Enhanced activity and stability of Ni/La2O2CO3 catalyst for CO2 methanation by metal-carbonate interaction

Abstract

The interaction between metal and support is critical for CO2 methanation reaction over supported Ni catalysts. This work provides a modification strategy using surface carbonate species for promoting the catalytic performances of lanthana-supported Ni catalyst. The carbonate-modified Ni/La2O2CO3 catalyst displays a superior catalytic activity, stability, and CO tolerance in CO2 methanation reactions in comparison with Ni/La2O3 catalyst. The structure of Ni-La2O2CO3 interfaces is verified to be stable against thermal decomposition and reduction reaction, determining catalytic roles through specific metal-carbonate interaction. The medium-strength surface basicity promotes the capability of CO2 chemisorption. The carbonate-modified interfaces facilitate the formation of monodentate and bidentate formates as the reaction intermediates. These species are highly reactive for further transformation into CH4 even in the presence of CO poison, which is benefited to both methanation activity and anti-CO ability.