Mechanistic Insights into Low-Temperature CO2 Methanation over LaNiO3/CeO2 Perovskite Catalyst
Perovskite-type catalysts show promise for CO2 methanation, yet their low-temperature performance and mechanisms remain unclear. Here, a LaNiO3/CeO2 catalyst was synthesized via sol-gel and impregnation. In situ reduction decomposed the perovskite into highly dispersed Ni0 particles (average 12.6 nm) on CeO2, which provided abundant oxygen vacancies (Ce3+/(Ce3++Ce4+) = 9.2%) and weak/moderate basic sites. This synergy enhanced CO2 adsorption and activation. At 200–300 °C, the catalyst achieved ~100% CH4 selectivity and CO2 conversion up to 23.6% at 300 °C. Comparative studies with LaNiO3, LaCeNiO4, Ni/CeO2, and La-Ni/CeO2 revealed that the perovskite pre-structuration and in situ reduction optimize Ni dispersion and metal-support interactions, stabilizing Ni0 and tuning surface basicity and oxygen vacancies. This work provides a design strategy for efficient low-temperature CO2 methanation catalysts.