Enhancing\nDonor–Acceptor Interaction and Framework\nStability by the Povarov Reaction for Photocatalytic H<sub>2</sub>O<sub>2</sub> Production

Although photocatalytic hydrogen peroxide production\nby covalent\norganic frameworks (COFs) is emerging as a sustainable alternative\nfor the traditional anthraquinone oxidation process, commonly studied\nCOFs built on reversible imine bonds often suffer from poor operational\nstability. Here, we leverage the Povarov reaction to simultaneously\nimprove the framework stability and install versatile functions, <i>i.e.</i>, tunable donor–acceptor pairs for optimizing\nphotocatalysis. By mixing the amine and aldehyde building blocks (each\ncontaining a triazine core), together with the styrene or 2-vinylthiophene\nreagent in one pot, the imine COF (<b>Tz-COF</b>; formed <i>in situ</i>) was converted into the more stable quinoline-linked\nanalogs, featuring phenyl (<b>PhTz-COF</b>) or 2-thiophene (<b>ThTz-COF</b>) donors conjugated with the quinoline and triazine\nacceptors. Both <b>PhTz-COF</b> and <b>ThTz-COF</b> show\nbetter (steady) cycling catalytic performances than <b>Tz-COF</b> for visible light-driven H<sub>2</sub>O<sub>2</sub> production from\nO<sub>2</sub> and pure water; with the stronger donor of thiophene, <b>ThTz-COF</b> achieves a production rate (2506 μmol g<sup>–1</sup> h<sup>–1</sup>) doubling that of <b>PhTz-COF</b> (1210 μmol g<sup>–1</sup> h<sup>–1</sup>). The\nstructure–property correlation is also theoretically studied.