Affiliation:
1. MOE Key Laboratory of High Performance Polymer Materials & Technology. School of Chemistry and Chemical Engineering Nanjing University Nanjing Jiangsu 210023 P. R. China
2. School of Materials and Chemistry University of Shanghai for Science and Technology Shanghai 200093 P.R. China
Abstract
AbstractThe direct production of hydrogen peroxide (H2O2) through photocatalytic reaction via H2O and O2 is considered as an ideal approach. However, the efficiency of H2O2 generation is generally limited by insufficient charge and mass transfer. Covalent organic framework (COFs) offer a promising platform as metal‐free photocatalyst for H2O2 production due to their potential for rational design at the molecular level. Herein, we integrated the multipolar structures and carboxyl groups into COFs to enhance the efficiency of photocatalytic H2O2 production in pure water without any sacrificial agents. The introduction of octupolar and quadrupolar structures, along with an increase of molecular planarity, created efficient oxygen reduction reaction (ORR) sites. Meanwhile, carboxyl groups could not only boost O2 and H2O2 movement via enhancement of pore hydrophilicity, but also promote proton conduction, enabling the conversion to H2O2 from ⋅O2−, which is the crucial intermediate product in H2O2 photocatalysis. Overall, we demonstrate that TACOF‐1‐COOH, consisting of optimal octupolar and quadrupolar structures, along with enrichment sites (carboxyl groups), exhibited a H2O2 yield rate of 3542 μmol h− 1 g−1 and a solar‐to‐chemical (SCC) efficiency of 0.55 %. This work provides valuable insights for designing metal‐free photocatalysts for efficient H2O2 production.