diffraction patterns combined with high-resolution transmission electron microscopic image showed that the TiO(2) nanorods are highly crystalline anatase crystal structure grown along the [001] direction. The diameters of the TiO(2) nanorods were controlled by adding 1-hexadecylamine to the reaction mixture as a cosurfactant. TiO(2) nanorods with average sizes of 2.7 nm x 28 nm, 2.2 nm x 32 nm, and 2.0 nm x 39 nm were obtained using 1, 5, and 10 mmol of 1-hexadecylamine, respectively. The optical absorption spectrum of the TiO(2) nanorods exhibited that the band gap of the nanorods was 3.33 eV at room temperature, which is 130 meV larger than that of bulk anatase (3.2 eV), demonstrating the quantum confinement effect. Oleic acid coordinated on the nanorod surface was removed by the reduction of the carboxyl group of oleic acid, and the Brunauer-Emmett-Teller surface area of the resulting naked TiO(2) nanorods was 198 m(2)/g. The naked TiO(2) nanorods exhibited higher photocatalytic activity than the P-25 photocatalyst for the photocatalytic inactivation of E. coli. PMID:16852938

Joo, Jin; Kwon, Soon Gu; Yu, Taekyung; Cho, Min; Lee, Jinwoo; Yoon, Jeyong; Hyeon, Taeghwan

2005-08-18

205

3D Bi12TiO20/TiO2 hierarchical heterostructure: synthesis and enhanced visible-light photocatalytic activities.  

PubMed

A three-dimensional (3D) multicomponent oxide, Bi(12)TiO(20)/TiO(2) hierarchical heterostructure was successfully synthesized via a one-step and template-free hydrothermal route. X-ray diffraction and X-ray photoelectron spectroscopy measurements confirm that the composition of the as-fabricated sample is Bi(12)TiO(20)/TiO(2) composite. Scanning and transmission electron microscopy observation reveals that the as-synthesized sample is microsized flower-like hierarchical networks consisted of Bi(12)TiO(20) nanorods decorated with the primary TiO(2) nanoparticles. Extension of the light absorption from the ultraviolet region to the visible-light region was confirmed by UV-vis absorption spectra. Due to the structure-property relationships, the 3D Bi(12)TiO(20)/TiO(2) heterostructure exhibited enhanced visible photocatalytic activity over that of Bi(12)TiO(20) and TiO(2) samples in the decomposition of Rhodamine B in water which is a typical model pollutant. The enhanced photocatalytic activity can be attributed to the extended absorption in the visible light region resulting from the 3D Bi(12)TiO(20)/TiO(2) heterostructures, and the effective separation of photogenerated carriers driven by the photoinduced potential difference generated at the Bi(12)TiO(20)/TiO(2) junction interface, demonstrating that the Bi(12)TiO(20)/TiO(2) heterostructure is a promising candidate as a visible light photocatalyst. PMID:21794977

Hou, Jungang; Wang, Zheng; Jiao, Shuqiang; Zhu, Hongmin

2011-07-08

206

Formation of crystalline TiO2-xNx and its photocatalytic activity  

NASA Astrophysics Data System (ADS)

Amorphous precursors to nitrogen-doped TiO2 (NTP) and pure TiO2 (ATP) powders were synthesized by hydrolytic synthesis and sol gel method (SGM), respectively. Corresponding crystalline phases were obtained by thermally induced transformation of these amorphous powders. From FT-IR and XPS data, it was concluded that a complex containing titanium and ammonia was formed in the precipitate stage while calcination drove weakly adsorbed ammonium species off the surface, decomposed ammonia bound on surface of precipitated powder and led to substitution of nitrogen atom into the lattice of TiO2 during the crystallization. The activation energies required for grain growth in amorphous TiO2-xNx and TiO2 samples were determined to be 1.6 and 1.7 kJ/mol, respectively. Those required for the phase transformation from amorphous to crystalline TiO2-xNx and TiO2 were determined to be 129 and 142 kJ/mol, respectively. A relatively low temperature was required for the phase transformation in NTP sample than in ATP sample. The fabricated N-doped TiO2 photocatalyst absorbed the visible light showing two absorption edges; one in UV range due to titanium oxide as the main edge and the other due to nitrogen doping as a small shoulder. TiO2-xNx photocatalyst demonstrated its photoactivity for photocurrent generation and decomposition of 2-propanol (IPA) under visible light irradiation (??420nm).

Jang, Jum Suk; Kim, Hyun Gyu; Ji, Sang Min; Bae, Sang Won; Jung, Jong Hyeon; Shon, Byung Hyun; Lee, Jae Sung

2006-04-01

207

Synthesis of TiO2/functionalized graphene sheets (FGSs) nanocomposites in super critical CO2  

NASA Astrophysics Data System (ADS)

Highly ordered TiO2 nanowire arrays were prepared on the surface of Functionalized Graphene sheets (FGSs) by solgel method using titanium isopropoxide monomer with acetic acid as the polycondensation agent in the green solvent, supercritical carbon dioxide (sc-CO2). Morphology of synthesized materials was studied by SEM and TEM. Optical properties of the nanocomposites studied by UV spectroscopy which showed high absorption in visible area as well as reduction in their band gap compared to TiO2. By high resolution XPS, chelating bidentate structure of TiO2 with carboxylic group on the surface of graphene sheets can be confirmed. Improvement in the optical properties of the synthesized composites compared to TiO2 alone was confirmed by photocurrent measurements.

Farhangi, Nasrin; Medina-Gonzalez, Yaocihuatl; Chen, Bo; Charpentier, Paul A.

2010-06-01

208

Enhanced photocatalytic performance of Hemin (chloro(protoporhyinato)iron(III)) anchored TiO2 photocatalyst for methyl orange degradation: A surface modification method  

NASA Astrophysics Data System (ADS)

TiO2 was prepared by sol-gel method through the hydrolysis of TiCl4 and its surface derivatization was carried out with molecular catalyst like Hemin (chloro(protoporhyinato)iron(III)). Catalyst was characterized by various analytical techniques like UV-vis spectroscopy, FT-IR, FE-SEM and XRD. The anchoring of Hemin on titania surface is confirmed by FT-IR spectra through the linkage of Odbnd Csbnd Osbnd Ti bond and also by TGA-DSC and elemental analysis. The photocatalytic activity of the surface modified catalyst is tested for the degradation of methyl orange (MO) as a model compound under UV light. The Hemin impregnated TiO2 (H-TiO2) in presence of H2O2 shows an excellent photocatalytic activity compared to pristine TiO2, Hemin, H2O2, TiO2/H2O2, and Hemin/H2O2 systems. The enhancement in the photocatalytic activity is attributed to the presence of iron (III) porphyrin ring on the TiO2 surface, which reduces the electron-hole recombination rate and also by acting as a mediator for continuous production of enriched concentration of hydroxyl radicals along with various other reactive free radicals.

Devi, L. Gomathi; ArunaKumari, M. L.

2013-07-01

209

Synthesis of poly(3-hexylthiophene) grafted TiO 2 nanotube composite  

Microsoft Academic Search

A composite of poly(3-hexylthiophene) (P3HT) grafted on TiO2 nanotubes was synthesized. It was characterized using XRD, TEM, TGA, FTIR and XPS. Cyclic voltammetry (CV) was used to elucidate the electrochemical behavior and evaluate the HOMO and LUMO energy levels. Photoluminescence (PL) measurements show that the emission intensity of P3HT mixed with TiO2 nanotubes was one third of that of random

Ming-De Lu; Sze-Ming Yang

2009-01-01

210

Synthesis of TiO2 Nanotubes and Its Photocatalytic Activity for H2 Evolution  

Microsoft Academic Search

TiO2-derived nanotubes were prepared by hydrothermal treatment in 10 M NaOH(aq) by using commercially available TiO2 (Degussa P-25) as starting material. N2-adsorption\\/desorption analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) observations of the obtained product revealed the formation of titanate nanotube structure with its diameter of about 10-20 nm. The effect of post-heat-treatment on the

Jaturong Jitputti; Sorapong Pavasupree; Yoshikazu Suzuki; Susumu Yoshikawa

2008-01-01

211

Effect of synthesis conditions on photocatalytic activities of nanoparticulate TiO 2 thin films  

Microsoft Academic Search

In the present study, design of experiments (DOE) was used to find an optimal combination for the factors affecting the preparation, morphology and catalytic activity of nano-crystalline TiO2 thin films synthesized by sol–gel method. Nine TiO2 thin films were prepared onto indium–tin oxide (ITO) substrates by changing four operating parameters at three levels. The four operating parameters are the volume

Lei Sun; Taicheng An; Shungang Wan; Guiying Li; Ningzhong Bao; Xiaohong Hu; Jiamo Fu; Guoying Sheng

2009-01-01

212

Synthesis and characterization of ultrahigh crystalline TiO2 nanotubes.  

PubMed

Ultrahigh crystalline TiO2 nanotubes were synthesized by hydrogen peroxide treatment of very low crystalline titania nanotubes (TiNT-as prepared), which were prepared with synthesized TiO2 nanoparticles by hydrothermal methods in an aqueous NaOH solution. Thus, prepared ultrahigh crystalline TiO2 nanotubes (TiNT-H2O2) showed comparable crystallinity with high crystalline TiO2 nanoparticles. The details of nanotubular structures were elucidated by high resolution-transmission electron microscopy (HR-TEM), field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray analysis in transmission electron microscopy (TEM-EDX), X-ray diffraction (XRD), photoluminescence (PL), and BET surface area. TiNT-H2O2 was found to be a multiwalled anatase phase only with an average outer diameter of approximately 8 nm and an inner diameter of approximately 5 nm and grown along the [001] direction to 500-700 nm long with an interlayer fringe distance of ca. 0.78 nm. The photocatalytic activity of TiNT-H2O2 was about 2-fold higher than those of TiNT-as prepared, synthesized TiO2 nanoparticles, and TiO2-P25 (Degussa) in the photocatalytic oxidation of trimethylamine gas under UV irradiation. PMID:16570964

Khan, M Alam; Jung, Hee-Tae; Yang, O-Bong

2006-04-01

213

Synthesis of one-dimensional TiO2/V2O5 branched heterostructures and their visible light photocatalytic activity towards Rhodamine B.  

PubMed

We present the synthesis and visible-light-induced catalytic activity of one-dimensional (1D) TiO(2)/V(2)O(5) branched heterostructures. The 1D TiO(2)/V(2)O(5) heterostructures were prepared by RF reactive magnetron sputtering of V(2)O(5) onto electrospun TiO(2) nanofibers. Then, the samples were annealed at 300?°C for 2 h in air ambient to form the 1D TiO(2)/V(2)O(5) branched heterostructures. The photodecomposition rate of Rhodamine B (RhB) by the 1D TiO(2)/V(2)O(5) branched heterostructures under visible light was much faster than that of pure TiO(2) nanofibers, revealing that the visible-light-induced catalytic activity of the 1D TiO(2)/V(2)O(5) branched heterostructures was greatly improved. The enhancement of the photocatalytic activity of the 1D TiO(2)/V(2)O(5) branched heterostructures can be ascribed to the coupling with a small bandgap semiconductor material V(2)O(5), where the absorption range is extended, the photogenerated electrons and holes are highly separated and the surface charge carrier transfer rate is promoted. PMID:21454938

Wang, Y; Su, Y R; Qiao, L; Liu, L X; Su, Q; Zhu, C Q; Liu, X Q

2011-04-01

214

One-pot solvothermal synthesis of graphene-supported TiO2 (B) nanosheets with enhanced lithium storage properties.  

PubMed

A facile process was developed for the synthesis of graphene-supported TiO2 (B) nanosheets (GTBN) composite based on the hydrothermal treatment titanium (III) chloride and graphene oxide in an ethylene glycol. The morphology and microstructure of the composites were examined by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectroscopy. The obtained GTBN show a high thermal stability and the phase transformation of TiO2 (B) to anatase can be prevented by graphene after pyrolysis of GTBN at 350°C for 2h. Furthermore, GTBN exhibited high rate performance and stability of lithium ion batteries, due to the enhanced conductivity of the electrode and accommodation to volume/strain changes during lithium insertion-extraction. PMID:23972503

Zhang, Zhe; Chu, Qingxin; Li, Huiyan; Hao, Jinhui; Yang, Wenshu; Lu, Baoping; Ke, Xi; Li, Jing; Tang, Jilin

2013-08-02

215

Photocatalytic degradation of metoprolol tartrate in suspensions of two TiO2-based photocatalysts with different surface area. Identification of intermediates and proposal of degradation pathways.  

PubMed

This study investigates the efficiency of the photocatalytic degradation of metoprolol tartrate (MET), a widely used ?(1)-blocker, in TiO(2) suspensions of Wackherr's "Oxyde de titane standard" and Degussa P25. The study encompasses transformation kinetics and efficiency, identification of intermediates and reaction pathways. In the investigated range of initial concentrations (0.01-0.1 mM), the photocatalytic degradation of MET in the first stage of the reaction followed approximately a pseudo-first order kinetics. The TiO(2) Wackherr induced a significantly faster MET degradation compared to TiO(2) Degussa P25 when relatively high substrate concentrations were used. By examining the effect of ethanol as a scavenger of hydroxyl radicals (OH), it was shown that the reaction with OH played the main role in the photocatalytic degradation of MET. After 240 min of irradiation the reaction intermediates were almost completely mineralized to CO(2) and H(2)O, while the nitrogen was predominantly present as NH(4)(+). Reaction intermediates were studied in detail and a number of them were identified using LC-MS/MS (ESI+), which allowed the proposal of a tentative pathway for the photocatalytic transformation of MET as a function of the TiO(2) specimen. PMID:22035693

Abramovi?, Biljana; Kler, Sanja; Soji?, Daniela; Lauševi?, Mila; Radovi?, Tanja; Vione, Davide

2011-10-08

216

Gold nanoparticles located at the interface of anatase/rutile TiO2 particles as active plasmonic photocatalysts for aerobic oxidation.  

PubMed

Visible-light irradiation (? > 450 nm) of gold nanoparticles loaded on a mixture of anatase/rutile TiO(2) particles (Degussa, P25) promotes efficient aerobic oxidation at room temperature. The photocatalytic activity critically depends on the catalyst architecture: Au particles with <5 nm diameter located at the interface of anatase/rutile TiO(2) particles behave as the active sites for reaction. This photocatalysis is promoted via plasmon activation of the Au particles by visible light followed by consecutive electron transfer in the Au/rutile/anatase contact site. The activated Au particles transfer their conduction electrons to rutile and then to adjacent anatase TiO(2). This catalyzes the oxidation of substrates by the positively charged Au particles along with reduction of O(2) by the conduction band electrons on the surface of anatase TiO(2). This plasmonic photocatalysis is successfully promoted by sunlight exposure and enables efficient and selective aerobic oxidation of alcohols at ambient temperature. PMID:22440019

Tsukamoto, Daijiro; Shiraishi, Yasuhiro; Sugano, Yoshitsune; Ichikawa, Satoshi; Tanaka, Shunsuke; Hirai, Takayuki

2012-04-02

217

Synthesis of hierarchical TiO2 nanowires with densely-packed and omnidirectional branches.  

PubMed

In this study, a hierarchical TiO2 nanostructure with densely-packed and omnidirectional branches grown by a hydrothermal method is introduced. This morphology is achieved via high-concentration TiCl4 treatment of upright backbone nanowires (NWs) followed by hydrothermal growth. Secondary nanobranches grow in all directions from densely distributed, needle-like seeds on the jagged round surface of the backbone NWs. In addition, hierarchical, flower-like branches grow on the top surface of each NW, greatly increasing the surface area. For dye-sensitized solar cell (DSSC) applications, the TiO2 nanostructure demonstrated a photoconversion efficiency of up to 6.2%. A parametric study of the DSSC efficiency showed that branched TiO2 DSSCs can achieve nearly four times the efficiency of non-branched TiO2 nanowire DSSCs, and up to 170% the efficiency of previously-reported sparsely-branched TiO2 NW DSSCs. PMID:24071926

Lee, Daeho; Rho, Yoonsoo; Allen, Frances I; Minor, Andrew M; Ko, Seung Hwan; Grigoropoulos, Costas P

2013-09-27

218

Synthesis and characterization of super paramagnetic composite photocatalyst—Titania\\/silica\\/nickel ferrite  

Microsoft Academic Search

Composite photocatalysts with TiO2 porous shell and magnetic core were synthesized by using NiFe2O4 as a magnetic core, SiO2 as an intermediate layer and polyethylene glycol with molecular weight of 1000 (PEG 1000) as a template direction agent. The samples were characterized with N2 adsorption–desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM)

Yu Li; Xiufang Dong; Junping Li

2011-01-01

219

Synthesis and Magnetotransport Properties of CrO2-TiO2 Composites  

NASA Astrophysics Data System (ADS)

CrO2-TiO2 composites are synthesized by using a high temperature and high pressure method using CrO3 and H2TiO3 as precursors. The composites consist of large rod-like CrO2 crystals separated by small TiO2 grains. The CrO2 in the composites is very pure and its saturation magnetization is very close to the theoretical value (i.e., 2?B per formula unit). The composites exhibit a large negative magnetoresistance (MR) at 5K. The MR in CrO2-TiO2 composites is mainly attributed to spin-polarized tunneling between CrO2 crystals. The conductivity of the composites is best described by a fluctuation-induced tunneling model below 230K.

Fan, Yin-Bo; Zhang, Cai-Ping; Du, Xiao-Bo; Wen, Ge-Hui; Ma, Hong-An; Jia, Xiao-Peng

2013-03-01

220

Sucrose monolaurate synthesis with Protex 6L immobilized on electrospun TiO 2 nanofiber  

Microsoft Academic Search

TiO2 nanofibers with uniform diameter about 125 nm were prepared based on sol–gel process and electrospinning technology. Protex\\u000a 6L, an industrial alkaline protease, was covalently immobilized on TiO2 nanofiber through ?-aminopropyltriethoxysilane modification and glutaraldehyde crosslinking. With 2 (v\\/v)% glutaraldehyde\\u000a as crosslinker, the enzyme loading is about 201 mg (g nanofiber membrane)?1, and the specific activity of the immobilized Protex 6L is 2.45 ?mol h?1

Xin-Ran WangSong-Ping; Song-Ping Zhang; Ping Wang

221

Large-scale synthesis and characterization of fan-shaped rutile TiO 2 nanostructures  

Microsoft Academic Search

Large-scale fan-shaped rutile TiO2 nanostructures have been synthesized by means of a simple hydrothermal method using only TiCl4 as titanium source and chloroform\\/water as solvents. The physicochemical features of the fan-shaped TiO2 nanostructures are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), nitrogen absorption–desorption, diffuse reflectance ultraviolet–visible spectroscopy (UV–vis) and Fourier

Miaomiao Ye; Zhonglin Chen; Wenshou Wang; Liang Zhen; Jimin Shen

2008-01-01

222

Synthesis of TiO2-based nanotube on Ti substrate by hydrothermal treatment.  

PubMed

TiO2-based titanate nanotube film was directly synthesized by hydrothermal treatment of Ti substrate in NaOH solution. The prepared high aspect ratio nanotubes have diameter of 10 nm and pore size of 5 nm with length of several microns. The nanotubes show the same structure and component characteristics as the nanotubes prepared through hydrothermal treatment of TiO2. Other nanostructured titanate as oriented nanofiber film and translucent film were also prepared by adjusting the hydrothermal conditions. The formation mechanism of nanostructured titanate was discussed. PMID:17450812

Chi, Bo; Victorio, Erick S; Jin, Tetsuro

2007-02-01

223

Synthesis of TiO 2 scaffold by a 2 step bi-layer process using a molten salt synthesis technique  

Microsoft Academic Search

TiO2 scaffolds of anisotropic rutile particles were grown from rutile seeds by using molten salt synthesis techniques. The rutile seeds were either in the form of a separate layer applied on a substrate or a sintered bulk pellet. Mixtures of amorphous titanium hydroxide and salt applied as coatings on the rutile seeds were heat treated. Depending on the morphology of

B. Roy; P. A. Fuierer; S. Aich

2011-01-01

224

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

NASA Astrophysics Data System (ADS)

A magnetically separable photocatalyst TiO2/SiO2/NiFe2O4 (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 TiO2 shell for photocatalysis. The SiO2 layer between the NiFe2O4 core and the TiO2 shell effectively prevents the injection of charges from TiO2 particles to NiFe2O4, which gives rise to an increase in photocatalytic activity. Moreover, the recycled TSN exhibits good repeatability of the photocatalytic activity.

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

2008-03-01

225

Synthesis and dye-sensitized solar cell performance of nanorods/nanoparticles TiO2 from high surface area nanosheet TiO2.  

PubMed

High surface area nanosheet TiO2 with mesoporous structure were synthesized by hydrothermal method at 130 degrees C for 12 h. The samples characterized by XRD, SEM, TEM, SAED, and BET surface area. The nanosheet structure was slightly curved and approximately 50-100 nm in width and several nanometers in thickness. The as-synthesized nanosheet TiO2 had average pore diameter about 3-4 nm. The BET surface area and pore volume of the sample were about 642 m(2)/g and 0.774 cm(3)/g, respectively. The nanosheet structure after calcinations were changed into nanorods/nanoparticles composite with anatase TiO2 structure at 300-500 degrees C (10-15 nm in rods diameter and about 5-10 nm in particles diameter). The solar energy conversion efficiency (eta) of the cell using nanorods/nanoparticles TiO2 (from the nanosheet calcined at 450 degrees C for 2 h) with mesoporous structure was about 7.08% with Jsc of 16.35 mA/cm(2), Voc of 0.703 V and ff of 0.627; while eta of the cell using P-25 reached 5.82% with Jsc of 12.74 mA/cm(2), Voc of 0.704 V, and ff of 0.649. PMID:17256316

Pavasupree, Sorapong; Ngamsinlapasathian, Supachai; Suzuki, Yoshikazu; Yoshikawa, Susumu

2006-12-01

226

Mechanical activation of the synthesis reaction of BaTiO 3 from a mixture of BaCO 3 and TiO 2 powders  

Microsoft Academic Search

The influence of long term milling in an attritor of a mixture of BaCO3 and TiO2 powders on the reaction synthesis of BaTiO3 was studied. Thermal analysis (TG and DTA) of the unmilled and milled powders and X-ray diffraction of powders calcined at different temperatures were undertaken. Milling does not change the reaction sequence between BaCO3 and TiO2. BaTiO3 and

C Gomez-Yañez; C Benitez; H Balmori-Ramirez

2000-01-01

227

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

228

Synthesis and investigations of rutile phase nanoparticles of TiO2  

Microsoft Academic Search

TiO2 nanoparticles have been synthesized at room temperature using a simple chemical precipitation route. Particles were further coated with polymer. Detailed structural analysis of the particles has been carried out. Wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM) confirm that \\

P. H. Borse; L. S. Kankate; F. Dassenoy; W. Vogel; J. Urban; S. K. Kulkarni

2002-01-01

229

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

230

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

231

A facile route to n-type TiO(2)-nanotube/p-type boron-doped-diamond heterojunction for highly efficient photocatalysts.  

PubMed

Anatase TiO(2) nanotube (TiNT) arrays have been fabricated on a p-type boron-doped diamond substrate by a liquid phase deposition method using a ZnO nanorod template. The n-type TiNT/p-type diamond heterojunction structures which are realized show significantly enhanced photocatalytic activities with good recyclable behavior, with respect to the cases of sole TiNTs. PMID:20424751

Yuan, Jvjun; Li, Hongdong; Gao, Shiyong; Lin, Yanhong; Li, Haiyan

2010-03-30

232

Polypropylene membrane surface modification by RAFT grafting polymerization and TiO 2 photocatalysts immobilization for phenol decomposition in a photocatalytic membrane reactor  

Microsoft Academic Search

The main technical barriers that impede photocatalytic membrane reactor (PMR) commercialization remain on the post-recovery of the catalyst particles after water treatment. To overcome this problem, surface modification of polypropylene macroporous membrane was performed with the technique of photoinduced reversible addition-fragmentation chain transfer grafting polymerization of acrylic acid. Titanium oxide photocatalysts were introduced to the acrylic acid grafted membrane surface.

Song Yang; Jia-Shan Gu; Hai-Yin Yu; Jin Zhou; Shi-Feng Li; Xiu-Min Wu; Liang Wang

2011-01-01

233

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

234

One-step hydrothermal synthesis of N-doped TiO2/C nanocomposites with high visible light photocatalytic activity.  

PubMed

N-doped TiO(2) nanoparticles modified with carbon (denoted N-TiO(2)/C) were successfully prepared by a facile one-pot hydrothermal treatment in the presence of L-lysine, which acts as a ligand to control the nanocrystal growth and as a source of nitrogen and carbon. As-prepared nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR) spectra, and N(2) adsorption-desorption analysis. The photocatalytic activities of the as-prepared photocatalysts were measured by the degradation of methyl orange (MO) under visible light irradiation at ?? 400 nm. The results show that N-TiO(2)/C nanocomposites increase absorption in the visible light region and exhibit a higher photocatalytic activity than pure TiO(2), commercial P25 and previously reported N-doped TiO(2) photocatalysts. We have demonstrated that the nitrogen was doped into the lattice and the carbon species were modified on the surface of the photocatalysts. N-doping narrows the band gap and C-modification enhances the visible light harvesting and accelerates the separation of the photo-generated electrons and holes. As a consequence, the photocatalytic activity is significantly improved. The molar ratio of L-lysine/TiCl(4) and the pH of the hydrothermal reaction solution are important factors affecting the photocatalytic activity of the N-TiO(2)/C; the optimum molar ratio of L-lysine/TiCl(4) is 8 and the optimum pH is ca. 4, at which the catalyst exhibits the highest reactivity. Our findings demonstrate that the as-obtained N-TiO(2)/C photocatalyst is a better and more promising candidate than well studied N-doped TiO(2) alternatives as visible light photocatalysts for potential applications in environmental purification. PMID:22143193

Wang, Dong-Hong; Jia, Li; Wu, Xi-Lin; Lu, Li-Qiang; Xu, An-Wu

2011-12-05

235

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

236

Study on the effects of complex ligands in the synthesis of TiO2 nanorod arrays using the sol gel template method  

NASA Astrophysics Data System (ADS)

This work reports the effects of complex ligands on the synthesis of TiO2 nanorod arrays prepared by the improved sol-gel template method. In this method, the obtained TiO2 sols from the sol-gel process were injected by a syringe into the templates and then the samples were immediately immersed into boiling TiO2-sol solutions. Densely and directionally aligned anatase nanorods of about 80-130 nm diameter and a length of several micrometres were successfully fabricated using an optimal molar ratio of the TiO2 sol. The results show that the molar ratio of the TiO2 sol plays an important role in the morphology and structure of TiO2 nanorods. The reaction between titanium alkoxide and acetylacetone leads to the formation of complex compounds, which can prevent the precipitation of undesired phases from the highly reactive precursors. These complex ligands can be removed after annealing at various temperatures, which depend on the molar ratio of the TiO2 sol.

Sadeghzadeh Attar, A.; Sasani Ghamsari, M.; Hajiesmaeilbaigi, F.; Mirdamadi, Sh; Katagiri, K.; Koumoto, K.

2008-08-01

237

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

238

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

2009-11-30

239

Synthesis and characterization of La2O3/TiO2-xFx and the visible light photocatalytic oxidation of 4-chlorophenol.  

