Enhancing the CO2 methanation activity of Ni/CeO2 via activation treatment-determined metal-support interaction

The metal-support interaction is of critical importance to enhance the catalytic activity and selectivity. However, it is still challenging to construct an appropriate interaction starting from the catalyst fabrication and/or activation. We herein established low-temperature treatment of Ni 2+ ions impregnated on ceria in reductive atmosphere and reduction–oxidation cycles as effective approachs to regulate the metal-support interaction and raise the catalytic performance in the CO 2 methanation. The proposed construction approach yielded Ni/CeO 2 that displayed highly dispersed Ni nanoparticles in contact with CeO 2 (111) and (100) facet, higher density of surface oxygen vacancies and larger amounts of weak basic sites relative to the reference samples, which increased the capacity for H 2 and CO 2 adsorption/activation. The interaction resulted in appreciably (2–3 fold) higher activity in the CO 2 methanation with maintaining almost full selectivity to CH 4 and high stability. Coverage of Ni surface by CeO 2− x thin layer as a typical structure of strong metal-support interaction resulting from high-temperature reduction, can be alleviated via reduction–oxidation cycles. We also demonstrate the activation treatment-determined metal-support interaction effect can generally extend to (TiO 2 and ZrO 2 ) supported Ni catalysts.