Dual-site atomic engineering of Ru Single-atoms and Ni clusters on CeO2 nanorods for solar-driven CO2 methanation

Solar-driven CO 2 reduction is confronted with challenges of limited light absorption and elevated reaction energy barriers. To address these, a solvothermal-wet coupled chemical reduction method was developed to precisely construct a bifunctional catalyst comprising single-atom Ru and clustered Ni on porous CeO 2 nanorods, featuring efficient CO 2 methanation in H 2 O vapor under concentrated solar irradiation (4.01 W·cm −2 ). Through lattice substitution at Ce sites, Ru single atoms form a distinctive pentacoordinate configuration, largely accelerating H 2 O dissociation to generate active hydrogen (*H). Conversely, Ni clusters enhance visible-to-near-infrared light capture via localized surface plasmon resonance effects, optimizing the CO 2 adsorption configuration to reduce the activation energy barrier of the C=O bond. The synergistic interplay between these dual sites, mediated by the hydrogen spillover effect, resolves the spatiotemporal mismatch between proton supply and carbon source activation. Based on the evidence from femtosecond and nanosecond transient absorption spectroscopy, the Ru/Ni dual-active sites enable spatially decoupled directional transport of charge carriers, synergistically handling the photogenerated carrier transfer dynamics. Furthermore, the robust photoelectric and thermal effects induced by concentrated irradiation enhance photogenerated carrier concentrations and the reaction temperature, reducing the apparent activation energy for CH 4 formation to 14.61 kJ·mol −1 (a 29.9% decrease compared to non-concentrated systems). This catalyst achieves a CH 4 production rate of 133.1 μmol·cm −2 ·h −1 (a 31-fold enhancement over non-concentrated systems) and a solar-to-chemical energy conversion efficiency of 0.423%, offering insights into the design of photothermal synergistic catalytic systems through atomic-scale active site decoupling and multi-physical field coupling.