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Jianmeng Chen - One of the best experts on this subject based on the ideXlab platform.
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influence of zirconium doping on the activities of zirconium and iodine co doped titanium dioxide in the decolorization of methyl orange under visible light irradiation
Applied Surface Science, 2011Co-Authors: Shuang Song, Hongyu Wang, Fangyue Hong, Jianmeng ChenAbstract:Abstract Zirconium and iodine co-doped titanium dioxide (Zr–I–TiO 2 ) was prepared by the hydrolysis of tetrabutyl titanate, premixed with zirconium nitrate in an iodic acid aqueous solution, followed by calcination in air. The structure and properties of the resultant catalyst powders were characterized by X-ray diffraction, the Brunauer–Emmett–Teller Method, X-ray photoelectron spectroscopy, transmission electron microscopy, and UV–vis absorption spectroscopy. The catalytic activity of the catalyst was evaluated by monitoring the photocatalytic decolorization of methyl orange under visible light irradiation. The results showed that the activities of Zr–I–TiO 2 catalysts were higher than that of TiO 2 doped with iodine alone (I–TiO 2 ), and the optimal doping concentration in the Zr–I–TiO 2 calcined at 400 °C was determined to be about 0.05 (molar ratio of Zr:Ti). In addition, the photocatalytic activity of Zr–I–TiO 2 calcined at 400 °C was found to be significantly higher than that calcined at 500 or 600 °C. Based on the physico-chemical characterization, we concluded that the role of zirconium on the I–TiO 2 surface is to increase the number of reactive sites by generating a small crystal size and large surface area. The inhibition of electron–hole pair recombination, by trapping photo-generated electrons with Zr 4+ , did not contribute markedly to the improved photocatalytic activity of Zr–I–TiO 2 .
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increasing the catalytic activities of iodine doped titanium dioxide by modifying with tin dioxide for the photodegradation of 2 chlorophenol under visible light irradiation
Journal of Hazardous Materials, 2011Co-Authors: Cheng Wang, Hongyu Wang, Fangyue Hong, Jianmeng Chen, Shuang SongAbstract:The photocatalytic degradation of 2-chlorophenol (2-CP) irradiated with visible light over iodine doped TiO2 (IT) modified with SnO2 (SIT) nanoparticles has been investigated in this study. The structure and optical properties of the SIT catalysts have been well characterized by X-ray diffraction, the Brunauer–Emmett–Teller Method, transmission electron microscopy, UV–visible absorption spectra and X-ray photoelectron spectroscopy. The effects of preparation conditions, such as SnO2 content and calcination temperature, on the photocatalytic degradation efficiency have been surveyed in detail. The improved photocatalytic activity of SIT is derived from the synergistic effect between the SnO2 and IT, which promoted the efficiency of migration of the photogenerated carriers at the interface of the catalysts and thereby enhanced the efficiency of photon harvesting in the visible region. The action of scavengers (fluoride ion, iodide ion, tert-butyl alcohol, and persulfate ion), as well as N2 purging on the photodegradation rate reveal that the valence band hole is mainly responsible for the effective photocatalytic removal of 2-CP and the corresponding TOC reduction.
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preparation of a titanium dioxide photocatalyst codoped with cerium and iodine and its performance in the degradation of oxalic acid
Chemosphere, 2008Co-Authors: Shuang Song, Jianping Qiu, Jianmeng ChenAbstract:Abstract A novel class of visible light-activated photocatalysts was prepared by codoping TiO 2 with cerium and iodine (Ce–I–TiO 2 ). The particles were characterized using the Brunauer–Emmett–Teller Method, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–Visible light absorption. Particles of Ce–I–TiO 2 had greater photoabsorption in the 400–800 nm wavelength range than iodine-doped TiO 2 (I–TiO 2 ). The effects on the photocatalytic degradation of oxalic acid under visible light or UV–Visible light irradiation were investigated. The photocatalytic activity of Ce–I–TiO 2 calcined at 673 K was significantly higher than that of Ce–I–TiO 2 calcined at 773 K and I–TiO 2 calcined at 673 K in aqueous oxalic acid solution under visible light or UV–Visible light irradiation. Under visible light irradiation, oxalic acid was first adsorbed on the surface of the catalysts rather than reacted with free radicals in the bulk solution, and then oxidized by OH ads to CO 2 , which was verified by studying the effects of nitrogen purging and scavengers, as well as by gas chromatography/mass spectrometry.
Shuang Song - One of the best experts on this subject based on the ideXlab platform.
