Light‐Driven Electronic Restructuring in RuCu Alloy Catalysts for Selective CO₂‐to‐Methanol Conversion

Achieving efficient and selective CO 2 hydrogenation to methanol under mild conditions remains a critical challenge due to the instability of monometallic Cu catalysts and the high energy input typically required by conventional thermocatalytic processes. Here, a light‐enhanced RuCu alloy catalyst supported on MgAl 2 O 4 is presented, which enables continuous‐flow CO 2 hydrogenation with high methanol selectivity (≈99%) under ambient pressure. Under light irradiation, the localized surface plasmon resonance of Cu promotes in situ alloying with Ru and stabilizes the Cu 0 state. Additionally, Ru incorporation induces electronic restructuring at the alloy interface, optimizing CO 2 adsorption and facilitating H 2 dissociation and spillover. In situ spectroscopic analyses and density functional theory calculations reveal that the RuCu alloy modulates charge distribution and lowers energy barriers for key intermediates, thereby accelerating the CO 2 ‐to‐CH 3 OH reaction pathway. This work offers a light‐driven, energy‐efficient strategy for CO 2 reduction and provides mechanistic guidance for designing plasmon‐activated alloy catalysts for selective hydrogenation under ambient conditions.