Ni/USY催化剂金属-载体相互作用对CO2甲烷化性能的影响OA北大核心

Tailoring of the metal-support interaction is one of the important ways to improve the CO2 methanation performances on the supported Ni-based catalysts.A series of Ni/USY-X(X=1,3 or 5)catalysts were prepared by impregnation by adjusting the pH value of the solution.And CO2 methanation performances of catalysts were investigated.Ni/USY-3 catalyst showes excellent CO2 methanation performance with CO2 conversion rate of 84.5％and CH4 selectivity of 95.7％in stability test at the condition of 450 ℃ and 20 h.XRD,H2-TPR,SEM and TEM were used to characterize the structure and morphology of the catalyst,and the effects of impregnating solution pH value on the structure and CO2 methanation performances of the catalysts were systematically investigated at the microscopic level.The results show that under appropriate pH value control,the metal-support interaction is enhanced,the particle size of the active metal Ni particles is reduced,and the dispersion is enhanced.Furthermore,the reaction paths of catalyst were analyzed by in situ FT-IR.The results indicate that the Ni/USY-3 catalyst follows the formate pathway.The highly dispersed and small particle size of the active metal Ni particles provide abundant active sites for the timely hydrogenation of bicarbonate into the key intermediate monodontate,leading to achieving efficient conversion of CO2.