In-situ growth of p-type Ag2O on n-type Bi2O2S with intimate interfacial contact for NIR light-driven photocatalytic CO2 reduction

Photocatalytic converting CO2 into organic carbon resources holds promise for achieving the utilization of CO2 resources and the development of clean energy. However, the low utilization efficiency of solar energy and poor separation efficiency of photo-generated carriers limit the application of photocatalytic CO2 reduction. Herein, Ag2O/Bi2O2S p-n heterojunction photocatalyst (xAO/BOS) was constructed by anchoring Ag2O on the surface of Bi2O2S through in-situ synthesis. The novel 27 %AO/BOS photocatalyst shows the enhanced photocatalytic CO2 reduction performance with 14.49 mu mol g(-1) of CO yield and 12.06 mu mol g(-1) of CH4 yield after 120 min of NIR light irradiation. The formed p-n heterojunction in 27 %AO/BOS photocatalyst by the in-situ synthesis contributes to facilitating the separation and transfer of photo-generated carriers and improving the adsorption and activation of CO2. The composite still exhibits excellent photocatalytic cycling stability, and Ag-0 species are produced in the photocatalytic CO2 reduction reaction owing to the in-situ photoreduction of Ag2O. Based on the experimental analyses and theoretical calculations, the proposed mechanism for the improved photocatalytic CO2 reduction activity over in-situ synthesis of 27 %AO/BOS p-n heterojunction photocatalyst is finally given. This work paves a promising way to construct effective NIR light-responsive photocatalysts for CO2 photoreduction.

Automated summary

Photocatalytic conversion of CO2 into organic carbon resources offers potential for CO2 resource utilization and clean energy development. However, the low solar energy utilization efficiency and poor separation efficiency of photo-generated carriers limit the application of photocatalytic CO2 reduction. In this study, a novel Ag2O/Bi2O2S p-n heterojunction photocatalyst was synthesized and exhibited enhanced photocatalytic CO2 reduction performance. The proposed mechanism for the improved activity of the photocatalyst is also provided.