The binary composite photo-catalysts CeO2/ZiO2, ZrO2/ZiO2 and the ternary composite photo-catalysts H3PW12040-CeO2/TiO2, H3PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermog...The binary composite photo-catalysts CeO2/ZiO2, ZrO2/ZiO2 and the ternary composite photo-catalysts H3PW12040-CeO2/TiO2, H3PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermogravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photocatalytic elimination of methanol was used as model reaction to evaluate the photocatalytic activity of the composite catalysts under ultraviolet light irradiation. The effects of doped content, activation temperature, time, initial concentration of methanol and gas flow rate on the catalytic activity were investigated. The results showed that after doping a certain amount of CeO2 and ZrO2, crystallization process of TiO2 was restrained, particles of catalysts are smaller and more uniform. Doping ZrO2 not only significantly improved the catalytic activity, but also increased thermal stability. Doping H3PW12O40 alSO enhanced the catalytic activity. The catalytic activities of binary and ternary composite photocatalysts were significantly higher than un-doped TiO2. The dynamics law of photocatalytic reaction over the binary CeO2/TiO2 and ZrO2/TiO2 catalysts has been studied. The activation energy 15.627 and 15.631 kJ/mol and pre-exponential factors 0.5176 and 0.9899 s^-1 over each corresponding catalyst were obtained. This reaction accords to the first order dynamics law.展开更多
A series of praseodymium added CeO2(ZrO2)/TiO2 catalysts separately prepared by methods of sol-gel and impregnation were tested for selective catalytic reduction of NO, and characterized by X-ray diffraction (XRD)...A series of praseodymium added CeO2(ZrO2)/TiO2 catalysts separately prepared by methods of sol-gel and impregnation were tested for selective catalytic reduction of NO, and characterized by X-ray diffraction (XRD), N2-brumauer-emmett-teller (N2-BET), NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), PL spectra, Ra-man spectra, electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS), respectively. Influence of prepara-tion method on catalytic performance was studied. Results showed that the influence of Pr addition on catalytic performance of the CeO2(ZrO2)/TiO2 catalysts was different between the sol-gel method and the impregnation method. The Pr addition tended to interact with TiO2 and formed the structure of Ti-O-Pr in the sol-gel method while it was more likely to interact with CeO2 forming the struc-ture of Ce-O-Pr in the impregnation method. The total acid amount and redox properties of the catalysts prepared by sol-gel method decreased with the addition of Pr element, which resulted in decrease of catalytic activity. In contrast, the Pr-added catalyst prepared by impregnation method was found to possess easier reducibility, more total acid amount and higher proportion of Ce3+ species, which was favourable for higher catalytic activity.展开更多
基金the Hunan Provin-cial Natural Science Foundationthe Scientific Research Fund of Education Department and the Organic Chemistry Key Subject
摘要The binary composite photo-catalysts CeO2/ZiO2, ZrO2/ZiO2 and the ternary composite photo-catalysts H3PW12040-CeO2/TiO2, H3PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermogravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photocatalytic elimination of methanol was used as model reaction to evaluate the photocatalytic activity of the composite catalysts under ultraviolet light irradiation. The effects of doped content, activation temperature, time, initial concentration of methanol and gas flow rate on the catalytic activity were investigated. The results showed that after doping a certain amount of CeO2 and ZrO2, crystallization process of TiO2 was restrained, particles of catalysts are smaller and more uniform. Doping ZrO2 not only significantly improved the catalytic activity, but also increased thermal stability. Doping H3PW12O40 alSO enhanced the catalytic activity. The catalytic activities of binary and ternary composite photocatalysts were significantly higher than un-doped TiO2. The dynamics law of photocatalytic reaction over the binary CeO2/TiO2 and ZrO2/TiO2 catalysts has been studied. The activation energy 15.627 and 15.631 kJ/mol and pre-exponential factors 0.5176 and 0.9899 s^-1 over each corresponding catalyst were obtained. This reaction accords to the first order dynamics law.
基金supported by National Key Research and Development Program of China(2016YFC0205500)National Natural Science Foundation of China(51272105)+1 种基金Jiangsu Provincial Science and Technology Supporting Program(BE2013718)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
摘要A series of praseodymium added CeO2(ZrO2)/TiO2 catalysts separately prepared by methods of sol-gel and impregnation were tested for selective catalytic reduction of NO, and characterized by X-ray diffraction (XRD), N2-brumauer-emmett-teller (N2-BET), NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), PL spectra, Ra-man spectra, electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS), respectively. Influence of prepara-tion method on catalytic performance was studied. Results showed that the influence of Pr addition on catalytic performance of the CeO2(ZrO2)/TiO2 catalysts was different between the sol-gel method and the impregnation method. The Pr addition tended to interact with TiO2 and formed the structure of Ti-O-Pr in the sol-gel method while it was more likely to interact with CeO2 forming the struc-ture of Ce-O-Pr in the impregnation method. The total acid amount and redox properties of the catalysts prepared by sol-gel method decreased with the addition of Pr element, which resulted in decrease of catalytic activity. In contrast, the Pr-added catalyst prepared by impregnation method was found to possess easier reducibility, more total acid amount and higher proportion of Ce3+ species, which was favourable for higher catalytic activity.