Enhanced CO₂ methanation activity over La_2-xCe_xNiO₄ perovskite-derived catalysts:Understanding the structure-performance relationships

The design of advanced catalysts for CO2 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 A2BO4-type catalysts derived from La2−xCexNiO4 perovskites are reported for CO2 methanation. The reduced La0.5Ce1.5NiO4 (r-La0.5Ce1.5NiO4) sample with tailored oxygen vacancies, higher reducibility, better Ni dispersion, and exposed Ni(111) crystal plane exhibited the highest CO2 conversion of 78.9% and 99.3% CH4 selectivity at 350 °C, which can also endure different H2/CO2 ratios and even up to 50 %v/v steam. Interestingly, the activity and structure of spent r-La0.5Ce1.5NiO4 can be fully recovered after 100 h TOS under 10 %v/v steam. In-situ DRIFTS experiments confirmed CO2 methanation over the r-La0.5Ce1.5NiO4 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 CO2 methanation.