Pyrimidine-containing covalent organic frameworks for efficient photosynthesis of hydrogen peroxide via one-step two electron oxygen reduction process

The photocatalytic oxygen reduction reaction (ORR), particularly the one-step two-electron (2e−) pathway, is a highly promising strategy for efficient and selective hydrogen peroxide (H2O2) synthesis. However, constructing efficient photocatalysts to achieve a one-step 2e− ORR process remains a significant challenge. Herein, we developed an efficient photocatalyst by incorporating pyrimidine units into benzotrithiophene-based covalent organic framework (BTT-MD-COF), enabling the photosynthesis of H2O2 via the one-step 2e− ORR pathway with O2 and water. Under visible-light irradiation, BTT-MD-COF exhibited a high H2O2 production rate of up to 5691.2 µmol·h−1·g−1. Further experimental results and theoretical studies revealed that the introduction of pyrimidine units accelerates the separation of photoinduced electron–hole pairs and promotes Yeager-type O2 adsorption, which alters the two-step 2e− ORR process to the direct one-step 2e− process. This work offers a new avenue to create metal-free catalysts for efficient photosynthesis of H2O2.