Engineering Separated Dual O2 Reduction Cores into One Polymer Framework for Boosting Hydrogen Peroxide Production

Abstract

Photocatalytic hydrogen peroxide (H₂O₂) production through the oxygen reduction reaction (ORR) pathway has emerged as a promising sustainable alternative. However, a significant challenge in this field lies in the development of highly efficient photocatalysts capable of achieving high-concentration H₂O₂ production. Here the rational design of two O₂ reduction cores into one polymer framework is showcased for synergistically facilitating H₂O₂ production via the "self-marketing & cooperation" strategy. Photoactive units of pyrrolo[3,2-b] pyrrole and porphyrin are successfully settled in covalent organic polymers (COPs) through polycyclizations of the relevant aldehydes, anilines, and butane-2,3-dione. Two orderly separated active sites not only involve each of them in the oxygen reduction reaction but also mutually promote the production of H₂O₂, which is demonstrated by electron spin resonance experiments, in situ diffuse reflectance infrared Fourier transform spectroscopy, and a series of control experiments. Remarkably, PP-COP-4 delivers an outstanding H₂O₂ concentration of 16.2 mM in a continuous-flow system, demonstrating its strong potential for scalable, solar-driven production of commercial-grade H₂O₂.

Keywords: covalent organic polymers; hydrogen peroxide; microreactor; oxygen reduction reaction; self‐marketing & cooperation.