High activity of Ag-doped Cd_0.1Zn_0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

<jats:p><jats:bold>Background:</jats:bold> The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd<jats:sub>0.1</jats:sub>Zn<jats:sub>0.9</jats:sub>S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd<jats:sub>0.1</jats:sub>Zn<jats:sub>0.9</jats:sub>S was studied for the hydrogen production from water reduction under visible light irradiation.</jats:p><jats:p><jats:bold>Results:</jats:bold> 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<jats:sub>0.1</jats:sub>Zn<jats:sub>0.9</jats:sub>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.</jats:p><jats:p><jats:bold>Conclusion:</jats:bold> This study demonstrated that Ag doping is a promising way to enhance the activity of Cd<jats:sub>0.1</jats:sub>Zn<jats:sub>0.9</jats:sub>S photocatalyst.</jats:p>