Enhancing photocatalytic hydrogen peroxide generation by tuning hydrazone linkage density in covalent organic frameworks

           The Paper of the Day article discusses the synthesis and characterization of a series of covalent organic frameworks (COFs) with varying imine and hydrazone linkages, and their application in photocatalytic hydrogen peroxide (H2O2) generation from water and air. The key findings are., COFs with a higher density of hydrazone linkages, such as BTT-H2 and BTT-H3, exhibited superior photocatalytic H2O2 generation performance compared to the imine-linked BTT-DAB COF. The BTT-H3 COF with the highest hydrazone linkage density showed an exceptional H2O2 generation rate of 1588 μmol g−1 h−1 under visible light. The enhanced photocatalytic activity of the hydrazone-linked COFs is attributed to their improved water affinity, oxygen uptake, charge separation, and reduced electron-hole recombination compared to the imine-linked COFs. Computational studies revealed that the hydrazone linkages provide abundant catalytic sites for water oxidation and oxygen reduction reactions, facilitating the efficient photosynthesis of H2O2.- The BTT-H3 COF demonstrated significant H2O2 production (550 μmol g−1) under natural sunlight exposure for 1 hour, showcasing its potential for renewable resource utilization.