Tuning acceptor content and molecular structure in linear donor-acceptor polymeric photocatalysts for ultrahigh-performance visible-light-driven hydrogen evolution

A series of linear conjugated polymers were synthesized by tuning the dibenzothiophene-S,S-dioxide (DBTO) content and varying their molecular structures, and applied to study the light-driven hydrogen generation from water. We found that the photocatalytic hydrogen evolution rate (HER) under visible light irradiation improved upon increasing the content of DBTO segment in donor-acceptor (D-A) structural polymers. Benefiting from the D-A structure and the high content of active centers of DBTO group, the polymer DB-Th displayed an unprecedentedly high HER of 334.50 mmol g- 1h-1 under visible-light-driven and cocatalyst-free conditions (one of the most effective bare polymer photocatalysts that has been reported), which is 1.38-fold as that of the 2D-A type polymer with the lower DBTO content and 255-fold as that of the D-D structural polymer without DBTO segment, demonstrating the significance of acceptor content in D-A structures for achieving ultrahigh photocatalytic hydrogen evolution activity under visible light.