Boosting low-temperature CO2 methanation over an Al2O3-modified Ni catalyst enabled through interfacial regulation

To address the limited low-temperature activity of conventional Ni-based catalysts for CO 2 methanation, a series of MO x /Ni catalysts were constructed to regulate the metal-oxide interfacial environment. Among the oxides investigated, Al 2 O 3 exhibited the most favorable promotional effect, and the optimized Al 2 O 3 /Ni-0.5 catalyst achieved approximately 97 % CO 2 conversion and 85.5 % CH 4 selectivity at 220 °C under a GHSV of 30,000 mL g −1 ·h −1 . During five consecutive reaction-shutdown-H 2 -treatment cycles with a cumulative methanation time of 120 h. Comprehensive characterization showed that Al 2 O 3 /Ni-0.5 possesses a distinct textural structure, modified Ni reduction behavior, favorable surface basicity, abundant oxygen-defect-related sites, and a strongly interacting Ni-Al-O interfacial environment. DFT calculations further revealed pronounced interfacial charge redistribution and energetically favorable adsorption of CO 2 and H 2 at the representative Al 2 O 3 /Ni interface, supporting the role of interfacial electronic coupling in regulating reactant adsorption. In situ DRIFTS detected formate- and formyl-related surface species during CO 2 methanation, suggesting that these intermediates may participate in the reaction network. Overall, these results demonstrate that engineering an intimate Al 2 O 3 -Ni interfacial environment is an effective approach for promoting low-temperature CO 2 methanation.