PubMed

In this work, we investigated the synergetic effect of La and F on the visible light photocatalytic activity of TiO(2) catalysts. La(2)O(3)/TiO(2-x)F(x) photocatalysts were prepared by a simple sol-gel process using tetrabutyl titanate (TBT), La(NO(3))(3) and NH(4)F as precursors. XPS results revealed that La(2)O(3) accumulated on the surface of TiO(2), which enhanced the surface area of TiO(2) and inhibited the recombination of electron-hole pairs. It also showed that two kinds of fluorine species were formed and these increased the acid active sites and enhanced the oxidation potential of the photogenerated holes in the valance band. UV-vis diffuse reflection spectra of La(2)O(3)/TiO(2-x)F(x) showed that intraband gap states were present and these are probably responsible for its absorption of visible light while the intrinsic absorption band was shifted slightly to a longer wavelength. At molar ratios of La and F to Ti of 1.5:100 and 5:100 and after calcination at 500 degrees C, the degradation rate of 4-chlorophenol (4-CP) over the sample was about 1.2-3.0 times higher than that of the other doped samples and undoped TiO(2). The total organic carbon (TOC) removal rates of 4-CP showed that 4-CP was mineralized efficiently in the presence of the sample under visible light illumination. PMID:20149531

Cao, Guangxiu; Li, Yaogang; Zhang, Qinghong; Wang, Hongzhi

2010-01-28

240

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

2011-04-06

241

Comparision of Zn2TiO4 and rutile TiO2 photocatalysts for H-2 production under UV and near-visible light irradiation  

Microsoft Academic Search

Zn2TiO4 a spinet-type structure photocatalyst, was synthesized by a solid-state reaction method, and obtained as a single phase in the temperature range of 900-1200 degrees C. The average particle size for case of the as-synthesized Zn2TiO4 sample, sintered at 1200 degrees C was found to be 5 mu m, whereas it lay in the range of 0.5-2 mu m for

Pramod H. Borse; C. R. Cho; K. T. Lim; T. E. Hong; E. D. Jeong; J. H. Yoon; S. M. Yu; H. G. Kim

2012-01-01

242

Preparation and characterization of TiO 2 photocatalysts co-doped with iron (III) and lanthanum for the degradation of organic pollutants  

Microsoft Academic Search

Titanium dioxide photocatalysts co-doped with iron (III) and lanthanum were prepared by a facile sol–gel method. The structure of catalysts was characterized by X-ray diffraction (XRD), Raman spectroscopy, UV–vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples were evaluated by the degradation of methylene blue in aqueous solutions under visible light (?>420nm) and UV

Qiangqiang Wang; Shihua Xu; Fenglei Shen

2011-01-01

243

N,S-co-doped TiO2 nanophotocatalyst: synthesis, electronic structure and photocatalysis.  

PubMed

N,S-co-doped anatase-phase TiO2 (N,S-TiO2) nanophotocatalysts were prepared from either benzothiazoline or aminothiol with titanium isopropoxide followed by a systematic thermal decomposition. The chemical nature of S and N in N,S-TiO2 have been identified by XPS to be sulfate and NO-like, respectively. A significant band broadening and red-shift in the UV-visible absorption spectrum of N,S-TiO2 suggests a band gap reduction compared to TiO2. A maximum band-gap narrowing of 0.22 +/- 0.02 eV was observed on N,S-TiO2. Higher energy width observed on N,S-TiO, is in contrast to 0.13 eV from N-doped TiO2 indicating the sulfate-like species might play a major role in narrowing the band-gap to a higher level. It is confirmed that the oxidation of N and S to NO and SO4(2-) occurs in the final stage of preparation of N,S-TiO2, during calcination in air. It is predicted that the oxygen associated with sulfate and NO structural features could be crucial in bringing down the energy gap and red shift in optical absorption and the role of sulfur is to facilitate the above. Photocatalytic decomposition of methylene blue has been carried out on N,S-TiO2 shows higher activity than the commercial TiO2 in the visible region. However, sulfate species seems to enhance the activity of N,S-TiO2 marginally compared to N-TiO2, and possible suggestions are given to improve the same. PMID:19441329

Sathish, M; Viswanath, R P; Gopinath, Chinnakonda S

2009-01-01

244

Synthesis of TiO2\\/functionalized graphene sheets (FGSs) nanocomposites in super critical CO2  

Microsoft Academic Search

Highly ordered TiO2 nanowire arrays were prepared on the surface of Functionalized Graphene sheets (FGSs) by solgel method using titanium isopropoxide monomer with acetic acid as the polycondensation agent in the green solvent, supercritical carbon dioxide (sc-CO2). Morphology of synthesized materials was studied by SEM and TEM. Optical properties of the nanocomposites studied by UV spectroscopy which showed high absorption

Nasrin Farhangi; Yaocihuatl Medina-Gonzalez; Bo Chen; Paul A. Charpentier

2010-01-01

245

Synthesis and optical properties of rutile TiO2 microspheres composed of radially aligned nanorods  

NASA Astrophysics Data System (ADS)

Rutile titania microspheres with diameters of about 2 5 ?m have been synthesized by a facile hydrothermal method. The products are characterized by scanning electron microscopy, transmission electron microscope, EDXA, X-ray diffractometer, and UV Vis NIR. It is found that each microsphere is composed of radially aligned nanorods with diameters of about 100 nm and lengths of 2 ?m. The influence of the reaction time on the morphologies of TiO2 microspheres has been investigated.

Han, Yi; Li, Guicun; Zhang, Zhikun

2006-09-01

246

Microwave-assisted synthesis of anatase TiO2 nanorods with mesopores  

Microsoft Academic Search

Pure anatase TiO2 nanorods with mesopores were synthesized by a simple and low cost microwave-assisted method when tri-block copolymer was used as a structure stabilization agent and TiCl4 as metal precursor. TEM investigation showed that larger nanorods were assembled by pearl-necklace-shaped nanorods following an oriented attachment mechanism in a specific direction. A proposed hypothetical scheme showed that the formation of

Xingtao Jia; Wen He; Xudong Zhang; Hongshi Zhao; Zhengmao Li; Yingjun Feng

2007-01-01

247

Synthesis and investigations of rutile phase nanoparticles of TiO 2  

Microsoft Academic Search

TiO2 nanoparticles have been synthesized at room temperature using a simple chemical precipitation route. Particles were further coated with polymer. Detailed structural analysis of the particles has been carried out. Wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM) confirm that “as-synthesized” particles as well as annealed particles are nanoparticles having pure rutile phase. Thermal annealing at 1000 °C of

Pramod H. Borse; Laxman S. Kankate; F. Dassenoy; W. Vogel; J. Urban; Sulabha K. Kulkarni

2002-01-01

248

First-principles study of the electronic and optical properties of the (Y, N)-codoped anatase TiO2 photocatalyst  

NASA Astrophysics Data System (ADS)

First-principles plane-wave pseudopotential calculations are performed to study the geometrical structures, formation energies, and electronic and optical properties of Y-doped, N-doped, and (Y, N)-codoped TiO2. The calculated results show that Y and N codoping leads to lattice distortion, easier separation of photogenerated electron-hole pairs and band gap narrowing. The optical absorption spectra indicate that an obvious red-shift occurs upon Y and N codoping, which enhances visible-light photocatalytic activity.

Lin, Yan-Ming; Jiang, Zhen-Yi; Hu, Xiao-Yun; Zhang, Xiao-Dong; Fan, Jun; Miao, Hui; Shang, Yi-Bo

2012-03-01

249

Synthesis and photocatalytic performances of the TiO2 pillared montmorillonite.  

PubMed

TiO(2) pillared clay materials were prepared by montmorillonite (Mt) and acidic solutions of hydrolyzed Ti alkoxides in the presence of high-molecular-weight polyoxypropylene (POP)-backboned di-quaternary salts (POP). The as-prepared materials were characterized by means of XRD, FTIR, TG-DTA, XRF, specific surface area and porosity determinations, TEM and SEM, respectively. The experiments showed that the resulting material was a porous delaminated structure containing pillared fragments and nano-scaled TiO(2) particles well dispersed among each other. Introducing polymer surfactant POP as an expanding agent of Mt cannot only promote the formation of the delaminated structure, but significantly improve the porosity and surface area of the composites. The resulting TiO(2) pillared Mt exhibited a good thermal stability as indicated by its surface area after calcination at 800 °C. No phase transformation from anatase to rutile was observed even under calcination at 900 °C. The grain size of anatase in as-prepared sample decreased with the increase of the POP concentration, but increased with the increment of calcination temperature. The photocatalytic performances of these new porous materials were evaluated by using methylene blue degradation. The composite solid exhibited superior photocatalyic property and the maximum removal efficiency was up to 98% within 90 min. PMID:22884731

Chen, Daimei; Zhu, Qian; Zhou, Fengsan; Deng, Xutao; Li, Fatang

2012-07-24

250

Synthesis, characterization and effect of calcination temperature on phase transformation and photocatalytic activity of Cu,S-codoped TiO 2 nanoparticles  

Microsoft Academic Search

A novel copper and sulfur codoped TiO2 photocatalyst was synthesized by modified sol–gel method using titanium(IV) isopropoxide, CuCl2·2H2O and thiourea as precursors. The samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy equipped with energy dispersive X-ray micro-analysis (SEM-EDX), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) analysis. The XRD results showed undoped and

M. Hamadanian; A. Reisi-Vanani; A. Majedi

2010-01-01

251

One-step hydrothermal synthesis of N-doped TiO2/C nanocomposites with high visible light photocatalytic activity  

NASA Astrophysics Data System (ADS)

N-doped TiO2 nanoparticles modified with carbon (denoted N-TiO2/C) were successfully prepared by a facile one-pot hydrothermal treatment in the presence of l-lysine, which acts as a ligand to control the nanocrystal growth and as a source of nitrogen and carbon. As-prepared nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR) spectra, and N2 adsorption-desorption analysis. The photocatalytic activities of the as-prepared photocatalysts were measured by the degradation of methyl orange (MO) under visible light irradiation at ? >= 400 nm. The results show that N-TiO2/C nanocomposites increase absorption in the visible light region and exhibit a higher photocatalytic activity than pure TiO2, commercial P25 and previously reported N-doped TiO2 photocatalysts. We have demonstrated that the nitrogen was doped into the lattice and the carbon species were modified on the surface of the photocatalysts. N-doping narrows the band gap and C-modification enhances the visible light harvesting and accelerates the separation of the photo-generated electrons and holes. As a consequence, the photocatalytic activity is significantly improved. The molar ratio of l-lysine/TiCl4 and the pH of the hydrothermal reaction solution are important factors affecting the photocatalytic activity of the N-TiO2/C the optimum molar ratio of l-lysine/TiCl4 is 8 and the optimum pH is ca. 4, at which the catalyst exhibits the highest reactivity. Our findings demonstrate that the as-obtained N-TiO2/C photocatalyst is a better and more promising candidate than well studied N-doped TiO2 alternatives as visible light photocatalysts for potential applications in environmental purification.N-doped TiO2 nanoparticles modified with carbon (denoted N-TiO2/C) were successfully prepared by a facile one-pot hydrothermal treatment in the presence of l-lysine, which acts as a ligand to control the nanocrystal growth and as a source of nitrogen and carbon. As-prepared nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR) spectra, and N2 adsorption-desorption analysis. The photocatalytic activities of the as-prepared photocatalysts were measured by the degradation of methyl orange (MO) under visible light irradiation at ? >= 400 nm. The results show that N-TiO2/C nanocomposites increase absorption in the visible light region and exhibit a higher photocatalytic activity than pure TiO2, commercial P25 and previously reported N-doped TiO2 photocatalysts. We have demonstrated that the nitrogen was doped into the lattice and the carbon species were modified on the surface of the photocatalysts. N-doping narrows the band gap and C-modification enhances the visible light harvesting and accelerates the separation of the photo-generated electrons and holes. As a consequence, the photocatalytic activity is significantly improved. The molar ratio of l-lysine/TiCl4 and the pH of the hydrothermal reaction solution are important factors affecting the photocatalytic activity of the N-TiO2/C the optimum molar ratio of l-lysine/TiCl4 is 8 and the optimum pH is ca. 4, at which the catalyst exhibits the highest reactivity. Our findings demonstrate that the as-obtained N-TiO2/C photocatalyst is a better and more promising candidate than well studied N-doped TiO2 alternatives as visible light photocatalysts for potential applications in environmental purification. Electronic supplementary informatio

Wang, Dong-Hong; Jia, Li; Wu, Xi-Lin; Lu, Li-Qiang; Xu, An-Wu

2012-01-01

252

Synthesis and magnetic properties of Fe2O3–TiO2 nano-composite particles using pulsed laser gas phase evaporation–liquid phase collecting method  

NASA Astrophysics Data System (ADS)

Fe2O3–TiO2 nano-composite particles were synthesized by a new method: pulsed laser gas phase evaporation–liquid phase collection. The targets are mixtures composed of 1%, 3%, 5%, 7% and 9% content micron-sized Fe2O3 powders each also mixed with micron-sized TiO2 powder. The morphology, structure, magnetic properties and synthesis mechanism of the samples were studied by means of transmission electron microscopy, X-ray diffraction, infrared spectroscopy, vibration magnetometer and other techniques. The results indicate that the Fe2O3–TiO2 nano-composite particles prepared with this new method are spherical, diameters of the primary particles range from 20 nm to 50 nm, and the particles have a tendency to form chain connections. All of the Fe2O3–TiO2 nano-composite particles contain TiO2 and Fe2O3 phases of both rutile and anatase crystal structures. With the addition of Fe2O3 content the magnetic saturation intensity and the coercivity both increase and the magnetic properties are obviously improved, the composite Fe2O3–TiO2 nanoparticles have added magnetic recovery functionality.

Chen, Suiyuan; Zhang, Yikun; Han, Weili; Wellburn, Daniel; Liang, Jing; Liu, Changsheng

2013-10-01

253

Synthesis and characterization of TiO2 nanocrystals through sol-gel and hydrothermal methods  

Microsoft Academic Search

Nanomaterials with special and interesting properties, which can be different comparing to the macro scale materials, offer a large area of practical applications in all social-economical fields. Incorporating metallic and non-metallic dopant ions into the titanium dioxide particles can influence the performance of these photocatalysts. This affects the dynamics of electron-ion recombination and interfacial charge transfer. In this paper it

Corina Ileana Orha; Carmen Lazau; Cornelia Elena Ratiu; Paula Sfirloaga; Paulina Vlazan; Paul Barvinschi; Ioan Muscutariu; Ioan Grozescu

2009-01-01

254

Facile synthesis of TiO2/graphene composites for selective enrichment of phosphopeptides  

NASA Astrophysics Data System (ADS)

TiO2/graphene composites were synthesized through a simple one-step hydrothermal reaction and successfully used to selectively capture phosphopeptides from peptide mixtures for matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis.TiO2/graphene composites were synthesized through a simple one-step hydrothermal reaction and successfully used to selectively capture phosphopeptides from peptide mixtures for matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. Electronic supplementary information (ESI) available: Experimental details, SEM image, and EDXA pattern. See DOI: 10.1039/c2nr11791f

Lu, Jin; Wang, Mengyi; Li, Yan; Deng, Chunhui

2012-02-01

255

Self-Assembly of Large-Scale Floating TiO2 Nanorod Arrays at the Gas-Liquid Interface.  

PubMed

This paper describes a facile one-step synthesis of large-scale floating TiO2 nanorod arrays via a hydrothermal reaction without using any surfactants, which opens a new way to prepare floating photocatalysts for photodecomposition of floating organics and free-standing nanorod arrays for flexible dye-sensitized solar cells. A general model is developed to analyze the driving force for the floating TiO2 film, which may be also useful for other two-dimensional materials to determine the obtainable size of an arbitrary shaped film floated by surface tension and buoyancy. PMID:23992522

Xia, Hua-Rong; Li, Jia; Peng, Chen; Li, Long-Wei; Sun, Wen-Tao; Peng, Lian-Mao

2013-09-04

256

Large-surface mesoporous TiO2 nanoparticles: synthesis, growth and photocatalytic performance.  

PubMed

This study demonstrates a facile and effective method to generate mono-dispersed titanium dioxide spheres at ambient conditions. The size of the colloids can be controlled from 60 to 500 nm by optimizing experimental parameters (e.g., concentration, time, and temperature). Anatase TiO(2) can be obtained through titanium glycolate colloids generated in acetone via two ways: water boiling approach and calcination at a high temperature of 500°C. Particle characteristics (shape, size, and size distribution) were measured by advanced techniques, including transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), UV/Vis absorption spectrum, nitrogen gas adsorption and desorption isotherms Brunauer-Emmett-Teller (BET) surface area measurement, and X-ray diffraction technique (XRD). The possible mechanism of nucleation and growth of such colloids was discussed. The role of acetone in the formation and growth of titanium glycolate colloids was also investigated by Fourier transform infrared (FT-IR) spectroscopy. Finally, the photocatalysis performance of such anatase TiO(2) particles was tested and proved to be efficient in degradation of organic dyes (e.g., phenolphthalein and methly orange). PMID:22975400

Yang, Xiaohong; Fu, Haitao; Yu, Aibing; Jiang, Xuchuan

2012-07-25

257

Synthesis, characterization and degradation of Bisphenol A using Pr, N co-doped TiO2 with highly visible light activity  

NASA Astrophysics Data System (ADS)

Praseodymium and nitrogen co-doped titania (Pr/N-TiO2) 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), N2 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-TiO2 samples exhibited enhanced visible-light photocatalytic activity compared to N-TiO2, undoped TiO2 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 TiO2. 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

258

Controlled synthesis and Li-electroactivity of rutile TiO2 nanostructure with walnut-like morphology.  

PubMed

Herein, we report on the synthesis of phase-pure rutile walnut-like TiO(2) (W-TiO(2)) spheres composed of single-crystalline nanorod-building blocks using a surfactant-free non-aqueous acidic modified "benzyl alcohol route". Based on the various HCl concentration- and reaction time-dependent experiments, an effect of hydrochloric acid on the phase formation mechanism in a non-aqueous system is suggested. As anodes for Li-ion batteries, the W-TiO(2) sphere electrodes exhibited superior cycling performance at a rate of 0.2 C without any conducting layers coated onto the anodes; this result is attributed to their high crystallinity and large surface area. PMID:23340880

Kim, Dong Hoe; Min, Kyung-Mi; Park, Kyung-Soo; Park, Ik Jae; Cho, In Sun; Seong, Won Mo; Kim, Dong-Wan; Hong, Kug Sun

2013-03-28

259

One-pot, solvothermal synthesis of TiO2-graphene composite nanosheets.  

PubMed

In this article, we propose a facile one-pot solvothermal route for synthesizing TiO(2)-graphene composite nanosheets (TGCN). In the system, ethylene glycol not only as a reducing agent can convert graphene oxide to reduced graphene oxide nanosheets, but also is employed to control the hydrolysis and condensation rates of tetrabutoxytitanium. The obtained TGCN hybrid materials are characterized by atomic force microscopy, transmission electron microscopy, UV-vis spectroscopy, Raman spectroscopy, X-ray photo-electron spectroscopy, X-ray diffraction, and thermal gravimetric analysis. It is found that the quantity of H(2)O used in the reaction is the key to obtain high-quality product. The photocatalytic activities of the products are evaluated using the photocatalytic degradation of methylene blue (MB) as a probe reaction. The results showed that the obtained TGCN have an enhanced adsorption capacity and remarkable improvements in the photodegradation rate of MB under visible light compared to P25. PMID:22925121

Zhang, Zhe; Yang, Wenshu; Zou, Xiaoxin; Xu, Fugang; Wang, Xiaodan; Zhang, Bailin; Tang, Jilin

2012-08-07

260

Hydrothermal synthesis of nanostructured TiO2 particles and characterization of their photocatalytic antimicrobial activity.  

PubMed

Nanostructured titania particles were synthesized by using hydrothermal processing and the photocatalytic antimicrobial activities were characterized. Both sol-gel synthesized and commercial TiO2 (anatase) samples were processed with two step hydrothermal treatments, under alkaline and neutral conditions. Scanning Electron Microscope (SEM) images showed that alkaline treatment yields nanofibers and lamellar structured particles from the commercial anatase and sol-gel synthesized samples respectively. Further treatment of nanofibers and nanostructured lamellar particles with distilled water results with crystal growth and the formation of nano structured bipyramidal crystalline particles. The photocatalytic antimicrobial activities of the samples were determined against Escherichia coil under irradiation. It was observed that the samples treated under alkaline conditions have improved activity than the original anatase samples. Limited activity and resulting time lag in bacterial inactivation were observed for hydrothermally treated samples with distilled water. However, a post treatment comprising the UV irradiation in aqueous conditions enhanced the photocatalytic activity. PMID:18464422

Erdural, Beril K; Yurum, Alp; Bakir, Ufuk; Karakas, Gurkan

2008-02-01

261

Microwave-assisted synthesis of anatase TiO2 nanorods with mesopores  

NASA Astrophysics Data System (ADS)

Pure anatase TiO2 nanorods with mesopores were synthesized by a simple and low cost microwave-assisted method when tri-block copolymer was used as a structure stabilization agent and TiCl4 as metal precursor. TEM investigation showed that larger nanorods were assembled by pearl-necklace-shaped nanorods following an oriented attachment mechanism in a specific direction. A proposed hypothetical scheme showed that the formation of lyotropic titania liquid crystal (TLC) serves a key role in the stabilization of nanorods, and the mesopores on nanorods are derived from the vacancy of inter-particles of nanorods and regions lacking inorganic precursors in the TLC structure. Control experiments showed that microwave treatment plays a key role in the maintenance of original morphologies and mesostructures free from destruction even under high temperature calcinations.

Jia, Xingtao; He, Wen; Zhang, Xudong; Zhao, Hongshi; Li, Zhengmao; Feng, Yingjun

2007-02-01

262

Synthesis and characterization of porous TiO2 with wormhole-like framework structure  

SciTech Connect

A fast and reliable synthetic route for preparing contaminant-free porous TiO2 with a wormhole-like framework and close packed macropores is demonstrated based on a sol-gel process involving acid hydrolysis of an alkoxide in the presence of a cationic surfactant. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements have been used to characterize the porous structure and the crystallinity. The XRD patterns, TEM and scanning electron microscopy (SEM) images confirm that these materials have disordered wormhole-like topology with close-packed nearly hexagonal macropores. The mesopore diameters and surface area of titanium dioxide, evaluated from the N2-sorption isotherms, indicate average pore diameters of about 7 and 6 nm and surface areas of about 100 and 335 m2/g, for as-prepared and calcined samples at 400 C.

Narayanaswamy, A. [Vanderbilt University; McBride, J. [Vanderbilt University; Swafford, L.A. [Vanderbilt University; Dhar, S. [Vanderbilt University; Budai, John D [ORNL; Feldman, Leonard C. [Vanderbilt University; Rosenthal, Sandra [Vanderbilt University

2008-01-01

263

Size-controlled synthesis of anisotropic TiO2 single nanocrystals using microwave irradiation and their application for dye-sensitized solar cells.  

PubMed

A microwave hydrothermal reaction of colloidal titanates is presented as a cost-effective synthesis to produce TiO(2) single nanocrystals. The photoelectrode consisting of anisotropic nanorods and V-shaped twins has a significant advantage for achieving an appreciable incident photon-to-current conversion efficiency of 85.6% for the dye-sensitized solar cell. PMID:23307102

Manseki, Kazuhiro; Kondo, Yosuke; Ban, Takayuki; Sugiura, Takashi; Yoshida, Tsukasa

2013-01-10

264

Effect of Nb doping on structural, optical and photocatalytic properties of flame-made TiO2 nanopowder.  

PubMed

TiO(2):Nb nanopowders within a dopant concentration in the range of 0.1-15 at.% were prepared by one-step flame spray synthesis. Effect of niobium doping on structural, optical and photocatalytic properties of titanium dioxide nanopowders was studied. Morphology and structure were investigated by means of Brunauer-Emmett-Teller isotherm, X-ray diffraction and transmission electron microscopy. Diffuse reflectance and the resulting band gap energy were determined by diffuse reflectance spectroscopy. Photocatalytic activity of the investigated nanopowders was revised for the photodecomposition of methylene blue (MB), methyl orange (MO) and 4-chlorophenol under UVA and VIS light irradiation. Commercial TiO(2)-P25 nanopowder was used as a reference. The specific surface area of the powders was ranging from 42.9 m(2)/g for TiO(2):0.1 at.% Nb to 90.0 m(2)/g for TiO(2):15 at.% Nb. TiO(2):Nb particles were nanosized, spherically shaped and polycrystalline. Anatase was the predominant phase in all samples. The anatase-related transition was at 3.31 eV and rutile-related one at 3.14 eV. TiO(2):Nb nanopowders exhibited additional absorption in the visible range. In comparison to TiO(2)-P25, improved photocatalytic activity of TiO(2):Nb was observed for the degradation of MB and MO under both UVA and VIS irradiation, where low doping level (Nb?photocatalyst. PMID:23054731

Michalow, Katarzyna A; Flak, Dorota; Heel, Andre; Parlinska-Wojtan, Magdalena; Rekas, Mieczyslaw; Graule, Thomas

2012-10-03

265

Studies on photocatalytic activity of the synthesised TiO2 and Ag/TiO2 photocatalysts under UV and sunlight irradiations.  

PubMed

Photocatalytic decolorisation and degradation of Reactive Red 120 (RR 120) has been investigated under UV (365 nm) and solar light as radiation sources using synthesised nano titania catalyst prepared via sol-gel method. The study encompassed calcination of synthesised titania catalyst at a range of temperature up to 1,000°C. The effects of calcination temperature on titania catalyst have been evaluated on the decolorisation of RR 120. The analysis revealed complete decolorisation of dye solution in 100 min under UV light with the TiO2 catalyst calcined at 200°C. Only a maximum of 47% dye decolorisation was achieved under sunlight in 4 h with no improvement even after prolonged irradiation. In an endeavour to improve the catalytic activity, bare titania was modified with silver metal and a comprehensive study on the characteristics of silver modified catalyst was made. The result was an enhancement of the rate of decolorisation of dye under both UV and solar light sources. All the catalysts were characterised by XRD and BET analyses. Optimisation of the degradation of RR 120 has been carried out using the unmodified catalyst by varying the amount of catalyst, substrate concentration, pH of dye solution. Effects of addition of small amounts of various oxidants such as H2O2, KBrO3 and (NH4)2S2O8 have also been studied. Pseudo first order kinetics was observed in the photocatalytic decolorisation of dye. The mineralisation of RR 120 was monitored by TOC analysis. PMID:21278457

Vaithiyanathan, R; Sivakumar, T

2011-01-01

266

Synthesis of uniform layered protonated titanate hierarchical spheres and their transformation to anatase TiO2 for lithium-ion batteries.  

PubMed

Layered protonated titanates (LPTs), a class of interesting inorganic layered materials, have been widely studied because of their many unique properties and their use as precursors to many important TiO(2)-based functional materials. In this work, we have developed a facile solvothermal method to synthesize hierarchical spheres (HSs) assembled from ultrathin LPT nanosheets. These LPT hierarchical spheres possess a porous structure with a large specific surface area and high stability. Importantly, the size and morphology of the LPT hierarchical spheres are easily tunable by varying the synthesis conditions. These LPT HSs can be easily converted to anatase TiO(2) HSs without significant structural alteration. Depending on the calcination atmosphere of air or N(2), pure anatase TiO(2) HSs or carbon-supported TiO(2) HSs, respectively, can be obtained. Remarkably, both types of TiO(2) HSs manifest excellent cyclability and rate capability when evaluated as anode materials for high-power lithium-ion batteries. PMID:22246679

Wu, Hao Bin; Lou, Xiong Wen David; Hng, Huey Hoon

2012-01-13

267

Synthesis of TiO2 Nanotube by Hydrothermal Method and Application for Dye-Sensitized Solar Cell  

Microsoft Academic Search

The TiO2 nanotube was synthesized by a hydrothermal method dependent on temperature. TiO2 nanotube was coated on FTO glass by screen printing The TiO2 nanotube was increasing as autoclaving temperature. The dye-sensitized solar cells were fabricated using ruthenium (II)(N719) dye and electrolyte (). The crystalline structure and morphology were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). The

Chang Hyo Lee; Kyung Hwan Kim; Kyung Uk Jang; Sang Jun Park; Hyung Wook Choi

2011-01-01

268

Sonoelectrochemical synthesis of highly photoelectrochemically active TiO2 nanotubes by incorporating CdS nanoparticles  

Microsoft Academic Search

Self-organized anodic TiO2 nanotube arrays (TiO2NTs) are functionalized with CdS nanoparticle based perfusion and deposition through a single-step sonoelectrodeposition method. Even controlled at 50 °C, CdS nanoparticles with smaller size and more homogeneous distribution are successfully synthesized in dimethyl sulfoxide (DMSO) under ultrasonic irradiation. Moreover, TiO2 nanotubes can be filled with nanoparticles because of the ultrasonic effect. The CdS incorporated

Cheng Lin Wang; Lan Sun; Hong Yun; Jing Li; Yue Kun Lai; Chang Jian Lin

2009-01-01

269

Development of a novel fast-hydrothermal method for synthesis of Ag-doped TiO 2 nanocrystals  

Microsoft Academic Search

Undoped and Ag-doped TiO2 anatase nanocrystals were successfully prepared from titanium isopropoxide by a novel fast-hydrothermal method. The as-prepared TiO2 nanocrystals were characterized by XRD, DRUV–VIS spectroscopy and SEM\\/EDX. The results show that the anatase TiO2 has a particle size of around 4nm from SEM and XRD results.

