Thiophene Functionalized\nLinear Conjugated Polymer\ntoward High-Performance Photocatalytic H<sub>2</sub>O<sub>2</sub> Production

Metal-free\npolymeric photocatalysts with tunable building\nblocks,\nample redox-active centers, and exceptional light-harvesting capability\nhave emerged as promising candidates for generating hydrogen peroxide\n(H<sub>2</sub>O<sub>2</sub>) through the oxygen reduction reaction\n(ORR) and water oxidation reaction (WOR). The slow kinetics of the\nWOR process coupled with rapid charge recombination nevertheless impedes\nthe efficient generation of H<sub>2</sub>O<sub>2</sub>. Herein, a\nthiophene functionalized linear conjugated polymer (DEB-Tp-S<sub>2</sub>) was fabricated for effective overall H<sub>2</sub>O<sub>2</sub> photoproduction. DEB-Tp-S<sub>2</sub> exhibits a high initial photocatalytic\nH<sub>2</sub>O<sub>2</sub> yield rate of 2762 μmol g<sup>–1</sup> h<sup>–1</sup> in the absence of sacrificial additives and\npossesses outstanding cycling stability. Experimental and density\nfunctional theory (DFT) results exhibit that thiophene moieties can\nreduce the strength of the O–H bond in H<sub>2</sub>O, which\npromotes the 4e<sup>–</sup> WOR process, thereby suppressing\ncharge recombination and improving proton supply. This work reveals\nthe indispensable role of chemical structure engineering in polymer\nphotocatalysts for optimizing their H<sub>2</sub>O<sub>2</sub> yield\nand offers fresh insights into the polymer design for achieving efficient\nH<sub>2</sub>O<sub>2</sub> production.