Insight into the synergistic effect of defect and strong interface coupling on ZnIn₂S₄/CoIn₂S₄ heterostructure for boosting photocatalytic H₂ evolution

Steering the directional carrier migration across the interface is a central mission for efficient photocatalytic reactions. In this work, an atomic-shared heterointerface is constructed between the defect-rich ZnIn2S4 (HVs-ZIS) and CoIn2S4 (CIS) via a defect-guided heteroepitaxial growth strategy. The strong interface coupling induces adequate carriers exchanging passageway between HVs-ZIS and CIS, enhancing the internal electric field (IEF) in the ZnIn2S4/CoIn2S4 (HVs-ZIS/CIS) heterostructure. The defect structure in HVs-ZIS induces an additional defect level, improving the separation efficiency of photocarriers. Moreover, promoted by the IEF and intimate heterointerface, photogenerated electrons trapped by the defect level can migrate to the valence band of CIS, contributing to massive photogenerated electrons with intense reducibility in HVs-ZIS/CIS. Consequently, the HVs-ZIS/CIS heterostructure performs a boosted H2 evolution activity of 33.65 mmol g-1 h-1. This work highlights the synergistic effects of defect and strong interface coupling in regulating carrier transfer and paves a brave avenue for constructing efficient heterostructure photocatalysts. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.