An S-scheme CdS/K2Ta2O6 heterojunction photocatalyst for production of H2O2 from water and air

The hydrogen peroxide (H2O2) production using solar energy is of great significance in chemical industry and environmental remediation. However, this technique requires that photocatalysts have efficient charge separation and migration efficiency. Herein, we designed a flower-like CdS/K2Ta2O6 (CdS/KTO) S-scheme heterojunction with promoted charge separation and migration by a facile two-step hydrothermal strategy. The CdS/KTO photocatalyst exhibited an outstanding performance with a H2O2 production rate of 160.89 μmol g−1 h−1 without using any sacrificial agents and adding additional O2. The combination of the in situ irradiated X-ray photoemission spectroscopy (XPS), electron paramagnetic resonance (EPR) and density functional theory (DFT) calculations revealed that the formation of an S-scheme heterojunction between CdS and KTO could greatly promote the separation of photogenerated electron-hole pairs toward efficient H2O2 production. This work provides insights for the charge transfer mechanism of S-scheme heterojunction and an innovative stratagem for green, energy-saving and sustainable H2O2 production.