Operando XAFS insights into the dynamic evolution of Cu-based catalysts for light-promoted CO₂ hydrogenation

Photothermal catalytic reduction of CO₂ to CO has been regarded as a promising strategy for solar-to-chemical energy conversion, yet the dynamic evolution of active sites under realistic reaction conditions remains poorly understood. Herein, we synthesized CuO/ZnO (CuZnO) catalysts with intimate interfacial contact via co-precipitation followed by calcination method. Under photothermal conditions, CuZnO underwent in situ reconstruction into low-coordinated metallic Cu in close contact with ZnO, delivering a CO generation rate of ∼18.1 mmol g^-1 h^-1 with a selectivity as high as 99% at 200 °C, outperforming that achieved under purely thermal conditions. Operando photothermal X-ray absorption fine structure (XAFS) spectroscopy revealed the real-time evolution of both Cu and Zn coordination environments in CuZnO, illustrating the formation and stabilization of metallic Cu on ZnO during photothermal catalysis. This study elucidates the mechanisms underlying photothermal synergy in CO₂ reduction and provides mechanistic insights into active-site dynamics under photothermal conditions.