The electrochemical characteristics of Ta2O5-IrO2 electrodes prepared from different chemical compositions and coating methods were observed by using cyclic voltammetry, potentiostatic polarization, galvanostatic pola...The electrochemical characteristics of Ta2O5-IrO2 electrodes prepared from different chemical compositions and coating methods were observed by using cyclic voltammetry, potentiostatic polarization, galvanostatic polarization and scanning electron microscopy. The efficiency for chloride oxidation and oxygen evolution processes was not only influenced by the chemical composition but also by the surface morphology of the oxide electrode which was susceptible to the ratio of the two components and the coating method. Ta2O5(50)-IrO2(50) electrodes revealed the highest catalytic activity for the chloride ion oxidation and oxygen evolution reaction because they had the largest effective surface area. The durability of the oxide electrodes in the accelerated life tests was improved as the thickness of the oxide layer increased and the ratio of [IrO2] to [Ta2O5] approached 80/20.展开更多
V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for N...V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for NOx conversion using NH3 as the reductant. Hydrothermal ageing decreased the NOx conversion of V2O5/WO3‐TiO2 catalyst severely over the entire measured tem‐perature range. Interestingly, the NH3‐SCR activity of the silica‐modified catalyst at 220–480℃ is enhanced after ageing. The catalysts were characterized by X‐ray diffraction, nitrogen adsorption, X‐ray fluorescence, Raman spectroscopy, H2 temperature‐programmed reduction, and NH3 temper‐ature‐programmed desorption. The addition of silica inhibited the phase transition from anatase to rutile titania, growth of TiO2 crystallite size and shrinkage of catalyst surface area. Consequently, the vanadia species remained highly dispersed and the hydrothermal stability of the V2O5/WO3‐TiO2 catalyst was significantly improved.展开更多
文摘The electrochemical characteristics of Ta2O5-IrO2 electrodes prepared from different chemical compositions and coating methods were observed by using cyclic voltammetry, potentiostatic polarization, galvanostatic polarization and scanning electron microscopy. The efficiency for chloride oxidation and oxygen evolution processes was not only influenced by the chemical composition but also by the surface morphology of the oxide electrode which was susceptible to the ratio of the two components and the coating method. Ta2O5(50)-IrO2(50) electrodes revealed the highest catalytic activity for the chloride ion oxidation and oxygen evolution reaction because they had the largest effective surface area. The durability of the oxide electrodes in the accelerated life tests was improved as the thickness of the oxide layer increased and the ratio of [IrO2] to [Ta2O5] approached 80/20.
基金supported by the National Natural Science Foundation of China (51372137)the National High Technology Research and Development Program of China (863 Program,2015AA034603)~~
文摘V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for NOx conversion using NH3 as the reductant. Hydrothermal ageing decreased the NOx conversion of V2O5/WO3‐TiO2 catalyst severely over the entire measured tem‐perature range. Interestingly, the NH3‐SCR activity of the silica‐modified catalyst at 220–480℃ is enhanced after ageing. The catalysts were characterized by X‐ray diffraction, nitrogen adsorption, X‐ray fluorescence, Raman spectroscopy, H2 temperature‐programmed reduction, and NH3 temper‐ature‐programmed desorption. The addition of silica inhibited the phase transition from anatase to rutile titania, growth of TiO2 crystallite size and shrinkage of catalyst surface area. Consequently, the vanadia species remained highly dispersed and the hydrothermal stability of the V2O5/WO3‐TiO2 catalyst was significantly improved.
