采用常压微反、程序升温还原(TPR)、程序升温硫化(TPS)及原位红外光谱(IR)等技术,对Co Mo Al2O3催化剂的表征研究发现:在Co Mo Al2O3催化剂中不仅存在着Co、Mo中心,而且存在由Co、Mo相互作用产生的中心,Co Mo Al2O3催化剂的催化性能是...采用常压微反、程序升温还原(TPR)、程序升温硫化(TPS)及原位红外光谱(IR)等技术,对Co Mo Al2O3催化剂的表征研究发现:在Co Mo Al2O3催化剂中不仅存在着Co、Mo中心,而且存在由Co、Mo相互作用产生的中心,Co Mo Al2O3催化剂的催化性能是由Co、Mo中心和Co、Mo相互作用产生的中心共同作用的结果。展开更多
Fe3O4 catalyst supported on spherical γ-Al2O3 was prepared with and without ultrasonic treatment during the impregnation step,and the heterogeneous catalytic oxidation of dimethoate wastewater was conducted with Fent...Fe3O4 catalyst supported on spherical γ-Al2O3 was prepared with and without ultrasonic treatment during the impregnation step,and the heterogeneous catalytic oxidation of dimethoate wastewater was conducted with Fenton reagent.Then,the physical and chemical properties of the catalysts were analyzed by means of XRD,ICP-AES and SEM,especially the effect of Fe3O4 dispersity on γ-Al2O3.The results showed that the activity of the supported catalysts prepared with ultrasonic treatment for dimethoate was higher than those without ultrasonic treatment and the corresponding degradation rate doubled those of the catalyst obtained by impregnation.The probable cause was that for catalysts prepared with ultrasonic treatment,Fe3O4 was well dispersed on the catalyst surface with small particle size,or existed in non-crystalline amorphous state,and Fe content on the catalyst surface was higher than those without ultrasonic treatment.展开更多
In this paper, zirconium and cerium modified alumina were prepared by homogeneous precipitation with urea, and denoted as AlZC and AlZC-l with specific surface area of 200?m 2/g and 86?m 2/g, respectively. The catalyt...In this paper, zirconium and cerium modified alumina were prepared by homogeneous precipitation with urea, and denoted as AlZC and AlZC-l with specific surface area of 200?m 2/g and 86?m 2/g, respectively. The catalytic oxidation of methane on Co, Mn, Fe and Ni transition metal supported on the modified alumina supports was then investigated. The highest catalytic activity was found on the Co supported catalyst, and methane conversions on these catalysts decreased in the order Co>Mn>Fe>Ni. On the other hand, 15% Co/AlZC showed higher activity than 2% or 5% Co/AlZC at the low temperature region; While the former catalyst is inferior to the latter one at the high temperature region. The similar result was observed on the supported Mn catalysts investigated. Addition of Mn to 10% or 15%Co/AlZC at?molar ratio of Mn∶Co=1∶1 would promote the methane conversion as well as the water vapor resistance ability particularly at the low temperature region. Further studies on such a promoting effect are believed to be helpful to develop a new catalyst with a still higher methane oxidation activity.展开更多
文摘采用常压微反、程序升温还原(TPR)、程序升温硫化(TPS)及原位红外光谱(IR)等技术,对Co Mo Al2O3催化剂的表征研究发现:在Co Mo Al2O3催化剂中不仅存在着Co、Mo中心,而且存在由Co、Mo相互作用产生的中心,Co Mo Al2O3催化剂的催化性能是由Co、Mo中心和Co、Mo相互作用产生的中心共同作用的结果。
文摘Fe3O4 catalyst supported on spherical γ-Al2O3 was prepared with and without ultrasonic treatment during the impregnation step,and the heterogeneous catalytic oxidation of dimethoate wastewater was conducted with Fenton reagent.Then,the physical and chemical properties of the catalysts were analyzed by means of XRD,ICP-AES and SEM,especially the effect of Fe3O4 dispersity on γ-Al2O3.The results showed that the activity of the supported catalysts prepared with ultrasonic treatment for dimethoate was higher than those without ultrasonic treatment and the corresponding degradation rate doubled those of the catalyst obtained by impregnation.The probable cause was that for catalysts prepared with ultrasonic treatment,Fe3O4 was well dispersed on the catalyst surface with small particle size,or existed in non-crystalline amorphous state,and Fe content on the catalyst surface was higher than those without ultrasonic treatment.
文摘In this paper, zirconium and cerium modified alumina were prepared by homogeneous precipitation with urea, and denoted as AlZC and AlZC-l with specific surface area of 200?m 2/g and 86?m 2/g, respectively. The catalytic oxidation of methane on Co, Mn, Fe and Ni transition metal supported on the modified alumina supports was then investigated. The highest catalytic activity was found on the Co supported catalyst, and methane conversions on these catalysts decreased in the order Co>Mn>Fe>Ni. On the other hand, 15% Co/AlZC showed higher activity than 2% or 5% Co/AlZC at the low temperature region; While the former catalyst is inferior to the latter one at the high temperature region. The similar result was observed on the supported Mn catalysts investigated. Addition of Mn to 10% or 15%Co/AlZC at?molar ratio of Mn∶Co=1∶1 would promote the methane conversion as well as the water vapor resistance ability particularly at the low temperature region. Further studies on such a promoting effect are believed to be helpful to develop a new catalyst with a still higher methane oxidation activity.
