Linker Engineering in Dibenzothiophene‐ S , S ‐Dioxide‐Containing Conjugated Polymers for Photocatalytic Hydrogen Peroxide Production in Pure Water

ABSTRACT

Donor–acceptor (D–A) conjugated polymers have emerged as promising photocatalysts for hydrogen peroxide (H ₂ O ₂ ) production due to their unique optoelectronic properties. While extensive studies have explored the impact of D/A structures on photocatalytic H ₂ O ₂ production performance of conjugated polymers, the role of the linkage structure in modulating photocatalytic activity was rarely investigated. In this study, three D–A conjugated polymers, including ethylene‐linked PSO‐CC, imine‐linked PSO‐CN, and azo‐linked PSO‐NN, have been designed and synthesized by Suzuki coupling reaction. Remarkably, although the linkages differ by a single atom, the three polymers exhibit significantly different optoelectronic characteristics and charge transfer kinetics. It was revealed that photogenerated electrons preferentially migrated to the N sites in imine and azo linkages in PSO‐CN and PSO‐NN, respectively, thereby increasing photocatalytic H ₂ O ₂ production activity. The moderate polarized polymer PSO‐CN shows excellent photocatalytic performance with an H ₂ O ₂ production rate of 1.43 mmol g ⁻¹  h ⁻¹ in pure water without any sacrificial agent. Theoretical investigation demonstrates that the imine linkages in PSO‐CN serve as the active sites for photocatalysis. This work highlights the critical role of linkage electronic properties in modulating photocatalytic H ₂ O ₂ production performance for D–A conjugated polymers.