In2O3/Bi19Br3S27 S-scheme heterojunction with enhanced photocatalytic CO2 reduction

In recent years, semiconductor catalysts have attracted lots of attention due to their substantial redox capability and adequate stability. However, many semiconductor catalysts have difficulties in realizing real word applications because of the high complexation and low oxidizing ability of photogenerated electron-holes. In-depth investigation has revealed that the S-scheme heterojunction possesses a unique mechanism of carrier movement, resulting in a robust redox capacity and strong driving force. Herein, we synthesized an In2O3/Bi19Br3S27 step-scheme (S-scheme) heterojunction through the hydrothermal method comprised of Bi19Br3S27 nanoflowers grown on In2O3 nanospheres. This configuration effectively facilitates the separation and transfer of photogenerated charge carriers. As a result, the reduction yield of CO2 by In2O3/Bi19Br3S27 composite reaches 28.36 µmol h−1 g−1, which is 19 times higher than that of In2O3 and 3.5 times higher than that of Bi19Br3S27. Furthermore, the intermediates involved in the photocatalytic reaction were examined through in situ diffuse reflectance infrared Fourier transform spectroscopy, revealing the reaction process of photocatalytic reduction of CO2. This work offers a concept on the method of constructing S-scheme heterojunction photocatalysts to enhance the catalyzed reduction of CO2.