Broad Light Absorption and Multichannel Charge Transfer Mediated by Topological Surface State in CdS/ZnS/Bi2Se3 Nanotubes for Improved Photocatalytic Hydrogen Production

Semiconductor heterojunctions have garnered extensive interest in photocatalytic hydrogen generation, yet the limited light absorption and charge transfer efficiencies still restrict the photocatalytic performance. The topological insulator has unique surface states and high-mobility electrons, demonstrating the significant potential for enhancing photocatalysis. Herein, a ternary photocatalyst based on a topological insulator, in which CdS and ZnS nanoparticles are grown on Bi2Se3 nanotube, is prepared for efficient photocatalysis driven by topological surface state for the first time. Under simulated solar light irradiation, the CdS/ZnS/Bi2Se3 nanotubes display a robust photocatalytic hydrogen production rate of 7.13 mmol h(-1) g(-1), which is 69.2 times of CdS and comparable to many CdS-based photocatalysts. The unique hollow structure, topological surface state of Bi2Se3, and cooperative bandgap excitations of the three components endow the hybrids with wide light response to harvest solar energy. Meanwhile, the multichannel charge transfer facilitated by topological surface state and internal electric fields within the hybrids effectively suppresses the recombination of the photogenerated charge carriers. This mechanism maintains a high concentration of stable electrons on Bi2Se3, resulting in highly efficient hydrogen production. This work provides a new inspiration for designing heterojunction photocatalysts based on topological insulators for high-efficiency solar-driven energy conversion.