Photocatalytic reduction of CO2 to CO on CuS/Bi2S3: Construction of Z-type heterojunction to promote the directional transfer of photogenerated electrons.

[Display omitted] • CuS/Bi 2 S 3 is prepared by a one-step hydrothermal method. • Heterojunctions are constructed between metal sulfides with narrow bandgaps. • The rate of CO generation from CuS/Bi 2 S 3 is 2.78 and 2.87 times higher than CuS and Bi 2 S 3. • Electron transmission channels promote the separation of photogenerated carriers. Enhancing the separation efficiency of photogenerated charge carriers and improving electron utilization are the primary challenges limiting the photocatalytic reduction performance. The utilization of heterojunctions to enhance the separation capability of photogenerated charge carriers, thereby increasing the product yield, is a common practice in the photocatalytic reduction of CO 2. In this work, a composite material of CuS and Bi 2 S 3 was synthesized via a one-step hydrothermal method, successfully constructing a Z-scheme heterojunction between the two materials. Under the influence of the heterojunction, CuS/Bi 2 S 3 overcame the predicament of rapid recombination of photogenerated charge carriers caused by the narrow bandgap of semiconductor materials. Facilitating the accumulation of electrons at reaction sites on CuS allows for their rapid participation in reactions, leading to increased production of CO 2 reduction products. The rate of CO generation from the photocatalytic conversion of CO 2 using CuS/Bi 2 S 3 was 108.57 μmol g−1h−1, representing an increase in the carbon monoxide yield by 2.78 times and 2.87 times compared to CuS and Bi 2 S 3 respectively, and CH 4 production of CuS/Bi 2 S 3 also increased. This study offers a new understanding of the construction of heterojunctions between metal sulfides. [ABSTRACT FROM AUTHOR]