Substoichiometric covalent organic frameworks with uncondensed aldehyde for highly efficient hydrogen peroxide photosynthesis in pure water

A substoichiometric covalent organic framework (Bpy-TAPT) with reserved polar aldehyde groups and dual active sites (bipyridine and triazine) was rationally designed for recorded photocatalytic production of H2O2 in pure water. Bpy-TAPT showed an unprecedented H2O2 production rate of 4038 μmol h-1 g-1 with no sacrificial agents or cocatalysts, exceeding all the previously reported COF-based photocatalysts. Both experimental and computational results suggested that the dual active sites widened the visible-light-responsive range of the catalyst as well as enhanced the charge generation, while the aldehyde groups with electron-rich properties effectively improved the separation of carriers and the adsorption of O2/H+. This substoichiometric strategy suggests a powerful polarization method for the development of highly efficient photocatalysts in artificial photosynthesis.