Directional Electron transport in In2S3 enabled by Bi3+ gradient doping and sulfur vacancies for efficient photocatalytic H2O2 production

Hydrogen peroxide (H 2 O 2 ) is a versatile green oxidant with wide-ranging applications. In this study, a bismuth ion (Bi 3+ )-gradient-doped indium sulfide (In 2 S 3 ) photocatalyst with abundant sulfur vacancies (V s ) was successfully prepared via a polyvinylpyrrolidone (PVP)-assisted hydrothermal method combined with solid-state grinding. The synergy of Bi 3+ doping and V s narrows the bandgap and constructs a built-in electric field for directional carrier transport, enabling the catalyst to achieve a H 2 O 2 production rate of 784.35 μmol g −1  h −1 under visible light (λ ≥ 420 nm). This work establishes a novel paradigm for designing high-performance sulfide photocatalysts.