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

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.