Carmen Lazau; Paula Sfirloaga; Corina Orha; Cornelia Ratiu; Ioan Grozescu

2011-01-01

270

Synthesis of TiO 2 submicro-rings and their application in dye-sensitized solar cell  

Microsoft Academic Search

In this paper, novel TiO2 submicro-rings were synthesized via potentiostatic anodization of titanium powder coated on transparent conducting oxide glass. The TiO2 submicro-rings film was characterized by SEM, XPS and 3D optical profiling. Accordingly, a possible growth mechanism of submicro-rings was discussed. The TiO2 submicro-rings based dye-sensitized solar cell (DSSC) with the film thickness of ca. 3.1?m was assembled and

Ming Li; Yong Liu; Hai Wang; Hui Shen

2011-01-01

271

Synthesis of high-density nanocavities inside TiO2-B nanoribbons and their enhanced electrochemical lithium storage properties.  

PubMed

Single crystalline TiO2-B nanoribbons with high-density nanocavities were successfully synthesized via a simple hydrothermal route. The as-prepared TiO2-B nanoribbons exhibited a large Brunauer, Emmett, and Teller (BET) surface area of about 305 m(2)/g because of the high-density nanocavities inside the thin nanoribbons. Electrochemical measurements indicated that the TiO2-B nanoribbons with dense nanocavities showed discharge specific capacity higher than those of TiO2-B nanotubes and nanowires. It was found that the dense nanocavities have an important influence on the electrochemical lithium intercalation properties. PMID:18837547

Li, Quanjun; Zhang, Jingwei; Liu, Bingbing; Li, Ming; Liu, Ran; Li, Xianglin; Ma, Honglei; Yu, Shidan; Wang, Lin; Zou, Yonggang; Li, Zepeng; Zou, Bo; Cui, Tian; Zou, Guangtian

2008-10-07

272

Tuning the surface structure of nitrogen-doped TiO2 nanofibres--an effective method to enhance photocatalytic activities of visible-light-driven green synthesis and degradation.  

PubMed

Nitrogen-doped TiO2 nanofibres of anatase and TiO2(B) phases were synthesised by a reaction between titanate nanofibres of a layered structure and gaseous NH3 at 400-700 °C, following a different mechanism than that for the direct nitrogen doping from TiO2. The surface of the N-doped TiO2 nanofibres can be tuned by facial calcination in air to remove the surface-bonded N species, whereas the core remains N doped. N-Doped TiO2 nanofibres, only after calcination in air, became effective photocatalysts for the decomposition of sulforhodamine B under visible-light irradiation. The surface-oxidised surface layer was proven to be very effective for organic molecule adsorption, and the activation of oxygen molecules, whereas the remaining N-doped interior of the fibres strongly absorbed visible light, resulting in the generation of electrons and holes. The N-doped nanofibres were also used as supports of gold nanoparticle (Au NP) photocatalysts for visible-light-driven hydroamination of phenylacetylene with aniline. Phenylacetylene was activated on the N-doped surface of the nanofibres and aniline on the Au NPs. The Au NPs adsorbed on N-doped TiO2(B) nanofibres exhibited much better conversion (80 % of phenylacetylene) than when adsorbed on undoped fibres (46 %) at 40 °C and 95 % of the product is the desired imine. The surface N species can prevent the adsorption of O2 that is unfavourable for the hydroamination reaction, and thus, improve the photocatalytic activity. Removal of the surface N species resulted in a sharp decrease of the photocatalytic activity. These photocatalysts are feasible for practical applications, because they can be easily dispersed into solution and separated from a liquid by filtration, sedimentation or centrifugation due to their fibril morphology. PMID:23463719

Zheng, Zhanfeng; Zhao, Jian; Yuan, Yong; Liu, Hongwei; Yang, Dongjiang; Sarina, Sarina; Zhang, Hongjie; Waclawika, Eric R; Zhu, Huaiyong

2013-03-05

273

Synthesis and study of magnetic properties of Co-doped anatase TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

Anatase phase Ti0.97Co0.03O2 nanoparticles were synthesized using two different preparation methods. The prepared samples were investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF) analysis, and magnetization measurements. The particle diameters were controlled by adjusting the annealing temperature, and they ranged from 4.2-7.0 nm for Ti0.97Co0.03O2 encapsulated in amorphous SiO2, and from 14-61 nm for Ti0.97Co0.03O2 that was not encapsulated in amorphous SiO2. Magnetization measurements were performed on the 7.0-nm sample from the former sample set, and on the 14-nm sample from the latter sample set, and both these samples exhibited an identical crystal structure and an equal number of magnetic ions, as confirmed by XRF and XRD measurements. The magnetization curves for the two samples indicated their ferromagnetic behavior at room temperature. However, the magnetic parameters of saturation magnetization MS and coercive force HC were clearly different for these two samples. We attribute this difference in magnetic properties between these samples to magnetic impurities present due to the different degrees of solubility of Co ions in the TiO2 lattice.

Yano, S.; Kurokawa, A.; Takeuchi, H.; Yanoh, T.; Onuma, K.; Kondo, T.; Miike, K.; Miyasaka, T.; Ichiyanagi, Y.

2013-04-01

274

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

275

Sulfated TiO 2 Decontaminate 2-CEES and DMMP in Vapor Phase  

Microsoft Academic Search

An acid photocatalyst TiO2, modified with H2SO4, is prepared and used to decontaminate Chemical Warfare Agents (CWAs) simulants 2-CEES (2-chloroethyl ethyl sulfide) and\\u000a DMMP (dimethyl methylphosphonate) in vapor phase. Compared with the unmodified pure TiO2 photocatalyst, the adsorption capacity on the sulfated photocatalyst increases by 50%, and the conversion for 2-CEES increases\\u000a more than 20%. It is found that the

ShiTong Han; GuoYing Zhang; HaiLing Xi; DaNian Xu; XianZhi Fu; XuXu Wang

2008-01-01

276

Synthesis, characterization and application of TiO2 nanopowders as special paper coating pigment  

NASA Astrophysics Data System (ADS)

TiO2 nanopigments in two pure crystallographic forms (anatase and rutile) have been synthesized successfully by two methods; hydrothermal and hydrolysis. The produced pigments from the two methods were investigated physicochemically by several analyses tools. Then they were applied in paper coating mixtures and their influence on coated paper properties was systematically investigated. XRD and FTIR investigations showed that the prepared pigments using hydrothermal method at 100 and 120 °C were a mixture of anatase and brookite and pure anatase, respectively, whereas hydrolysis method produced pure rutile phase pigment. TEM investigation showed that the crystallite size of anatase, mixture of anatase and brookite and rutile samples are 6.2, 11.7, and 9.2 nm, respectively. BET studies proved that anatase pigment has 140.74 m2/g, 0.237 cc/g and 18.33 Å, whereas rutile has 60.621 m2/g, 0.122 cc/g and 14.669 Å, surface area, pore volume and pore diameter, respectively. UV-Vis absorption and PL emission characteristics of the prepared pigments showed that the energy gaps for anatase, mixture of anatase and brookite and rutile are 3.36, 3.30 and 3.37 eV, respectively. The addition of the prepared nanopigments in conjugation with clay in coating mixture increased both brightness and opacity of the coated papers. The greatest effect was obtained upon using rutile nanopigment. Also there was a significant decrease in coated paper roughness while the air permeance started to decrease then increased at 50 % addition levels. In all coated paper, rutile pigment showed the highest enhancement effect on coated paper properties.

El-Sherbiny, Samya; Morsy, Fatma; Samir, Marwa; Fouad, Osama A.

2013-03-01

277

CdS and CdTeS quantum dot decorated TiO2 nanowires. Synthesis and photoefficiency.  

PubMed

An easy process was developed to synthesize TiO(2) nanowires sensitized with CdS and CdTeS quantum dots (QDs) requiring no pretreatment of the TiO(2) nanowires prior to nanoparticle generation. CdS and CdTeS nanoparticles were firstly grown by an in situ colloidal method directly onto the TiO(2) surface, hence not requiring subsequent functionalization of the QDs. The resulting nanostructure assembly and composition was confirmed by transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Successful decoration of the TiO(2) nanowires by the QDs was observed by TEM, while XPS spectra provided clear evidence for the coexistence of CdS and CdTeS QDs and TiO(2) nanowires. The electronic structure of the TiO(2) nanowires was preserved as indicated by Raman spectroscopy. Preliminary photocurrent measurements showed that inclusion of Te in CdS QDs improved the photocurrent efficiency. Compared to bare TiO(2) nanowires, CdS/TiO(2) nanoassemblies showed an enhancement in photocurrent efficiency of 300% while CdTeS/TiO(2) presented an improvement of 350%. This study indicates that the generation of strongly anchored CdS and CdTeS QDs on a TiO(2) nanowire surface is achievable without introduction of a linker molecule, whose presence is known to decrease the electron injection efficiency. PMID:21212494

Medina-Gonzalez, Yaocihuatl; Xu, William Z; Chen, Bo; Farhanghi, Nasrin; Charpentier, Paul A

2011-01-07

278

Synthesis of nanosize MCM-41 loaded with TiO2 and study of its photocatalytic activity  

NASA Astrophysics Data System (ADS)

In recent years, nanosized mesoporous materials have received significant attention due to their impact in different processes. Several diverse applications of these materials, e.g. high density magnetic recording, magnetic fluids, magnetic refrigeration as well as in photocatalysis, solar cells, photosensors, have triggered considerable research activities in the area of nanotechnology. In this work, nanosize MCM-41 was synthesized and loaded then with TiO2 using tetra butoxy titanium (TBT). As prepared TiO2 loaded materials was investigated by using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activity of the prepared TiO2 loaded MCM-41 was finally evaluated by the degradation of methyl orange under irradiation of UV light. The result showed that TiO2 loaded on nanosize MCM-41 has higher photocatalytic activity than that of TiO2.

Sadjadi, M. S.; Farhadyar, N.; Zare, K.

2009-07-01

279

Facile synthesis and catalytic activity of MoS 2\\/TiO 2 by a photodeposition-based technique and its oxidized derivative MoO 3\\/TiO 2 with a unique photochromism  

Microsoft Academic Search

UV-light irradiation to TiO2 in an aqueous ethanol solution of (NH4)2MoS4 under deaerated conditions has yielded molybdenum(IV) sulfide nanoparticles on a TiO2 surface (MoS2\\/TiO2) to be transformed into molybdenum(VI) oxide species highly dispersed at a molecular level by a subsequent heating at 773K in air (m-MoO3\\/TiO2). In HCOOH aqueous solutions, the MoS2\\/TiO2 system exhibits a high level of photocatalytic activity

Shigeki Kanda; Tomoki Akita; Musashi Fujishima; Hiroaki Tada

2011-01-01

280

Effect of plasma treatment with various gases on nanocrystalline TiO2 for dye-sensitized solar cell (DSSC)  

Microsoft Academic Search

Titanium dioxide (TiO2) photocatalyst with anatase phase has been extensively investigated for Dye-sensitized solar cell (DSSC). The chemical activation of OH group on TiO2 surface can provide valuable electron transfer from sensitizer dye to TiO2. The plasma treatment is suggested as improving hydrophilic property of nano-structured TiO2 surface, and has different effects on TiO2 surface depending on the gas to

Jumi Kim; Min Jae Sin; Hyung Jin Kim; Byungyou Hong

2010-01-01

281

Scalable synthesis of TiO2/graphene nanostructured composite with high-rate performance for lithium ion batteries.  

PubMed

A simple and scalable method is developed to synthesize TiO(2)/graphene nanostructured composites as high-performance anode materials for Li-ion batteries using hydroxyl titanium oxalate (HTO) as the intermediate for TiO(2). With assistance of a surfactant, amorphous HTO can condense as a flower-like nanostructure on graphene oxide (GO) sheets. By calcination, the HTO/GO nanocomposite can be converted to TiO(2)/graphene nanocomposite with well preserved flower-like nanostructure. In the composite, TiO(2) nanoparticles with an ultrasmall size of several nanometers construct the porous flower-like nanostructure which strongly attached onto conductive graphene nanosheets. The TiO(2)/graphene nanocomposite is able to deliver a capacity of 230 mA h g(-1) at 0.1 C (corresponding to a current density of 17 mA g(-1)), and demonstrates superior high-rate charge-discharge capability and cycling stability at charge/discharge rates up to 50 C in a half cell configuration. Full cell measurement using the TiO(2)/graphene as the anode material and spinel LiMnO(2) as the cathode material exhibit good high-rate performance and cycling stability, indicating that the TiO(2)/graphene nanocomposite has a practical application potential in advanced Li-ion batteries. PMID:23185962

Xin, Xing; Zhou, Xufeng; Wu, Jinghua; Yao, Xiayin; Liu, Zhaoping

2012-11-29

282

Hydrothermal synthesis of anatase TiO2 nanorods with high crystallinity using ammonia solution as a solvent.  

PubMed

Anatase TiO2 nanorods with high crystallinity were synthesized using ammonia solution (28%) as a solvent by through the hydrothermal method. The X-ray diffraction pattern confirmed the product's anatase phase and high crystallinity, and the transmission electron microscope (TEM) image demonstrated the unique morphologies of the two ends of the TiO2 nanorods (two tringle-horn shapes and one round-horn shape), whose lengths and widths were within the ranges of 200-300 and 60-110 nm, respectively. The high-resolution TEM image clearly displayed the crystal lattices of the (101) planes lying along the direction of the lengthes of the TiO2 nanorods. The energy dispersive X-ray spectrum of a TiO2 nanorod revealed the presence of about 4 atm% nitrogen element as a trace in the anatase TiO2 nanorod. The Raman spectrum of the TiO2 nanorods also showed the typical bands of anatase TiO2 and very weak peaks resulting from the TiN first-order defect-induced Raman scattering. The UV-vis diffuse-reflectance spectra showed a slight red shift (about 3 nm) of the anatase TiO2 nanorods compared with P25, which probably resulted from the trace of TiN on the surfaces of the anatase TiO2 nanorods. A three-stage-process mechanism model is proposed for the formation of the nanorods: Rhombus crystallites bounded by four {101} faces are first formed through anisotropic growth, then longer rhombus crystallites are grown via oriented attachment, finally, nanorods with a unique morphology are self-assembled by Van Der Waals forces. PMID:22121648

Zhang, Dong Ri; Cha, Hyun Gil; Kang, Young Soo

2011-07-01

283

Preillumination of TiO2 and Ta2O5 photoactive thin films as a tool to tailor the synthesis of composite materials.  

PubMed

Illumination of TiO 2 thin films with UV light is known to induce the transformation of the surface of this material from partially hydrophobic into fully hydrophilic. The present work shows that this transformation is accompanied by other effects that may be used to control the synthesis of composite materials. For this purpose, TiO 2 and Ta 2O 5 transparent thin films with a columnar structure and open pores were prepared by electron evaporation at glancing angles. Transparent TiO 2 thin films with micropores (i.e., pores smaller than 2 nm) prepared by plasma enhanced chemical vapor deposition (PECVD) were also used. All these films became hydrophilic upon UV illumination. Rhodamine 6G and Rhodamine 800 dyes were irreversibly adsorbed within the columns of the TiO 2 and Ta 2O 5 thin films by immersion into a water solution of these molecules. Isolated and aggregated molecules of these two dyes were detected by visible absorption spectroscopy. The infiltration adsorption efficiency was directly correlated with the acidity of the medium, increasing at basic pHs as expected from simple considerations based on the concepts of the point of zero charge (PZC) in colloidal oxides. The infiltration experiments were repeated with columnar TiO 2 and Ta 2O 5 thin films that were subjected to preillumination with UV light. It was found that this treatment produced a modification in the type (isolated or aggregated) and amount of dye molecules incorporated into the pores. Moreover, the selective adsorption of a given dye in preilluminated areas of the films permitted the lithographic coloring of the films. Preillumination also controls the UV induced deposition of silver on the surface of the microporous TiO 2 thin films. It was found that the size distribution of the formed silver nanoparticles was dependent on the preillumination treatment and that a well-resolved surface plasmon resonance at around 500 nm was only monitored in the preilluminated films. A model is proposed to account for the effects induced by UV preillumination on the TiO 2 and Ta 2O 5 oxide surfaces. The possibilities of this type of light treatment for the tailored synthesis of nanocomposite thin films (i.e., dye-oxide, metal nanoparticles-oxide) are highlighted. PMID:18642860

Sánchez-Valencia, Juan R; Borrás, Ana; Barranco, Angel; Rico, Victor J; Espinós, Juan P; González-Elipe, Agustín R

2008-07-19

284

TiO2 nanoparticles are phototoxic to marine phytoplankton.  

PubMed

Nanoparticulate titanium dioxide (TiO(2)) is highly photoactive, and its function as a photocatalyst drives much of the application demand for TiO(2). Because TiO(2) generates reactive oxygen species (ROS) when exposed to ultraviolet radiation (UVR), nanoparticulate TiO(2) has been used in antibacterial coatings and wastewater disinfection, and has been investigated as an anti-cancer agent. Oxidative stress mediated by photoactive TiO(2) is the likely mechanism of its toxicity, and experiments demonstrating cytotoxicity of TiO(2) have used exposure to strong artificial sources of ultraviolet radiation (UVR). In vivo tests of TiO(2) toxicity with aquatic organisms have typically shown low toxicity, and results across studies have been variable. No work has demonstrated that photoactivity causes environmental toxicity of TiO(2) under natural levels of UVR. Here we show that relatively low levels of ultraviolet light, consistent with those found in nature, can induce toxicity of TiO(2) nanoparticles to marine phytoplankton, the most important primary producers on Earth. No effect of TiO(2) on phytoplankton was found in treatments where UV light was blocked. Under low intensity UVR, ROS in seawater increased with increasing nano-TiO(2) concentration. These increases may lead to increased overall oxidative stress in seawater contaminated by TiO(2), and cause decreased resiliency of marine ecosystems. Phototoxicity must be considered when evaluating environmental impacts of nanomaterials, many of which are photoactive. PMID:22276179

Miller, Robert J; Bennett, Samuel; Keller, Arturo A; Pease, Scott; Lenihan, Hunter S

2012-01-20

285

Controlled synthesis of nitrogen-doped binary and ternary TiO2 nanostructures with enhanced visible-light catalytic activity  

NASA Astrophysics Data System (ADS)

Nitrogen doping in association with a heterostructure not only modifies the band structure of TiO2 to make it more responsive to visible light, but also suppresses charge recombination and leads TiO2 to have enhanced photoactivity. In this paper, we report on the controlled synthesis of nitrogen doped binary and ternary TiO2 nanostructures through a hydrazine-mediated solvothermal approach. The phase, size, and morphology of the samples can be tuned by simply changing the reaction time. Also, the visible-light photoactivity of the samples was evaluated by decomposing methyl orange and formaldehyde in aqueous solution without any external oxidative or reductive radical-generating sources. The as-prepared catalysts exhibit enhanced photocatalytic activity compared to P25 and the undoped counterpart, and the selected catalyst shows high photostability and photoactivity after reuse four times. This new-type TiO2 nanostructures present a promising candidate for applications in photocatalysis, photochemistry, sensors, and solar cells.

Gai, Ligang; Mei, Qinghu; Duan, Xiuquan; Jiang, Haihui; Zhou, Guowei; Tian, Yan; Lu, Xifeng

2013-03-01

286

One-pot synthesis and optical properties of Eu3+-doped nanocrystalline TiO2 and ZrO2  

NASA Astrophysics Data System (ADS)

A simple and versatile one-pot sol-gel synthesis of Eu3+-doped nanocrystalline TiO2 and ZrO2 nanomaterials is reported in this paper. It consists of the controlled crystallization of Eu3+-doped TiO2 or ZrO2 nanoparticles from an initial solution containing the metal alkoxide, the lanthanide precursor, a complexing agent and a non-complexing acid. The main interest is that it could be extended to different lanthanide ions and inorganic metal oxides to prepare other multifunctional nanomaterials. The characterization by XRD, HRTEM and SAED techniques showed that the TiO2 and ZrO2 crystallization takes place at very low temperatures (60 °C) and that the crystallite size can be tailored by modifying the synthetic conditions. The optical properties of the resulting materials were studied by emission spectra and decay measurements. Both Eu3+:TiO2 and Eu3+:ZrO2 samples exhibited long lifetime values after removing organic components (? = 0.7 and 1.3 ms, respectively), but the Eu3+:ZrO2 system is specially promising for photonic applications since its ? value is longer than some reported for other inorganic or hybrid matrices in which Eu3+ ions are complexed. This behaviour has been explained through an effective dispersion of the lanthanide ions within the ZrO2 nanocrystals.

Julián, Beatriz; Corberán, Rosa; Cordoncillo, Eloisa; Escribano, Purificación; Viana, Bruno; Sanchez, Clément

2005-11-01

287

Synthesis of biomorphological mesoporous TiO2 templated by mimicking bamboo membrane in supercritical CO2.  

PubMed

A new approach is presented for preparing biomorphological mesoporous TiO2 templated by mimicking bamboo inner shell membrane via supercritical CO2 (SCCO2) transportation through titanium tetrabutyloxide (TTBO). The analysis of wide-angle X-ray powder diffraction (XRD) showed the prepared TiO2 in phase of anatase, and the small-angle XRD revealed the presence of mesopores without periodicity. The product exhibited the shape of crinkled films and extended in two dimensions up to centimeters. The electron microscopic observation showed that the TiO2 films were around 200 nm in thickness, and across the films there were numerous round or ellipse-shaped mesopores, being 10-50 nm in diameter, which were formed by the close packing of TiO2 particles. High-resolution transmission electron microscope (HRTEM) displayed that the single TiO2 particle size was about 12.5 nm. The UV-vis absorption spectrum was transparent in the wavelength of 320-350 nm for suspensions of the prepared mesoporous TiO2 in ethanol at the concentration of 5.0 mg/l. The mesoporous TiO2 prepared with the aid of SCCO2 exhibited an obvious blue shift compared with the TiO2 prepared by sol-gel infiltration. The possible mechanism for the formation of the mesoporous TiO2 is summarized into a biomimetic mineralization pathway. First, TTBO was transported to the membrane surface via SCCO2, and then condensed. Hydrolysis reactions between the functional groups of organic membrane and TTBO took place to form the nuclear TiO2, and the TiO2 seeds grew around the organic membrane into TiO2 mesoporous materials. The approach provides a low-cost and efficient route for the production of ceramics nanomaterials with unique structural features, which may have potential application in designing UV-selective shielding devices [S. Zhao, X.H. Wang, S.B. Xin, Q. Jiang, X.P. Liang, Rare Metal Mater. Eng. 35 (2006) 508-510]. PMID:17689547

Li, Jinhong; Shi, Xiaoying; Wang, Lijuan; Liu, Fei

2007-08-08

288

Synthesis and electrorheological effect of Cr doped TiO2 nanorods with nanocavities in silicone oil suspensions  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) nanorods with nanocavities doped with chromium (Cr) were synthesized by hydrothermal method. The morphology of prepared nanorods was determined by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The electrorheological (ER) behaviour of suspensions based on TiO2 was investigated under the steady shear, and the yield stress was chosen as a suitable tool for a comparison of ER performance. Some optimum in level of Cr doping of TiO2 was found.

Almajdalawi, S.; Pavlinek, V.; Mrlik, M.; Cheng, Q.; Sedlacik, M.

2013-02-01

289

Synthesis of a Sonogel-Carbon Modified Sensor Electrode with Titanium Oxide (TiO2) to Detect Catechol in the Presence of Common Interferent by Voltammetric Studies  

Microsoft Academic Search

This experiment was part of an Analytical\\/Instrumental Analysis course. It requires the synthesis of a sonogel-carbon electrode (SGC) modified with a TiO2 sol-gel and heated at high temperatures. The electrochemical response of the synthesized SGC\\/TiO2 electrode was compared to that of an unmodified sonogel-carbon electrode to detect catechol (catecholamines). The design of the experiment encourages some choices to be made

Suzanne K. Lunsford; Amber Yeary; Jelynn Stinson; Hyeok Choi; Dionysios D. Dionysiou

290

Chemical vapor deposition of carbon on particulate TiO 2 from CH 4 and subsequent carbothermal reduction for the synthesis of nanocrystalline TiC powders  

Microsoft Academic Search

The present study aims to investigate chemical vapor deposition of carbon from CH4 on TiO2 particles and to establish optimal conditions for the synthesis of nanocrystalline TiC powders. Mass measurements, XRD, HR-TEM and SEM were used to characterize the products at various stages of the reactions. Oxide particles gained mass rapidly at 1300K under CH4 atmosphere and were coated with

S. Cetinkaya; S. Eroglu

2011-01-01

291

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

292

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

293

Solvothermal synthesis of N-doped TiO2 nanotubes for visible-light-responsive photocatalysis.  

PubMed

Visible-light-responsive tubular N-doped TiO2 nanocrystallites were synthesized via an environment-conscious solvothermal treatment of protonated titanate nanotubes in an NH4Cl/ethanol/water solution. PMID:19048159

Jiang, Zheng; Yang, Fan; Luo, Nianjun; Chu, Bryan T T; Sun, Deyin; Shi, Huahong; Xiao, Tiancun; Edwards, Peter P

2008-11-04

294

Anatase TiO2 hollow microspheres with exposed {0 0 1} facets: Facile synthesis and enhanced photocatalysis  

NASA Astrophysics Data System (ADS)

Anatase TiO2 hollow microspheres with a high percentage of exposed {0 0 1} facets have been successfully synthesized by a one-step hydrothermal strategy in the presence of hydrogen peroxide and hydrofluoric acid solution. It is found that both HF and H2O2 play an essential role in the formation of TiO2 hollow polyhedron TiO2 microspheres with exposed {0 0 1} facets. A plausible mechanism for formation of the TiO2 hollow spheres with exposed {0 0 1} facets by dissolution-recrystallization and Ostwald ripening is proposed based on the experimental observations. The products exhibited enhanced photocatalytic activities for degradation of methylene blue dye present in aqueous solution under ultraviolet light irradiation at ambient temperature.

