Boosting Photocatalytic Metal-Free Hydrogen Production of Viologen-Based Covalent Organic Frameworks

In the pursuit of efficient and sustainable methods for photocatalytic hydrogen generation from water, covalent organic frameworks (COFs) have risen to prominence. Serving as a crucial link between organic flexibility and synthetic tunability, COFs present themselves as highly promising candidates for visible light-driven hydrogen production. Herein, we demonstrated that donor-acceptor (D-A) type viologen-derived COF containing 1,4-bismethylbenzene linker (COF-MB-TPCBP) as a noble metal-free catalyst could achieve a high hydrogen production rate of up to 4 mmol g(-1) h(-1) under visible light irradiation. Moreover, the adsorption of COF-MB-TPCBP onto the TiO2 semiconductor surface has led to an approximate 1.35-fold enhancement in efficiency value. This strategy could contribute to the development of innovative, metal-free COFs for hydrogen evolution through solar energy conversion by refining the associated structure.