Abstract：

Photocatalytic hydrogen evolution reaction (HER) has been considered as a promising technology to solve both energy crisis and environmental problems. CdS/ZnS hybrid composite structure has been proved an ideal system for photocatalytic hydrogen production. It is commonly referred to as a type-I semiconductor heterostructure. After an in-depth research work, it is found that the CdS/ZnS has a type II structure or direct Z-scheme structure due to the defect energy levels of zinc vacancies. In this work, the zinc vacancy mediated CdS/ZnS core/shell hybrid structure on FTO was synthesized. The best hydrogen production activities of CdS/ZnS reached 6.27 µmol cm-2 h-1 and 137 μmol cm-2 h-1 in the photocatalytic and photoelectrochemical (PEC) systems. More importantly, it exhibited excellent stability of 5 cycles for 25 h. The photoluminescence emissions spectra peaking in the visible light region verified the existence of zinc vacancies. Kelvin probe force microscopy (KPFM) proved the efficient transfer of photogenerated electrons from the CdS to the ZnS, thus forming a Z-scheme photocatalytic system.

Citation

Cong Guo, Lizi Chu, Qiao Zhang,* Zheng Li, Guangxing Yang, Feng Peng.* The Zinc Vacancy Induced CdS/ZnS Z-scheme Structure as a Highly Stable Photocatalyst for Hydrogen Production, J. Alloys Compd., 2021, 888, 161620