In Situ Construction of Thiazole-Linked Covalent Organic Frameworks on CuO for High-Efficiency Photocatalytic Tetracycline Degradation.

The strategic construction of heterojunctions through a simple and efficient strategy is one of the most effective means to boost the photocatalytic activity of semiconductor materials. Herein, a thiazole-linked covalent organic framework (TZ-COF) with large surface area, well-ordered pore structure, and high stability was developed. To further boost photocatalytic activity, the TZ-COF was synthesized in situ on the surface of CuO through a simple multicomponent reaction, yielding an encapsulated composite material (CuO@TZ-COF-18). In this composite, the outermost COF endows the material with abundant redox active sites and mass transfer channels, while the innermost CuO exhibits unique photoelectric properties. Notably, the synthesized CuO@TZ-COF-18 was proven to have the heterojunction structure, which can efficiently restrain the recombination of photogenerated electron-hole pairs, thereby enhancing the photocatalytic performance. The photocatalytic degradation of tetracycline demonstrated that 3-CuO@TZ-COF-18 had the highest photocatalytic efficiency, with the removal rate of 96.3% within 70 min under visible light, which is better than that of pristine TZ-COF-18, CuO, the physical mixture of CuO and TZ-COF-18, and numerous reported COF-based composite materials. 3-CuO@TZ-COF-18 retained its original crystallinity and removal efficiency after five cycles in photodegradation reaction, displaying high stability and excellent cycle performance.