Synergistic Enhancement of Vectorial Separation of Photogenerated Charge Carriers via Heterojunction and Quantum Confinement Effects

Solar-driven water splitting for hydrogen production is a promising solution to the energy crisis. Reducing the recombination of photogenerated charge carriers is a key strategy for enhancing the hydrogen evolution performance. In this study, a type-II heterojunction catalyst, CdS/Co3O4, was successfully prepared using a self-assembly method. The tight coupling between CdS and Co3O4 facilitates efficient electron transfer. The heterojunction promotes the separation of photogenerated electrons, thereby reducing the charge carrier recombination. Additionally, the quantum confinement effect of Co3O4 shortens the electron migration distance. Under illumination with a 10 W white light source, the hydrogen evolution rate of CdS/Co3O4 reached 21.07 mmol g–1 h–1, approximately three times that of pure CdS. Electron paramagnetic resonance and density functional theory calculations were employed to elucidate the electron transfer mechanism during the photocatalytic process. This study provides a theoretical foundation for the design and mechanistic investigation of quantum-dot-based heterojunction photocatalysts.