Fused-Thiophene and Sulfone-Based Donor–Acceptor Conjugated Polymers for Enhanced Hydrogen Production

Conjugated porous polymers (CPPs) are highly promising hydrogen production (PHP) photocatalysts. The key lies in incorporating suitable functional groups into the molecular framework. Herein, we design two donor–acceptor (D–A) type CPP photocatalysts with alternately arranged molecular structures, incorporating 4,8-di(thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene as the donor unit and monosulfone or bisulfone as the acceptor unit. Small molecular structural changes in the acceptor unit lead to substantial differences in the PHP activity. Compared with polymer ThSo-2 containing a bisulfone group, the superior planar conjugated structure of polymer ThSo-1 containing a monosulfone group has broader visible light absorption and efficient charge separation capability, facilitating electron transport along the polymer skeleton. Without Pt cocatalyst, ThSo-1 exhibits an excellent hydrogen evolution rate of 111.79 mmol h–1 g–1 under full-spectrum light irradiation and an apparent quantum yield of 6.8% at 420 nm. This work shows an effective rational molecular design strategy for crafting efficient conjugated polymer photocatalysts.