Oxygen defects and S-scheme heterojunctions synergistically promote the photocatalytic hydrogen evolution activity and stability of WO 2.72 /Zn 0.5 Cd 0.5 S-DETA nanocomposites

• Published in: Journal of colloid and interface science Vol. 646; p. 834
• Main Authors: Li, Zhen, Li, Wen, Zhai, Ligong, Chen, Chunxu, Zhang, Jinfeng, Wang, Zhenghua
• Format: Journal Article
• Language: English
• Published: United States 15-09-2023
• Subjects: Oxygen defects; Nanocomposites; S-scheme; Hydrogen; Photocatalysts; Heterojunction
• ISSN: 1095-7103

The study analyzed the impact of oxygen defects and S-scheme heterojunction on the performance and stability of WO
/Zn
Cd
S-DETA (WO/ZCS) nanocomposites photocatalysts for hydrogen evolution. Results showed that ZCS alone under visible light had good photocatalytic hydrogen evolution activity (1.762 mmol g
h
) and stability (79.5 % activity retention rate after seven cycles, 21 h). The WO
/ZCS nanocomposites with S-scheme heterojunction had better hydrogen evolution activity (2.287 mmol g
h
), but poor stability (41.6 % activity retention rate). The WO/ZCS nanocomposites with S-scheme heterojunction and oxygen defects showed excellent photocatalytic hydrogen evolution activity (3.94 mmol g
h
) and stability (89.7 % activity retention rate). The specific surface area measurement and ultraviolet-visible spectroscopy diffuse reflectance spectroscopy indicate that oxygen defects lead to larger specific surface area and improved light absorption, respectively. The charge density difference confirms the existence of the S-scheme heterojunction and the amount of charge transfer, which accelerates the separation of photogenerated electron-hole pairs and enhances the utilization efficiency of light and charge. This study offers a new approach using the synergistic impact of oxygen defects and S-scheme heterojunction to enhance the photocatalytic hydrogen evolution activity and stability.