Interfacial engineering improved internal electric field contributing to direct Z-scheme-dominated mechanism over CdSe/SL-ZnIn2S4/MoSe2 heterojunction for efficient photocatalytic hydrogen evolution

Abstract

Purposefully design and steering charge flow in heterostructure remains a crucial challenge for realizing efficient solar-to-fuel conversion. Herein, a newfangled ternary dual direct Z-scheme-dominated heterostructure of CdSe/lower-coordinated S atoms (SL)-rich ZnIn2S4/MoSe2 (CdSe/SL-ZIS/MoSe2) is fabricated, where the lower-coordinated S atoms in ZIS can serve as the highly active sites for anchoring CdSe and MoSe2 on the surface of ZIS through Cd-S and Mo-S bonds. The optimized CdSe/SL-ZIS/MoSe2 displays the ultrahigh visible-light (λ > 420 nm) driven H2 production rate of 70789.2 umol·g−1·h−1 with an apparent quantum efficiency (AQE) of 44.1% at 420 nm. Mechanism analysis and DFT calculations reveal that the interfacial chemical bond contributes to the intense internal electric field (IEF) in CdSe/SL-ZIS/MoSe2, and finally lead to the direct Z-scheme-dominated and II-scheme-assisted charge transfer mechanism. This work establishes an atomic-scale interfacial engineering design model on directionally modulating charge transfer for efficient solar energy conversion applications.