Simple donor functionalization in D-A type conjugated polymers for improved photocatalytic H2O2 production activity under visible light

Anthraquinone (AQ) based organic conjugated polymers are promising photocatalysts for H₂O₂ photosynthesis from O₂ and H₂O, since the AQ unit with strong electron withdrawing ability can not only promote the charge separation but also act as redox active center to generate H₂O₂ via oxygen reduction reaction (ORR). Herein, three novel donor–acceptor type organic polymers are reported to elucidate the influence of simple donor functionalization on charge dynamics and ORR activity. Compared to biphenyl donor without functionalized group, acetylene functionalized diphenylacetylene donor and diacetylene functionalized 1,4-diphenylbutadiyne donor show reduced twisted angles between adjacent benzene rings and increased coplanarity of polymer chains, which promotes the charge transfer and separation along the polymer chains. Besides, the presence of diacetylene group in donor extends the π conjugation and broadens the light absorption range of DPB-AQ. Benefiting from the donor–acceptor structure, broad absorption range of visible light, upgraded charge transfer and separation ability, DPB-AQ exhibits a higher photocatalytic H₂O₂ yield of 7.8 mmol h⁻¹ g⁻¹ than BPH-AQ (1.0 mmol h⁻¹ g⁻¹) and DPA-AQ (3.8 mmol h⁻¹ g⁻¹) in pure water without additives. This work highlights the critical role of simple donor functionalization in polymers for H₂O₂ photosynthesis from H₂O and O₂.