Accelerating Hydrogen Spillover on Cu ^δ+ /Ru ^δ+ ‐O _v ‐Ce ³⁺ Tandem Sites for Enhanced Photothermal CO ₂ Methanation

ABSTRACT Photothermal CO ₂ methanation represents a promising strategy for sustainable fuel synthesis under mild conditions, yet its efficiency remains constrained by the kinetic mismatch between CO ₂ activation and active H delivery. Herein, we constructed atomically dispersed Cu ^δ+ /Ru ^δ+ tandem sites anchored on the oxygen‐vacancy‐rich CeO ₂ (111) surface. Advanced characterizations verify the coordination of both metals within the CeO ₂ lattice, forming a well‐defined dual‐site configuration. Under simulated solar irradiation, the optimized catalyst achieves a remarkable CH ₄ production rate of 4.92 mmol·g _cat ⁻¹ ·h ⁻¹ at a moderate surface temperature of 349.6°C while maintaining excellent long‐term stability. Through a combination of in situ spectroscopic studies, catalytic evaluations, and density functional theory calculations, we elucidate a synergistic tandem mechanism, in which Cu ^δ+ sites facilitate CO ₂ adsorption and primary activation, while adjacent Ru ^δ+ sites promote H ₂ dissociation and subsequent hydrogen spillover. This spatially coupled process ensures efficient transfer of active hydrogen species to the reaction intermediates, dramatically accelerating the cleavage of the C─O bond and the intermediates hydrogenation. This work offers atomistic insights into bifunctional synergy, establishing a design paradigm for efficient CO ₂ conversion photothermal catalysts.