• • LaNiO3/CeO2 achieved 23.6% CO2 conversion at 300 °C with ~100% CH4 selectivity, demonstrating superior low-temperature activity for power-to-gas applications.
• • In situ reduction of LaNiO3 yielded highly dispersed Ni0 particles with average diameter 12.6 nm, providing abundant active sites and mitigating sintering.
• • CeO2 support exhibited high oxygen vacancy concentration (Ce3+/(Ce3++Ce4+) = 9.2%, ID/IF2g = 0.35), which facilitates CO2 activation and enhances catalytic performance.
• • The catalyst's surface basicity (weak and moderate basic sites) and oxygen vacancies synergistically promote CO2 adsorption and methanation, offering a benchmark for designing efficient Ni-based catalysts.