Wang, Xiaoliang; He, Huanlong; Chen, Yan; Zhao, Jinqiu; Zhang, Xiangyi

2012-05-01

295

Ionic liquid-assisted one-step hydrothermal synthesis of TiO 2 -reduced graphene oxide composites  

Microsoft Academic Search

We have demonstrated a facile and efficient strategy for the fabrication of soluble reduced graphene oxide sheets (RGO) and\\u000a the preparation of titanium oxide (TiO2) nanoparticle-RGO composites using a modified one-step hydrothermal method. It was found that graphene oxide could be easily\\u000a reduced under solvothermal conditions with ascorbic acid as reductant, with concomitant growth of TiO2 particles on the RGO

Jianfeng Shen; Min Shi; Bo Yan; Hongwei Ma; Na Li; Mingxin Ye

296

A novel shape-controlled synthesis of dispersed silver nanoparticles by combined bioaffinity adsorption and TiO 2 photocatalysis  

Microsoft Academic Search

Shape-controlled silver nanoparticles (Ag NPs) were prepared in a well-dispersed mode on the active imprinting sites of chitosan-TiO2 adsorbent (CTA) by means of bioaffinity adsorption and TiO2 photocatalysis. Nontoxic hydrogen peroxide (H2O2) was used as a suitable etching reagent in our production of shape-controlled Ag NPs, since it could regulate the TiO2 photocatalysis and accelerate the generation of O2. With

Enzan Chen; Haijia Su; Wanying Zhang; Tianwei Tan

2011-01-01

297

Efficient synthesis of titania nanotubes and enhanced photoresponse of Pt decorated TiO 2 for water splitting  

Microsoft Academic Search

We investigated the effect of HMT (hexamethylenetetraamine) on the anodic growth of TiO2 nanotube arrays. The tube length increases to 4.3 ?m with HMT concentration increasing to 0.04 mol·L?1. Adsorption of HMT on the TiO2 surface is shown to markedly decrease the chemical dissolution rate of tube mouth, resulting in longer nanotube length. Furthermore,\\u000a Pt nanoparticles were successfully deposited on

Yuxin Yin; Xin Tan; Feng Hou; Lin Zhao

2009-01-01

298

Facile and effective synthesis of hierarchical TiO2 spheres for efficient dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) crystalline anatase TiO2 hierarchical spheres were successfully derived from Ti foils via a fast, template-free, low-temperature hydrothermal route followed by a calcination post-treatment. These dandelion-like TiO2 spheres are composed of numerous ultrathin nanoribbons, which were subsequently split into fragile nanoflakes as a result of the decomposition of Ti-complex intermediates to TiO2 and H2O at high temperature. The dye-sensitized solar cells (DSSCs) employing such hierarchically structured TiO2 spheres as the photoanodes exhibited a light-to-electricity conversion efficiency of 8.50%, yielding a 28% enhancement in comparison with that (6.64%) of P25-based DSSCs, which mainly benefited from the enhanced capacity of dye loading in combination with effective light scattering and trapping from hierarchical architecture.Three-dimensional (3D) crystalline anatase TiO2 hierarchical spheres were successfully derived from Ti foils via a fast, template-free, low-temperature hydrothermal route followed by a calcination post-treatment. These dandelion-like TiO2 spheres are composed of numerous ultrathin nanoribbons, which were subsequently split into fragile nanoflakes as a result of the decomposition of Ti-complex intermediates to TiO2 and H2O at high temperature. The dye-sensitized solar cells (DSSCs) employing such hierarchically structured TiO2 spheres as the photoanodes exhibited a light-to-electricity conversion efficiency of 8.50%, yielding a 28% enhancement in comparison with that (6.64%) of P25-based DSSCs, which mainly benefited from the enhanced capacity of dye loading in combination with effective light scattering and trapping from hierarchical architecture. Electronic supplementary information (ESI) available: FESEM images of samples prepared in other control experiments and a cross-sectional view of the three films. See DOI: 10.1039/c3nr01604h

Ye, Meidan; Chen, Chang; Lv, Miaoqiang; Zheng, Dajiang; Guo, Wenxi; Lin, Changjian

2013-06-01

299

Synthesis, structural and optical properties of well dispersed anatase TiO 2 nanoparticles by non-hydrothermal method  

Microsoft Academic Search

The formation of nanocrystalline TiO2 particles has been investigated via a surfactant-free synthetic non- hydrothermal method. Titanium isopropoxide and toluene were used as the starting materials. At a low temperature of 250 °C for 6 h, the reaction mixture turned in to a white precipitate (TiO2) as a result of the thermal decomposition of metal alkoxide. The obtained product was

P. Dennis Christy; N. S. Nirmala Jothi; N. Melikechi; P. Sagayaraj

2009-01-01

300

Synthesis of TiO2 nanotube films via pulsed laser deposition followed by a hydrothermal treatment  

Microsoft Academic Search

Titanium dioxide nanotube (TNT) films were prepared by pulsed laser deposition (PLD) of P25 and P90 TiO2 nanoparticles onto stainless steel foils followed by a hydrothermal treatment (HT). Heating the PLD films in a TNT precursor solution at 150°C resulted in a well-adhered dense mat of TNTs that were ?10?nm in diameter with a pore size of ?4?nm. The TiO2

Jose A. Losilla; Chalita Ratanatawanate; Kenneth J. Balkus Jr

2012-01-01

301

Synthesis and enhanced gas sensing properties of crystalline CeO 2\\/TiO 2 core\\/shell nanorods  

Microsoft Academic Search

Crystalline CeO2\\/TiO2 core\\/shell nanorods were fabricated by a hydrothermal method and a subsequent annealing process under the hydrogen and air atmosphere. The thickness of the outer shell composed of crystal TiO2 nanoparticles can be tuned in the range of 5–11nm. The crystal core\\/shell nanorods exhibited enhanced gas-sensing properties to ethanol vapor in terms of sensor response and selectivity. The calculated

Yu-Jin Chen; Gang Xiao; Tie-Shi Wang; Fan Zhang; Yang Ma; Peng Gao; Chun-Ling Zhu; Endi Zhang; Zhi Xu; Qiu-hong Li

2011-01-01

302

Synthesis of TiO 2 Nanoparticles by Microemulsion\\/Heat Treated Method and Photodegradation of Methylene Blue  

Microsoft Academic Search

In this work, TiO2 nanoparticles were prepared by microemulsion (ME)\\/heat treated method and its photodecomposition property of methylene blue.\\u000a Microemulsion (ME) consisted of water, cyclohexane and an anionic surfactant such as bis (2-ethylhexyl) sodium sulfosuccinate\\u000a (AOT). Titanium tetraisopropoxide (TTIP) was dropped into the ME solution and then then TiO2 nanoparticles were formed by the hydrolysis reaction between TTIP in the

Maryam Hosseini Zori

2011-01-01

303

Sonoelectrochemical synthesis of highly photoelectrochemically active TiO2 nanotubes by incorporating CdS nanoparticles  

NASA Astrophysics Data System (ADS)

Self-organized anodic TiO2 nanotube arrays (TiO2NTs) are functionalized with CdS nanoparticle based perfusion and deposition through a single-step sonoelectrodeposition method. Even controlled at 50 °C, CdS nanoparticles with smaller size and more homogeneous distribution are successfully synthesized in dimethyl sulfoxide (DMSO) under ultrasonic irradiation. Moreover, TiO2 nanotubes can be filled with nanoparticles because of the ultrasonic effect. The CdS incorporated TiO2NTs (CdS-TiO2NTs) effectively harvest solar light in the UV as well as the visible light (up to 480 nm) region. Compared with pure TiO2NTs, a more than ninefold enhancement in photocurrent response is observed using the CdS-TiO2NTs. Maximum incident photon to charge carrier efficiency (IPCE) values of 99.95% and 9.85% are observed respectively for CdS-TiO2 nanotubes and pure TiO2NTs. The high value of IPCE observed with the CdS-TiO2NTs is attributed to the increased efficiency of charge separation and transport of electrons. A schematic diagram is proposed to illustrate the possible process of CdS formation in nanotubes under sonochemical and electrochemical conditions.

Wang, Cheng Lin; Sun, Lan; Yun, Hong; Li, Jing; Lai, Yue Kun; Lin, Chang Jian

2009-07-01

304

Facile hydrothermal synthesis of porous TiO2 nanowire electrodes with high-rate capability for Li ion batteries  

NASA Astrophysics Data System (ADS)

Anatase TiO2 nanowires were successfully synthesized using a low-temperature hydrothermal treatment on as-prepared one-dimensional (1D) hydrogen titanate nanowires (H2Ti3O7) at 180 °C. The anatase TiO2 nanowires were porous in nature with a high specific surface area. These nanowires were characterized using transmission electron microscopy (TEM), high-resolution TEM, x-ray powder diffraction, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) measurements. The topochemical phase transformation mechanism from H2Ti3O7 to anatase TiO2 is discussed. The porous anatase TiO2 nanowire electrodes demonstrated an excellent cycling performance and superior rate capabilities compared with the H2Ti3O7 nanowires and the anatase TiO2 nanowires that were prepared through calcination at 700 °C. The porous anatase TiO2 nanowires exhibited a capacity of ~ 145 mA h g - 1 at 1 C after 500 cycles and 115 mA h g - 1 at 20 C. This improvement in the long-term cycle stability and outstanding rate capability was explained by various microscopic observations of the porous 1D nanostructured nature of the nanowires during the Li intercalation/deintercalation cycles.

Shim, Hyun-Woo; Lee, Duk Kyu; Cho, In-Sun; Hong, Kug Sun; Kim, Dong-Wan

2010-06-01

305

Synthesis and photocatalytic property of N-doped TiO2 nanorods and nanotubes with high nitrogen content  

NASA Astrophysics Data System (ADS)

Nano N-doped TiO2 nanotubes were fabricated by hydrothermally treating N-doped TiO2 nanorods in a 8 M NaOH solution at 110 °C for 20 h. The N-doped TiO2 nanorods were synthesized by a solvothermal process with precursor solution containing titanium sulfate, urea, and dichloroethane. The N-doped TiO2 nanorods and nanotubes were characterized with X-ray diffraction, transmission electron microscopy, and UV-vis spectrophotometry. The nitrogen contents of the N-doped TiO2 nanorods and nanotubes were reached to high values of 36.9 at.% and 25.7 at.%, respectively. The nitrogen doping narrowed the band gap of the N-doped TiO2 nanorods and nanotubes and introduced indirect band gap to the powders, which respectively extended the absorption edge to visible light and infrared region. The nanotubes showed larger specific surface area and greater degradation efficiency to methyl orange than the nanorods.

He, Z.; He, H. Y.

2011-11-01

306

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

307

Facile synthesis and catalytic activity of MoS(2)/TiO(2) by a photodeposition-based technique and its oxidized derivative MoO(3)/TiO(2) with a unique photochromism.  

PubMed

UV-light irradiation to TiO(2) in an aqueous ethanol solution of (NH(4))(2)MoS(4) under deaerated conditions has yielded molybdenum(IV) sulfide nanoparticles on a TiO(2) surface (MoS(2)/TiO(2)) to be transformed into molybdenum(VI) oxide species highly dispersed at a molecular level by a subsequent heating at 773K in air (m-MoO(3)/TiO(2)). In HCOOH aqueous solutions, the MoS(2)/TiO(2) system exhibits a high level of photocatalytic activity for H(2) generation, while the m-MoO(3)/TiO(2) system shows unique photochromism. PMID:21167494

Kanda, Shigeki; Akita, Tomoki; Fujishima, Musashi; Tada, Hiroaki

2010-11-12

308

Low-frequency ultrasound induces oxygen vacancies formation and visible light absorption in TiO2 P-25 nanoparticles.  

PubMed

Low-frequency ultrasound (LFUS) irradiation induces morphological, optical and surface changes in the commercial nano-TiO(2)-based photocatalyst, Evonik-Degussa P-25. Low-temperature electron spin resonance (ESR) measurements performed on this material provided the first experimental evidence for the formation of oxygen vacancies (V(o)), which were also found responsible for the visible-light absorption. The V(o) surface defects might result from high-speed inter-particle collisions and shock waves generated by LFUS sonication impacting the TiO(2) particles. This is in contrast to a number of well-established technologies, where the formation of oxygen vacancies on the TiO(2) surface often requires harsh technological conditions and complicated procedures, such as annealing at high temperatures, radio-frequency-induced plasma or ion sputtering. Thus, this study reports for the first time the preparation of visible-light responsive TiO(2)-based photocatalysts by using a simple LFUS-based approach to induce oxygen vacancies at the nano-TiO(2) surface. These findings might open new avenues for synthesis of novel nano-TiO(2)-based photocatalysts capable of destroying water or airborne pollutants and microorganisms under visible light illumination. PMID:22192787

Osorio-Vargas, Paula A; Pulgarin, Cesar; Sienkiewicz, Andrzej; Pizzio, Luis R; Blanco, Mirta N; Torres-Palma, Ricardo A; Pétrier, Christian; Rengifo-Herrera, Julián A

2011-12-02

309

A simple route for the preparation of Eu, N-codoped TiO2 nanoparticles with enhanced visible light-induced photocatalytic activity.  

PubMed

A simple route has been developed for the synthesis of europium, nitrogen-codoped titania photocatalysts under mild conditions (i.e., low temperature, < or = 348 K, and ambient pressure). The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and diffuse reflectance spectra (DRS) analyses. The results showed that the codoped photocatalyst with a spheroidal shape exhibited a smaller size than the undoped titania. The transformation from anatase to rutile was suppressed by doping with Eu and N atoms. Furthermore, the absorbance spectra of Eu, N-codoped TiO(2) exhibited a significant red shift to the visible region. The photocatalytic activity of Eu, N-codoped TiO(2) was evaluated by photodegradation of the dye reactive brilliant red X-3B under visible light. This codoped sample exhibited enhanced photocatalytic activity compared to N-doped TiO(2), pure TiO(2), and P25. PMID:18840383

Xu, Jingjing; Ao, Yanhui; Fu, Degang; Yuan, Chunwei

2008-10-05

310

Synthesis and characterization of TiO2 nanoparticles: anatase, brookite, and rutile  

NASA Astrophysics Data System (ADS)

Titanium dioxide nanoparticles have been prepared by solution-phase methods in the three phases that occur naturally, anatase, rutile, and brookite. The amorphous titania starting material was prepared from titanium(IV) iso-propoxide using iso-propanol as solvent and a small quantity of water. The resulting material was treated hydrothermally in an acid digestion vessel at temperatures between 175 °C and 230 °C with different reactants to obtain the three phases or controlled mixtures of two phases. The nanomaterials were characterized by a variety of techniques, including X-ray diffraction, Raman spectroscopy, electron microscopy, dynamic light scattering, and UV-Vis absorbance spectrophotometry. The results illustrate the relation between the properties of the nanoparticles in the colloid, in the powder, and in nanostructured thin films prepared with the materials. A thorough understanding of synthesis methods is essential for the preparation of nanomaterials with tailored structural, morphological, and ultimately, physical properties.

Reyes-Coronado, David; Rodriguez-Gattorno, Geonel; Espinosa-Pesqueira, Manuel; Gardner, James M.; Meyer, Gerald J.; Oskam, Gerko

2007-10-01

311

Solar photocatalytic degradation of a reactive azo dye in TiO 2suspension  

Microsoft Academic Search

The photocatalytic decolourisation and degradation of an azo dye reactive orange 4 (RO4) in aqueous solution with TiO2-P25 (Degussa) as photocatalyst in slurry form have been investigated using solarlight. There is a significant difference in adsorption of dye on TiO2 surface with the change in solution pH. The effect of various photocatalysts such as TiO2-P25, TiO2 (anatase), ZnO, CdS, Fe2O3,

M Muruganandham; M Swaminathan

2004-01-01

312

Synthesis and photocatalytic properties of porous TiO2 films prepared by ODA/sol-gel method  

NASA Astrophysics Data System (ADS)

Porous TiO2 films were deposited on SiO2 pre-coated glass-slides by sol-gel method using octadecylamine (ODA) as template. The amount of ODA in the sol played an important role on the physicochemical properties and photocatalytic performance of the TiO2 films. The films prepared at different conditions were all composed of anatase titanium dioxide crystals, and TiO2 crystalline size got larger with increasing ODA amount. The maximum specific surface area of 41.5 m2/g was obtained for TiO2 powders prepared from titanium sol containing 2.0 g ODA. Methyl orange degradation rate was enhanced along with increasing ODA amount and reached the maximal value at 2.0 g addition of ODA. After 40 min of UV-light irradiation, methyl orange degradation rate reached 30.5% on the porous film, which was about 10% higher than that on the smooth film. Porous TiO2 film showed almost constant activity with slight decrease from 30.5% to 28.5% after 4 times of recycles.

Zhang, Wenjie; Bai, Jiawei

2012-01-01

313

Synthesis of TiO2/SnO2 core shell nanocomposite via sol-gel method  

NASA Astrophysics Data System (ADS)

The particles of TiO2 core/ SnO2 shell nanocomposite were prepared by hydrolysis of SnCl4.5H2O in the presence of titania nanoparticle after drying and calcinations treatments. TiO2 particle were produced from titanium isopropoxide sol by hydrothermal processing. X-ray diffraction (XRD), Fourier transformed infrared (FTIR), and transmission electron microscopy (TEM) were used to characterize the TiO2/ SnO2 core shell nanocomposites. The obtained results from XRD show that the SnO2 nanoparticles coated on TiO2 yields diffraction peaks correspond to the crystalline SnO2 phase. Also, TEM results show that the nanocomposite particles have a spherical morphology and a narrow size distribution. The thickness of SnO2 shell on the surface of TiO2 particles were about 8 nm. Moreover, the results obtained from EDX analysis show that the core-shell structured nanocomposites have crystalline structure.

Khoby-Shendy, Soraia; Vaezi, Mohammad Reza; Ebadzadeh, Toraj

314

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

315

Size-controllable synthesis of surface-enhanced Raman scattering-active gold nanoparticles coated on TiO2.  

PubMed

As shown in the literature, gold nanoparticles (NPs) were popularly used in the fields of catalyst and surface-enhanced Raman scattering (SERS). In this work, size-controllable Au NPs coated on TiO(2) are synthesized by adjusting the pH of solutions based on sonoelectrochemical methods. The size-controlled Au NPs on TiO(2), ranging from 2 to 80 nm in diameter, can be obtained by varying the pH of solutions from 3 to 7 and placing the sample for 3 h before sonoelectrochemical reductions. The optimal particle sizes of Au NPs on TiO(2) to obtain the strongest SERS effects under an irradiation of 785 nm for probe molecules of adsorbed Rhodamine 6G (R6G) and deposited polypyrrole (PPy) are all ca. 60 nm. PMID:22763981

Kuo, Tai-Chih; Hsu, Ting-Chu; Liu, Yu-Chuan; Yang, Kuang-Hsuan

2012-07-05

316

Synthesis of titanate nanotube from different phases of TiO2 powders and its hydrogen absorption capacity.  

PubMed

Titanate nanotubes were synthesized by hydrothermal method with different NaOH concentration using various TiO2 powders (P-25, rutile, anatase, and Ni doped TiO2) at 120 degrees C for 24 hrs. At 10 M NaOH, Ni doped TiO2 powders formed the titanate nanotubes which consisted of layered structure such as A2Ti2O5.H2O, A2Ti3O7, H2TiO.H2O (A = Na and/or H) with outer and inner diameter of approximately 10 nm and 6 nm. Ni doped nanotubes absorbed a small amount of hydrogen at 6 and 10 atm, however, uptake of hydrogen was 1.2 wt% at 20 atm. PMID:19441427

Kim, Dong Hyun; Jung, Yi Hun; Choi, Duck-Kyun; Kim, Sun-Jae; Lee, Kyung Sub

2009-02-01

317

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

318

Synthesis of highly-active single-crystalline TiO 2 nanorods and its application in environmental photocatalysis  

Microsoft Academic Search

Highly-active anatase TiO2 nanorods have been successfully synthesized via a simple two-step method, hydrothermal treatment of anatase\\/rutile titanium dioxide nanoparticle powder in a composite-hydroxide eutectic system of 1:1 M KOH\\/NaOH, followed by acid post-treatment. The morphology and crystalline structure of the obtained nanorods were characterized using XRD, TEM, SEM\\/EDX and BET surface area analyzer. The obtained TiO2 nanorods have a good

Hoda S. Hafez

2009-01-01

319

TiO2 nanopowders doped with boron and nitrogen for photocatalytic applications  

NASA Astrophysics Data System (ADS)

TiO2-based systems have attracted an increasing interest for their potential use as photocatalysts under visible-light irradiation. In this context, the present work was dedicated to the tailored synthesis of TiO2 nanopowders doped with boron, nitrogen or both species for the photocatalytic degradation of organic dyes. In particular, the systems were synthesized by a sol gel route starting from titanium(IV) butoxide as a Ti source and thoroughly characterized by the combined use of N2 physisorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV Vis reflectance spectroscopy and temperature-programmed oxidation (TPO). Finally, the photocatalytic performances in the decomposition of the azo-dye methyl orange (MO) were investigated. The obtained results suggest that both dopants promote the photocatalytic activity with respect to pure TiO2 systems. Nevertheless, while our surface N-doping does not appreciably modify the titania structure and texture, B incorporation inhibits the TiO2 crystallite growth and induces an increase in the surface area. As regards the codoped systems, a remarkable reactivity improvement was observed only when B is present in excess with respect to N. A rational interpretation of the observed behaviour was attempted by calculations based on the density functional theory (DFT). We suggest that the presence of B in molar excess with respect to N generates reactive Ti(III) sites, which, in turn, might induce the formation of reactive superoxide species.

Gombac, V.; de Rogatis, L.; Gasparotto, A.; Vicario, G.; Montini, T.; Barreca, D.; Balducci, G.; Fornasiero, P.; Tondello, E.; Graziani, M.

2007-10-01

320

Electrical and electro-optical investigations of liquid crystal cells containing TiO2-V2O5 thin films prepared by sol-gel synthesis  

NASA Astrophysics Data System (ADS)

This work is aimed at a deeper understanding of the polarity-sensitive electro-optical response observed in a liquid crystal (LC) cell with asymmetric insertion of thin films of TiO2-V2O5 having a Ti/V atomic ratio of 1/1, prepared by sol-gel synthesis on a transparent indium tin oxide substrate. After preliminary structural characterization of the films, the electro-optical response of the liquid crystal cells containing a TiO2-V2O5 layer has been analyzed. The voltage thresholds of the Freedericksz transition are increased or decreased for anodic or the cathodic polarization, respectively, of the TiO2-V2O5 film. In such a way a polarity-sensitive electro-optical response is generated that has the same frequency as the field applied. Impedance and cyclic voltammetry measurements were performed on liquid crystal cells having TiO2-V2O5 films inserted as the electrode, for as-deposited films as well as for films annealed at 400 degC. The LC cell containing thermally annealed Ti/V 1/1 film showed a rectified square wave response instead of the usual impulsive one, quadratic versus electric field. On the contrary, the LC cell containing as-deposited Ti/V 1/1 film exhibits more complex electro-optical behavior with a weak asymmetric response. All the measurements suggest that charge redistribution of the ions, always present in the films, occurs during the intercalation-deintercalation processes induced by the voltage applied, and this is responsible for changes of the effective electric field that act on the liquid crystal layer.

Bruno, V.; Cazzanelli, E.; Scaramuzza, N.; Strangi, G.; Ceccato, R.; Carturan, G.

2002-11-01

321

Synthesis and structure of nanocrystalline TiO2 with lower band gap showing high photocatalytic activity.  

PubMed

Nanocrystalline TiO2 was synthesized by the solution combustion method using titanyl nitrate and various fuels such as glycine, hexamethylenetetramine, and oxalyldihydrazide. These catalysts are active under visible light, have optical absorption wavelengths below 600 nm, and show superior photocatalytic activity for the degradation of methylene blue and phenol under UV and solar conditions compared to commercial TiO2, Degussa P-25. The higher photocatalytic activity is attributed to the structure of the catalyst. Various studies such as X-ray diffraction, Raman spectroscopy, Brunauer-Emmett-Teller surface area, thermogravimetric-differential thermal analysis, FT-IR spectroscopy, NMR, UV-vis spectroscopy, and surface acidity measurements were conducted. It was concluded that the primary factor for the enhanced activity of combustion-synthesized catalyst is a larger amount of surface hydroxyl groups and a lowered band gap. The lower band gap can be attributed to the carbon inclusion into the TiO2 giving TiO(2-2x)C(x) VO2**. PMID:15835170

Nagaveni, K; Hegde, M S; Ravishankar, N; Subbanna, G N; Madras, Giridhar

2004-03-30

322

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...

323

Phosphorus-doped TiO2 catalysts with stable anatase-brookite biphase structure: synthesis and photocatalytic performance.  

PubMed

Phosphorus-doped (P-doped) TiO2 catalysts with a stable anatase-brookite biphase structure were successfully synthesized by integrating ultrasonication with phosphorus doping and Pluronic P123 surfactant. The synthesized catalysts were characterized using X-ray diffraction, transmission electron microscopy, nitrogen adsorption-desorption, Fourier transform infrared, and UV-visible diffuse reflectance spectra. Ultrasonication facilitates the appearance of brookite phase. Phosphorus doping was demonstrated an effective strategy to stabilize the anatase-brookite biphase structure and inhibits undesirable grain growth. Triblock copolymer Pluronic P123 used in the reaction facilitates the formation of catalyst particles with mesoporous structure and large surface area and prevents particles from agglomeration. The low band-gap of brookite phase enables the synthesized P-doped TiO2 catalysts outperform commercial P25 TiO2 and N-doped TiO2 in the degradation of methylene blue under both solar light and visible light irradiation. PMID:23901520

Feng, Huajun; Zhang, Min-Hong; Yu, Liya E

2013-07-01

324

Flower-like TiO2 nanostructures with exposed {001} facets: facile synthesis and enhanced photocatalysis.  

PubMed

Flower-like TiO(2) nanostructures with exposed {001} facets were synthesized by a low-temperature hydrothermal process from Ti powders for the first time, and they exhibited enhanced photocatalytic degradation of methylene blue dye under ultraviolet light irradiation. PMID:20644783

Liu, Min; Piao, Lingyu; Lu, Weiming; Ju, Siting; Zhao, Lei; Zhou, Chunlan; Li, Hailing; Wang, Wenjing

2010-03-17

325

Synthesis of highly active thin film based on TiO2 nanomaterial for self-cleaning application  

NASA Astrophysics Data System (ADS)

Highly active self-cleaning surfaces were prepared from hydrothermally treated TiO2 nanomaterials for different times (0, 12, 24 and 36 h) under acidic condition. TiO2 thin films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). TiO2 thin film (hydrothermal 24 h) exhibited hybrid morphology from accumulated plates, clusters, rods and spheres. The photo self-cleaning activity in term of quantitative determination of the active oxidative species (rad OH) produced on the thin film surfaces was evaluated using fluorescent probe method. The results show that, the highly active thin film is the hydrothermally treated for 24 h at 200 °C. The structural, morphology and photoactivity properties of nano-TiO2 thin films make it promising surfaces for self-cleaning application. Mineralization of commercial textile dye (Remazol Red RB-133, RR) from highly active TiO2 thin film surface was applied. Moreover, the durability of this nano-TiO2 thin film (hydrothermal 24 h) was studied.

Saif, M.; El-Molla, S. A.; Aboul-Fotouh, S. M. K.; Hafez, H.; Ibrahim, M. M.; Abdel-Mottaleb, M. S. A.; Ismail, L. F. M.

2013-08-01

326

H2O-EG-Assisted Synthesis of Uniform Urchinlike Rutile TiO2 with Superior Lithium Storage Properties.  

PubMed

A facile green method to synthesize uniform nanostructured urchinlike rutile TiO2 is demonstrated. Titanium trichloride was selected as the TiO2 precursor, and a mixed solvent containing H2O and ethylene glycol was used. By using this binary medium, the nucleation and crystal growth of rutile TiO2 can be regulated, giving rise to very uniform urchinlike structures with tailorable sizes. As confirmed by the SEM and TEM analysis, large particles with dense aggregation of needle-like building blocks or small ones with loosely packed subunits could be obtained at different reaction conditions. The as-prepared samples were applied as the anode material for lithium-ion batteries, and they were shown to have superior properties with a high reversible capacity of 140 mA h g(-1) at a high current rate of 10 C for up to 300 cycles, which is almost unmatched by other rutile TiO2-based electrodes. A stable capacity of 88 mA h g(-1) can also be delivered at an extremely high rate of 50 C, suggesting the great potential of the as-prepared product for high-rate lithium-ion batteries. PMID:24020604

Chen, Jun Song; Liang, Yen Nan; Li, Yongmei; Yan, Qingyu; Hu, Xiao

2013-10-02

327

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

2012-11-30

328

Single-crystalline rutile TiO2 nanowires by mass selected Ni catalyst: Synthesis and electrical properties  

NASA Astrophysics Data System (ADS)

We present a novel method for growing high quality TiO2 nanowires using mass-selected Ni clusters of nanometer sizes produced by magnetron sputtering and also show their electric field-effect functions. Single-crystalline TiO2 nanowires(NWs) are grown by atmospheric pressure physical vapour deposition(APPVD) process, using TiO and Ti metal powders as a Ti source and Ni nanoparticles as a catalyst, respectively. For the TiO2 NWs growth, first, the Ti metal layer with a thickness of ˜50nm was then deposited on the SiO2/Si substrate by the e-beam evaporation technique and subsequently, the mass selected Ni clusters by using magnetron sputtering source combined with a quadrupole mass filter was deposited onto the Ti layer. APPVD growth was then performed in a horizontal quartz tube furnace at 800^oC-950^oC by introducing high purity Ar carrier gas (99.999%) with the flow rate of 300 sccm for 2 hours. The I-V curves are linear over the entire annealing temperature range at 200 ˜500^oC, showing that the electrodes form good ohmic contacts with the nanowires. The I vs VG curves for various values of VSD and gate dependent I-V curves of a TiO2 nanowire configured as a back-gated FET are also obtained and will be discussed.

Kim, Myung Hwa; Larson, Christopher; Back, Jeong Min; Chen, Xihong; Moskovits, Martin; Wodtke, Alec

2008-03-01

329

Graphene-spindle shaped TiO2 mesocrystal composites: Facile synthesis and enhanced visible light photocatalytic performance.  

