Hydrothermal synthesis of zinc indium sulfide microspheres with Ag+ doping for enhanced H2 production by photocatalytic water splitting under visible light

Abstract

Two series of ZnIn_xS_1+1.5x and Ag(y)–ZnIn_xS_1+1.5x+0.5y solid solutions are prepared by hydrothermal methods. The synthetic conditions such as the molar ratio of In/Zn, the pH value, the hydrothermal temperature and the reaction time are found to intensely influence the crystal structure and the morphology of the photocatalyst as well as its photocatalytic activity for H₂ generation from water. It is revealed that the ZnIn_1.5S_3.25 solid solution (In/Zn = 1.5) prepared at 160 °C for 6 h by adding 1 mL hydrochloric acid to the precursor solution shows the highest photocatalytic H₂ evolution rate of 1.85 mmol h⁻¹ g⁻¹ in the presence of Ru as the co-catalyst and Na₂S/Na₂SO₃ as sacrificial reagents. Furthermore, after Ag⁺ doping, the photocatalytic H₂ evolution rate remarkably increased to 3.20 mmol h⁻¹ g⁻¹ for the Ag(1.5%)–ZnIn_1.5S_3.2575 sample. This work provides a new opportunity to develop efficient photocatalysts for photosplitting water into hydrogen.