Au nanostars/Bi2S3/TiO2 Schottky/S-scheme dual heterojunctions for efficient photocatalytic hydrogen evolution

To overcome the narrow light absorption range and high charge carrier recombination rate of TiO₂ as a widely utilized photocatalyst for hydrogen evolution, we present a rational design of the Bi₂S₃/TiO₂ Schottky/S-scheme dual heterojunction photocatalyst modified with Au nanostars (AuNSs). The S-scheme Bi₂S₃/TiO₂ heterojunction effectively extends light absorption into the visible region and facilitates efficient photogenerated carrier separation. As co-catalysts, AuNSs exhibit abundant active sites and the SPR effect, which can broaden the light absorption range to NIR and accelerate surface hydrogen evolution. Additionally, the Schottky junction formed between AuNSs and Bi₂S₃ establishes a strong internal electric field, which introduces hot electron injection from AuNSs to Bi₂S₃ and effectively suppresses carrier recombination. The AuNSs/Bi₂S₃/TiO₂ catalyst exhibited a high hydrogen production rate (5.754 mmol g⁻¹ h⁻¹), along with excellent cycling stability. This study offers insights into interfacial modulation and performance enhancement of heterojunction materials for broad-spectrum-responsive photocatalysts.