Enhanced photocatalytic degradation and H2/H2O2 production performance of S-pCN/WO2.72 S-scheme heterojunction with appropriate surface oxygen vacancies

Rational design of the photocatalysis is of vital importance to mediate many important photocatalytic reactions such as water splitting, pollutant degradation and CO2 reduction. In this work, we employed a solvent evaporation induced self-assembly method to prepare a novel S-scheme heterojunction composite by combining sulfur-doped porous graphite carbon nitride (S-pCN) with tungsten oxide (WO2.72) semiconductors which manifest effective interface contact and excellent photocatalytic performance. During the formation of the heterojunction, the electron defect state of surface oxygen vacancies on WO2.72 can be filled by the lone pair electrons of sulfur and nitrogen elements on S-pCN. Through the adjustment of composite ratios, appropriate surface oxygen vacancies were retained on WO2.72, thereby fascinate the migration of electrons and the generation of free radicals. The internal electric field (IEF) and the band bending effects accelerate the transfer of photogenerated charges at the interface, thereby promotes the recombination of useless photogenerated carriers, retains photogenerated electron (e−) and hole (h+) with the higher redox potentials, improves the separation and utilization efficiency of the photogenerated carriers and enhances the photocatalytic activity of the system. This work provides new insights for the design of a novel S-scheme heterojunction photocatalyst for highly efficient simultaneous photocatalytic degradation and hydrogen evolution activity.