Insight into energy level modulation via Mn doping solid solutions for enhanced photocatalytic hydrogen production

Energy level modulation is an effective strategy of increasing the separation efficiency of the photogenerated electrons and holes of sulfide solid solution. In this work, Mn element was introduced to Zn0.5Cd0.5S sulfide solid solution to modulate energy level of photocatalyst. Compared with pure Zn0.5Cd0.5S, Mn-doped Zn0.5Cd0.5S can effectively improve the separation of photogenerated electrons and holes. As a result, the hydrogen production rate of Mn-doped Zn0.5Cd0.5S photocatalyst is 4 and 12 times than that of Zn0.5Cd0.5S and CdS under visible-light irradiation. This improvement of photocatalytic activity of Mn-doped Zn0.5Cd0.5S is attributed to an emerging impurity band, narrow band gap, and negative conduction band after Mn doping. This work provides a rational doping strategy of catalyst and a deep insight of the enhancement mechanism of doping effect for photocatalytic reactions.