Z-scheme CoWO₄/g-C₃N₄ heterojunction for enhanced ultraviolet-light-driven photocatalytic activity towards the degradation of tetracycline

The photocatalytic performance of g-C₃N₄ could be effectively improved by reducing the recombination rate of photogenerated electron–hole pairs. In this work, g-C₃N₄ was combined with CoWO₄ to construct Z-scheme heterojunction by ultrasonic impregnation method. The successful synthesis of CoWO₄/g-C₃N₄ composites was confirmed by comprehensive characterization. Systematic studies showed that the well-matched band structures between them contributed to the formation of close interfacial contacts, which could effectively increase the transfer rate of photogenerated electrons. The photocatalytic degradation performance showed that the degradation efficiency of tetracycline (TC) reached 98.3% in 150 min under ultraviolet light, which was mainly due to the establishment of Z-scheme heterojunction. At the same time, CoWO₄/g-C₃N₄ composites could still maintain good stability after four cycles. In addition, the possible photocatalytic mechanism of CoWO₄/g-C₃N₄ composites was also proposed. This work provided an effective way for the preparation of efficient photocatalyst with the Z-scheme heterojunction.