Time-Dependent synthesis of ZnS and its influence on photocatalytic hydrogen generation

Abstract

This study explores the impact of varied synthesis times on the properties and performance of zinc sulfide (ZnS) in the photocatalytic hydrogen production. Validating the synthesis of ZnS from hydrozincite, our investigation extends to diverse solvothermal synthesis durations (0.5, 5, 24 and 72 h). X-ray diffraction analyses confirm a direct correlation between synthesis time and crystallite size growth. Mesoporosity and consistent functional groups characterize all materials. Prolonged synthesis times induce ethylenediamine-Zn2+ complexes, elevating defect density and causing a red shift in materials, impacting electronic structure and reducing band gap. Paradoxically, extended synthesis times correlate with diminished hydrogen production, emphasizing the role of surface area over electronic properties in photocatalytic performance. The 05H catalyst produces an average of 2.11 times more hydrogen than 24H and 72H catalysts with a hydrogen production rate of 276 µmolg−1h−1 The study underscores the intricate interplay of parameters, providing insights into achieving optimal photocatalytic performance.