Delicately Regulating the π-Spacer of D−π–A-Conjugated Polymers for Improved Visible-Light-Driven Hydrogen Evolution

Developing visible-light-driven conjugated polymers with a high photocatalytic performance is still a big challenge. The rational molecular design is a critical step in the development of an efficient polymer photocatalyst. Herein, we develop a series of donor−π–acceptor (D−π–A)-type conjugated copolymers employing pyrene (Py), dibenzothiophene-S,S-dioxide (DBTDO), and benzene with different substituent groups including methyl and fluorobenzene as the donor, acceptor, and π-spacers, respectively. By adopting different π-spacers and ternary statistical copolymerization, we assess the impact of the molecular structures on the photocatalytic performance of the resulting photocatalysts. The photocatalyst PyTFBS-m with tetrafluorobenzene as the π-spacer and a molar ratio of 1:2 for the Py to DBTDO shows remarkably high hydrogen evolution rates of 279 ± 6 and 111 ± 5 mmol h–1 g–1 under full spectrum light (λ > 300 nm) and visible light (λ > 420 nm) irradiation, respectively, with a 3 wt % Pt cocatalyst. The structure–performance relationships in this study provide important insights into the molecular design of highly active polymer photocatalysts.