Surface Functionalization and Defect Construction of SnO 2 with Amine Group for Enhanced Visible‐Light‐Driven Photocatalytic CO 2 Reduction

Abstract Photocatalytic CO 2 reduction to hydrocarbon fuels through solar energy provides a feasible channel for reducing CO 2 emission and resource depletion. Nevertheless, severe charge recombination and high energy barrier limit the CO 2 reduction efficiency. Herein, a surface amine‐functionalized SnO 2 with oxygen vacancies (A‐Vo‐SnO 2 ) is fabricated to achieve visible‐light‐driven photocatalytic CO 2 reduction. Specifically, amino groups modified onto the surface of the catalyst can provide more active sites to promote the adsorption of CO 2 . Meanwhile, the synchronously induced oxygen defect level reduces the band‐gap energy and expands the light‐absorption region from UV light to visible light. The oxygen vacancies can modulate the electronic structure and work as the separation centers of spatial charges, thus promoting the interfacial charge transfer efficiency and providing more catalytic sites, as evidenced by experimental observation and theoretical calculation. As expected, this A‐Vo‐SnO 2 exhibits a CH 4 evolution rate of 17.27 µmol g −1 h −1 without adding sacrificial agent and co‐catalyst, much higher than 5.98 µmol g −1 h −1 of pure SnO 2 . This work can provide significant inspiration for the design of defect engineering based on visible‐light‐driven photocatalysts towards photocatalytic CO 2 conversion.