Interfacial Chemical Bond and Oxygen Vacancy-Enhanced In2O3/CdSe-DETA S-scheme Heterojunction for Photocatalytic CO2 Conversion

The S-scheme heterojunctions have great potential for photocatalytic carbon dioxide reduction due to their unique carrier migration pathways, superior carrier separation efficiencies, and high redox capacities. However, the precise process of the oriented powerful electron transport remains a great challenge. Herein, an In-O-Cd bond-modulated S-scheme heterojunction of In2O3/CdSe-DETA is synthesized by a simple microwave-assisted hydrothermal method for the accelerated photogenerated electron transfer. Meanwhile, the oxygen vacancies (Vo) of In2O3 have an electron capture effect. Consequently, thanks to the synergistic effect of this In-Vo-In-O-Cd structural units at the interface, electrons are extracted and rapidly transferred to the surface-active sites, which improves the electronic coupling of CO2. This finding precisely adjusts the electron transfer pathway and shortens the electron transfer distance. The synergistic effect of this chemical bond established in the S-scheme heterostructure with oxygen vacancies in In2O3 (Vo-In2O3) provides new insights into photocatalytic CO2 reduction.