SINCE Pt supported on non-acidic KL zeolite was found to be a highly active and selective cata-lyst for the aromatization of n-hexane,numerous significant studies have been conducted.Der-ouane et al.attributed the spe...SINCE Pt supported on non-acidic KL zeolite was found to be a highly active and selective cata-lyst for the aromatization of n-hexane,numerous significant studies have been conducted.Der-ouane et al.attributed the specific behavior of Pt/KL catalyst to the unique channel struc-ture of L zeolite,which might stabilize extremely small Pt clusters.In contrast,Pt展开更多
Autoreduction of Pt2+ ions during calcination of ets-Pt (NH3):Cl2/Kβ was found directly by CO adsorbed FTIR. Reoxidation of the reduced sample could decrease the extent of Pt agglomeration caused by autoreduction. T...Autoreduction of Pt2+ ions during calcination of ets-Pt (NH3):Cl2/Kβ was found directly by CO adsorbed FTIR. Reoxidation of the reduced sample could decrease the extent of Pt agglomeration caused by autoreduction. The unique effect of Ba2+ ions on Pt dispersion was also studied.展开更多
This study was focused on the influence of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation. A series of CeO2 supports with different contents of active oxygen were obtained by adding surfactant ...This study was focused on the influence of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation. A series of CeO2 supports with different contents of active oxygen were obtained by adding surfactant at different synthesis steps. 0.25 wt% Pt was loaded on these CeO2 supports by incipientwetness impregnation methods. The catalysts were characterized by N2 adsorption, X-ray diffraction（XRD）, high-resolution transmission electron microscopy（HRTEM）, H2 temperature-programmed reduction（H2-TPR）, dynamic oxygen storage capacity（DOSC） and in-situ DRIFTS technologies. For S-f supports, the surfactant was added into the solution before spray-drying in the synthesis process, which facilitates more active oxygen formation on the surface of CeO2. After loading Pt, the more active oxygen on CeO2 contributes to dispersing Pt species and enhancing the CO oxidation activity. As for the aged samples,Pt-R-h shows the highest activity above 190 ℃ because of the presence of more partly oxidized Pt^（δ＋） species. Thus the activity is also influenced by the states of Pt and the Pt^（δ＋） species may contribute to the high activity at elevated temperature.展开更多
Activity and stability of 1%Pd-0.2%Pt/Al2O3 and 1%Pd-0.2%Pt/0.6%Ce/Al2O3 catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction ...Activity and stability of 1%Pd-0.2%Pt/Al2O3 and 1%Pd-0.2%Pt/0.6%Ce/Al2O3 catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction were characterized by BET, CO chemisorption, XRD and XPS techniques. Results showed that the presence of Ce significantly increased the activity and thermal stability of the Pd-Pt/Al2O3 catalyst towards methane combustion, which could be attributed to more highly-dispersed active PdO particles over the Pd-Pt/Ce/Al2O3 catalyst surface as well as the retarded sintering of PdO and the maintained oxidized state of surface Pd during the combustion process in the presence of Ce.展开更多
文摘SINCE Pt supported on non-acidic KL zeolite was found to be a highly active and selective cata-lyst for the aromatization of n-hexane,numerous significant studies have been conducted.Der-ouane et al.attributed the specific behavior of Pt/KL catalyst to the unique channel struc-ture of L zeolite,which might stabilize extremely small Pt clusters.In contrast,Pt
文摘Autoreduction of Pt2+ ions during calcination of ets-Pt (NH3):Cl2/Kβ was found directly by CO adsorbed FTIR. Reoxidation of the reduced sample could decrease the extent of Pt agglomeration caused by autoreduction. The unique effect of Ba2+ ions on Pt dispersion was also studied.
基金Project supported by the National key research and development program(2016YFC0204901)the National Natural Science Foundation of China(21576207)+1 种基金the Introduction Of Talent and Technology Cooperation Plan Of Tianjin(14RCGFGX00849)GM Global Research&Development(GAC 1539)
文摘This study was focused on the influence of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation. A series of CeO2 supports with different contents of active oxygen were obtained by adding surfactant at different synthesis steps. 0.25 wt% Pt was loaded on these CeO2 supports by incipientwetness impregnation methods. The catalysts were characterized by N2 adsorption, X-ray diffraction（XRD）, high-resolution transmission electron microscopy（HRTEM）, H2 temperature-programmed reduction（H2-TPR）, dynamic oxygen storage capacity（DOSC） and in-situ DRIFTS technologies. For S-f supports, the surfactant was added into the solution before spray-drying in the synthesis process, which facilitates more active oxygen formation on the surface of CeO2. After loading Pt, the more active oxygen on CeO2 contributes to dispersing Pt species and enhancing the CO oxidation activity. As for the aged samples,Pt-R-h shows the highest activity above 190 ℃ because of the presence of more partly oxidized Pt^（δ＋） species. Thus the activity is also influenced by the states of Pt and the Pt^（δ＋） species may contribute to the high activity at elevated temperature.
基金supported by the National High Technology Research and Development Program (863) of China (No.2010AA064904)
文摘Activity and stability of 1%Pd-0.2%Pt/Al2O3 and 1%Pd-0.2%Pt/0.6%Ce/Al2O3 catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction were characterized by BET, CO chemisorption, XRD and XPS techniques. Results showed that the presence of Ce significantly increased the activity and thermal stability of the Pd-Pt/Al2O3 catalyst towards methane combustion, which could be attributed to more highly-dispersed active PdO particles over the Pd-Pt/Ce/Al2O3 catalyst surface as well as the retarded sintering of PdO and the maintained oxidized state of surface Pd during the combustion process in the presence of Ce.
