Recent progress in designing heterogeneous COFs with the photocatalytic performance

In recent years, covalent organic framework (COFs) has emerged as a new class due to the high structural designability and functional tunability. The purpose of this review article is to present the latest and most significant applications with photo-responsive COFs as photo-catalysts. At the first, the subjects containing of bottom-up, post modification and blending techniques were investigated to form composites based on COFs. This review provided a comprehensive overview of the synthesis strategy of COFs. There are the synthesis strategies to synthesize COFs, including solvothermal, microwave, the microwave-assisted solvothermal synthesis, sonochemical, ionothermal, mechanochemical, light promoted and one-pot methods. Additionally, based on three methods including reactive skeletons, reactive pendant groups and reactive metals, COF-based catalysts were designed to apply in various fields. So, it confirmed that photocatalytic performance as metal-free and metal-COFs photocatalysts was developed by doping metal ions and metal NPs. In this review, some viewpoints of metal- COF photocatalysts as heterogeneous photocatalysts, discussed the applications in reactions' products, Suzuki-Miyaura reactions, Heck cross-coupling reaction, olefins reactions, energy conversion. Additionally, in the review, the photo-based applications of the COFs, MOFs@COFs' composites and metal composites based on COFs were investigated in photo-degradation of pollutants. At last, COF was used as a photocatalytic nicotinamide cofactor regeneration.