Introducing Secondary Acceptors into Conjugated Polymers to Improve Photocatalytic Hydrogen Evolution

As a class of the efficacious photocatalysts for water-splitting, conjugated polymers (CPs) have drawn considerable attention in recent years. However, the unexpectedly fast charge recombination always constricts their further application, leading to poor photocatalytic behavior. Here, we report a series of dibenzothiophene-S,S-dioxide-based polymers with electron-property-dependent reactivity as well as their photocatalysis in hydrogen evolution. The results reveal that the introduction of a secondary acceptor unit into the repeating units of a CP skeleton is an effective method to enhance the photocatalytic hydrogen production activity, which is conducive to the separation and transport of photogenerated charge carriers. Therefore, the Pt-free B-SO and C3N3-SO photocatalysts in an A1–π–A2 form exhibit a competitive hydrogen evolution rate (HER) of 778 and 1603 μmol g–1 h–1 under visible light, respectively. Notably, under the same conditions, the 3 wt % Pt-modified B-SO and C3N3-SO provide a satisfactory HER of 1253 and 2966 μmol g–1 h–1, respectively. Our study proffered an effective strategy for enhancing the photocatalytic hydrogen evolution of CPs, which could be used for the design and optimization of other photocatalytic systems.