An oxygen vacancy-rich BiO 2- x /COF heterojunction for photocatalytic degradation of diclofenac.

A BiO 2- x /COF composite was successfully synthesized by simple mechanical ball milling. Compared to pure BiO 2- x and COFs, the BiO 2- x /COF composite (1 : 9) showed superior photocatalytic capability. Under visible light irradiation for 90 min, the photocatalytic degradation rate of DCF reached 97%. In addition, the characterization results showed that the formation of heterojunctions and the increase in oxygen vacancy concentration were the reasons for the enhancement of the photocatalytic activity. It is confirmed by free radical capture experiments that ˙O 2 - and h + are the main reactive substances in the photocatalytic process. The photocatalytic degradation mechanism of the composite and the photocatalytic degradation pathway of diclofenac were deduced.