Harnessing quantum confinement and Schottky interfaces for efficient visible light H2 production over Cd0.9Zn0.1S

A noble-metal-free photocatalyst featuring a Schottky heterojunction between ultrasmall Co 3 O 4 quantum dots and tetrapod-like Cd 0.9 Zn 0.1 S has been developed to achieve efficient hydrogen evolution under visible light. The Co 3 O 4 quantum dots act as strong electron traps and establish a Schottky barrier that facilitates directional electron transfer while suppressing charge recombination. Under optimal conditions, the composite achieves a hydrogen evolution rate of 34 mmol g −1 h −1 , markedly outperforming pristine Cd 0.9 Zn 0.1 S. Characterizations including UV–vis diffuse reflectance spectroscopy, photoelectrochemical analysis, and transient photocurrent measurements confirm the improved charge separation efficiency attributed to the introduction of Co 3 O 4 . This approach offers a promising strategy for designing high-efficiency photocatalysts for solar-driven hydrogen production. • A Schottky heterojunction between Cd 0.9 Zn 0.1 S and Co 3 O 4 QDs was constructed for efficient H 2 production. • Co 3 O 4 QDs act as electron sinks to promote charge separation and directional electron transfer. • The optimized photocatalyst achieves a high H 2 evolution rate of 34 mmol g −1 h −1 under visible light. • Transient spectroscopy and in situ XPS confirm enhanced interfacial charge transfer. • The system exhibits excellent stability and avoids noble-metal cocatalysts.