Insights into the Operation of Noble‐Metal‐Free Cocatalyst 1T‐WS₂‐Decorated Zn_0.5Cd_0.5S for Enhanced Photocatalytic Hydrogen Evolution

Abstract

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-WS₂ with excellent conductivity can function for this reaction. Herein, 1T-WS₂ /Zn_0.5 Cd_0.5 S is constructed via a simple and feasible grinding approach. The composite containing 7.5 % 1T-WS₂ in 1T-WS₂ /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-WS₂ 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-WS₂ 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-WS₂ . More importantly, the close interface contact between 1T-WS₂ 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-WS₂ in the photocatalytic hydrogen evolution process.