Highly efficient direct Z-scheme WO3/CdS-diethylenetriamine photocatalyst and its enhanced photocatalytic H2 evolution under visible light irradiation

Abstract

Cadmium sulfide (CdS) has demonstrated great promise in artificial photocataytic hydrogen (H2) production. However, the serious photocorrosion hinders its effective interaction and real-life application. In this work, a typical direct Z-scheme WO3/CdS-diethylenetriamine (CdS-DETA) composite has been designed via facile in-situ solvothermal method, which exhibits excellent H2 production properties in visible light region. In this system, the inorganic–organic CdS-DETA nanobelts (NBs) possess enough active sites and large surface area for the encouraging nanojunction structure information. Furthermore, we also systematically calculated energy band structure and investigated charge transfer of the WO3/CdS-DETA by PL and photocurrent test, the results demonstrated that the suitable band gap matching between CdS-DETA and WO3 and high redox potential improve the separation of photogenerated holes and electrons, restraining intrinsic photocorrosion of CdS as well as improving the photocatalytic activity. 5%WO3/CdS-DETA presented the most outstanding H2 evolution rate (15522 μmol g−1 h−1), which is twice higher than that of pure CdS-DETA. WO3/CdS-DETA composites also presented high stability after three recycle H2 production experiment. Finally, direct Z-scheme photocatalytic mechanism is calculated.