Fabrication Of Robust Covalent Organic Frameworks For Enhanced Visible-Light-Driven H-2 Evolution

Developing photocatalysts capable of visible-light-driven water splitting to produce clean hydrogen (H-2) is one of the premier challenges for solar energy conversion into clean and sustainable fuels. Inspired from the structure feature of photosystem I in nature, we have designed and synthesized a series of robust covalent organic frameworks (NKCOFs = Nankai University COFs) based on electric donor-acceptor moieties, in which the electron-donor group of pyrene can be used for harvesting light. Meanwhile, benzothiadiazole with different functional groups was introduced as an electron acceptor to tune the light-adsorption ability of COFs. Notably, the activity of NKCOF-108 for photochemical H-2 evolution under visible light was among the highest in COFs without hybridization with other materials. We attribute the high hydrogen evolution rate of NKCOF-108 to its distinct structural features and wide visible-light-response range. The highly ordered layered structure ensures that sufficient active sites are accessible for H-2 production, and the donor-acceptor design can promote the separation of photogenerated carriers. Our findings have provided an effective strategy to design photocatalysts for light-driven H-2 evolution.