Thiophene Functionalized Linear Conjugated Polymer toward High-Performance Photocatalytic H2O2 Production

Abstract

Metal-free polymeric photocatalysts with tunable building blocks, ample redox-active centers, and exceptional light-harvesting capability have emerged as promising candidates for generating hydrogen peroxide (H₂O₂) through the oxygen reduction reaction (ORR) and water oxidation reaction (WOR). The slow kinetics of the WOR process coupled with rapid charge recombination nevertheless impedes the efficient generation of H₂O₂. Herein, a thiophene functionalized linear conjugated polymer (DEB-Tp-S₂) was fabricated for effective overall H₂O₂ photoproduction. DEB-Tp-S₂ exhibits a high initial photocatalytic H₂O₂ yield rate of 2762 μmol g^–1 h^–1 in the absence of sacrificial additives and possesses outstanding cycling stability. Experimental and density functional theory (DFT) results exhibit that thiophene moieties can reduce the strength of the O–H bond in H₂O, which promotes the 4e^– WOR process, thereby suppressing charge recombination and improving proton supply. This work reveals the indispensable role of chemical structure engineering in polymer photocatalysts for optimizing their H₂O₂ yield and offers fresh insights into the polymer design for achieving efficient H₂O₂ production.