Ni-based hydrotalcite-derived catalysts for enhanced CO2 methanation: Thermal tuning of the metal-support interaction

Metal-support interaction (MSI) is recognized as an important factor affecting catalyst activity in CO2 methanation, but a feasible strategy to adjust MSI during catalyst preparation is not yet very clear. Herein, we designed a series of Mg-Al hydrotalcites calcined at different temperatures as supports for Ni-based catalysts preparation and investigated the relationship between MSI and catalytic activity. Through various characterizations, it is confirmed that the MSI can be tailored by thermal treatment resulting from phase transformation, and Ni/ MAO1000 (which has strong MSI) showed the highest activity for CO2 conversion (1821 mmolCO2 mol-1 Ni min- 1). Furthermore, in-situ DRIFTS experiments and DFT calculations proved that methoxy/carbonyls are key intermediates and Ni(111) is the determined crystal plane to produce CH4. This work provides an effective way to tailor the MSI of Ni-based catalysts for enhanced performance in CO2 methanation.