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

Abstract

In the pursuit of\nefficient and sustainable methods for photocatalytic\nhydrogen generation from water, covalent organic frameworks (COFs)\nhave risen to prominence. Serving as a crucial link between organic\nflexibility and synthetic tunability, COFs present themselves as highly\npromising candidates for visible light-driven hydrogen production.\nHerein, we demonstrated that donor–acceptor (D–A) type\nviologen-derived COF containing 1,4-bismethylbenzene linker (COF-MB-TPCBP)\nas a noble metal-free catalyst could achieve a high hydrogen production\nrate of up to 4 mmol g^–1 h^–1 under\nvisible light irradiation. Moreover, the adsorption of COF-MB-TPCBP\nonto the TiO₂ semiconductor surface has led to an approximate\n1.35-fold enhancement in efficiency value. This strategy could contribute\nto the development of innovative, metal-free COFs for hydrogen evolution\nthrough solar energy conversion by refining the associated structure.