Efficient Photoelectrochemical Hydrogen Evolution via Hydrogen‐Bond‐Driven Self‐Assembly of 1D Covalent Organic Frameworks

Covalent organic frameworks (COFs) have shown significant application potential in the field of photoelectrochemical hydrogen evolution. However, it is a pressing scientific challenge to improve their processing performance to meet the requirements of photoelectrode films. In this study, a 1D COF (BC1COF) has been developed successfully, which can form a stable and easily processable solution through hydrogen bonding interactions. Moreover, the presence of hydrogen bonds promotes the self-assembly behavior of the material during the solution spin-coating process, enabling the preparation of smooth and flat COF films. The obtained COF films not only exhibit controllable thickness and excellent stability but also significantly enhance the carrier density and photoresponse characteristics of the material, thereby greatly improving its photoelectrocatalytic hydrogen evolution performance. The prepared photoelectrode film exhibited a photocurrent density of up to 97.5 µA cm^{- 2} at 0.4 V versus the reversible hydrogen electrode (RHE), which is ≈40 times that of the bulk photoelectrode. This synthesis strategy of COF films with controllable thickness provides the possibility for them to exhibit excellent performance in the field of photoelectrocatalysis.