Efficient and stable hydrogen evolution from ZnWO₄/Zn_1.95Cd_8.05S₁₀-DETA via S-scheme heterojunction under visible light irradiation without co-catalysts

This study examines the production of hydrogen without a co-catalyst, using a ZnWO4/ Zn1.95Cd8.05S10-diethylenetriamine (ZW/ZCS, diethylenetriamine is referred to as DETA) photocatalyst that operates under visible light. The photocatalyst was synthesized using a hydrothermal method and characterized through various methods. Among ZW/ZCS nanocomposites, the 50-ZW/ZCS nanocomposite exhibited a remarkable hydrogen evolution rate of 4.46 mmol h-1 g-1. This significantly outperformed cadmium sulfide (CS, 1.96 mmol h-1 g-1), ZCS (2.78 mmol h-1 g-1), 50-ZW/CS (2.23 mmol h-1 g-1), and ZW (trace), thus highlighting the superior performance of the synthesized solid solution and nanocomposite. The S-scheme structure at the ZW/ZCS heterojunction served to separate photogenerated electron-hole pairs more effectively, leading to improved charge transfer efficiency and enhanced photocatalytic activity. Theoretical calculations and EPR results confirmed the presence of the S-scheme. Additionally, the ZW/ZCS photocatalyst demonstrated remarkable stability during hydrogen evolution. This research provides a novel methodology for the design and synthesis of efficient and stable photocatalysts that can facilitate hydrogen evolution under visible light, without the need for co-catalysts.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.