Construction of topological insulator Bi2Te3 bridged Zn3In2S6/C3N5 ternary heterojunction with step-scheme/type-I synergistic charge transfer for boosted visible-light photocatalytic hydrogen evolution

A novel Zn 3 In 2 S 6 @Bi 2 Te 3 @C 3 N 5 ternary S-scheme/Type-I heterojunction is constructed. • Topological insulator Bi 2 Te 3 serves as the charge transport bridge. • The catalyst has an exceptional HER rate (42384.11 μmol g −1  h −1 ) with a 29.83% AQY. Addressing the core electrochemical bottlenecks of sluggish interfacial charge transfer and the charge separation-redox capability trade-off in photoelectrochemical water splitting, this work introduces 3D topological insulator Bi 2 Te 3 as a backscattering-free electrochemical charge transport bridge to construct a Zn 3 In 2 S 6 @Bi 2 Te 3 @C 3 N 5 ternary heterojunction with Step-scheme/Type-I synergistic charge transfer. The rationally optimized sample achieves an exceptional visible-light-driven hydrogen evolution rate of 42384.11 μmol g −1  h −1 with an apparent quantum yield of 29.83% at 420 nm, which are 1.68 and 27.43 times higher than those of pristine Zn 3 In 2 S 6 and as-synthesized C 3 N 5 , respectively. The superior performance originates from three synergistic effects: enhanced light harvesting by the multi-component system, promoted carrier separation driven by the robust built-in electric field at heterointerfaces, and improved charge transport efficiency along with optimized hydrogen evolution reaction (HER) kinetics endowed by Bi 2 Te 3 's topological properties. These advantages accelerate electron transport and suppress non-radiative recombination, providing insights for optimizing the kinetics of the HER at the electrochemical interface. Photocatalytic water splitting for hydrogen production offers a promising route to address the energy crisis; however, the rapid recombination of photogenerated carriers in conventional photocatalysts severely limits their efficiency. To overcome this bottleneck, we designed and constructed a novel Zn 3 In 2 S 6 @Bi 2 Te 3 @C 3 N 5 ternary heterojunction photocatalyst. In this system, Bi 2 Te 3 acts as a topological insulator and charge-transport bridge, forming a cascaded band alignment with Zn 3 In 2 S 6 and C 3 N 5 . This establishes a synergistic charge-transfer pathway that effectively promotes the spatial separation of photogenerated electron–hole pairs. The optimized catalyst exhibits outstanding visible-light-driven hydrogen evolution performance, achieving a remarkable HER rate of 42384.11 μmol g −1  h −1 and a high apparent quantum yield of 29.83% at 420 nm, along with excellent long-term cycling stability. This work provides new insights into designing efficient and stable photocatalysts for hydrogen evolution. Download: Download high-res image (381KB) Download: Download full-size image