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

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.