Weixia Wang+, Yongji Zhang+, Fei Zhao, Libo Wang, Fanpeng Meng*, Shuchao Qin*, Jinsheng Zhao*

Cite this article: Chin. J. Struct. Chem., 2026, 45(3), 100833. DOI: 10.1016/j.cjsc.2025.100833

Publication date: March 1, 2026

Keywords: Conjugated porous polymers; Carbon nitride; S-scheme; Photocatalytic hydrogen evolution; Extended π-delocalized network

ABSTRACT

Carrier recombination in polymer photocatalysts involves both undissociated exciton decay and charge recombination, which are the main obstacles limiting their photocatalytic activity. Achieving efficient charge generation and separation in a polymer system is a fundamental strategy for the potential success of solar energy conversion to hydrogen, but it remains a huge challenge. In this study, we propose an innovative intermolecular π–π stacking strategy to construct a π-delocalized all-polymer S-scheme heterojunction for photocatalytic hydrogen evolution. Two conjugated porous polymers (CPPs)—PyB, composed of benzo[1,2-b:4,5-b′]dithiophene (BDT) and pyrene units, and PhB, composed of BDT and benzene—were synthesized and integrated with CN nanosheets. The highly planar and π-extended structure of PyB facilitated strong interfacial π–π stacking with CN, forming an extended π-delocalized network that enhanced the internal electric field (IEF), improved charge separation, and boosted visible-light absorption. As a result, the optimized PyB/CN-20 composite achieved a remarkable hydrogen evolution rate (HER) of 23.84 mmol?h?1?g?1?under visible light, approximately 287 times higher than that of pristine CN. This work underscores the critical role of polymer planarity and π-conjugation in heterojunction efficiency, and provides new insights into the rational design of π-delocalized S-scheme systems and establishes a general strategy for developing highly efficient, metal-free photocatalysts by leveraging molecular-level structural control.