水滑石基NiAl复合氧化物催化剂的CO2甲烷化催化性能研究OA

CO2 methanation offers a crucial route for carbon recycling by transforming greenhouse gas CO2 into high-value CH4.Ni-based catalysts have attracted extensive research interest in CO2 methanation due to their low cost and favorable activity.However,Ni-based catalysts often suffer from issues such as sintering of active metal particles and low CH4 selectivity.To address these challenges,a series of hydrotalcite-derived NiAl composite oxide catalysts(NiAl-m)with different Ni contents(10%,30%,50%and 60%,mass fraction)were prepared via hydrothermal-calcination method,and characterized by XRD,XPS,SEM and so on,and the chemical state of Ni species and the surface basicity of the catalysts were controlled.The results show that with the Ni content increasing,the specific surface area of catalysts decreases,and the Ni species gradually transform NiAl2O4 spinel phase to NiO phase.At the same time,the number of surface basic sites first increases and then decreases.NiAl-50 exhibits the best performance under the conditions of 400℃,0.1 MPa and space velocity of 6400 mL/(g·h),with the CO2 conversion rate of about 80%and CH4 selectivity of 99.8%.The synergistic effect between active Ni species and basic sites is key to the catalytic performances of catalysts for CO2 methanation,and the reaction catalyzed by NiAl-m follows the formate pathway.This study can provide important theoretical basis for designing high-performance Ni-based catalysts for CO2 methanation.