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influence of zirconium doping on the activities of zirconium and iodine co doped titanium dioxide in the decolorization of methyl orange under visible light irradiation
Applied Surface Science, 2011Co-Authors: Shuang Song, Hongyu Wang, Fangyue Hong, Jianmeng ChenAbstract:Abstract Zirconium and iodine co-doped titanium dioxide (Zr–I–TiO 2 ) was prepared by the hydrolysis of tetrabutyl titanate, premixed with zirconium nitrate in an iodic acid aqueous solution, followed by calcination in air. The structure and properties of the resultant catalyst powders were characterized by X-ray diffraction, the Brunauer–Emmett–Teller Method, X-ray photoelectron spectroscopy, transmission electron microscopy, and UV–vis absorption spectroscopy. The catalytic activity of the catalyst was evaluated by monitoring the photocatalytic decolorization of methyl orange under visible light irradiation. The results showed that the activities of Zr–I–TiO 2 catalysts were higher than that of TiO 2 doped with iodine alone (I–TiO 2 ), and the optimal doping concentration in the Zr–I–TiO 2 calcined at 400 °C was determined to be about 0.05 (molar ratio of Zr:Ti). In addition, the photocatalytic activity of Zr–I–TiO 2 calcined at 400 °C was found to be significantly higher than that calcined at 500 or 600 °C. Based on the physico-chemical characterization, we concluded that the role of zirconium on the I–TiO 2 surface is to increase the number of reactive sites by generating a small crystal size and large surface area. The inhibition of electron–hole pair recombination, by trapping photo-generated electrons with Zr 4+ , did not contribute markedly to the improved photocatalytic activity of Zr–I–TiO 2 .
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increasing the catalytic activities of iodine doped titanium dioxide by modifying with tin dioxide for the photodegradation of 2 chlorophenol under visible light irradiation
Journal of Hazardous Materials, 2011Co-Authors: Cheng Wang, Hongyu Wang, Fangyue Hong, Jianmeng Chen, Shuang SongAbstract:The photocatalytic degradation of 2-chlorophenol (2-CP) irradiated with visible light over iodine doped TiO2 (IT) modified with SnO2 (SIT) nanoparticles has been investigated in this study. The structure and optical properties of the SIT catalysts have been well characterized by X-ray diffraction, the Brunauer–Emmett–Teller Method, transmission electron microscopy, UV–visible absorption spectra and X-ray photoelectron spectroscopy. The effects of preparation conditions, such as SnO2 content and calcination temperature, on the photocatalytic degradation efficiency have been surveyed in detail. The improved photocatalytic activity of SIT is derived from the synergistic effect between the SnO2 and IT, which promoted the efficiency of migration of the photogenerated carriers at the interface of the catalysts and thereby enhanced the efficiency of photon harvesting in the visible region. The action of scavengers (fluoride ion, iodide ion, tert-butyl alcohol, and persulfate ion), as well as N2 purging on the photodegradation rate reveal that the valence band hole is mainly responsible for the effective photocatalytic removal of 2-CP and the corresponding TOC reduction.
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preparation of a titanium dioxide photocatalyst codoped with cerium and iodine and its performance in the degradation of oxalic acid
Chemosphere, 2008Co-Authors: Shuang Song, Jianping Qiu, Jianmeng ChenAbstract:Abstract A novel class of visible light-activated photocatalysts was prepared by codoping TiO 2 with cerium and iodine (Ce–I–TiO 2 ). The particles were characterized using the Brunauer–Emmett–Teller Method, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–Visible light absorption. Particles of Ce–I–TiO 2 had greater photoabsorption in the 400–800 nm wavelength range than iodine-doped TiO 2 (I–TiO 2 ). The effects on the photocatalytic degradation of oxalic acid under visible light or UV–Visible light irradiation were investigated. The photocatalytic activity of Ce–I–TiO 2 calcined at 673 K was significantly higher than that of Ce–I–TiO 2 calcined at 773 K and I–TiO 2 calcined at 673 K in aqueous oxalic acid solution under visible light or UV–Visible light irradiation. Under visible light irradiation, oxalic acid was first adsorbed on the surface of the catalysts rather than reacted with free radicals in the bulk solution, and then oxidized by OH ads to CO 2 , which was verified by studying the effects of nitrogen purging and scavengers, as well as by gas chromatography/mass spectrometry.
Qi Xiao - One of the best experts on this subject based on the ideXlab platform.
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photocatalytic activity and hydroxyl radical formation of carbon doped tio2 nanocrystalline effect of calcination temperature
Chemical Engineering Journal, 2009Co-Authors: Qi Xiao, Linli OuyangAbstract:Abstract Carbon-doped TiO2 nanocrystalline was prepared by sol–gel auto-combustion Method and characterized by X-ray diffraction, X-ray photoelectron spectra (XPS), Brunauer–Emmett–Teller Method (BET), UV–vis diffuse reflectance spectroscopy (DRS). The analysis of OH radical formation on the sample surface under visible light irradiation was performed by fluorescence technique with using terephthalic acid, which readily reacted with OH radical to produce highly fluorescent product, 2-hydroxyterephthalic acids. It was found that the order of photocatalytic activity per unit surface area was the same as that of the formation rate of OH radicals unit surface area, namely, the greater the formation rate of OH radicals unit surface area was, the higher photocatalytic activity unit surface area was achieved, indicating that the photocatalytic activity unit surface area was positive correlation to the formation rate of OH radicals unit surface area over the catalysts. In this study, the optimum calcination temperature was 600 °C, at which the highest formation rate of OH radicals per unit surface area was, and thereby the highest photocatalytic activity per unit surface area was achieved. In addition, it could be found that the order of photocatalytic activity correlated very well with the amount of visible light absorption, namely, the stronger the visible light absorption, the higher the photocatalytic activity.
