Photothermal synergy-driven low-temperature CO₂ Methanation: Interfacial effects and reaction pathways on Ce/Ni...

Low-temperature CO₂ methanation efficiently enables efficient conversion of CO₂ into methane under mild conditions, presenting substantial potential for enhanced energy efficiency and economic feasibility. However, achieving highly efficient low-temperature CO₂ activation remains a critical challenge due to inherent kinetic constraints. In this study, the inverse-supported Ce/Ni catalyst (11 mol% Ce/Ni) was synthesized, which achieved 82% CO₂ conversion and nearly 100% CH₄ selectivity under photothermal synergy at 220 °C (300 W xenon lamp, 300-2500 nm, 1.5 W·cm^-2), outperforming most conventional nickel-based catalysts. Moreover, the catalyst exhibited outstanding long-term stability, with only an 8% activity loss after 100 h of continuous operation. This superior performance was attributed to its CeO₂-Ni interfacial configurations and abundant oxygen vacancies. In situ diffuse reflectance infrared Fourier transform spectroscopy analysis revealed that the CO₂ methanation over this catalyst proceeds via a dual-intermediate pathway involving CO* and HCOO*, with photothermal synergy significantly accelerating the intermediate conversion without altering the intrinsic reaction pathway. This study establishes an innovative strategy for designing low-temperature and high-performance CO₂ methanation catalysts via the integration of an inverse Ce/Ni configuration with photothermal synergy.