Effect of Controlling the Number of Fused Rings on Polymer Photocatalysts for Visible-Light-Driven Hydrogen Evolution
Searching an efficient and robust photocatalyst is important in converting solar energy into chemical energy for the clean and renewable fuel. Thiophene and fluorene has been used in this field widely, however, no study exits for understanding the effect of increasing the number of fused thiophene and fluorene rings. Here, we demonstrate a series of polymer photocatalysts based on fused rings with fluorene (F) and indenofluorene (IF) units with fused-thiophene rings (thiophene (T), thienothiophene (2T), and dithienothiophene (3T)) in different combinations, denoted PFnT and PIFnT, where n is the number of fused thiophene rings. We show that the increased the number of fused rings on fluorene units or on thiophene units is important result in the effect of photocatalytic performance. Specifically, without adding the noble Pt cocatalysts, our PF3T present an excellent efficiency of hydrogen evolution rate (HER) of 1,095 μmol h−1 g−1 (λ > 420 nm). We show that the photocatalysts are robust; that is, PF2T could be used for over 70 hours. More importantly, even we stored PF2T in water/methanol/TEA solution for 20 days, its photocatalytic performance remained constant. This contribution first documents a systematic study for construct of efficient and robust polymer photocatalysts, allowing the researcher potentially target about the number of fused rings on polymers, providing an important impact in this field.