Insights into the Operation of Noble-Metal-Free Cocatalyst 1T-WS2-Decorated Zn0.5Cd0.5S for Enhanced Photocatalytic Hydrogen Evolution

Graphical The schottky heterojunction is constructed based on the Fermi energy level difference between the metal phase 1T-WS 2 and Zn 0.5 Cd 0.5 S. Under visible light irradiation, the tight interfacial contact leads to strong electronic interactions and facilitates the transfer of photogenerated carriers from Zn 0.5 Cd 0.5 S to 1T-WS 2 , further enhancing photocatalytic hydrogen production. Due to inefficient charge separation and low surface catalytic conversion efficiencies, cocatalysts are required for achieving photocatalytic hydrogen evolution. Being a noble-metal-free cocatalyst, metallic 1T-WS 2 with excellent conductivity can function for this reaction. Herein, 1T-WS 2 /Zn 0.5 Cd 0.5 S is constructed via a simple and feasible grinding approach. The composite containing 7.5 % 1T-WS 2 in 1T-WS 2 /Zn 0.5 Cd 0.5 S achieves a hydrogen evolution rate of 61.65 mmol g −1 h −1 and an external quantum efficiency of 8.04 % at 420 nm, which is 37 times that of bare Zn 0.5 Cd 0.5 S (1.67 mmol g −1 h −1 ). The electrical conductivity of metallic 1T-WS 2 reduces the transfer impedance at the interface and thus accelerates the non-radiative energy transfer and electron transport rate. The different Fermi levels of 1T-WS 2 and Zn 0.5 Cd 0.5 S form a Schottky junction, which promotes the transfer of photogenerated electrons from Zn 0.5 Cd 0.5 S to 1T-WS 2 . More importantly, the close interface contact between 1T-WS 2 and Zn 0.5 Cd 0.5 S results in strong electron interactions, which is conducive to the spatial separation of photogenerated electrons and holes. This work will further expand the application of 1T-WS 2 in the photocatalytic hydrogen evolution process.