Inverse Ni/CeCrOx Catalysts for Enhanced Low-Temperature CO2 Methanation

Low-temperature methanation technology offers a promising pathway for carbon recycling and sustainable energy storage by enabling near-equilibrium CO 2 conversion under atmospheric pressure. However, efficiently activating CO 2 at low temperatures remains a significant challenge due to the kinetic limitations of hydrogenation intermediates. We construct a composite oxide–metal interface structure by anchoring highly dispersed CeCrO x nanoclusters onto metallic nickel via an ion-exchange method. This catalyst exhibits superior activity compared to conventional Ni/oxide catalysts with identical composition. Under atmospheric pressure at 220 °C, it achieves nearly 80% CO 2 conversion with over 99% methane selectivity and maintains excellent catalytic performance and structural stability during a 240-h continuous test. Systematic characterizations, including high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, CO 2 temperature-programmed desorption, and in situ DRIFTS reflectance infrared Fourier-transform spectroscopy, reveal that the synergistic modification by CeO 2 and Cr 2 O 3 not only optimizes the electronic structure of Ni to promote CO 2 adsorption and activation, but also enhances H 2 dissociation and intermediate conversion by regulating oxygen vacancy concentration and alkaline site distribution. Mechanistic studies indicate that the reaction follows a synergistic mechanism dominated by the formate pathway and assisted by the CO pathway. Moreover, the interfacial structure effectively stabilizes active sites and inhibits carbon deposition from CH 4 decomposition. This study provides a universal and effective strategy for designing Ni-based CO 2 conversion catalysts suited for mild reaction conditions and characterized by high energy efficiency.