Defect Engineering Modulation of CdS-Based Nanorods to Promote the Visible Light Driven Photocatalytic Hydrogen Production

Sulfide semiconductor materials are widely used in photocatalytic hydrogen production, and specifically, CdS-based photocatalysts have excellent photocatalytic performance. Here, the precursor of zinc cadmium diethyldithiocarbamate was synthesized using sodium diethyldithiocarbamate as a ligand, and then, ternary metal sulfide Zn–Cd–S nanorods were prepared by the solvothermal method using ethylenediamine as a solvent. The influence of the defect content on photocatalysis was investigated by adjusting the ratio of Zn and Cd. Surface defects can capture photogenerated holes, retain more photogenerated electrons, and serve as active centers for hydrogen evolution reactions. In addition, based on the first step, ZnS/Zn–Cd–S composite photocatalysts were synthesized by hydrothermal method. Due to the presence of Zn vacancies in ZnS, they can also be excited to generate photogenerated electrons under visible light conditions, forming a type-II heterojunction with Zn–Cd–S, promoting electron hole separation. The synergistic effect of heterojunction and surface defects greatly improves the photocatalytic performance of the catalyst, achieving high hydrogen resolution activity of 13.7 mmol·g^–1·h^–1.