Construction of a Z-scheme CdIn2S4/ZnS heterojunction for the enhanced photocatalytic hydrogen evolution

In this paper, CdIn2S4/ZnS (CIS/ZnS) nanocomposites were prepared by a one-step hydrothermal method. The structures and physicochemical properties of the nanocomposites were characterized by XRD, SEM, TEM, XPS, UV-Vis, TPR, EIS, PL, and ESR. The photocatalytic activity of CdIn2S4/xZnS composites for water splitting hydrogen evolution (the molar ratio of CdIn2S4 and ZnS is 1: x) is much better than that of the pristine ZnS and CdIn2S4. The optimal catalyst CdIn2S4/12ZnS exhibits the best performance. The hydrogen production rate reaches 3743 μmol·g−1·h−1, which is about 59.1 and 14.4 times that of pure CdIn2S4 and ZnS. The reasons for the better performance of CdIn2S4/xZnS are the strong interaction between CdIn2S4 and ZnS, the formation of Z-scheme heterojunction, the more efficient charge separation, the extension light response in comparison with the single component, and the stronger redox properties. Moreover, the possible hydrogen production mechanism is proposed by the study of VB-XPS, Mott-Schottky, and EPR, which implies it is a Z-scheme photosystem. This work provides an effective method for the modification of ZnS catalysts for the application in photocatalytic hydrogen evolution.