PubMed

Graphene (GR)-TiO2 mesocrystal composites were prepared by a facile template-free process based on the combination of sol-gel and solvothermal methods, and were characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-vis DRS), nitrogen absorption and electron spin resonance (ESR). Visible light photocatalytic performance of GR-TiO2 composites was evaluated for photocatalytic degradation of organic dye Rhodamine B. It was found that the amount of graphene oxide (GO) added obviously affects morphologies of TiO2 mesocrystals and photocatalytic activities of as-prepared nanocomposites. Composites prepared in the presence of different amounts of GO all exhibit higher photocatalytic activity than pure TiO2 mesocrystals and P25, the composite obtained by using 20mg GO presents the most uniform TiO2 mesocrystals in the composite and shows the highest photocatalytic efficiency. The mechanism for the generation of TiO2 mesocrystals in the GR-TiO2 composite is proposed and possible reasons for the enhancement in visible light photocatalytic efficiency are also discussed. PMID:23959254

Yang, Xiaofei; Qin, Jieling; Li, Yang; Zhang, Rongxian; Tang, Hua

2013-07-26

330

Anatase TiO(2) single crystals with exposed {001} and {110} facets: facile synthesis and enhanced photocatalysis.  

PubMed

Anatase TiO(2) single crystals with exposed {001} and {110} facets have been successfully synthesized using a modified hydrothermal technique in the presence of hydrogen peroxide and hydrofluoric acid solution; these single crystals exhibited enhanced photocatalytic activities for degradation of Methylene Blue dye under ultraviolet light irradiation. PMID:20177609

Liu, Min; Piao, Lingyu; Zhao, Lei; Ju, Siting; Yan, Zijie; He, Tao; Zhou, Chunlan; Wang, Wenjing

2010-02-05

331

Synthesis of lanthanide-doped NaYF4@TiO2 core-shell composites with highly crystalline and tunable TiO2 shells under mild conditions and their upconversion-based photocatalysis.  

PubMed

NaYF4:Yb,Tm@TiO2 core-shell composites were synthesized via a facile hydrothermal method. The highly crystalline TiO2 shell can be uniformly coated onto lanthanide-doped NaYF4 microrods and nanorods under mild conditions without calcination. The thickness of the TiO2 shell can be tuned by varying the ratio of fluoride rods and Ti precursors. The microcomposite with a moderate TiO2 shell shows excellent photocatalytic activity under near-infrared irradiation. PMID:23955272

Zhang, Yuewei; Hong, Zhanglian

2013-08-19

332

Characterization of La 2O 3-TiO 2 and V 2O 5\\/La 2O 3-TiO 2 catalysts and their activity for synthesis of 2,6-dimethylphenol  

Microsoft Academic Search

The La2O3-TiO2 (1:5 molar ratio) mixed oxide was prepared by a co-precipitation method with in situ generated ammonia and was impregnated with various amounts of vanadia (4–12wt.%). The La2O3-TiO2 and the V2O5\\/La2O3-TiO2 catalysts were subjected to thermal treatments from 773 to 1073K and were investigated by X-ray diffraction, FT-infrared, BET surface area, and O2 chemisorption methods to establish the effects

Benjaram M. Reddy; Ibram Ganesh

2001-01-01

333

Development of the IR laser pyrolysis for the synthesis of iron-doped TiO2 nanoparticles: Structural properties and photoactivity  

NASA Astrophysics Data System (ADS)

The preparation of TiO2-based nanoparticles of closely controlled sizes and purity gives rise to considerable interest in the frame of environmental applications, e.g. in photocatalysis. When nanoparticles instead of their bulk counterpart are used the synthesis method plays a fundamental role in defining specific structural properties. Between the different gas-phase synthesis techniques, the CO2 laser pyrolysis is a versatile method allowing for the preparation of nanostructures of various chemical compositions. Here we demonstrate that pure and Fe-doped TiO2 nanoparticles with rather low Fe concentration may be prepared by applying the sensitized IR laser pyrolysis to a gas mixtures containing titanium tetrachloride, air and iron pentacarbonyl (vapors). The structures of TiO2-based particles were systematically investigated by X-ray diffraction, transmission electron microscopy, high-resolution electron microscopy, selected area electron diffraction and X-ray Photoelectron Spectroscopy. Depending on the synthesis parameters, the nanoparticle system contains mixtures of anatase and rutile, with a preponderance of the anatase phase. Higher rutile proportion was found in the iron-doped samples. Mean particle diameters of around 14 nm and 12 nm were estimated for undoped and doped anatase titania, respectively. From UV-Vis diffuse reflectance spectra, higher absorbance and red shifted absorption were evidenced at higher amount of doped iron. Preliminary evaluation tests of the UV photoactivity of samples were performed by using the scanning electrochemical microscopy for determining the evolution of the oxygen consumption in the presence of IV-chlorophenol. They show that the undoped nano titania samples perform better than the reference P25 Degussa sample. A drop of the nano-titania photoactivity as a consequence of Fe doping was observed. Possible reasons of this effect are tentatively discussed.

Alexandrescu, R.; Morjan, I.; Scarisoreanu, M.; Birjega, R.; Fleaca, C.; Soare, I.; Gavrila, L.; Ciupina, V.; Kylberg, W.; Figgemeier, E.

2010-03-01

334

Catalytic synthesis of 2-(N-benzyl-N-phenylamino) phenol by mesoporous Pd-doped TiO2: an environmentally benign approach  

NASA Astrophysics Data System (ADS)

A facile and environmentally route for catalytic Synthesis of 2-(N-benzyl-N-phenylamino) phenol under UV irradiation conditions has been developed in the presence of a catalytic amount of mesoporous Pd-doped TiO2 (Pd/TiO2) based on a ionic liquid process to fabricate. The particles were characterized with XRD, TEM and XPS. The FT-IR and HNMR spectra confirmed the expected function groups and the structure of 2-(N-benzyl-N-phenylamino) phenol synthesized.

Wang, Huqun; Hu, Tiegang; Yang, Xiaofeng; Yan, Junping; Xiong, Weifeng; Zhang, Zhimin

2013-03-01

335

The preparation of Zn 2+-doped TiO 2 nanoparticles by sol–gel and solid phase reaction methods respectively and their photocatalytic activities  

Microsoft Academic Search

The photocatalytic oxidation of the organic pollutants with TiO2 as photocatalyst has been widely studied in the world, and many achievements have been made. The degradation of pollutants is highly related to the photocatalytic activity of TiO2. It is demonstrated that doping ions to TiO2 is one way to enhance the photocatalytic activity of TiO2. In this paper, Zn2+-doped TiO2

Guoguang Liu; Xuezhi Zhang; Yajie Xu; Xinshu Niu; Liqing Zheng; Xuejun Ding

2005-01-01

336

PHOTOCATALYTIC DEGRADATION OF TOLUENE vapour USING FIXED BED MULTICHANNEL PHOTOREACTORS EQUIPPED WITH TiO2?COATED FABRICS  

Microsoft Academic Search

The feasibility of producing TiO2?coated fabric using nonwoven polyester as a photocatalyst support was examined through investigations on (i) changes in the fabric properties after coating with TiO2, (ii) the toluene removal capacity of a multichannel TiO2\\/fabric\\/UV reactor in removing the toluene vapour with and without O3 addition, and (iii) the photocatalytic effect of regenerated TiO2. The value and usefulness

2008-01-01

337

Effect of ZnFe 2O 4 doping on the photocatalytic activity of TiO 2  

Microsoft Academic Search

The photocatalytic oxidation of the organic pollutants with the TiO2 as photocatalyst has been widely studied in the world, and many achievements have been got. The degradation of pollutants is highly related with the photocatalytic activity of TiO2. It is demonstrated that doping ions or oxides to TiO2 is one way to enhance the photocatalytic activity of TiO2. In this

Guo-guang Liu; Xue-zhi Zhang; Ya-jie Xu; Xin-shu Niu; Li-qing Zheng; Xue-jun Ding

2004-01-01

338

Effectofsamarium dopant on photocatalytic activity of TiO2 nano-particle for the degradation of reactive orange 4  

Microsoft Academic Search

TiO2 is an ideal material for catalytic technology due to its unique properties. In this paper, the effect of Sm3+ dopant on the photocatalytic activity of TiO2 was studied to improve the catalytic efficiency of TiO2. The Sm3+-TiO2 photocatalyst was made from Titanium Tetrabutoxide and Samarium Oxide with the Sol-Gel process and used to degrade reactive orange 4 (RO4) in

Baoqing Xiao

2010-01-01

339

A combined experimental and theoretical analysis of Fe-implanted TiO 2 modified by metal plasma ion implantation  

Microsoft Academic Search

Photocatalyst titanium dioxide (TiO2) thin films were prepared using sol–gel process. To improve the photosensitivity of TiO2 at visible light, transition metal of Fe was implanted into TiO2 matrix at 20keV using the metal plasma ion implantation process. The primary phase of the Fe-implanted TiO2 films is anatase, but X-ray diffraction revealed a slight shift of diffraction peaks toward higher

Chung-Chih Yen; Da-Yung Wang; Ming-Huei Shih; Li-Shin Chang; Han C. Shih

2010-01-01

340

Synthesis of lanthanide-doped NaYF4@TiO2 core-shell composites with highly crystalline and tunable TiO2 shells under mild conditions and their upconversion-based photocatalysis  

NASA Astrophysics Data System (ADS)

NaYF4:Yb,Tm@TiO2 core-shell composites were synthesized via a facile hydrothermal method. The highly crystalline TiO2 shell can be uniformly coated onto lanthanide-doped NaYF4 microrods and nanorods under mild conditions without calcination. The thickness of the TiO2 shell can be tuned by varying the ratio of fluoride rods and Ti precursors. The microcomposite with a moderate TiO2 shell shows excellent photocatalytic activity under near-infrared irradiation.NaYF4:Yb,Tm@TiO2 core-shell composites were synthesized via a facile hydrothermal method. The highly crystalline TiO2 shell can be uniformly coated onto lanthanide-doped NaYF4 microrods and nanorods under mild conditions without calcination. The thickness of the TiO2 shell can be tuned by varying the ratio of fluoride rods and Ti precursors. The microcomposite with a moderate TiO2 shell shows excellent photocatalytic activity under near-infrared irradiation. Electronic supplementary information (ESI) available: Experimental details, size distribution, EDX analysis, other related TEM images, PL dynamic curves, optical images, etc. See DOI: 10.1039/c3nr03051b

Zhang, Yuewei; Hong, Zhanglian

2013-09-01

341

Lanthanide Oxide Doped Titanium Dioxide Photocatalysts: Effective Photocatalysts for the Enhanced Degradation of Salicylic Acid and t-Cinnamic Acid  

Microsoft Academic Search

The photocatalytic degradation of salicylic acid and t-cinnamic acid has been investigated in aqueous suspensions of lanthanide oxide doped TiO2 photocatalysts. Complete mineralization has been achieved in the case of lanthanide oxide doped TiO2 photocatalysts in total contrast to the formation of intermediates in case of nonmodified TiO2. The equilibrium dark adsorption of salicylic acid and t-cinnamic acid is ca.

K. T Ranjit; I Willner; S. H Bossmann; A. M Braun

2001-01-01

342

Large-scale synthesis of transition-metal-doped TiO2 nanowires with controllable overpotential.  

PubMed

Practical implementation of one-dimensional semiconductors into devices capable of exploiting their novel properties is often hindered by low product yields, poor material quality, high production cost, or overall lack of synthetic control. Here, we show that a molten-salt flux scheme can be used to synthesize large quantities of high-quality, single-crystalline TiO2 nanowires with controllable dimensions. Furthermore, in situ dopant incorporation of various transition metals allows for the tuning of optical, electrical, and catalytic properties. With this combination of control, robustness, and scalability, the molten-salt flux scheme can provide high-quality TiO2 nanowires to satisfy a broad range of application needs from photovoltaics to photocatalysis. PMID:23815410

Liu, Bin; Chen, Hao Ming; Liu, Chong; Andrews, Sean C; Hahn, Chris; Yang, Peidong

2013-07-01

343

Synthesis and characterization of highly ordered TiO 2 nanotube arrays for hydrogen generation via water splitting  

Microsoft Academic Search

Highly ordered TiO2 nanotube arrays (TNA) have been synthesized by anodization of Ti foils using an established electrochemical process. The parameters such as anodization potentials and durations have been varied to fabricate the specific morphology of TNA. In addition, Pt nanoparticles were deposited on these TNA via microwave irradiation. The photocurrent density–voltage (J–V) properties induced by the standard AM 1.5

Kao-Chen Sun; Ying-Chieh Chen; Ming-Yuan Kuo; Hong-Wen Wang; Yung-Fang Lu; Jen-Chieh Chung; Yu-Chang Liu; Yu-Zhen Zeng

2011-01-01

344

Photocatalytic oxidation of cyanide on TiO 2: An electrochemical approach  

Microsoft Academic Search

Photocatalytic oxidation of cyanide on TiO2 was studied by means of voltammetry, linear polarization resistance and Tafel polarization using TiO2–carbon paste electrodes (TiO2–CPEs). In all cases, a positive effect with UV–vis illumination on the oxidation current (i.e. oxidation rate) was observed, showing the convenience of this type of electrodes for the electrochemical evaluation of powdered semiconductor photocatalysts. Voltammetric results indicated

J. A. Pedraza-Avella; P. Acevedo-Peña; J. E. Pedraza-Rosas

2008-01-01

345

Hydrothermal Synthesis of a Crystalline Rutile TiO2 Nanorod Based Network for Efficient Dye-Sensitized Solar Cells.  

PubMed

One-dimensional (1D) TiO2 nanostructures are desirable as photoanodes in dye-sensitized solar cells (DSSCs) due to their superior electron-transport capability. However, making use of the DSSC performance of 1D rutile TiO2 photoanodes remains challenging, mainly due to the small surface area and consequently low dye loading. Herein, a new type of photoanode with a three-dimensional (3D) rutile-nanorod-based network structure directly grown on fluorine-doped tin oxide (FTO) substrates was developed by using a facile two-step hydrothermal process. The resultant photoanode possesses oriented rutile nanorod arrays for fast electron transport as the bottom layer and radially packed rutile head-caps with an improved large surface area for efficient dye adsorption. The diffuse reflectance spectra showed that with the radially packed top layer, the light-harvesting efficiency was increased due to an enhanced light-scattering effect. A combination of electrochemical impedance spectroscopy (EIS), dark current, and open-circuit voltage decay (OCVD) analyses confirmed that the electron-recombiantion rate was reduced on formation of the nanorod-based 3D network for fast electron transport. As a resut, a light-to-electricity conversion efficiency of 6.31?% was achieved with this photoanode in DSSCs, which is comparable to the best DSSC efficiencies that have been reported to date for 1D rutile TiO2 . PMID:23939704

Yu, Hua; Pan, Jian; Bai, Yang; Zong, Xu; Li, Xinyong; Wang, Lianzhou

2013-08-12

346

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

347

Functionalisation versus mineralisation of some N-heterocyclic compounds upon UV-illumination in the presence of un-doped and iron-doped TiO 2 photocatalysts  

Microsoft Academic Search

Heterogeneous photocatalytic oxidation of some N-heterocyclic compounds (4-picoline, and 6- and 8-methylquinoline) in oxygenated solvents (water or acetonitrile), containing dispersed photocatalyst (un-doped or iron-doped titanium dioxide), was investigated under UV-illumination in a photochemical reactor. This work aimed to correlate experimental parameters such as structural aspects of the substrates, photocatalyst chemical and surface properties, illumination times, and the nature of the

J. A. Navío; M. Macias; M. Garcia-Gómez; M. A. Pradera

2008-01-01

348

The effects of synthesis procedures on the structure and morphology of multiwalled carbon nanotubes (MWNTs)\\/titania (TiO 2 ) nanocomposites prepared by hydrothermal method  

Microsoft Academic Search

The nanocomposites of multiwalled carbon nanotubes (MWNTs)\\/titania (TiO2) were prepared by direct growth of TiO2 nanocrystals onto carboxyl-modified MWNTs under hydrothermal condition. The structure and morphology of TiO2 nanocrystals growing on MWNTs were tuned by adjusting acidity, reaction temperature, and reactant ratio. The results showed\\u000a that a uniform layer of anatase TiO2 nanocrystals on MWNTs could be achieved at proper

Huifang Xu; Jing Wang; Haijiao Zhang; Yudong Huang

2010-01-01

349

Synthesis, structure and photocatalytic properties of Fe(III)-doped TiO 2 prepared from TiCl 3  

Microsoft Academic Search

Iron(III)-doped titanium dioxide photocatalysts were prepared from aqueous titanium(III) chloride solution in the presence of dissolved FeCl3 (0–10.0at.% relative to TiCl3) by co-precipitation method. The precipitate was completely oxidized in the aerated suspension, hydrothermally treated, washed and calcinated. The structure of the powders was characterized by thermoanalysis (TG-DTA), diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), nitrogen adsorption and transmission electron

Zoltán Ambrus; Nándor Balázs; Tünde Alapi; Gyula Wittmann; Pál Sipos; András Dombi; Károly Mogyorósi

2008-01-01

350

Synthesis, characterization and photocatalytic evaluation of visible light activated C-doped TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

We have demonstrated heterogeneous photocatalytic degradation of microcystin-LR (MC-LR) by visible light activated carbon doped TiO2 (C-TiO2) nanoparticles, synthesized by a modified sol-gel route based on the self-assembly technique exploiting oleic acid as a pore directing agent and carbon source. The C-TiO2 nanoparticles crystallize in anatase phase despite the low calcination temperature of 350?°C and exhibit a highly porous structure that can be optimized by tuning the concentration of the oleic acid surfactant. The carbon modified nanomaterials exhibited enhanced absorption in the broad visible light region together with an apparent red shift in the optical absorption edge by 0.5 eV (2.69 eV), compared to the 3.18 eV of reference anatase TiO2. Carbon species were identified by x-ray photoelectron spectroscopy analysis through the formation of both Ti-C and C-O bonds, indicative of substitution of carbon for oxygen atoms and the formation of carbonates, respectively. Electron paramagnetic resonance spectroscopy revealed the formation of two carbon related paramagnetic centers in C-TiO2, whose intensity was markedly enhanced under visible light illumination, pointing to the formation of localized states within the anatase band gap, following carbon doping. The photocatalytic activity of C-TiO2 nanomaterials was evaluated for the degradation of MC-LR at pH 3.0 under visible light (? > 420 nm) irradiation. The doped materials showed a higher MC-LR degradation rate than reference TiO2, behavior that is attributed to the incorporation of carbon into the titania lattice.

Liu, Guanglong; Han, Changseok; Pelaez, Miguel; Zhu, Duanwei; Liao, Shuijiao; Likodimos, Vlassis; Ioannidis, Nikolaos; Kontos, Athanassios G.; Falaras, Polycarpos; Dunlop, Patrick S. M.; Byrne, J. Anthony; Dionysiou, Dionysios D.

2012-07-01

351

Photocatalytic properties of Small Sized TiO2 Supported on Clays for the Degradation of Indoor Pollutants: Toluene and Limonene.  

NASA Astrophysics Data System (ADS)

Novel materials for the degradation of hydrophobic organic pollutants by photocatalytic oxidation were developed. Intercalation of TiO2 on clays provide favorable properties to the photocatalyst due to the adsorption properties of the clay, its content of mesopores that enables pollutant trapping and its further interaction with TiO2, leading to mineralization. Particularly, we are interested in hydrophobic pollutants for which bare TiO2 had been shown less effective than for polar species. Synthesis was carried out by the sol-gel method using titanium isopropoxide (Ti(OC3H7)4 ) as precursor; the formation of anatase phase was achieved by hydrothermal treatment. Clays used were Hectorite [SHCa-1, Na0.4Mg2.7Li0.3Si4O10(OH)2 ] from San Bernardino Country, California, USA and Kaolinite [KGa-1b, Al2Si2O5(OH)4 ] from Washington Country, Georgia, USA. Samples characterization was conducted using XRD, SEM, XPS, ICP-OES. Our results showed a strong intercalation of TiO2 on hectorite and a poor one on kaolinite. Nanoparticle size obtained on hectorite was of 9.6 nm compared to 17.39 nm of commercial TiO2 (Degussa P25). Photocatalytic experiments were realized by the FTIR-ATR technique monitoring the concentration of the organic compound on the surface of the material. Results were compared with commercial TiO2 (Degussa P25). For limonene bare TiO2 showed better degradation rates, while for toluene, degradation rates using TiO2 supported on clays were higher.

Kibanova, D.; Trejo, M.; Destaillats, H.; Cervini-Silva, J.

2007-12-01

352

Fabrication of hydroxyl group modified monodispersed hybrid silica particles and the h-SiO 2\\/TiO 2 core\\/shell microspheres as high performance photocatalyst for dye degradation  

Microsoft Academic Search

The monodisperse hybrid silica particles (h-SiO2) were firstly prepared by a modified sol–gel process and the surface was modified in situ with double bonds, then abundant carboxyl moieties were introduced onto the surface of the silica core via thiol–ene click reaction. Afterward, the h-SiO2\\/TiO2 core\\/shell microspheres were prepared by hydrolysis of titanium tetrabutoxide (TBOT) via sol–gel process in mixed ethanol\\/acetonitrile

Zhe-Ying Shen; Long-Yu Li; Yat Li; Chang-Chun Wang

2011-01-01

353

Fabrication of hydroxyl group modified monodispersed hybrid silica particles and the h-SiO(2)/TiO(2) core/shell microspheres as high performance photocatalyst for dye degradation.  

PubMed

The monodisperse hybrid silica particles (h-SiO(2)) were firstly prepared by a modified sol-gel process and the surface was modified in situ with double bonds, then abundant carboxyl moieties were introduced onto the surface of the silica core via thiol-ene click reaction. Afterward, the h-SiO(2)/TiO(2) core/shell microspheres were prepared by hydrolysis of titanium tetrabutoxide (TBOT) via sol-gel process in mixed ethanol/acetonitrile solvent, in which the activity of TBOT could be easily controlled. The carboxyl groups on the surface of silica particles promote the formation of a dense and smooth titania layer under well control, and the layer thickness of titania could be tuned from 12 to 100nm. The well-defined h-SiO(2)/TiO(2) core/shell structures have been confirmed by electron microscopy and X-ray photoelectron spectroscopy studies. After calcination at 500°C for 2h, the amorphous TiO(2) layer turned into anatase titania. These anatase titania-coated silica particles showed good photocatalytic performance in degradation of methyl orange aqueous solution under UV light. PMID:21047643

Shen, Zhe-Ying; Li, Long-Yu; Li, Yat; Wang, Chang-Chun

2010-10-16

354

Synthesis of uniformly dispersed anatase nanoparticles inside mesoporous silica thin films via controlled breakup and crystallization of amorphous TiO2 deposited using atomic layer deposition.  

PubMed

Amorphous titanium dioxide was introduced into the pores of mesoporous silica thin films with 75% porosity and 12 nm average pore diameter via Atomic Layer Deposition (ALD) using alternating pulses of tetrakis(dimethylamino)titanium and water. Calcination provoked fragmentation of the deposited amorphous TiO2 phase and its crystallization into anatase nanoparticles inside the nanoporous film. The narrow particle size distribution of 4 ± 2 nm and the uniform dispersion of the particles over the mesoporous silica support were uniquely revealed using electron tomography. These anatase nanoparticle bearing films showed photocatalytic activity in methylene blue degradation. This new synthesis procedure of the anatase nanophase in mesoporous silica films using ALD is a convenient fabrication method of photocatalytic coatings amenable to application on very small as well as very large surfaces. PMID:23636429

Sree, Sreeprasanth Pulinthanathu; Dendooven, Jolien; Masschaele, Kasper; Hamed, Heidari M; Deng, Shaoren; Bals, Sara; Detavernier, Christophe; Martens, Johan A

2013-05-02

355

Synthesis of uniformly dispersed anatase nanoparticles inside mesoporous silica thin films via controlled breakup and crystallization of amorphous TiO2 deposited using atomic layer deposition  

NASA Astrophysics Data System (ADS)

Amorphous titanium dioxide was introduced into the pores of mesoporous silica thin films with 75% porosity and 12 nm average pore diameter via Atomic Layer Deposition (ALD) using alternating pulses of tetrakis(dimethylamino)titanium and water. Calcination provoked fragmentation of the deposited amorphous TiO2 phase and its crystallization into anatase nanoparticles inside the nanoporous film. The narrow particle size distribution of 4 +/- 2 nm and the uniform dispersion of the particles over the mesoporous silica support were uniquely revealed using electron tomography. These anatase nanoparticle bearing films showed photocatalytic activity in methylene blue degradation. This new synthesis procedure of the anatase nanophase in mesoporous silica films using ALD is a convenient fabrication method of photocatalytic coatings amenable to application on very small as well as very large surfaces.

Sree, Sreeprasanth Pulinthanathu; Dendooven, Jolien; Masschaele, Kasper; Hamed, Heidari M.; Deng, Shaoren; Bals, Sara; Detavernier, Christophe; Martens, Johan A.

2013-05-01

356

Low temperature preparation and visible light photocatalytic activity of mesoporous carbon-doped crystalline TiO 2  

Microsoft Academic Search

A visible-light-active TiO2 photocatalyst was prepared through carbon doping by using glucose as carbon source. Different from the previous carbon-doped TiO2 prepared at high temperature, our preparation was performed by a hydrothermal method at temperature as low as 160°C. The resulting photocatalyst was characterized by XRD, XPS, TEM, nitrogen adsorption, and UV–vis diffuse reflectance spectroscopy. The characterizations found that the

Wenjie Ren; Zhihui Ai; Falong Jia; Lizhi Zhang; Xiaoxing Fan; Zhigang Zou

2007-01-01

357

Synthesis and characterisation of new titanium amino-alkoxides: precursors for the formation of TiO2 materials.  

PubMed

Reaction of the amino-alkoxides HOCH(CH(2)NMe(2))(2) (Hbdmap) and HOC(CH(2)NMe(2))(3) (Htdmap) with [Ti(OR)(4)] yields a series of heteroleptic titanium alkoxides [Ti(OR)(4-n)(L)(n)] (L = bdmap, tdmap). Substitution of the monodentate alkoxide with the chelating alkoxides becomes progressively more difficult, with homogeneous products being obtained only for n = 1, 2. The structure of [Ti(OEt)(3)(bdmap)](2), a mu-OEt bridged dimer, has been determined. Hydrolysis of [Ti(OR)(2)(L)(2)], by adventitious moisture affords the dimeric oxo-alkoxides [Ti(O)(L)(2)](2), both of which have been characterised crystallographically. These two compounds have also been prepared by reaction of [Ti(NMe(2))(2)(L)(2)] with the hydrated metal salts [Zn(acac)(2).2H(2)O] and [Zn(OAc)(2).2H(2)O] using the intrinsic water molecules in these salts to react with the labile amido groups, though the former also produces Me(Me(2)N)C=C(H)C(O)Me from reaction of liberated HNMe(2) with the coordinated acac ligand, while the latter also affords the ligand exchange product [Zn(OAc)(bdmap)]. In neither case does the free dimethylamino group of [Ti(O)(L)(2)](2) coordinate a second metal. The dimeric structure of [Zn(OAc)(bdmap)](2) has been established, and the structure of the tetrameric oxo-alkoxide [Ti(O)(OPr(i))(OCH(2)CH(2)NMe(2))](4) is reported for comparison with others in this study. [Ti(OEt)(3)(bdmap)](2) has been used as a precursor in AACVD (Aerosol-Assisted Chemical Vapour Deposition) to generate amorphous TiO(2) films on glass at 440 degrees C, and TiO(2)@C nanoparticles of approximate diameter 350 nm with a carbon coating of width ca. 75 nm on heating in a sealed container at 700 degrees C. PMID:18217119

Hollingsworth, Nathan; Kanna, Miki; Kociok-Köhn, Gabriele; Molloy, Kieran C; Wongnawa, Sumpun

2007-11-13

358

Synthesis and characterization of TiO 2\\/Fe 2O 3 core–shell nanocomposition film and their photoelectrochemical property  

Microsoft Academic Search

TiO2\\/Fe2O3 core–shell nanocomposition film has been fabricated via two-step method. TiO2 nanorod arrays are synthesized by a facile hydrothermal method, and followed by Fe2O3 nanoparticles deposited on TiO2 nanorod arrays through an ordinary chemical bath deposition. The phase structures, morphologies, particle size, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM)

Hui Zhao; Wuyou Fu; Haibin Yang; Yang Xu; Wenyan Zhao; Yanyan Zhang; Hui Chen; Qiang Jing; Xuefeng Qi; Jing Cao; Xiaoming Zhou; Yixing Li

2011-01-01

359

Two novel hierarchical homogeneous nanoarchitectures of TiO2 nanorods branched and P25-coated TiO2 nanotube arrays and their photocurrent performances  

Microsoft Academic Search

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,

Anzheng Hu; Cuixia Cheng; Xin Li; Jian Jiang; Ruimin Ding; Jianhui Zhu; Fei Wu; Jinping Liu; Xintang Huang

2011-01-01

360

Au/PO43-/TiO2 and PO43-/Au/TiO2 catalysts for CO oxidation: effect of synthesis details on catalytic performance  

SciTech Connect

Supported gold catalysts are active for CO oxidation, but the high-temperature deactivation is a shortcoming that may constrain their applications. Herein, we attempted to address this problem by using phosphate-doped Au/TiO{sub 2} synthesized via two routes. In route I, Au/PO{sub 4}{sup 3-}/TiO{sub 2} catalysts were prepared by treating TiO{sub 2} (Degussa P25) with diluted H{sub 3}PO{sub 4}, followed by loading gold via deposition-precipitation. In route II, PO{sub 4}{sup 3-}/Au/TiO{sub 2} catalysts were prepared by treating H{sub 2}-reduced Au/TiO{sub 2} with diluted H{sub 3}PO{sub 4}. These catalysts were systematically pretreated at 200 or 500 C before reaction testing. The overall CO conversion on 200 C-pretreated Au/PO43-/TiO2 or PO43-/Au/TiO2 was always lower than that on 200 C-pretreated Au/TiO2. However, the advantage of the phosphate addition became apparent after thermal treatment at a higher temperature. Both Au/PO43-/TiO2 and PO43-/Au/TiO2 pretreated at 500 C retained significant activities at room temperature, whereas 500 C-pretreated Au/TiO2 lost its activity. Control experiments and catalyst characterization were performed to investigate the impact of synthesis details on catalytic performance.

