Hydrothermal synthesis of CdS/CoWO4 heterojunctions with enhanced visible light properties toward organic pollutants degradation

Effective solar energy harvesting and charge carrier separation are two key factors of the photocatalysis system. In this work, the heterojunction photocatalyst of CdS/CoWO4 was fabricated by a facile hydrothermal method. Compared with the pristine CdS and CoWO4, the CdS/CoWO4 heterojunction photocatalyst showed enhanced photocatalytic activity for the methylene blue (MB) degradation under visible light irradiation. Particularly, the sample with molar ratio of CdS:CoWO4 (sample C2) controlled at 3:5 showed the highest MB degradation ratio (83%) in 1 h among all samples, which is about 3 times over the pure CdS and 8 times over pure CoWO4, respectively. The greatly enhanced photocatalytic activity (3-8 times) of CdS/CoWO4 is due to the efficient separation of electron-hole pairs by the heterojunction structure and strong visible light absorption of CdS. This work provides a new insight into the application of tungstate-based heterojunction photocatalysts in environmental remediation.