Redox-driven CO2-to-CO conversion over Ni/CeO2 catalysts: role of oxygen vacancies and weakened metal-support interaction

The methanation side reaction significantly limits CO selectivity in Ni-based catalysts for the reverse water-gas shift (RWGS) reaction, despite their high CO 2 conversion. To enhance CO selectivity and catalytic stability, this study modulated the metal-support interaction (MSI) by controlling CeO 2 particle size and evaluated its impact on CO selectivity. A series of Ni/CeO 2 -C catalysts was synthesized via a conventional hydrothermal-impregnation method. Precursor CeO 2 supports were calcined at different temperatures (500–1000 °C) to precisely control their particle size and morphology. Results demonstrate that the 5Ni/CeO 2 -C-1000 catalyst, derived from the support calcined at 1000 °C, delivered optimal performance: achieving a CO formation rate of 320.1 μmol min −1 at 600 °C and maintaining