Atomic Interface Engineering of Single-Atom Pt/TiO₂ -Ti₃ C₂ for Boosting Photocatalytic CO₂ Reduction

Solar-driven CO₂ conversion into valuable fuels is a promising strategy to alleviate the energy and environmental issues. However, inefficient charge separation and transfer greatly limits the photocatalytic CO₂ reduction efficiency. Herein, single-atom Pt anchored on 3D hierarchical TiO₂ -Ti₃ C₂ with atomic-scale interface engineering is successfully synthesized through an in situ transformation and photoreduction method. The in situ growth of TiO₂ on Ti₃ C₂ nanosheets can not only provide interfacial driving force for the charge transport, but also create an atomic-level charge transfer channel for directional electron migration. Moreover, the single-atom Pt anchored on TiO₂ or Ti₃ C₂ can effectively capture the photogenerated electrons through the atomic interfacial PtO bond with shortened charge migration distance, and simultaneously serve as active sites for CO₂ adsorption and activation. Benefiting from the synergistic effect of the atomic interface engineering of single-atom Pt and interfacial TiOTi, the optimized photocatalyst exhibits excellent CO₂ -to-CO conversion activity of 20.5 µmol g^-1  h^-1 with a selectivity of 96%, which is five times that of commercial TiO₂ (P25). This work sheds new light on designing ideal atomic-scale interface and single-atom catalysts for efficient solar fuel conversation.