Ma, Zhen [ORNL; Overbury, Steven {Steve} H [ORNL; Dai, Sheng [ORNL

2007-01-01

361

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

2013-03-05

362

Synthesis and characterization of nano TiO2-SiO2: PVA composite - a novel route  

NASA Astrophysics Data System (ADS)

A novel, simple, less time consuming and cost-effective sol-gel method has been developed to synthesize nano titania-silica with polyvinyl alcohol (PVA) composite relatively at low temperature in acidic pH. Titania sol is prepared by hydrolysis of titanium tetrachloride and was mixed with silicic acid and tetrahydrofuran mixture. The reaction was carried out under vigorous stirring for 6 h and dried at room temperature with the addition of PVA solution. The resulting powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FT-IR), UV-visible spectroscopy and thermal techniques. The grain size of the particles was calculated by X-ray diffraction; surface morphology and chemical composition were determined from scanning electron microscopy-energy dispersive spectroscopy; metal oxide stretching was confirmed from FT-IR spectroscopy; bandgap was calculated using UV-visible spectroscopy, and thermal stability of the prepared composite was determined by thermogravimetric/differential thermal analysis. Since TiO2 got agglomerated on the surface of SiO2, effective absorptive sites increase which in turn increase the photocatalytic efficiency of the resulting composite.

Venckatesh, Rajendran; Balachandaran, Kartha; Sivaraj, Rajeshwari

2012-07-01

363

The preparation of TiO 2–nitrogen doped by calcination of TiO 2· xH 2O under ammonia atmosphere for visible light photocatalysis  

Microsoft Academic Search

The investigation on incorporating nitrogen group into titanium dioxide in order to obtain powdered visible light-active photocatalysts is presented. The industrial hydrated amorphous titanium dioxide (TiO2·xH2O) obtained directly from sulphate technology installation was modified by heat treatment at temperatures of 100–800°C for 4h in an ammonia atmosphere. The photocatalysts were characterized by UV–VIS–DR and XRD techniques. The UV–VIS–DR spectra of

Beata Kosowska; Sylwia Mozia; Antoni W. Morawski; Barbara Grzmil; Magdalena Janus; Kazimierz Ka?ucki

2005-01-01

364

Au or Ag nanoparticle-decorated 3D urchin-like TiO2 nanostructures: synthesis, characterization, and enhanced photocatalytic activity.  

PubMed

The semiconductors decorated with noble metals have attracted increasing attention due to their interesting physical and chemical properties. Here, 3D urchin-like hierarchical TiO2 nanostructures decorated with Au or Ag nanoparticles were prepared by wet-chemical process. The morphology and structure were characterized by different techniques. It shows that Au or Ag nanoparticles with narrow distribution are uniformly loaded on urchin-like TiO2 nanostructures, and the resulted composite nanostructures show distinct surface plasmon absorption band and quenched photoluminence compared to pure TiO2 nanostructures. Photocatalytic tests show both Au-decorated TiO2 and Ag-decorated TiO2 exhibit enhanced photocatalytic activity for photodegradation of methyl blue in water. PMID:23673007

Xiang, Liqin; Zhao, Xiaopeng; Shang, Chaohong; Yin, Jianbo

2013-04-23

365

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

Microsoft Academic Search

BackgroundTitania 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 FindingsUsing thermal reduction method, here we synthesized silver-nanostructures coated TiO2 thin films that contain a

Ming-Show Wong; Der-Shan Sun; Hsin-Hou Chang; Stefan Bereswill

2010-01-01

366

Recovery properties of hydrogen gas sensor with Pd\\/titanate and Pt\\/titanate nanotubes photo-catalyst by UV radiation from catalytic poisoning of H 2S  

Microsoft Academic Search

Recovery properties after H2S catalytic poisoning of catalytic-type gas sensor with photo-catalysts and UV radiation have been examined. Each sensing material of the sensor consists of Pd, Pt supported on ?-Al2O3 and Pd\\/titanate, Pt\\/titanate nanotubes or TiO2 particles. Pd\\/titanate and Pt\\/titanate nanotubes photo-catalyst were synthesized by hydrothermal synthesis method. All the sensors were deactivated after 500ppm H2S exposure for 20h.

Dae Ung Hong; Chi-Hwan Han; Sang Hyun Park; Il-Jin Kim; Jihye Gwak; Sang-Do Han; Hyun Jae Kim

2009-01-01

367

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

2013-09-01

368

Photocatalytic degradation and mineralization of bisphenol A by TiO 2 and platinized TiO 2  

Microsoft Academic Search

Bisphenol A (BPA) was degraded photocatalytically by different TiO2 photocatalysts at pHs 3 and 10. It was found that the mineralization of BPA showed a stronger dependence on the pH and different oxidation products were detected during BPA degradations at pHs 3 and 10. At pH 3, 20ppm of BPA was completely mineralized into CO2 after 120min of UV illumination.

Ken Chiang; Tuti M. Lim; Leslie Tsen; Chee Chow Lee

2004-01-01

369

A facile method for synthesis of N-doped TiO2 nanooctahedra, nanoparticles, and nanospheres and enhanced photocatalytic activity  

NASA Astrophysics Data System (ADS)

N-doped TiO2 nanooctahedra, nanoparticles and nanospheres were successfully synthesized through nitrification of the corresponding TiO2 nanostructures in the presence of ammonia gas at 700 °C for 30 min. The crystal phase and compositions of N-doped TiO2 samples were confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The product morphology was characterized with scanning microscopy (SEM) and transmission electron microscopy (TEM). UV–vis absorption results show that all the as-synthesized N-doped TiO2 samples present red-shift absorption up to ˜410 nm, which can be ascribed to the addition energy level between TiO2 valence and conducion band. Surface areas of all samples were measured through nitrogen absorption–desorption isothermal. In order to evaluate the photocatalytic activity of N-doped TiO2 samples, photodecomposition for methyl orange (MO) was performed under UV–vis light irradiation for 30 min, indicating that N-doped TiO2 nanooctahedra with the exposed {1 0 1} crystallized surfaces show good photocatalytic behavior in comparison with other samples.

Du, Jimin; Zhao, Guoyan; Shi, Yunfeng; HaoYang; Li, Yaxiao; Zhu, Gaigai; Mao, Yanjun; Sa, Rongjian; Wang, Weiming

2013-05-01

370

Synthesis and characterization of TiO2/Fe2O3 core-shell nanocomposition film and their photoelectrochemical property  

NASA Astrophysics Data System (ADS)

TiO2/Fe2O3 core-shell nanocomposition film has been fabricated via two-step method. TiO2 nanorod arrays are synthesized by a facile hydrothermal method, and followed by Fe2O3 nanoparticles deposited on TiO2 nanorod arrays through an ordinary chemical bath deposition. The phase structures, morphologies, particle size, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and ultraviolet-visible (UV-vis) spectrophotometer. The results confirm that Fe2O3 nanoparticles of mean size ca. 10 nm coated on the surface of TiO2 NRs. After depositing Fe2O3, UV-vis absorption property is induces the shift to the visible-light range, the annealing temperature of 600 °C is the best condition for UV-vis absorption property of TiO2/Fe2O3 nanocomposite film, and increasing Fe content, optical activity are enhanced one by one. The photoelectrochemical (PEC) performances of the as-prepared composite nanorods are determined by measuring the photo-generated currents under illumination of UV-vis light. The TiO2 NRs modified by Fe2O3 show the photocurrent value of 1.36 mA/cm2 at 0 V vs Ag/AgCl, which is higher than those of unmodified TiO2 NRs.

Zhao, Hui; Fu, Wuyou; Yang, Haibin; Xu, Yang; Zhao, Wenyan; Zhang, Yanyan; Chen, Hui; Jing, Qiang; Qi, Xuefeng; Cao, Jing; Zhou, Xiaoming; Li, Yixing

2011-08-01

371

TiO2 nanofibre assisted photocatalytic degradation of Reactive Blue 19 dye from aqueous solution  

Microsoft Academic Search

The photocatalytic degradation of Reactive Blue 19 (RB19) dye has been studied using TiO2 nanofibre as the photocatalyst in aqueous solution under UV irradiation. Titanium dioxide nanofibre was prepared using a templating method with tetraisopropylorthotitanate as a precursor. The experiments were carried out in the presence of the TiO2 nanofibre, and the effects of pH and electron acceptors on the

A. Rezaee; M. T. Ghaneian; N. Taghavinia; M. K. Aminian; S. J. Hashemian

2009-01-01

372

TiO2 Photocatalysis: A Historical Overview and Future Prospects  

Microsoft Academic Search

Photocatalysis has recently become a common word and various products using photocatalytic functions have been commercialized. Among many candidates for photocatalysts, TiO2 is almost the only material suitable for industrial use at present and also probably in the future. This is because TiO2 has the most efficient photoactivity, the highest stability and the lowest cost. More significantly, it has been

Kazuhito Hashimoto; Hiroshi Irie; Akira Fujishima

2005-01-01

373

Photocatalytic degradation of aqueous pollutants using silica-modified TiO 2  

Microsoft Academic Search

Photocatalytic degradation (PCD) of several aqueous pollutants was investigated using a porous silica-coated titanium dioxide (SiO2–TiO2) photocatalyst. Several cationic, neutral and anionic pollutants were tested. The results indicate that modifying the surface properties of TiO2 using silica significantly enhances the PCD rate of the cationic pollutants. The rate enhancement decreased with an increase in substrate concentration, especially for the quaternary

Muhammad Shariq Vohra; Keiichi Tanaka

2003-01-01

374

Decomposition of MEK and toluene over nanolayered TiO2 photocatalyts prepared from metallic titanium chip.  

PubMed

The Nanolayered TiO2 photocatalysts were prepared by thermal treatment of metallic titanium chips. Photocatalytic activity for methyl ethyl ketone (MEK) and toluene was investigated using a closed circulating system. The photocatalysts were characterized by SEM and XRD. Surface of the Ti chips changed to be rough with increase of treatment temperature, and severe oxidation over 900 degrees C resulted in TiO2 powder. Uniform TiO2 nanolayer was formed as a rutile type on the metallic chip. Photocatalytic decomposition of MEK over the TiO2 photocatalysts occurred efficiently by UV-C irradiation. The maximum activity for MEK was obtained over Ti Chip treated at 700 degrees C. It was known that the prepared photocatalyts could be applied to remove various VOCs. PMID:22103201

Moon, In-Seob; Seo, Hyeong-Seok; Kim, Ki-Joong; Jang, Seung-Ho; Jeong, Woon-Jo; Moon, So-Lim; Lee, Hye-Ran; Chung, Min-Chul; Cho, Soon-Kye; Jung, Sang-Chul; Ahn, Ho-Geun

2011-08-01

375

Synthesis of Titanates with a Ramsdellite-Type Tunnel Structure Crystallizing in the Li 2 O-Fe 2 O 3 -TiO 2 System in Different Gaseous Media  

Microsoft Academic Search

The ramsdellite-type phases crystallizing in the Li2O-Fe2O3-TiO2 system in the course of synthesis in gaseous media at different oxygen partial pressures are studied. Solid solutions based on the ramsdellite structure with the composition Li2Ti3?xFexO7 ? ? (0 ? x ? 0.7) are prepared in an oxidizing medium (PO2 = 1 atm) for the first time. Analysis of the results obtained

S. A. Petrov; O. Yu. Sinel'shchikova; L. F. Grigor'eva; I. B. Patrina; N. O. Ovchinnikov; V. V. Gusarov

2005-01-01

376

Synthesis of hierarchically organized nanostructured TiO2 by pulsed laser deposition and its application to dye-sensitized solar cells  

Microsoft Academic Search

Hierarchically organized TiO2 nanostructures were synthesized on fluorine-doped SnO2(FTO)\\/glass substrate at room temperature under various oxygen pressures using pulsed laser deposition (PLD). The microstructures of the obtained TiO2 nanostructures were changed sensitively as oxygen pressure. A fully dense structure could be achieved below oxygen pressure of 50 mTorr. However, ultrafine nanoparticles (5~15 nm) were produced over 50 mTorr and they

Jun Hong Noh; Jong Hun Park; Hyun Soo Han; Sangwook Lee; Dong Hoe Kim; Hyun Suk Jung; Kung Sun Hong

2010-01-01

377

Facile one-step synthesis of inorganic-framework molecularly imprinted TiO2/WO3 nanocomposite and its molecular recognitive photocatalytic degradation of target contaminant.  

PubMed

Inorganic-framework molecularly imprinted TiO2/WO3 nanocomposites with molecular recognitive photocatalytic activity were first prepared successfully by a facile one-step sol-gel method using 2-nitrophenol and 4-nitrophenol as template molecules, and tetrabutyl orthotitanate as titanium source as well as the precursor of functional monomer which could complex with template molecules. The template molecules could be completely removed by means of high-temperature calcination, avoiding the traditional extraction procedures that are time- as well as solvent-consuming. Compared to nonimprinted TiO2/WO3, the molecularly imprinted TiO2/WO3 shows a much higher adsorption capacity and selectivity toward the template molecules. The enhancement in terms of adsorption capacity and selectivity can be attributed to the chemical interaction between target molecules and imprinted cavities, as well as size matching between imprinted cavities and target molecules. The photocatalytic activity of molecularly imprinted TiO2/WO3 toward the target molecules is more than two times that of non-imprinted TiO2/WO3, a result of selective adsorption of target molecules on molecularly imprinted TiO2/WO3. The formation pathway of intermediate products in 2-nitrophenol and 4-nitrophenol degradation process was provided. Moreover, molecularly imprinted TiO2/WO3 exhibits high stability. The results indicate that inorganic-framework molecularly imprinted TiO2/WO3 nanocomposites have a promising prospect in the treatment of wastewater for irrigation. PMID:23746077

Luo, Xubiao; Deng, Fang; Min, Lujuan; Luo, Shenglian; Guo, Bin; Zeng, Guisheng; Au, Chaktong

2013-06-21

378

Synthesis of TiO 2–Ag nanocomposite with sol–gel method and investigation of its antibacterial activity against E. coli  

Microsoft Academic Search

TiO2–Ag nanocomposite was prepared by the sol–gel method and an azeotropic distillation with benzene was used for dehydration of the gel. Because of gel dehydration by distillation method a nanopowder with a surface area of 230 m2\\/g was produced which decreased to 80 m2\\/g after calcination. TEM micrographs and XRD patterns showed that spherical nanosized Ag particles (?10 nm) were deposited among TiO2

Shahab Ansari Amin; Mohammad Pazouki; Azarmidokht Hosseinnia

2009-01-01

379

?-MoO 3\\/TiO 2 core\\/shell nanorods: Controlled-synthesis and low-temperature gas sensing properties  

Microsoft Academic Search

Crystalline ?-MoO3\\/TiO2 core\\/shell nanorods are fabricated by a hydrothermal method and subsequent annealing processes under H2\\/Ar flow and in the ambient atmosphere. The shell layer is composed of crystalline TiO2 particles with a diameter of 2–6nm, and its thickness can be easily controlled in the range of 15–45nm. The core\\/shell nanorods show enhanced sensing properties to ethanol vapor compared to

Yu-Jin Chen; Gang Xiao; Tie-Shi Wang; Fan Zhang; Yang Ma; Peng Gao; Chun-Ling Zhu; Endi Zhang; Zhi Xu; Qiu-hong Li

2011-01-01

380

Synthesis and characterization of substitutional and interstitial nitrogen-doped titanium dioxides with visible light photocatalytic activity  

NASA Astrophysics Data System (ADS)

Both substitutional and interstitial nitrogen-doped titanium dioxides (N-TiO2) were prepared. Their surface states were clarified by XPS spectra of N 1s, O 1s and Ti 2p. The results of photocatalysis show that both substitutional and interstitial N impurities greatly enhance the photoactivity of TiO2 in visible light. Moreover, the visible light activity of interstitial N-doped TiO2 is higher than that of substitutional N-doped TiO2. The microwave synthesis presented in this paper is a promising and practical method to produce interstitial nitrogen-doped photocatalysts with high visible light activity.

Peng, Feng; Cai, Lingfeng; Yu, Hao; Wang, Hongjuan; Yang, Jian

2008-01-01

381

One step activation of WO x \\/TiO 2 nanocomposites with enhanced photocatalytic activity  

Microsoft Academic Search

New photocatalyst (WOx–TiO2) powder was successfully prepared by a sol–gel method with an attempt to extend light absorption of the TiO2-based photocatalyst towards the visible light range and eliminate the rapid recombination of excited electrons\\/holes during photoreaction. The photo composite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), BET,

Ahmed Khan Leghari Sajjad; Sajjad Shamaila; Baozhu Tian; Feng Chen; Jinlong Zhang

2009-01-01

382

Visible light photocatalytic activity of TiO 2\\/D-PVA for MO degradation  

Microsoft Academic Search

A novel visible light (VL) active photocatalyst (TiO2\\/D-PVA) was prepared in one portion of polyvinyl alcohol (PVA) and Ti(OH)4 by means of hydrothermal method, and the relationship between the prepared conditions and VL photocatalytic activity was investigated. The synthesized photocatalyst was characterized by XRD, UV–vis, XPS, FTIR and EPR. The results show that PVA was dehydrated to produce conjugated unsaturated

Yongzhong Wang; Mingqiang Zhong; Feng Chen; Jintao Yang

2009-01-01

383

Photocatalysis of SiO 2-loaded TiO 2  

Microsoft Academic Search

SiO2 was loaded to TiO2 by sol–gel method, and the resulting SiO2\\/TiO2 was calcined at different temperatures. The loading of SiO2 improved photocatalytic activity of TiO2. The optimum calcination temperature was 300°C, and the optimum amount of loaded SiO2 was 1.5–4.8wt.%. This modified photocatalyst was tested for the degradation of nitrobenzene (NB), benzyltrimethylammonium chloride (BTMA), phenol and propionic acid. The

Y. Arai; K. Tanaka; A. L. Khlaifat

2006-01-01

384

(Mo + N) codoped TiO 2 for enhanced visible-light photoactivity  

NASA Astrophysics Data System (ADS)

Mo or N mono-doped and (Mo + N) co-doped anatase TiO 2 nanoparticles have been fabricated by sol-gel method. (Mo + N) co-doped TiO 2 has high photo absorption in whole visible region. Band structure calculations indicate more impurity bands can be induced by co-doping. The up-limit of dopant concentrations is increased by co-doping. (Mo + N) co-doped TiO 2 is promising to have high photocatalystic efficiency under visible light.

Liu, Hailin; Lu, Zhihong; Yue, Ling; Liu, Jing; Gan, Zhanghua; Shu, Chang; Zhang, Ting; Shi, Jing; Xiong, Rui

2011-09-01

385

Photocatalytic activation of TiO 2 under visible light using Acid Red 44  

Microsoft Academic Search

The activation of TiO2 photocatalyst for photocatalysis under the visible light using Acid Red 44 (C10H7N=NC10H3(SO3Na)2OH) is described. Adjustment of the pH enhanced the photocatalytic activation of TiO2 in the presence of visible light. This confirms that the adsorption of a dye on TiO2 surface is an important factor in dye-photosensitization. The differences in the photocatalytic activation mechanism under visible

Jungwoo Moon; Chang Yeon Yun; Kyung-Won Chung; Min-Soo Kang; Jongheop Yi

2003-01-01

386

Origin of photoactivity of oxygen-deficient TiO2 under visible light  

NASA Astrophysics Data System (ADS)

As it is now well established that oxygen vacancies are spontaneously introduced during nitrogen doping of anatase TiO2, there is a lively debate on whether nitrogen dopant or oxygen vacancy contributes to the visible light photoactivity of the doped catalyst. We showed that the coordinately unsaturated Ti site is integral to the visible light photoactivity in anatase oxygen-deficient TiO2 catalyst. Accordingly, oxygen vacancies may contribute to the visible light photoactivities in N-doped TiO2 and other nonmetallic ion-doped TiO2 as well. A redox active visible light photocatalyst has been developed based on oxygen-deficient structure in anatase TiO2.

Lo, Hsin-Hsi; Gopal, Neeruganti O.; Ke, Shyue-Chu

2009-08-01

387

Enhancement of photocatalytic activity of TiO2 nanoparticles by coupling Sb2O3  

NASA Astrophysics Data System (ADS)

Sb2O3/TiO2 nanoparticles were synthesized by a facile hydrothermal method, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transfer infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of Sb2O3/TiO2 nanoparticles were evaluated by the degradation of methyl orange. The results show that the Sb2O3 doping enhanced the photocatalytic activity of TiO2, and the 0.5%Sb2O3/TiO2 nanoparticles show the best photocatalytic activity. The separation of photoinduced electron-hole pairs on the Sb2O3/TiO2 photocatalyst surface is an important step in the photocatalytic reaction because of the Sb2O3 coupling.

Liu, Dan-Ni; He, Guo-Hua; Zhu, Li; Zhou, Wu-Yi; Xu, Yue-Hua

2012-08-01

388

A two-dimensional phase of TiO2 with a reduced bandgap  

NASA Astrophysics Data System (ADS)

Titanium dioxide is the prototypical transition metal oxide photocatalyst. However, the larger than 3 eV bandgap of common bulk phases of TiO2 limits its light absorption to UV light, making it inefficient for solar energy conversion. Attempts at increasing visible light activity by narrowing the bandgap of TiO2 through doping have proven difficult, because of defect-induced charge trapping and recombination sites of photo-excited charge carriers. Here, we report the existence of a dopant-free, pure TiO2 phase with a narrow bandgap. This new pure TiO2 phase forms on the surface of rutile TiO2(011) by oxidation of bulk titanium interstitials. We measure a bandgap of only ~2.1 eV for this new phase, matching it closely with the energy of visible light.

Tao, Junguang; Luttrell, Tim; Batzill, Matthias

2011-04-01

389

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

390

Beta zeolite supported sol-gel TiO2 materials for gas phase photocatalytic applications.  

PubMed

Beta zeolite supported sol-gel TiO(2) photocatalytic materials were prepared according to a sol-gel route in which high specific surface area Beta zeolite powder was incorporated into the titanium isopropoxide sol during the course of the sol-gel process. This led to an intimate contact between the zeolite surface and the TiO(2) precursors, and resulted in the anchorage of large amounts of dispersed TiO(2) nanoparticles and in the stabilization of TiO(2) in its anatase form, even for high TiO(2) wt. contents and high calcination temperatures. Taking the UV-A photocatalytic oxidation of methanol as gas phase target reaction, high methanol conversions were obtained on the Beta zeolite supported TiO(2) photocatalysts when compared to bulk sol-gel TiO(2), despite lower amounts of TiO(2) within the photoactive materials. The methanol conversion was optimum for about 40 wt.% TiO(2) loading and calcination temperatures of 500-600°C. PMID:21177024

Lafjah, Mama; Djafri, Fatiha; Bengueddach, Abdelkader; Keller, Nicolas; Keller, Valérie

2010-12-08

391

Sol-gel synthesis, characterization and optical properties of mercury-doped TiO2 thin films deposited on ITO glass substrates  

NASA Astrophysics Data System (ADS)

The Hg-doped and undoped nano-crystalline TiO2 films on ITO glass substrates surface and polycrystalline powders were prepared by sol-gel dip coating technique. The crystal structure and surface morphology of TiO2 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 TiO2, 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 TiO2 films was about 8.17 nm and was increased with Hg-doping in the TiO2 films. Moreover, the grains distributed more uniform and the surface roughness was greater in the Hg-doped TiO2 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 TiO2 thin films.

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

2011-08-01

392

Band gap engineering of compensated (N, H) and (C, 2H) codoped anatase TiO2: A first-principles calculation  

NASA Astrophysics Data System (ADS)

The electronic structures and optical properties of non-compensated (C, H)-, compensated (N, H)- and (C, 2H)-doped anatase TiO2 have been investigated using spin-polarized density functional theory. The calculated results indicated that compensated (N, H) codoped TiO2 exhibited the enhanced optical absorption under visible-light irradiation in comparison with N doped TiO2 and pure TiO2. Compensated (C, 2H) codoped TiO2 may also be a good candidate for visible-light photocatalyst materials due to the band gap narrowing significantly and the elimination of some local states.

Li, Min; Zhang, Junying; Guo, Dong; Zhang, Yue

2012-06-01

393

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

394

Photocatalytic oxidation of water on TiO 2-coated WO 3 particles by visible light using Iron(III) ions as electron acceptor  

Microsoft Academic Search

Photocatalytic oxidation of water on TiO2-coated WO3 particles was studied using iron(III) ions as the electron acceptor with the aim of constructing a photochemical energy conversion system. Although WO3 photocatalysts can utilize part of visible light, the reaction was decelerated as the concentration of iron(II) ions in solution increased. This was a marked contrast with the reaction using TiO2 photocatalysts,

Teruhisa Ohno; Fumihiro Tanigawa; Kan Fujihara; Shinobu Izumi; Michio Matsumura

1998-01-01

395

Effect of dissolved ozone or ferric ions on photodegradation of thiacloprid in presence of different TiO2 catalysts.  

PubMed

Combining TiO(2) photocatalysis with inorganic oxidants (such as O(3) and H(2)O(2)) or transition metal ions (Fe(3+), Cu(2+) and Ag(+)) often leads to a synergic effect. Electron transfer between TiO(2) and the oxidant is usually involved. Accordingly, the degree of synergy could be influenced by TiO(2) surface area. With this in mind, the disappearance of thiacloprid, a neonicotinoid insecticide, was studied applying various photochemical AOPs and different TiO(2) photocatalysts. In photocatalytic ozonation experiments, synergic effect of three different TiO(2) photocatalysts was quantified. Higher surface area resulted in a more pronounced synergic effect but an increasing amount of TiO(2) did not influence the degree of the synergy. This supports the theory that the synergy is a consequence of adsorption of ozone on the TiO(2) surface. No synergy was observed in photocatalytic degradation of thiacloprid in the presence of dissolved iron(III) species performed under varied experimental conditions (concentration, age of iron(III) solution, different TiO(2) films, usage of TiO(2) slurries). This goes against the literature for different organic compounds (i.e., monuron). It indicates different roles of iron(III) in the photodegradation of different organic molecules. Moreover, TiO(2) surface area did not affect photodegradation efficiency in iron(III)-based experiments which could confirm absence of electron transfer between TiO(2) photocatalyst and iron(III). PMID:20056320

Cernigoj, Urh; Stangar, Urska Lavrencic; Jirkovský, Jaromír

2009-12-14

396

Atomic layer deposition in nanometer-level replication of cellulosic substances and preparation of photocatalytic TiO2/cellulose composites.  

