Indium-doped Zinc Sulfide Nanopowders for Boosting Photocatalytic Stream Water Splitting

Abstract

This study investigates the photocatalytic hydrogen production efficiency of indium-doped ZnS (In-doped ZnS) nanopowders synthesized via microwave-assisted heating. This method provides a rapid and effective fabrication process, with nanopowders capable of using stream water directly for photocatalytic water splitting. Results show that higher ZnS precursor concentrations increase particle size, while indium doping reduces particle size, improves surface area, and significantly boosts hydrogen production rates. In-doped ZnS nanopowders' hydrogen evolution rate is 29.97 times higher than that of undoped ZnS nanopowders. Indium doping optimizes visible light absorption, adjusts the band gap, and improves charge separation efficiency by reducing recombination rates. Morphological studies reveal that indium chloride concentrations above 5 mM lead to nanosheet formation, reducing surface area. The optimal doping concentration of 2.5 mM indium chloride results in a surface area of 153.9 m²/g, yielding the best performance. Stream water outperforms deionized water and seawater as a reaction medium, emphasizing the practical potential of these materials for sustainable hydrogen production. Reaction conditions such as precursor concentration, temperature, and microwave heating rates were systematically explored to identify optimal parameters, demonstrating the potential of In-doped ZnS as efficient, eco-friendly photocatalysts for hydrogen production from natural water sources.