Enhanced CO2 methanation activity over La2-xCexNiO4 perovskite-derived catalysts: Understanding the structure-performance relationships

• La 2−x Ce x NiO 4 perovskite-derived catalysts were proved to be active for methanation. • CO 2 conversion and CH 4 selectivity reached to 78.9% and 99.3% over r-La 0.5 Ce 1.5 NiO 4 at 350 °C. • r-La 0.5 Ce 1.5 NiO 4 with large Ni(1 1 1) plane and abundant oxygen vacancies exhibited great stability and regenerability. • CO 2 methanation pathway over r-La 0.5 Ce 1.5 NiO 4 follows CO hydrogenation route. The design of advanced catalysts for CO 2 methanation remains as a research challenge. Besides, the effects of feed composition on the activity and stability of existed catalysts are not well addressed yet. In this work, novel A 2 BO 4 -type catalysts derived from La 2−x Ce x NiO 4 perovskites are reported for CO 2 methanation. The reduced La 0.5 Ce 1.5 NiO 4 (r-La 0.5 Ce 1.5 NiO 4 ) sample with tailored oxygen vacancies, higher reducibility, better Ni dispersion, and exposed Ni(111) crystal plane exhibited the highest CO 2 conversion of 78.9% and 99.3% CH 4 selectivity at 350 °C, which can also endure different H 2 /CO 2 ratios and even up to 50 %v/v steam. Interestingly, the activity and structure of spent r-La 0.5 Ce 1.5 NiO 4 can be fully recovered after 100 h TOS under 10 %v/v steam. In-situ DRIFTS experiments confirmed CO 2 methanation over the r-La 0.5 Ce 1.5 NiO 4 to proceed via CO route. The present work suggests that both basicity and the presence of oxygen vacancy facilitate superior catalytic activity and stability during CO 2 methanation.