One-pot synthesized inverse-structured CeO2/Ni catalysts for enhanced low-temperature CO2 methanation via metal-support interactions.

Conventional Ni-based catalysts often exhibit limited metal-support interactions (MSI) and limited density of active interfacial sites, which significantly restrict their low-temperature activity for CO2 methanation. In this study, we report a binary inverse-structured CeO2/Ni catalyst synthesized via a facile one-pot sol-gel method. The optimal 10% CeO2/Ni catalyst achieved a CO2 conversion of 85.4 ± 0.5% with 98.8 ± 0.2% CH4 selectivity at 200 °C under a gas hourly space velocity of 12,000 mL·gcat-1·h-1 during 150 h long-term stability test, substantially outperforming the conventional 10% Ni/CeO2 catalyst. Comprehensive characterizations collectively indicate that the enhanced low-temperature performance arises from synergistic effects induced by the inverse architecture. The MSI facilitates hydrogen spillover from metallic Ni to CeO2, while enriched interfacial oxygen vacancies provide abundant active sites for CO2 adsorption and activation. In-situ diffuse reflectance infrared Fourier transform spectroscopy results further suggest that the inverse structure steers the reaction toward a highly efficient formate-mediated pathway. This work highlights structural inversion as a facile and effective design strategy to reinforce MSI, offering a promising approach for developing high-efficiency low-temperature CO2 hydrogenation catalysts.