Cyanide-based Covalent Organic Frameworks for Enhanced Overall Photocatalytic Hydrogen Peroxide Production.

Photocatalytic oxygen reduction to produce hydrogen peroxide (HO) is a promising route to providing oxidants for various industrial applications. However, the lack of well-designed photocatalysts for efficient overall HO production in pure water has impeded ongoing research and practical thrusts. Here we present a cyanide-based covalent organic framework (TBTN-COFs) combining 2,4,6-trimethylbenzene-1,3,5-tricarbonitrile (TBTN) and benzotrithiophene-2,5,8-tricarbaldehyde (BTT) building blocks with water-affinity and charge-separation. The ultrafast intramolecular electron transfer (<500 fs) and prolonged excited state lifetime (748 ps) can be realized by TBTN-COF, resulting in a hole accumulated BTT and electron-rich TBTN building block. Under one sun, the 11013 μmol h g yield rate of HO can be achieved without any sacrificial agent, outperforming most previous reports. Furthermore, the DFT calculation and in situ DRIFTS spectrums suggesting a Yeager-type absorption of *O⋅ intermediate in the cyanide active site, which prohibits the formation of superoxide radical and revealing a favored HO production pathway.