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solar photocatalytic degradation of methylene blue in carbon doped tio2 nanoparticles suspension
Solar Energy, 2008Co-Authors: Qi Xiao, Jiang Zhang, Chong Xiao, Xiaoke TanAbstract:Abstract Carbon-doped TiO 2 nanoparticles were prepared by sol–gel auto-combustion Method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Brunauer–Emmett–Teller Method (BET), UV–vis diffuses reflectance spectroscopy (DRS). UV–vis diffuse reflectance spectra showed that carbon-doped TiO 2 exhibited obvious absorption in the visible light range. The visible light photocatalytic activity of carbon-doped TiO 2 was ascribed to the presence of oxygen vacancy state between the valence and the conduction bands because of the formation of Ti 3+ species in the as-synthesized carbon-doped TiO 2 . The sample calcined at 873 K showed the highest photocatalytic activity under solar irradiation. The effects of photocatalyst concentration, initial concentration of methylene blue, and pH value in aqueous solution were also presented.
Suojiang Zhang - One of the best experts on this subject based on the ideXlab platform.
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Effects of Support for Vanadium Phosphorus Oxide Catalysts on Vapor-Phase Aldol Condensation of Methyl Acetate with Formaldehyde
Industrial & Engineering Chemistry Research, 2016Co-Authors: Hui Zhao, Dan Yang, Chunshan Li, Suojiang ZhangAbstract:Vapor-phase aldol condensation of methyl acetate with formaldehyde over vanadium phosphorus oxide (VPO) deposited on SiO2, TiO2, ZrO2, Nb2O5, Sb2O3, γ-Al2O3, and n-γ-Al2O3 (γ-Al2O3 treated with H3PO4) for methyl acrylate production was developed. The VPO/n-γ-Al2O3 was found to have the best performance based on the evaluated experiments in a fixed-bed reactor. The physicochemical properties of the catalysts were investigated by different characterization Methods such as the Brunauer–Emmett–Teller Method, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, H2 temperature programmed reduction, Fourier transfrom infrared spectroscopy, and NH3- and CO2-temperature programmed desorption. The influence of P–OH intensity and acid strength on activity was obtained through systematic studies over the formation process of VPO phases and the acidity distribution. Preparation and reaction parameters were investigated and optimized.
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deactivation and regeneration of the supported bimetallic pd pb catalyst in direct oxidative esterification of methacrolein with methanol
Applied Catalysis B-environmental, 2013Co-Authors: Yanyan Diao, Pu Yang, Ruiyi Yan, Li Jiang, Lei Wang, Heng Zhang, Suojiang ZhangAbstract:The deactivation of the supported bimetallic Pd-Pb catalyst in the repeated runs of direct oxidative esterification of methacrolein with methanol in the atmosphere was investigated. The catalysts before and after stability tests were characterized by X-ray diffraction, transmission electron microscopy, X-ray photo-electron spectroscopy, inductively coupled plasma mass spectrometry, Brunauer-Emmett-Teller Method and thermogravimetric analysis. The results indicated that the major factor affecting the deactivation of the catalyst was the deposition of organic substances on the surface active sites of the catalyst during batch reaction. Washing the deactivated catalyst with either MeOH or an aqueous hydrazine solution at 80 degrees C could completely recover the initial activity of the catalyst, and calcining the deactivated catalyst in air at 500 degrees C and then reducing in an aqueous hydrazine solution could partly recover its activity. The deactivation and regeneration of the catalyst in the direct oxidative esterification at gas-liquid-solid phase are important and meaningful. (c) 2013 Elsevier B.V. All rights reserved.
Xiaoke Tan - One of the best experts on this subject based on the ideXlab platform.
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solar photocatalytic degradation of methylene blue in carbon doped tio2 nanoparticles suspension
Solar Energy, 2008Co-Authors: Qi Xiao, Jiang Zhang, Chong Xiao, Xiaoke TanAbstract:Abstract Carbon-doped TiO 2 nanoparticles were prepared by sol–gel auto-combustion Method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Brunauer–Emmett–Teller Method (BET), UV–vis diffuses reflectance spectroscopy (DRS). UV–vis diffuse reflectance spectra showed that carbon-doped TiO 2 exhibited obvious absorption in the visible light range. The visible light photocatalytic activity of carbon-doped TiO 2 was ascribed to the presence of oxygen vacancy state between the valence and the conduction bands because of the formation of Ti 3+ species in the as-synthesized carbon-doped TiO 2 . The sample calcined at 873 K showed the highest photocatalytic activity under solar irradiation. The effects of photocatalyst concentration, initial concentration of methylene blue, and pH value in aqueous solution were also presented.
