A Dual-Functional Metalloporphyrin-Fluorenone Covalent Organic Framework for Solar Hydrogen and Oxygen Production

Developing efficient dual-functional photocatalysts for the solar-driven conversion of H2O into H2 and O2 is a challenging yet promising approach to achieve carbon-free fuel production. Herein, we present a newly developed covalent organic framework (COF), integrated with cobalt porphyrin (Co-TP) and fluorenone (FO), as an efficient dual-functional photocatalyst. The Co-TPFO-COF exhibits structural advantages in photocatalysis due to its highly crystalline structure with high surface area and porosity. Additionally, the Co-TP unit serves not only as an electron donor enabling intramolecular electron transport to the FO unit for H2 production, but also an oxidation-active moiety for efficient O2 evolution. An O2 yield rate of 2399 mu mol g-1 h-1 was achieved with an apparent quantum efficiency of 1.06%, while the H2 production rate reached 1015 mu mol g-1 h-1. The performances can be ascribed to the synergy between directional charge transfer, decreased O2 evolution barriers and enhanced H+ adsorption. This study paves the way for the development of dual-functional COF photocatalysts for solar-to-fuel conversion. Developing efficient dual-functional photocatalysts for the solar-driven conversion of H2O into H2 and O2 is a challenging yet promising approach to achieve carbon-free fuel production.