High activity of Ag-doped Cd(0.1)Zn(0.9)S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd(0.1)Zn(0.9)S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd(0.1)Zn(0.9)S was studied for the hydrogen production from water reduction under visible light irradiation. Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd(0.1)Zn(0.9)S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation. Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd(0.1)Zn(0.9)S photocatalyst.