n(Pd)/n(Pt)对Pd-Pt/Al2O3催化甲烷燃烧性能的影响OA

Methane catalytic combustion is a key method for controlling methane emissions.However,the deactivation of Pd-based catalysts due to sintering under reaction conditions limits their industrial application,and the development of catalysts that combine high catalytic activities with excellent anti-sintering properties is a key challenge in this field.To elucidate the effects of n(Pd)/n(Pt)on the sizes of active species and the catalytic performances of Pd-Pt bimetallic catalysts,Pd-Pt/Al2O3 bimetallic catalysts with varying n(Pd)/n(Pt)were prepared by impregnation method,with keeping the total loading amount(mass fraction)of Pd and Pt at 0.46%.The physicochemical properties of the catalysts were investigated by characterization methods such as XRD and N2 adsorption/desorption.The performances of the catalysts for methane catalytic combustion were investigated in a fixed-bed reactor.The results indicate that in the Pd-Pt/Al2O3 bimetallic catalyst with n(Pd)/n(Pt)=12.2(Pd-Pt/Al2O3(12.2)),the Pd/Pt species consist of sub-nanometre clusters ranging in size from 0.5 nm to 2.0 nm,and the Pd/Pt species are preferentially located at pentacoordinate AlO5 sites via oxygen-bridge bonds.Pd-Pt/Al2O3(12.2)exhibits both good catalytic activity and stability,with T50(the reaction temperature at which the methane conversion rate reaches 50%)of 396 ℃ and deactivation rate of 0.0082%/h.