Strong electron-coupled integrated WS₂/ZnCdS nanoparticles for enhanced photocatalytic hydrogen evolution

The development of efficient hydrogen production catalysts, by implementing co-catalyst loading strategies and thus regulating photogenerated electron-transfer pathways represents a promising approach to advance the development of hydrogen energy. A simple hydrothermal method is used to integrate WS₂, which exhibits a strong electron coupling effect, as a co-catalyst with ZnCdS nanoparticles, obtaining WS₂/ZnCdS nanoparticles that exhibit excellent photocatalytic activity in hydrogen evolution. The internal electric field established between WS₂ and ZnCdS, along with the second-order electron-transfer pathways, facilitates the transfer of photogenerated electrons. Moreover, the inherent strong electron coupling effect in WS₂ promotes the accelerated separation of e⁻−h⁺ pairs, owing to which the H₂ evolution rate of the WS₂/ZnCdS nanoparticles reaches 5.30 mmol g⁻¹·h⁻¹, which is 22.1 and 2.55 times higher than those of CdS and ZnCdS nanoparticles, respectively. Furthermore, electron paramagnetic resonance and transient photocurrent spectroscopic investigations confirm that the increased H₂ yield could also be attributed to increase in both the number of active sites and photogenerated electrons within the WS₂/ZnCdS nanoparticles. This study provides valuable insights on WS₂ as a co-catalyst for efficient photocatalytic hydrogen production.