Hydrothermal synthesis of WO3/CoS2 n–n heterojunction for Z-scheme photocatalytic H2 evolution

Abstract

One of the most effective methods to improve electron-transfer efficiency and photocatalytic reaction activity is to construct a photocatalyst with a heterojunction interface. Herein, a WO₃/CoS₂ n–n heterojunction composite catalyst was synthesized, and used in photocatalytic hydrogen evolution, and was optimized by adjusting the pH of the triethanolamine solution, the amount of Eosin Y added, and the content of WO₃ in the composite catalyst. After 5 h of photocatalytic reaction, WO₃/CoS₂ (WCS-2) had a H₂ production of 221.15 μmol, which was 80.41 times that of single WO₃ and 2.17 times that of CoS₂, and had good stability. XRD, SEM, TEM, and XPS characterization results indicated that WO₃/CoS₂ was successfully prepared. Fluorescence test and electrochemical test results showed that the WO₃/CoS₂ catalyst had a higher photoelectron transfer efficiency. Finally, it is pointed out that WO₃/CoS₂ enhanced the photocatalytic activity, which may be due to the electron migration of WO₃ and CoS₂ following the Z-scheme mechanism. This work presents a new idea for constructing n–n heterojunction to enhance the activity in photocatalytic hydrogen production.