ZIF‐8‐Derived ZnS/Cu ₂ S p–n Heterojunctions for Accelerated Charge Transfer and Solar Hydrogen Production

ABSTRACT The development of highly efficient and stable photocatalysts for water splitting is essential for achieving sustainable, clean hydrogen production. In this work, a novel photocatalyst was fabricated by anchoring zeolitic imidazolate framework‐8 (ZIF‐8)—derived ZnS quantum dots (QDs) onto Cu ₂ S snowflake obtained from a solvothermal process, and its activity toward hydrogen production was investigated. The as‐synthesized quantum dot composites are examined by XRD, TEM, UV–vis spectroscopy, and XPS. The average diameter of the spherical ZnS QDs is determined to be 3.7 nm, and they are uniformly distributed across the Cu ₂ S snowflake‐like structures. The ZnS/Cu ₂ S composite with an optimal ZnS loading of 9 wt.% (ZCS‐9) achieves a hydrogen evolution rate of 13.32 mmol g ⁻¹ h ⁻¹ with an AQY of 32.56%, representing an 8.8‐fold enhancement compared to pure ZnS (1.5 mmol g ⁻¹ h ⁻¹ ). Moreover, optical, electrochemical, and photocatalytic performance analyses collectively demonstrate that the enhanced activity originates from the establishment of a p‐n heterojunction at the ZnS/Cu ₂ S interface, which effectively facilitates charge transfer and suppresses the recombination of photogenerated charge carriers.