PubMed

TiO2 replicas of filter paper with nanometer-level accuracy were prepared by atomic layer deposition of thin conformal TiO2 coating, followed by a removal of the paper by air-anneal at 450 degrees C. Photocatalytic anatase TiO2/cellulose composites were also made by leaving the paper intact. The TiO2 films were deposited from Ti(OMe)4 and H2O at 150-250 degrees C. The photocatalytic activity of the TiO2/cellulose composite was verified by photocatalytic reduction of Ag(I) from an aqueous solution to Ag nanoparticles on the TiO2 surface. The TiO2/cellulose composites are mechanically more stable than the free-standing TiO2 replicas and are therefore potentially suitable as lightweight, high surface area photocatalysts. PMID:16218600

Kemell, Marianna; Pore, Viljami; Ritala, Mikko; Leskelä, Markku; Lindén, Mika

2005-10-19

397

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

398

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

399

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

400

Synthesis of TiO2(110) ultra-thin films on W(100) and their reactions with H2O  

NASA Astrophysics Data System (ADS)

We present a study of the growth and reactivity of ultra-thin films of TiO2 grown on W(100). Three approaches to film growth are investigated, each resulting in films that show order in low-energy diffraction (LEED) and a low level of non-stoichiometry in X-ray photoelectron spectroscopy (XPS). H2O is used as a probe of the reactivity of the films, with changes in the Ti 2p and O 1s core levels being monitored by XPS. Evidence for the dissociation of H2O on the TiO2(110) ultra-thin film surface is adduced. These results are discussed with reference to related studies on native TiO2(110).

Matharu, J.; Cabailh, G.; Thornton, G.

2013-10-01

401

Effect of void structure of photocatalyst paper on VOC decomposition.  

PubMed

TiO2 powder-containing paper composites, called TiO2 paper, were prepared by a papermaking technique, and their photocatalytic efficiency was investigated. The TiO2 paper has a porous structure originating from the layered pulp fiber network, with TiO2 powders scattered on the fiber matrix. Under UV irradiation, the TiO2 paper decomposed gaseous acetaldehyde more effectively than powdery TiO2 and a pulp/TiO2 mixture not in paper form. Scanning electron microscopy and mercury intrusion analysis revealed that the TiO2 paper had characteristic unique voids ca. 10 microm in diameter, which might have contributed to the improved photocatalytic performance. TiO2 paper composites having different void structures were prepared by using beaten pulp fibers with different degrees of freeness and/or ceramic fibers. The photodecomposition efficiency was affected by the void structure of the photocatalyst paper, and the initial degradation rate of acetaldehyde increased with an increase in the total pore volume of TiO2 paper. The paper voids presumably provided suitable conditions for TiO2 catalysis, resulting in higher photocatalytic performance by TiO2 paper than by TiO2 powder and a pulp/TiO2 mixture not in paper form. PMID:17166561

Fukahori, Shuji; Iguchi, Yumi; Ichiura, Hideaki; Kitaoka, Takuya; Tanaka, Hiroo; Wariishi, Hiroyuki

2006-12-12

402

Room-temperature synthesis of single-phase anatase TiO2 by aging and its self-cleaning properties.  

PubMed

A facile process to synthesize single-phase anatase titanium dioxide nanocrystallites at room temperature was presented. The process included a sol-gel reaction in an aqueous media followed by aging at room temperature. The anatase TiO2 was characterized using XRD, TEM and SEM. The cotton fabrics-coated by the anatase nanocrystallites possessed significant photocatalytic self-cleaning properties as demonstrated by their ability to decompose a colorant and degrade red wine and coffee stains, which was equivalent to that of prepared by heating or hydrothermal methods described previously. The anatase TiO2-coated cotton substrate also showed a high UPF rating of 50+, which means excellent UV protection to human wearers. The study of the adhesion between the anatase TiO2 and the cotton substrate showed that even after 20 times of repeated launderings, the-coated substrate was still capable of decomposing stains, which indicated its photocatalytic power, though this was reduced compared to that before laundering. The tensile strength results of the anatase TiO2-coated cotton fabrics indicate that the anatase TiO2 will not damage the cotton substrate even after 20 h of continuous UV irradiation. The method of preparing single-phase anatase TiO2 revealed in this study not only eliminates the need for high temperature processing, which means energy saving, but also broadens its applications to poor acid-resistant and low thermal stability materials such as many of the biomaterials and cellulosic materials. PMID:21070041

Qi, Kaihong; Xin, John H

2010-11-11

403

Photocatalytic degradation of dyes on a magnetically separated photocatalyst under visible and UV irradiation  

Microsoft Academic Search

A novel kind of magnetically separable photocatalyst of TiO2\\/SiO2\\/?-Fe2O3 (TSF) is prepared. Scanning tunnel microscope (STM) and X-ray diffractometer (XRD) were used to characterize the structure of the photocatalyst. In the TSF photocatalyst, a TiO2 shell is for photocatalysis, a ?-Fe2O3 core as a carrier is for separation by the magnetic field and a SiO2 membrane between the TiO2 shell

Feng Chen; Yinde Xie; Jincai Zhao; Gongxuan Lu

2001-01-01

404

Nylon 6\\/TiO2 Composites by in situ Anionic Ring-Opening Polymerization of ?-Caprolactam: Synthesis, Characterization, and Properties  

Microsoft Academic Search

Two series of nylon 6\\/TiO2 composites were obtained via anionic ring opening polymerization of ?-caprolactam in the presence of untreated and surface-treated TiO2 with 3-aminopropyltriethoxysilane (APTEOS) as coupling agent by the rotational molding technique. The polymerization process was carried out using a system initiator\\/activator based on sodium dicaprolactamato-bis(2-methoxyethoxo)aluminate and N,N?-[methylene-di(4,4?-phenylene)bis-carbamoyl]bis-?-caprolactam. All tests were performed at the initial polymerization temperature of

Gheorghe Rusu; Elena Rusu

2011-01-01

405

Study on Molecular Contamination Prevention by Using Photocatalysts under Vacuum Conditions  

NASA Astrophysics Data System (ADS)

To better understand the characteristics for preventing organic contaminants from accumulating on the critical surfaces of spacecraft, we studied on the effective prevention of molecular contaminants by using photocatalysts under ultraviolet irradiation and vacuum conditions. Squalene, tetra-methyl tetra-phenyl tri-siloxane, oleamide and diethylhexyl phthalate were used as model contaminants. TiO2 particles and TiO2-coated substrates were used as photocatalysts. TiO2 was effective in weight losses of all organics under the conditions. Transmittance of the TiO2-coated substrates increased depending on UV irradiation time.

Urayama, Fumitaka; Furukawa, Mutsuhisa; Ozawa, Kiyoshi; Tosa, Masahiro; Kimura, Hideo

406

Performance of photocatalytic reactors using immobilized TiO 2 film for the degradation of phenol and methylene blue dye present in water stream  

Microsoft Academic Search

TiO2 thin film photocatalyst was successfully synthesized and immobilized on glass reactor tube using sol–gel method. The synthesized TiO2 coating was transparent, which enabled the penetration of ultra-violet (UV) light to the catalyst surface. Two photocatalytic reactors with different operating modes were tested: (a) tubular photocatalytic reactor with re-circulation mode and (b) batch photocatalytic reactor. A new proposed TiO2 synthesized

Chin Mei Ling; Abdul Rahman Mohamed; Subhash Bhatia

2004-01-01

407

Enhanced photocatalytic reduction reaction over Bi 3+–TiO 2 nanoparticles in presence of formic acid as a hole scavenger  

Microsoft Academic Search

A series of Bi3+-doped TiO2 (Bi3+–TiO2) catalysts with a doping concentration up to 2wt% were prepared by a sol–gel method. The prepared photocatalysts were characterized by different means to determine their chemical composition, surface structure and light absorption properties. The photocatalytic activity of different Bi3+–TiO2 catalysts was evaluated in the photocatalytic reduction of nitrate in aqueous solution under UV illumination.

S. Rengaraj; X. Z. Li

2007-01-01

408

Photocatalytic Destruction of an Organic Dye Using TiO2 and Solar Energy.  

ERIC Educational Resources Information Center

|Describes a general chemistry experiment that is carried out in sunlight to illustrate the ability of TiO2 to act as a photocatalyst by mineralizing an organic dye into carbon dioxide. Details about the construction of the reactor system used to perform this experiment are included. (DDR)|

Giglio, Kimberly D.; And Others

1995-01-01

409

PHOTOELECTROCHEMICAL DEGRADATION OF METHYLENE BLUE WITH NANO TiO 2 UNDER HIGH POTENTIAL BIAS  

Microsoft Academic Search

In this work, photoelectrocatalytic degradation of wastewater containing methylene blue (MB) was investigated using a novel photoelectrochemical reactor - a three dimensional electrodes-photocatalytic oxidation reactor in which nano TiO 2 was used as photocatalyst. The experimental results are assessed in the terms of decolorization and Chemical Oxygen Demanded (COD) removal efficiencies. The experimental results showed that the three dimensional electrode-

Taicheng An; Guiying Li; Ya Xiong; Xihai Zhu; Hengtai Xing; Guoguang Liu

2001-01-01

410

Tunable growth of TiO2 nanostructures on Ti substrates  

NASA Astrophysics Data System (ADS)

A simple and facile method is described to directly synthesize TiO2 nanostructures on titanium substrates by oxidizing Ti foil using small organic molecules as the oxygen source. The effect of reaction temperature and oxygen source on the formation of the TiO2 nanostructures has been studied using scanning electron microscopy, x-ray diffraction, transmission electron microscopy, Raman spectroscopy and water contact angle measurement. Polycrystalline grains are formed when pure oxygen and formic acid are used as the oxygen source; elongated micro-crystals are produced when water vapour is used as the oxygen source; oriented and aligned TiO2 nanorod arrays are synthesized when ethanol, acetaldehyde or acetone are used as the oxygen source. The growth mechanism of the TiO2 nanostructures is discussed. The diffusion of Ti atoms to the oxide/gas interface via the network of the grain boundaries of the thin oxide layer is the determining factor for the formation of well-aligned TiO2 nanorod arrays. The wetting properties of the TiO2 nanostructured surfaces formed are dictated by their structure, varying from a hydrophilic surface to a strongly hydrophobic surface as the surface structure changes from polycrystalline grains to well-aligned nanorod arrays. This tunable growth of TiO2 nanostructures is desirable for promising applications of TiO2 nanostructures in the development of optical devices, sensors, photo-catalysts and self-cleaning coatings.

Peng, Xinsheng; Wang, Jingpeng; Thomas, Dan F.; Chen, Aicheng

2005-10-01

411

Electrochemical and photocatalytic properties of TiO2/WO3 photoelectrodes  

NASA Astrophysics Data System (ADS)

Porous films of TiO2 and TiO2/WO3 were deposited onto transparent electrodes from aqueous suspensions with polyethylene glycol, TiO2 particles and different amounts of tungistic acid. After annealing, crystalline samples were obtained. The band gap energy, approximately 3.1 eV for TiO2, decreased from 2.9 to 2.7 eV for varying W/Ti molar ratios from 3 to 12 %. The electrochemical properties were investigated in Na2SO4 aqueous solution; for the TiO2 electrode, the open circuit potential changed from 0.18 V in the dark to -0.25 V under irradiation from a solar simulator. For hybrid TiO2/WO3 electrodes, the VOC values were almost independent of the WO3 content and corresponded to 0.3 V in the dark and -0.1 V under irradiation; however, photocurrent and interfacial capacitance increased with a higher WO3 concentration. The electrodes were then used as photocatalysts for 17-?-etinylestradiol removal from water, and the mixed TiO2/WO3 exhibited better performance for photocatalytic oxidation of estradiol than TiO2. Adding WO3 enhances the visible light harvesting and minimizes the charge recombination resulting in higher efficiency for solar energy conversion.

Oliveira, Haroldo G.; Silva, Erika D.; Longo, Claudia

2010-08-01

412

Influence of surface treatment on preparing nanosized TiO 2 supported on carbon nanotubes  

NASA Astrophysics Data System (ADS)

In this paper, nanosize titanium dioxide (TiO 2) deposited on pristine and acid treated carbon nanotubes (CNTs) were prepared by a modified sol-gel method. The nanoscale materials were extensively characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR) and Raman spectra. The results indicated that about 6.8 nm TiO 2 nanoparticles were successfully deposited on acid-treated CNTs surface homogeneously and densely, which was smaller than TiO 2 coated on pristine CNTs. The surface state of CNTs was a critical factor in obtaining a homogeneous distribution of nanoscale TiO 2 particles. Acid oxidization could etch the surface of CNTs and introduce functional groups, which were beneficial to controllable homogeneous deposition. The TiO 2 coated on acid-treated CNTs was used as photocatalyst for Reactive Brilliant Red X-3B dye degradation under UV irradiation, which showed higher efficiency than that of TiO 2 coated on pristine CNTs and commercial photocatalyst P25.

Wang, Shuo; Ji, LiJun; Wu, Bin; Gong, Qianming; Zhu, Yuefeng; Liang, Ji

2008-12-01

413

Photocatalytic properties of nanostructured TiO2 surfaces  

NASA Astrophysics Data System (ADS)

Photocatalytic chemical reactions are actively explored for direct production of chemical fuels from sun light through electrolysis or for the clean-up of organic pollutants through photocatalysis. Titanium dioxide is a prototypical photocatalyst which has been studied extensively. However, there are still unanswered questions regarding the relationship between surface morphology and photocatalytic properties. In this study, we used ion beam assisted surface nanopatterning and UV-catalysis to investigate the dependence of photoreactivity on surface nanostructures. Energetic argon gas ions were used to induce self-formation of nanopatterns on TiO2 surfaces and the structure formation was characterized by atomic force microscopy. The influence of the surface structure on the photochemical properties was assessed through photocatalytic degradation of methyl orange in aqueous solution with a flat sample and a nanopatterned sample of TiO2, respectively. The resulting absorbance spectrums were then compared.

Moore, Lauren; Luttrell, Timothy; Batzill, Matthias

2012-02-01

414

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

415

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

416

Visible-light-induced bactericidal activity of vanadium-pentoxide (V2O5)-loaded TiO2 nanoparticles.  

PubMed

The bactericidal activity of TiO(2) nanoparticles under visible light is very important in regards to its practical applications. In this paper, we synthesized vanadium-pentoxide-loaded TiO(2) nanoparticles (V(2)O(5)-TiO(2)) using a chemical vapor condensation method, followed by the impregnation method, and characterized its physicochemical properties through X-ray diffraction patterning, X-ray photoelectron spectroscopy analysis, Raman spectra analysis, and Fourier transform infrared analysis. In addition, the antibacterial activity of V(2)O(5)-TiO(2) nanoparticles against E. coli was evaluated and compared with pure TiO(2) nanoparticles. In these experiments, the population of E. coli was shown to be significantly reduced by V(2)O(5)-TiO(2) nanoparticles under illumination with fluorescent light, whereas pure TiO(2) nanoparticles showed about 3.3-fold lower antibacterial activity than the V(2)O(5)-TiO(2) nanoparticles. This result was most likely due to the change in surface conditions of the TiO(2) nanoparticles, which was due to the loading of vanadium pentoxide on the TiO(2) nanoparticles. Furthermore, both photocatalysts showed similar antibacterial activity under UV-A (352 nm) irradiation. PMID:22948603

Kim, Yeon Seok; Song, Min Young; Park, Eun Seuk; Chin, Sungmin; Bae, Gwi-Nam; Jurng, Jongsoo

2012-09-05

417

Fabrication and growth mechanism of three-dimensional spherical TiO2 architectures consisting of TiO2 nanorods with {110} exposed facets  

NASA Astrophysics Data System (ADS)

In this paper, we report on the fabrication of a novel rutile TiO2 architecture consisting of nanorods with {110} exposed facets through a simple hydrothermal method without using any templates. An outside-in ripening mechanism is proposed to account for the formation of the TiO2 architectures. The formation of the TiO2 architectures can be attributed to the Ostwald step rule and highly acidic medium. Significantly, the current method is suitable for high-yield (>98%) production of the TiO2 architectures with nearly 100% morphological yield. This research provides a facile route to fabricate rutile TiO2 with three-dimensional microstructures based on nanounits. It is easy to realize their industrial-scale synthesis and application because of the simple synthesis method, low cost, and high yield.In this paper, we report on the fabrication of a novel rutile TiO2 architecture consisting of nanorods with {110} exposed facets through a simple hydrothermal method without using any templates. An outside-in ripening mechanism is proposed to account for the formation of the TiO2 architectures. The formation of the TiO2 architectures can be attributed to the Ostwald step rule and highly acidic medium. Significantly, the current method is suitable for high-yield (>98%) production of the TiO2 architectures with nearly 100% morphological yield. This research provides a facile route to fabricate rutile TiO2 with three-dimensional microstructures based on nanounits. It is easy to realize their industrial-scale synthesis and application because of the simple synthesis method, low cost, and high yield. Electronic supplementary information (ESI) available: EDS pattern of TiO2 products (Fig. S1) and XRD patterns of products obtained after reaction at different temperatures (Fig. S2) or for different times (Fig. S3). See DOI: 10.1039/c0nr00151a

Sang, Yan; Geng, Baoyou; Yang, Jie

2010-10-01

418

Solar photocatalysis for detoxification and disinfection of water: Different types of suspended and fixed TiO 2 catalysts study  

Microsoft Academic Search

Photocatalysis by titanium dioxide (TiO2), operational in the UV-A domain with a potential use of solar radiation, could be an alternative to conventional water detoxification and disinfection technologies. However, employing the photocatalyst as a suspension or slurry makes the scaling-up of the process difficult, as the TiO2 has to be removed from the decontaminated water to be reused several times.

D. Gumy; A. G. Rincon; R. Hajdu; C. Pulgarin

2006-01-01

419

Inactivation of Staphylococcus aureus and Escherichia coli in Water Using Photocatalysis with Fixed TiO 2  

Microsoft Academic Search

Photocatalytic activity in titanium dioxide (TiO2) has been extensively studied because of its potential use in sterilization, sanitation, and remediation applications. The\\u000a aim of the study reported here was to assess the feasibility of “fixed” TiO2 as the photocatalyst for inactivating pathogenic bacteria selected, Staphylococcus aureus and Escherichia coli, from a water stream. The investigation was undergone in a properly

Chih-Yu Chen; Li-Chun Wu; Hsuan-Yu Chen; Ying-Chien Chung

2010-01-01

420

Photocatalytic activity of sol–gel derived TiO 2 co-doped with iron and niobium  

Microsoft Academic Search

Titanium dioxide (TiO2) photocatalysts co-doped with iron (Fe) and niobium (Nb) were synthesized using a temperature-controlled sol–gel method.\\u000a The photocatalysis products were characterized and the photocatalytic activities were evaluated by the degradation of aqueous\\u000a methyl orange solution. Enhanced photocatalytic activity compared to undoped TiO2 was attributed to the cooperative effects of metal dopants, Fe and Nb.

Carl Renan Estrellan; Chris Salim; Hirofumi Hinode

2009-01-01

421

Synthesis of dandelion-like TiO2 microspheres as anode materials for lithium ion batteries with enhanced rate capacity and cyclic performances  

NASA Astrophysics Data System (ADS)

Dandelion-like TiO2 microspheres consisting of numerous rutile single-crystalline nanorods were synthesized for the first time by a hydrothermal method. Their crystal structure, morphology and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and galvanostatic charge and discharge tests. The results show that the synthesized TiO2 microspheres exhibit good rate and cycle performances as anode materials of lithium ion batteries. It can be found that the dandelion-like structure provides a larger specific surface area and the single-crystalline nanorod provides a stable structure and fast pathways for electron and lithium ion transport, which contribute to the rate and cycle performances of the battery.

Yi, Jin; Liu, Yan-lin; Wang, Yuan; Li, Xiao-ping; Hu, She-jun; Li, Wei-shan

2012-11-01

422

A facile synthesis of uniform NH4TiOF3 mesocrystals and their conversion to TiO2 mesocrystals.  

PubMed

Uniform mesocrystals of TiO2 (anatase) have been prepared from mesocrystals of NH4TiOF3. NH4TiOF3 was synthesized from an aqueous solution containing (NH4)2TiF6 and H3BO3 in the presence of a nonionic surfactant Brij 56, Brij 58, or Brij 700, at low temperatures. The exterior shapes of NH4TiOF3 mesocrystals can be tuned by adjusting the reagent concentration, reaction time, reaction temperature, and rate of stirring. The formation of the NH4TiOF3 mesocrystals proceeds via a self-assembly process involving nonclassical crystal growth. By sintering in air at 450 degrees C, or washing with H3BO3 solution at ambient temperatures, the NH4TiOF3 mesocrystals can be converted to mesocrystals of TiO2 (anatase), and the original architecture is retained. PMID:18181623

Zhou, Lei; Smyth-Boyle, David; O'Brien, Paul

2008-01-09

423

Large-scale synthesis of single-crystalline rutile TiO2 nanorods via a one-step solution route  

NASA Astrophysics Data System (ADS)

A convenient hydrothermal method has been developed to synthesize rutile titanium dioxide (TiO2) nanorods by employing TiCl3 and ethanol. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) investigations reveal that the rods with average diameter of 35 nm are well dispersed with single-crystalline nature. In addition, part nanorods are attached by some nanoparticles. The band gap Eg of obtained TiO2 is about 3.0 eV by ultraviolet (UV) vis absorption spectrum. An important role of ethanol played in the formation of rod-like nanocrystals is found and the concentration of HCl could also influence their morphologies.

Huang, Xiangping; Pan, Chunxu

2007-08-01

424

Simple synthesis and size-dependent surface-enhanced Raman scattering of Ag nanostructures on TiO2 by thermal decomposition of silver nitrate at low temperature  

Microsoft Academic Search

A low-temperature dry-process was proposed to synthesize silver nanoparticles, nanorods, and nanoplates on TiO2 films via thermal decomposition of silver nitrate. X-ray diffraction (XRD) shows only silver crystals were synthesized on the substrate without other byproducts remaining. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal the Ag nanoparticles are single-crystalline face-centered cubic (FCC) structures and their average diameters

Ruey-Chi Wang; Yong-Siang Gao; Shu-Jen Chen

2009-01-01

425

Investigation on synthesis, characterisation and electrochemical properties of TiO 2–Al 2O 3 nanocomposite thin film coated on 316 L stainless steel  

Microsoft Academic Search

TiO2–Al2O3 nanocomposite coatings have been applied on the surface of 316L stainless steel by a sol–gel process and dip-coating technique. The film with different compositions and thickness have been prepared. The phase composition and morphology of samples has been analyzed by Simultaneous Thermal Analyzer (STA), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Fourier Transform Infrared

H. Vaghari; Z. Sadeghian; M. Shahmiri

2011-01-01

426

Large-scale synthesis of single-crystalline rutile TiO 2 nanorods via a one-step solution route  

Microsoft Academic Search

A convenient hydrothermal method has been developed to synthesize rutile titanium dioxide (TiO2) nanorods by employing TiCl3 and ethanol. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) investigations reveal that the rods with average diameter of 35nm are well dispersed with single-crystalline nature. In addition, part nanorods are attached by some nanoparticles. The band gap Eg

Xiangping Huang; Chunxu Pan

2007-01-01

427

Synthesis, characterization, photocatalytic activity and dye-sensitized solar cell performance of nanorods\\/nanoparticles TiO 2 with mesoporous structure  

Microsoft Academic Search

Nanorods\\/nanoparticles TiO2 with mesoporous structure were synthesized by hydrothermal method at 150°C for 20h. The samples characterized by XRD, SEM, TEM, SAED, HRTEM, and BET surface area. The nanorods had diameter about 10–20nm and the lengths of 100–200nm, the nanoparticles had diameter about 5–10nm. The prepared material had average pore diameter about 7–12nm. The BET surface area and pore volume

Sorapong Pavasupree; Supachai Ngamsinlapasathian; Masafumi Nakajima; Yoshikazu Suzuki; Susumu Yoshikawa

2006-01-01

428

Wet-chemical synthesis of monodispersed barium titanate particles — hydrothermal conversion of TiO 2 microspheres to nanocrystalline BaTiO 3  

Microsoft Academic Search

A low-temperature hydrothermal reaction scheme has been developed to produce pure, ultrafine, uniform-sized, nanocrystalline barium titanate (BaTiO3) microspheres from two inorganic precursors: synthesized titania microspheres and barium hydroxide solutions. The size and morphology of titania (TiO2) microspheres were controlled using isopropanol to fine-tune the dielectric constant of the isopropanol–water mixed solvent system. Monodispersed titania microspheres approximately 0.1–1 ?m in diameter

Michael Z.-C Hu; Vino Kurian; E. Andrew Payzant; Claudia J Rawn; Rodney D Hunt

2000-01-01

429

Optimization of solar photocatalytic degradation conditions of Reactive Yellow 14 azo dye in aqueous TiO 2  

Microsoft Academic Search

The photocatalytic decolourisation and degradation of an azo dye Reactive Yellow 14 (RY14) in aqueous solution with TiO2-P25 (Degussa) as photocatalyst in slurry form have been investigated using solar light. The study on the effect of various photocatalysts on the decolourisation and degradation reveals the following order of reactivity: ZnO>TiO2-P25>TiO2 (anatase). CdS, Fe2O3 and SnO2 have negligible activity on RY14

M. Muruganandham; N. Shobana; M. Swaminathan

2006-01-01

430

Synthesis of high-quality brookite TiO2 single-crystalline nanosheets with specific facets exposed: tuning catalysts from inert to highly reactive.  

PubMed

The brookite phase of TiO(2) is hardly prepared and rarely studied in comparison with the common anatase and rutile phases. In addition, there exist immense controversies over the cognition of the light-induced liveliness of this material. Here, a novel, low-basicity solution chemistry method was first used to prepare homogeneous high-quality brookite TiO(2) single-crystalline nanosheets surrounded with four {210}, two {101}, and two {201} facets. These nanosheets exhibited outstanding activity toward the catalytic degradation of organic contaminants superior even to that of Degussa P25, due to the exposure of high-energy facets and the effective suppression of recombination rates of photogenerated electrons and holes by these facets as the oxidative and reductive sites. In contrast, irregularly faceted phase-pure brookite nanoflowers and nanospindles were inactive in catalytic reactions. These results demonstrate that the photocatalytic activity of brookite TiO(2) is highly dependent upon its exposed facets, which offers a strategy for tuning the catalysts from inert to highly active through tailoring of the morphology and surface structure. PMID:22559221

Lin, Haifeng; Li, Liping; Zhao, Minglei; Huang, Xinsong; Chen, Xiaomei; Li, Guangshe; Yu, Richeng

2012-05-10

431

Synthesis of mesoporous anatase TiO2 nanotubes by a hydrothermal treatment and their use in solid-state dye-sensitized solar cells.  

