Transition metal (Ni, Cu, Ga, Fe) doped LaCoO3 improve surface hydrogen activation to promote low-temperature CO2 methanation

Abstract

The LaCo0.7X0.3O3 (XCo, Ni, Cu, Ga, Fe) perovskite catalyst was prepared by the sol-gel method, and the effect of the partially substituted catalyst at the B-site for the hydrogenation of CO2 to methane reaction was studied. XRD, H2-TPR, TEM, BET, CO2-TPD and XPS technologies were used to characterize the catalyst. It was found that the reduced ability of LaCoO3, the specific surface area and surface defects of the material could be enhanced with the B-site element doping, the dissociation ability of H2 also be improved for the CO2 methanation reaction. The catalyst dissociates more H* radicals and combines with the CO2 adsorbed on the La site to form HCOO* , then hydrogenates to form H2CO* and removes H2O, and finally hydrogenates to form CH4. The CO2 conversion rate and CH4 yield of the doped catalyst have been significantly improved. At 220–280 ℃, the CO2 conversion rate can reach 13%, and the highest CH4 selectivity can reach 99%.