Synergistic photothermal-dual site strategy to accelerate proton–electron transfer enables enhanced CO₂-to-syngas conversion

Efficient photocatalytic CO₂ reduction necessitates optimal charge balance and proton migration between the CO₂ reduction and H₂O oxidation half-reactions. However, traditional research has predominantly focused on optimizing these half-reactions independently, neglecting potential synergistic effects. Here, this work demonstrates a photothermal catalyst of Pt/Ta2O5-x nanoplates that synergistically leverages the photothermal effect and redox dual-site cooperation to simultaneously accelerate the CO₂ reduction and H₂O oxidation, thereby maximizing proton-electron transfer. The integration of photothermal effect and photocatalysis ensures a strong driving force for CO2 conversion while accelerating proton migration, with Pt plasmonics generating localized heat from solar energy. In-situ characterizations reveal that O vacancy in Ta2O5-x enhances H2O dissociation to provide abundant protons, while Pt acts as electron acceptor sites, effectively activating the C=O bond. Theoretical calculations further illustrate the synergistic CO2 reduction and H2O oxidation on Pt and O vacancy sites, where the oxidation of *OH to *OOH is synchronized with the *CO desorption to CO, significantly lowering the energy barrier for proton-coupled electron transfer. Impressively, the Pt/Ta2O5-x exhibits exceptional photothermal catalytic performance in CO2-to-syngas conversion with a syngas yield up to 1.97 mmol g⁻¹ h⁻¹, which is 16.3-fold higher than Ta2O5-x. Furthermore, the apparent quantum efficiency reaches 3.5% at 365 nm, and the syngas selectivity is a remarkable 82%, while also exhibiting good stability.