PubMed

Mesoporous anatase TiO2 nanotubes (NTs) with the diameter of about 7 12 nm and the length of several hundred nanometers were synthesized by a hydrothermal method on commercial TiO2 particles in NaOH followed by HCI washing. The samples were characterized by X-ray diffraction (XRD), transmitting electron microscopy (TEM), and Brunauer-Emmet-Teller (BET) measurements. The hydrothermal treatment temperature at 130 degrees C was shown to affect not only the extent of particle-to-sheet conversion, and thus the resulting structures of the NTs, but also the anatase-to-rutile transformation. The surface area of the NTs was 200 m2g(-1). This value was much higher in comparison to TiO2 nanoparticles of 50 m2g(-1). It was also found that the NT photoelectrodes had a pronounced impact on the performance of solar cells as compared to nanoparticle ones. This was probably due to lead to a significantly higher specific dye loading and, for certain hydrothermal treatments, resulting in a doubling of the solar cell efficiency (in our case from 2.84% to 4.03% of AM 1.5 conditions). PMID:21780512

Seo, Min-Kang; Park, Soo-Jin

2011-05-01

432

Highly visible-light active C- and V-doped TiO 2 for degradation of acetaldehyde  

Microsoft Academic Search

C-doped and C- and V-doped TiO2 photocatalysts were prepared by a sol–gel process. Both catalysts showed high activity for the degradation of acetaldehyde under visible irradiation (>420 nm). The co-doped TiO2 catalysts also were highly active in the dark; 2.0% V-containing co-doped TiO2 had the highest activity, comparable with the activity under visible light irradiation. The catalysts were characterized by X-ray

Xiangxin Yang; Chundi Cao; Keith Hohn; Larry Erickson; Ronaldo Maghirang; Dambar Hamal; Kenneth Klabunde

2007-01-01

433

Photocatalytic degradation of p-phenylenediamine with TiO 2-coated magnetic PMMA microspheres in an aqueous solution  

Microsoft Academic Search

This study investigates the photocatalytic degradation of p-phenylenediamine (PPD) with titanium dioxide-coated magnetic poly(methyl methacrylate) (TiO2\\/mPMMA) microspheres. The TiO2\\/mPMMA microspheres are employed as novel photocatalysts with the advantages of high photocatalytic activity, magnetic separability, and good durability. The scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and transmission electron microscopy (TEM) images of the TiO2\\/mPMMA microspheres are used to characterize

Yi-Hung Chen; Yi-You Liu; Rong-Hsien Lin; Fu-Shan Yen

2009-01-01

434

N-Doped SiO 2\\/TiO 2 mesoporous nanoparticles with enhanced photocatalytic activity under visible-light irradiation  

Microsoft Academic Search

Mesoporous nanocrystalline N-doped SiO2\\/TiO2 visible-light photocatalysts were prepared by treating SiO2\\/TiO2 xerogels in a flow of nitrogen gas bubbled through concentrated ammonia solution. Structural characterization and performance analysis results revealed that the addition of SiO2 remarkably altered the phase composition, specific surface area, microstructure, as well as the photocatalytic activity of N-doped TiO2. The presence of SiO2 in N-doped TiO2

Y. D. Hou; X. C. Wang; L. Wu; X. F. Chen; Z. X. Ding; X. X. Wang; X. Z. Fu

2008-01-01

435

Effect of Ce, N and S multi-doping on the photocatalytic activity of TiO2  

NASA Astrophysics Data System (ADS)

A visible light active photocatalyst was synthesized by multiple doping of TiO2 with Ce, N and S. The multidoped catalyst showed higher photocatalytic activity for methyl orange degradation from aqueous solution compared to P25 and undoped TiO2. The photocatalytic activity decreased in the order Ce0.6NS-TiO2 > P25 > NS-TiO2 > Ce0.6-TiO2 > TiO2. TiO2 and doped TiO2 existed as anatase phase with average particle size of 10 nm. In the multidoped TiO2, N substituted for O whereas S substituted for Ti. UV-vis absorption spectra showed an increased visible light absorption for doped TiO2 compared to the undoped one. An increased fluorescence lifetime for the charge carriers was observed for the doped samples as compared to undoped TiO2. The enhanced photocatalytic activity of Ce0.6NS-TiO2 is attributed to a synergistic effect of the dopants in increasing the visible light absorption and lifetime of the photogenerated charge carriers.

Charanpahari, A.; Umare, S. S.; Sasikala, R.

2013-10-01

436

Facile synthesis of carbon doped TiO2 nanowires without an external carbon source and their opto-electronic properties  

NASA Astrophysics Data System (ADS)

The present study demonstrates a simple protocol for the preparation of one dimensional (1D) oxidized titanium carbide nanowires and their opto-electronic properties. The oxidized titanium carbide nanowires (Ox-TiC-NW) are prepared from TiC nanowires (TiC-NW) that are in turn synthesized from micron sized TiC particles using the solvothermal technique. The Ox-TiC-NW is characterized by X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. Thermal oxidation of TiC-NW yields carbon doped TiO2-NW (C-TiO2-NW), a simple methodology to obtain 1D C-TiO2-NW. Temperature dependent Raman spectra reveal characteristic bands for TiO2-NW. Electrical characterization of individual C-TiO2-NW is performed by fabricating a device structure using the focused ion beam deposition technique. The opto-electronic properties of individual C-TiO2-NW demonstrate visible light activity and the parameters obtained from photoconductivity measurements reveal very good sensitivity. This methodology opens up the possibility of using C-TiO2-NW in electronic and opto-electronic device applications.The present study demonstrates a simple protocol for the preparation of one dimensional (1D) oxidized titanium carbide nanowires and their opto-electronic properties. The oxidized titanium carbide nanowires (Ox-TiC-NW) are prepared from TiC nanowires (TiC-NW) that are in turn synthesized from micron sized TiC particles using the solvothermal technique. The Ox-TiC-NW is characterized by X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. Thermal oxidation of TiC-NW yields carbon doped TiO2-NW (C-TiO2-NW), a simple methodology to obtain 1D C-TiO2-NW. Temperature dependent Raman spectra reveal characteristic bands for TiO2-NW. Electrical characterization of individual C-TiO2-NW is performed by fabricating a device structure using the focused ion beam deposition technique. The opto-electronic properties of individual C-TiO2-NW demonstrate visible light activity and the parameters obtained from photoconductivity measurements reveal very good sensitivity. This methodology opens up the possibility of using C-TiO2-NW in electronic and opto-electronic device applications. Electronic supplementary information (ESI) available: SEM image of a hydrothermally treated TiC sample (S1), spectral output of a commercial halogen lamp (S2), preparation and characterization of C-TiO2-NW (prepared at 800 °C) and pristine TiO2-NW, comparison of the optical response between various TiO2-NWs (S3-S6), procedure for measuring Potical, photocurrent growth and decay transients (S7). See DOI: 10.1039/c3nr03309k

Kiran, Vankayala; Sampath, Srinivasan

2013-10-01

437

Electrochemical approach to evaluate the mechanism of photocatalytic water splitting on oxide photocatalysts  

Microsoft Academic Search

Photoelectrochemical measurements of TiO2, NaTaO3, and Cr or Sb doped TiO2 and SrTiO3 photocatalysts were carried out in H2 and O2 saturated electrolytes in order to evaluate the reverse reactions during water photolysis. The poor activity of TiO2 as a result of reverse photoreactions of O2 reduction and H2 oxidation was revealed with the respective high cathodic and anodic photocurrents.

Yasumichi Matsumoto; Ugur. Unal; Noriyuki Tanaka; Akihiko Kudo; Hideki Kato

2004-01-01

438

Nanostructured N-doped TiO2 marigold flowers for an efficient solar hydrogen production from H2S.  

PubMed

Nitrogen-doped TiO2 nanostructures in the form of marigold flowers have been synthesized for the first time using a facile solvothermal method. The structural analysis has shown that such an N-doped TiO2 system crystallizes in the anatase structure. The optical absorption spectra have clearly shown the shift in the absorption edge towards the visible-light range, which indicates successful nitrogen doping. The nitrogen doping has been further confirmed by photoluminescence and photoemission spectroscopy. Microscopy studies have shown the thin nanosheets (petals) of N-TiO2 with a thickness of ?2-3 nm, assembled in the form of the marigold flower with a high surface area (224 m(2) g(-1)). The N-TiO2 nanostructure with marigold flowers is an efficient photocatalyst for the decomposition of H2S and production of hydrogen under solar light. The maximum hydrogen evolution obtained is higher than other known N-TiO2 systems. It is noteworthy that photohydrogen production using the unique marigold flowers of N-TiO2 from abundant H2S under solar light is hitherto unattempted. The proposed synthesis method can also be utilized to design other hierarchical nanostructured N-doped metal oxides. PMID:23958807

Chaudhari, Nilima S; Warule, Sambhaji S; Dhanmane, Sushil A; Kulkarni, Milind V; Valant, Matjaz; Kale, Bharat B

2013-08-19

439

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.

2012-01-01

440

Synthesis of Au nanoparticle doped SiO2–TiO2 films: tuning of Au surface plasmon band position through controlling the refractive index  

Microsoft Academic Search

derived from tetraethyl orthosilicate-3-(glycidoxypropyl)trimethoxysilane-titanium tetraethoxide containing gold chloride, following a sol-gel dip-coating method. The film samples of nominal formula (SiO2)x(TiO2)0.972xAu0.03 (x 5 0.97, 0.679, 0.485, 0.388 and 0.242) were prepared after heat treatment at 500 uC in air. The Au SPR peak, in the case of a SiO2 host (SiO2 : TiO2 5 1:0 , n 5 1.411), observed at

Samar Kumar Medda; Sucheta De; Goutam De

2005-01-01

441

Synthesis of TiO2 hollow nanofibers by co-axial electrospinning and its superior lithium storage capability in full-cell assembly with olivine phosphate  

NASA Astrophysics Data System (ADS)

We report the formation and extraordinary Li-storage properties of TiO2 hollow nanofibers by co-axial electrospinning in both the half-cell and full-cell configurations. Li-insertion properties are first evaluated as anodes in the half-cell configuration (Li/TiO2 hollow nanofibers) and we found that reversible insertion of ~0.45 moles is feasible at a current density of 100 mA g-1. The half-cell displayed a good cyclability and retained 84% of its initial reversible capacity after 300 galvanostatic cycles. The full-cell is fabricated with a commercially available olivine phase LiFePO4 cathode under optimized mass loading. The LiFePO4/TiO2 hollow nanofiber cell delivered a reversible capacity of 103 mA h g-1 at a current density of 100 mA g-1 with an operating potential of ~1.4 V. Excellent cyclability is noted for the full-cell configuration, irrespective of the applied current densities, and it retained 88% of reversible capacity after 300 cycles in ambient conditions at a current density of 100 mA g-1.We report the formation and extraordinary Li-storage properties of TiO2 hollow nanofibers by co-axial electrospinning in both the half-cell and full-cell configurations. Li-insertion properties are first evaluated as anodes in the half-cell configuration (Li/TiO2 hollow nanofibers) and we found that reversible insertion of ~0.45 moles is feasible at a current density of 100 mA g-1. The half-cell displayed a good cyclability and retained 84% of its initial reversible capacity after 300 galvanostatic cycles. The full-cell is fabricated with a commercially available olivine phase LiFePO4 cathode under optimized mass loading. The LiFePO4/TiO2 hollow nanofiber cell delivered a reversible capacity of 103 mA h g-1 at a current density of 100 mA g-1 with an operating potential of ~1.4 V. Excellent cyclability is noted for the full-cell configuration, irrespective of the applied current densities, and it retained 88% of reversible capacity after 300 cycles in ambient conditions at a current density of 100 mA g-1. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01128c

Zhang, X.; Aravindan, V.; Kumar, P. Suresh; Liu, H.; Sundaramurthy, J.; Ramakrishna, S.; Madhavi, S.

2013-06-01

442

Synthesis of samarium- and nitrogen-co-doped TiO 2 by modified hydrothermal method and its photocatalytic performance for the degradation of 4-chlorophenol  

Microsoft Academic Search

Sm- and nitrogen-co-doped TiO2 (Sm–N–TiO2) catalysts were prepared via the modified hydrothermal method using tetrabutyl titanate as the precursor and calcination at 200°C. The microstructure of the sample was characterized by X-ray diffraction (XRD), ultraviolet–visible diffuse reflection spectroscopy (UV–vis-DRS), Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS). The average particle size was ca. 16.0nm as calculated from XRD

D. G. Huang; S. J. Liao; W. B. Zhou; S. Q. Quan; L. Liu; Z. J. He; J. B. Wan

2009-01-01

443

Investigations of metal-doped titanium dioxide photocatalysts  

Microsoft Academic Search

Chromium-, manganese- and cobalt-doped titanium dioxide photocatalysts containing 0.2, 0.5 or 1at.% of metal-dopant were investigated by UV–VIS, FT-IR, near-IR and electron paramagnetic resonance (EPR) spectroscopic techniques. The presence of the doping ions in the titania structure caused significant absorption shift to the visible region compared to pure TiO2 powder (P25 Degussa). The EPR spectra of TiO2 powders containing chromium

Dana Dvoranová; Vlasta Brezová; Milan Mazúr; Mounir A. Malati

2002-01-01

444

Visible-light-driven TiO 2 catalysts doped with low-concentration nitrogen species  

Microsoft Academic Search

Visible-light-driven nitrogen-doped TiO2 was synthesized using a novel nitrogen-ion donor of hydrazine hydrate. Low-concentration (?0.2at%) nitrogen species and Ti3+ were detected in the TiO2-based photocatalyst by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) spectroscopy. The trace amount of Ti–N would contribute to the minor band-gap narrowing of about 0.02eV. Those nitrogen-containing species, especially the NO22? species, form surface

Hongqi Sun; Yuan Bai; Wanqin Jin; Nanping Xu

2008-01-01

445

Enhanced photocatalytic activity of Ag microgrid connected TiO2 nanocrystalline films  

NASA Astrophysics Data System (ADS)

One reason for the high degree of photogenerated carrier recombination was found to be the charge accumulation caused by the uneven reaction area on the photocatalyst surface. The authors connected TiO2 nanoparticles with conducting Ag microgrid. Obvious photocatalytic activity improvement (81%) over the pure TiO2 was observed, which is attributed to the electron-hole pairs separation by the metal-semiconductor contact and the large specific area of metal grid, which increased the O2 absorption and transported the electrons to the sites needed for the deoxidize reactions. This structure lowers the electron accumulation on the particles and improves the utilization ratio of the photoexcited carriers.

Pan, Feng; Zhang, Junying; Zhang, Weiwei; Wang, Tianmin; Cai, Chao

2007-03-01

446

Band alignment of rutile and anatase TiO2  

NASA Astrophysics Data System (ADS)

The most widely used oxide for photocatalytic applications owing to its low cost and high activity is TiO2. The discovery of the photolysis of water on the surface of TiO2 in 1972 launched four decades of intensive research into the underlying chemical and physical processes involved. Despite much collected evidence, a thoroughly convincing explanation of why mixed-phase samples of anatase and rutile outperform the individual polymorphs has remained elusive. One long-standing controversy is the energetic alignment of the band edges of the rutile and anatase polymorphs of TiO2 (ref. ). We demonstrate, through a combination of state-of-the-art materials simulation techniques and X-ray photoemission experiments, that a type-II, staggered, band alignment of ~ 0.4?eV exists between anatase and rutile with anatase possessing the higher electron affinity, or work function. Our results help to explain the robust separation of photoexcited charge carriers between the two phases and highlight a route to improved photocatalysts.

Scanlon, David O.; Dunnill, Charles W.; Buckeridge, John; Shevlin, Stephen A.; Logsdail, Andrew J.; Woodley, Scott M.; Catlow, C. Richard A.; Powell, Michael. J.; Palgrave, Robert G.; Parkin, Ivan P.; Watson, Graeme W.; Keal, Thomas W.; Sherwood, Paul; Walsh, Aron; Sokol, Alexey A.

2013-09-01

447

Simple synthesis and size-dependent surface-enhanced Raman scattering of Ag nanostructures on TiO2 by thermal decomposition of silver nitrate at low temperature.  

PubMed

A low-temperature dry-process was proposed to synthesize silver nanoparticles, nanorods, and nanoplates on TiO(2) films via thermal decomposition of silver nitrate. X-ray diffraction (XRD) shows only silver crystals were synthesized on the substrate without other byproducts remaining. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal the Ag nanoparticles are single-crystalline face-centered cubic (FCC) structures and their average diameters decrease from 100 to 15 nm with the increase in distance from the source, which corresponds to a decrease of substrate temperature from 350 to 110 degrees C. The Ag nanorods are also single-crystalline FCC structures growing along the [110] direction with diameter and length around 40 and 500 nm, respectively. The morphology of silver nanostructures could be adjusted by varying the working pressure as well as the roughness of the substrates. An obvious size-dependent SERS effect on the TiO(2) substrate with silver nanoparticles was observed for the first time. The enhancement factor increases as the size of the Ag nanoparticles decreases, which is attributed to the increase of hot spots. In addition, fractional brookite in the anatase films could be detected only after being loaded with Ag nanoparticles, which demonstrates the application of SERS in detecting fractional and important features of semiconductors. PMID:19706939

Wang, Ruey-Chi; Gao, Yong-Siang; Chen, Shu-Jen

2009-08-26

448

Morphology and Structure of ZrO2/TiO2/SiO2 Nanocomposites Obtained by Synthesis on Carbon Microfiber  

NASA Astrophysics Data System (ADS)

We present novel nanomaterials based on Ti, Zr, and Si oxides, synthesized by the template method on a carbon fiber support. We have studied their structural and morphological properties. All the oxide fibers obtained have an extended surface formed from nanoparticle aggregates. We show that by selecting the components and varying their ratios, we can change the microorganization of the fiber surface and the structure of the composites. Due to microstress arising in the lattice, rearrangement of the structure of the composite is accompanied by a decrease in the fiber length and diameter. Increasing the amount of stabilizing additives of SiO2 in the titanium dioxide reduces the size of the nanoparticles and inhibits their growth, and makes it possible to stabilize the structure of the TiO2 nanoparticles in the anatase phase. At the same time, the presence of ZrO2 in the composition of the composites allows us to modify the particles at the reactive interface between the components and to obtain a fiber composite with a new crystal structure. For a low ZrO2 concentration (~10 wt.%), the structure of the oxide fibers is formed by TiO2 nanoparticles of the anatase modification, coated with an amorphous mixture of the oxides SiO2 and ZrO2. When the ZrO2 concentration is increased (~50.5 wt.%), we observe formation of nanoparticles with the structure of the orthorhombic phase of the compound ZrTiO4.

Zheleznov, V. V.; Sushkov, Yu. V.; Voit, E. I.; Kuryavyi, V. G.

2013-09-01

449

Simple synthesis and size-dependent surface-enhanced Raman scattering of Ag nanostructures on TiO2 by thermal decomposition of silver nitrate at low temperature  

NASA Astrophysics Data System (ADS)

A low-temperature dry-process was proposed to synthesize silver nanoparticles, nanorods, and nanoplates on TiO2 films via thermal decomposition of silver nitrate. X-ray diffraction (XRD) shows only silver crystals were synthesized on the substrate without other byproducts remaining. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal the Ag nanoparticles are single-crystalline face-centered cubic (FCC) structures and their average diameters decrease from 100 to 15 nm with the increase in distance from the source, which corresponds to a decrease of substrate temperature from 350 to 110 °C. The Ag nanorods are also single-crystalline FCC structures growing along the [110] direction with diameter and length around 40 and 500 nm, respectively. The morphology of silver nanostructures could be adjusted by varying the working pressure as well as the roughness of the substrates. An obvious size-dependent SERS effect on the TiO2 substrate with silver nanoparticles was observed for the first time. The enhancement factor increases as the size of the Ag nanoparticles decreases, which is attributed to the increase of hot spots. In addition, fractional brookite in the anatase films could be detected only after being loaded with Ag nanoparticles, which demonstrates the application of SERS in detecting fractional and important features of semiconductors.

Wang, Ruey-Chi; Gao, Yong-Siang; Chen, Shu-Jen

2009-09-01

450

Facile synthesis of carbon doped TiO2 nanowires without an external carbon source and their opto-electronic properties.  

PubMed

The present study demonstrates a simple protocol for the preparation of one dimensional (1D) oxidized titanium carbide nanowires and their opto-electronic properties. The oxidized titanium carbide nanowires (Ox-TiC-NW) are prepared from TiC nanowires (TiC-NW) that are in turn synthesized from micron sized TiC particles using the solvothermal technique. The Ox-TiC-NW is characterized by X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. Thermal oxidation of TiC-NW yields carbon doped TiO2-NW (C-TiO2-NW), a simple methodology to obtain 1D C-TiO2-NW. Temperature dependent Raman spectra reveal characteristic bands for TiO2-NW. Electrical characterization of individual C-TiO2-NW is performed by fabricating a device structure using the focused ion beam deposition technique. The opto-electronic properties of individual C-TiO2-NW demonstrate visible light activity and the parameters obtained from photoconductivity measurements reveal very good sensitivity. This methodology opens up the possibility of using C-TiO2-NW in electronic and opto-electronic device applications. PMID:24057050

Kiran, Vankayala; Sampath, Srinivasan

2013-09-20

451

Bactericidal effects and mechanisms of visible light-responsive titanium dioxide photocatalysts on pathogenic bacteria.  

PubMed

This review focuses on the antibacterial activities of visible light-responsive titanium dioxide (TiO(2)) photocatalysts. These photocatalysts have a range of applications including disinfection, air and water cleaning, deodorization, and pollution and environmental control. Titanium dioxide is a chemically stable and inert material, and can continuously exert antimicrobial effects when illuminated. The energy source could be solar light; therefore, TiO(2) photocatalysts are also useful in remote areas where electricity is insufficient. However, because of its large band gap for excitation, only biohazardous ultraviolet (UV) light irradiation can excite TiO(2), which limits its application in the living environment. To extend its application, impurity doping, through metal coating and controlled calcination, has successfully modified the substrates of TiO(2) to expand its absorption wavelengths to the visible light region. Previous studies have investigated the antibacterial abilities of visible light-responsive photocatalysts using the model bacteria Escherichia coli and human pathogens. The modified TiO(2) photocatalysts significantly reduced the numbers of surviving bacterial cells in response to visible light illumination. They also significantly reduced the activity of bacterial endospores; reducing their toxicity while retaining their germinating abilities. It is suggested that the photocatalytic killing mechanism initially damages the surfaces weak points of the bacterial cells, before totally breakage of the cell membranes. The internal bacterial components then leak from the cells through the damaged sites. Finally, the photocatalytic reaction oxidizes the cell debris. In summary, visible light-responsive TiO(2) photocatalysts are more convenient than the traditional UV light-responsive TiO(2) photocatalysts because they do not require harmful UV light irradiation to function. These photocatalysts, thus, provide a promising and feasible approach for disinfection of pathogenic bacteria; facilitating the prevention of infectious diseases. PMID:22678625

Liou, Je-Wen; Chang, Hsin-Hou

2012-06-08

452

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

2012-03-05

453

Rational Design and Synthesis of Freestanding Photoelectric Nanodevices as Highly Efficient Photocatalysts  

PubMed Central

Photocatalysts are of significant interest for solar energy harvesting and conversion into chemical energy. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here we report the rational design of a new generation of freestanding photoelectric nanodevices as highly efficient and stable photocatalysts by integrating a nanoscale photodiode with two redox catalysts in a single nanowire heterostructure. We show that a platinum-silicon-silver nanowire heterostructure can be synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. We further demonstrated that the Schottky diodes exhibited pronounced photovoltaic effect with nearly unity internal quantum efficiency, and that the integrated nanowire heterostructures could be used as highly efficient photocatalysts for a wide range of thermodynamically downhill and uphill reactions including photocatalytic degradation of organic dyes, reduction of metal ions and carbon dioxide using visible light. Our studies for the first time demonstrated the integration of multiple distinct functional components into a single nanostructure to form a standalone active nanosystem, and for the first time successfully realized a photoelectric nanodevice that is both highly efficient and highly stable throughout the entire solar spectrum. It thus opens a rational avenue to design and synthesize a new generation of photoelectric nanosystems with unprecedented efficiency and stability, and will impact broadly in areas including environmental remediation and solar fuel production.

Qu, Yongquan; Liao, Lei; Cheng, Rui; Wang, Yue; Lin, Yung-chen; Huang, Yu; Duan, Xiangfeng

2010-01-01

454

Sonochemical synthesis of solar-light-driven Ag°-PbMoO4 photocatalyst.  

PubMed

Ag°-PbMoO4 photocatalysts were synthesized by facile sonochemical method with different mol.% of Ag nanoparticles dispersed on the surface of PbMoO4. The synthesized powders were characterized by X-ray Diffraction (XRD) Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), and Diffuse Reflectance Spectroscopy (UV-vis DRS) to investigate the crystal structure, morphology, chemical composition, and optical properties of the photocatalyst. Photocatalytic activities of the Ag°-PbMoO4 samples were evaluated by the degradation of Indigo Carmine (IC) dye under simulated solar light irradiation. It has been observed that the sample containing 0.3mol.% of Ag showed the best photocatalytic activity as compared to other samples. The results suggest that the dispersion of Ag nanoparticles on the surface of PbMoO4 significantly enhances the photocatalytic activity of PbMoO4. Increase in photocatalytic activity of Ag°-PbMoO4 photocatalyst has been explained on the basis of surface plasmon resonance (SPR) effect caused by the silver nanoparticles present in the photocatalyst. PMID:23643197

Gyawali, Gobinda; Adhikari, Rajesh; Joshi, Bhupendra; Kim, Tae Ho; Rodríguez-González, Vicente; Lee, Soo Wohn

2013-04-01

455

Synthesis of visible light-activated TiO{sub 2} photocatalyst via surface organic modification  

SciTech Connect

A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to sol-gel-hydrothermal synthesized TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex that was confirmed by the FT-IR and XPS spectra. Due to the existence of surface complex, the absorption edge of as-prepared TDI-modified TiO{sub 2} nanomaterial extended well into visible region. Compared with unmodified TiO{sub 2} and Degussa P25, the TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation. - Graphical abstract: A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex. The TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation.

Jiang Dong [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China)], E-mail: jdred@sxicc.ac.cn; Xu Yao [Key Laboratory of Carbon Material, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)], E-mail: xuyao@sxicc.ac.cn; Hou Bo [Key Laboratory of Carbon Material, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Wu Dong [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Sun Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)], E-mail: yhsun@sxicc.ac.cn

2007-05-15

456

TiO 2: As a versatile catalyst for the ortho-selective methylation of phenol  

Microsoft Academic Search

The investigation describes synthesis of active pure and mixed phase TiO2 catalysts by a TiCl3–urea–oxalic acid precursor method. Pure and mixed phase TiO2 catalysts could be obtained by varying the concentration of oxalic acid during synthesis. A minimum of 25mol% of oxalic acid during synthesis was found to bring about complete phase transition from rutile to anatase. The catalysts were

Aditi R. Gandhe; Julio B. Fernandes; Salil Varma; N. M. Gupta

2005-01-01

457

Low-temperature synthesis of anatase C-N-TiO2 photocatalyst with enhanced visible-light-induced photocatalytic activity  

NASA Astrophysics Data System (ADS)

Visible-light-activated C-N-TiO2 powders were synthesized by a facile peptization-reflux method at 120 °C. The physical and photophysical properties of the photocatalyst have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectra. The as-prepared C-N-TiO2 possessed a diameter of ca. 7 nm with anatase crystalline structure, and showed a shift of the absorption edge to a lower energy and a stronger absorption in the visible region. XPS results indicated that the retained alkoxyl groups existed on the surface of TiO2 and the doped nitrogen incorporated in the TiO2 as formation of N-Ti-O and Ti-O-N. And C-N-TiO2 samples had excellent photocatalytic activity for methyl orange degradation under visible light irradiation, which could be assigned to synergistic effect between the retained alkoxyls and the nitrogen doping.

Wu, Deyong; Wang, Lianzhi

2013-04-01

458

Linear correlation between inactivation of E. coli and OH radical concentration in TiO 2 photocatalytic disinfection  

Microsoft Academic Search

The biocidal action of the TiO2 photocatalyst has been now well recognized from massive experimental evidences, which demonstrates that the photocatalytic disinfection process could be technically feasible. However, the understanding on the photochemical mechanism of the biocidal action largely remains unclear. In particular, the identity of main acting photooxidants and their roles in the mechanism of killing microorganisms is under

Min Cho; Hyenmi Chung; Wonyong Choi; Jeyong Yoon

2004-01-01

459

TiO 2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations  

Microsoft Academic Search

The photocatalytic degradation of azo dyes containing different functionalities has been reviewed using TiO2 as photocatalyst in aqueous solution under solar and UV irradiation. The mechanism of the photodegradation depends on the radiation used. Charge injection mechanism takes place under visible radiation whereas charge separation occurred under UV light radiation. The process is monitored by following either the decolorization rate

Ioannis K Konstantinou; Triantafyllos A Albanis

2004-01-01

460

Pathways of solar light-induced photocatalytic degradation of azo dyes in aqueous TiO 2 suspensions  

Microsoft Academic Search

The photocatalytic degradation of aqueous solutions of Acid Orange 7 in TiO2 suspensions has been investigated with the use of a solar light simulating source. The photoreaction was followed by monitoring the degradation of the dye and the formation of intermediates and final products, as functions of time of irradiation, both in solution and on t