Bimetallic Sulfide Attached to Mn_0.2Cd_0.8S Induces Electron Transfer to Form S-Scheme Heterojunction to Promote Efficient Photocatalytic Hydrogen Evolution

A simple solvothermal method was used in this paper. Zn_0.76Co_0.24S (ZCS) nanoparticles were smoothly synthesized by this method and loaded on the external surface of Mn_0.2Cd0_.8S (MCS) to form an S-scheme heterojunction. A comparative evaluation was performed with two other single catalysts, and the compound catalyst MCS/ZCS achieved great gain in the process of catalytic action of H₂ generated under sunlight. The H₂ production of the pure MCS catalyst over a 5 h period was 17 μmol, while the hydrogen production of the composite catalyst formed by combining it with the ZCS group reached 944 μmol within 5 h, which indicates extremely high H₂ production activity. In this paper, it is found that the photocatalytic property of the MCS/ZCS system can be substantially improved, which is largely attributed to the construction of an S-scheme heterojunction. The S-scheme electron transfer path can improve the electron-hole pair separation efficiency. This improvement plays a decisive role in the relevant process and also enhances the charge transfer effect of the MCS/ZCS system. Through XPS, DFT calculation and electrochemical measurement, further exploration of the S-scheme heterojunction structure of MCS/ZCS was studied in this experiment, and then an additional research idea and direction was added for designing and constructing the S-scheme heterojunction and enhancing photocatalytic H₂ production response.