Rational design of covalent organic frameworks for efficient photocatalytic hydrogen peroxide production

Abstract

Hydrogen peroxide (H₂O₂) is an important chemical for environmental applications and also used in large-scale industrial processes. Recent studies have demonstrated photocatalytic production of H₂O₂, but the observed production rates are low, making the materials unpractical for applications at scale. Herein, covalent organic frameworks (COFs) have been studied as photocatalysts for H₂O₂ production. Two related COFs show markedly different performances, which can be explained by the presence of donor–acceptor configurations in the backbone. N₀-COF has increased charge-separation efficiencies and a better band alignment compared to its nitrogen containing analogue N₃-COF. The result is that N₀-COF has a H₂O₂ production rate of 15.7 μmol h⁻¹ for 10 mg, which is ten times higher compared to N₃-COF. In this study, both experimental and theoretical studies have been used to understand the improved performance. This study reveals the importance of the backbone design of metal-free materials for advanced photocatalytic applications.