Pyrimidine-containing covalent organic frameworks for efficient photosynthesis of hydrogen peroxide via one-step two electron oxygen reduction process
Hongyu Chen, Hao Zhang, Kai Chi, Yan Zhao
Abstract
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 (H 2 O 2 ) 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 H 2 O 2 via the one-step 2e − ORR pathway with O 2 and water. Under visible-light irradiation, BTT-MD-COF exhibited a high H 2 O 2 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 O 2 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 H 2 O 2 .