Inverse Al2O3/NiCo catalyst with bimetallic electronic modulation for low-temperature CO2 Methanation

Low-temperature CO 2 methanation demands concurrent optimization of CO 2 activation and H 2 dissociation, which traditional catalysts seldom achieve within a single architecture. Herein, we design an inverse Al 2 O 3 /NiCo catalyst that couples the inverse oxide–metal interface with NiCo alloying to enable rapid H* spillover and synergistic CO 2 conversion at low temperatures. The optimized catalyst delivers >90% CO 2 conversion with near 100% CH 4 selectivity at 240 °C, a markedly reduced apparent activation energy of 63 kJ mol −1 , and negligible deactivation over 120 h on stream. Relative to monometallic inverse catalysts, the NiCo alloy effectively suppresses coking and permits activity recovery after regeneration. Multiple characterization techniques reveal that the inverse architecture synchronizes CO 2 adsorption/activation and H 2 dissociation within a low-temperature window, while the continuous NiCo network facilitates H* spillover. Kinetic analysis reveals that the combined effect of the inverse configuration and NiCo alloying shifts the reaction orders from H 2 limited (0.90) to a balanced regime (H 2 0.43, CO 2 0.37). DRIFTS and DFT calculations further demonstrate that NiCo alloying induces Ni → Co charge transfer, upshifting the d-band center from −1.62 to −1.42 eV and concurrently lowering barriers for both formate (1.22 → 1.01 eV) and CO (1.87 → 1.55 eV) pathways, thereby enabling dual-path synergy that accelerates methanation kinetics. The catalyst also exhibits excellent CO x methanation performance, achieving 99% CO and 80% CO 2 conversion at 240 °C under mixed feed, with stable activity over 120 h under stepwise feed changes. This work establishes a general strategy combining inverse interface engineering with bimetallic electronic modulation, offering a scalable and cost-effective design for high-performance CO 2 hydrogenation catalysts.