Construction of NH2-MIL-101(Fe)@Bi2MoO6 S‐scheme heterojunction for efficient and selective photocatalytic CO2 conversion to CO

Abstract

Developing efficient photocatalyst to promote the conversion of CO2 into value-added chemicals remains challenging. Here, novel NH2-MIL-101(Fe)@Bi2MoO6 S-scheme heterojunctions were fabricated via a solvothermal method, in which Bi2MoO6 (BMO) nanoparticles uniformly growing on the NH2-MIL-101(Fe) (NM101) octahedrons with intimate contact interface. The resultant heterojunctions revealed significantly enhanced activity for CO2 photoreduction. The optimal performance was achieved when the content of BMO was 10 wt%, and the formation rate of CO reached 67.0 μmol·g−1·h−1 under visible light illumination (with apparent quantum efficiency of 0.09 % at 450 nm), which was 3.2-fold of individual NM101. The boosting activity benefited from the formation of S-scheme heterojunction at the NM101 @BMO interfaces, which facilitated the separation of photoinduced electron-hole pairs with strong redox ability at the interface. This S-scheme charge transfer mechanism was further validated by the in-situ XPS and fluorescence probe molecular experiment. Besides, the intermediates and preliminary mechanism of photoreaction were unraveled based on in-situ DRIFTS analysis. This work provides some novel insights for designing efficient S-scheme photocatalysts for CO2 photoreduction.