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. (Figure presented.).