Double Vacancy CdS / Bi 19 Cl 3 S 27 Heterojunction with Inverted F‐Scheme and Internal Electric Field Constructed Via an Electrostatic Self‐Assembly Strategy for Boosted Photocatalytic Hydrogen Evolution

Rationally designing heterojunction photocatalysts with directional charge transfer characteristics remains a challenge. Herein, we report a novel 0D/1D dual‐vacancy CdS/Bi 19 Cl 3 S 27 (denoted as CdS v /BCS v ) heterojunction photocatalyst with an inverted F‐scheme charge transfer mechanism via electrostatic self‐assembly. This unique charge transfer mechanism enables the optimized CdS v /BCS v ‐2 heterojunction to achieve a H 2 production rate of 446.8 μmol h −1 g −1 , which is 3.6 times higher than that of pure CdS v (123.3 μmol h −1 g −1 ) and 60.4 times higher than that of pure BCS v (7.4 μmol h −1 g −1 ). Mechanistic investigations, incorporating in situ characterization and density functional theory (DFT) calculations, reveal that the enhanced activity originates from the formation of the CdS v /BCS v heterojunction, which promotes efficient photoelectron transfer from CdS v to BCS v . This work proposes an inverted F‐scheme charge transfer mechanism to enhance photocatalytic activity and provides a new strategy for constructing high performance dual‐defect composite photocatalysts for photocatalytic H 2 evolution.