Coupling Electron Transfer and Redox Site in Boranil Covalent Organic Framework Toward Boosting Photocatalytic Water Oxidation

The efficient polymeric semiconducting photocatalyst for solar -driven sluggish kinetics with multielectron transfer oxygen evolution has spurred scientific interest. However, existing photocatalysts limited by pi-conjugations, visible-light harvest, and charge transfer often compromise the O-2 production rate. Herein, we introduced an alternative strategy involving a boranil functionalized-based fully pi-conjugated ordered donor and acceptor (D-A) covalent organic frameworks (Ni-TAPP-COF-BF2) photocatalyst. The co-catalystfree Ni-TAPP-COF-BF2 exhibits an excellent similar to 11-fold photocatalytic water oxidation rate, reaching 1404 mu mol g- 1h-1under visible light irradiation compared to pristine Ni-TAPP-COF (123 mu mol g(-1) h(- 1)) alone and surpasses to reported organic frameworks counterpart. Both experimental and theoretical results demonstrate that the push/pull mechanism (metalloporphyrin/ BF2) is responsible for the appropriate light-harvesting properties and extending pi-conjugation through chelating BF2 moieties. This strategy benefits in narrowing band structure, improving photo-induced charge separation, and prolonged charge recombination. Further, the lower spin magnetic moment of M-TAPP-COF-BF2 and the closer d -band center of metal sites toward the Fermi level lead to a lower energy barrier for *O intermediate. Reveal the potential of the functionalization strategy and opens up an alternative approach for engineering future photocatalysts in energy conversion applications.