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The excellent reactivity toward C–H direct arylation, water wettability and O–C p–π conjugation endow EDOT to be an attractive electron donor unit for CP photocatalysts, yielding an unprecedented hydrogen evolution rate up to 0.95 mmol h−1/6 mg catalyst.

A library of STP-based CP photocatalysts with –CN groups at varied positions were designed and facilely synthesized by an atom- and step-economic one-component direct arylation polymerization for a structure–property–performance correlation study.

Conjugated polymers (CPs) as photocatalysts have evoked substantial interest. Their geometries and physical (e.g., chemical and thermal stability and solubility), optical (e.g., light absorption range), and electronic properties (e.g., charge carrier mobility, redox potential, and exciton binding energy) can be easily tuned via structural design. In addition, they are of light weight (i.e., mainly composed of C, N, O, and S). To improve the photocatalytic performance of CPs and better understand the catalytic mechanisms, many strategies with respect to material design have been proposed. These include tuning the bandgap, enlarging the surface area, enabling more efficient separation of electron–hole pairs, and enhancing the charge carrier mobility. In particular, donor–acceptor (D–A) polymers were demonstrated as a promising platform to develop high-performance photocatalysts due to their easily tunable bandgaps, high charge carrier mobility, and efficient intramolecular charge transfer. In this minireview, recent advances of D–A polymers in photocatalytic hydrogen evolution are summarized with a particular focus on modulating the optical and electronic properties of CPs by varying the acceptor units. The challenges and prospects associated with D–A polymer-based photocatalysts are described as well.

In this contribution, we developed a simple, scalable, and universal strategy to exfoliate conjugated porous polymers (CPPs) into 2D nanosheets. A series of pyrenyl (Py)-, benzene (B)-, thienyl (T)-, thieno[3,2-b]thiophene (Tt)- and dithieno[3,2-b:2′,3′-d]thiophene (Ttt)-based CPPs were facilely exfoliated into 2D ultrathin sheets with a thickness of 5–18 nm in reasonable yields of 6–20% upon sonication in N-methyl pyrrolidone. Owing to more exposed active sites and shorter migration distances of charge carriers, the photocatalytic hydrogen production rate of the CPP 2-D nanosheets is 1.5–20 times higher than those of their bulk counterparts. The current study represents the first systematic report on the solvent-assisted exfoliation of CPP materials to produce 2D ultrathin lamellae from bulk CPPs with common structures, which might provide new possibilities for the practical application of 2D CPPs.

Semiconductor heterojunctions benefiting from efficient charge transfer and separation have been widely used in photocatalysis. Herein, heterojunctions based on polymeric and inorganic semiconductors, namely PyOT@TiO2, have been successfully constructed via in situ C–H activation polycondensation of the pyrene unit (Py-) and 3-(2-(2-ethoxyethoxy)ethoxy)thiophene unit (-OT) in the presence of titanium dioxide (TiO2). The combination of the polymeric semiconductor PyOT with TiO2 not only broadens the light response of TiO2, but also dramatically promotes the photo-generation exciton separation of PyOT. As a result, the optimized 50% PyOT@TiO2 composite exhibited extensive visible light absorption (400–520 nm) and the highest photocatalytic hydrogen evolution rate using ascorbic acid (AA) as the sacrificial agent, which is approximately 135 and 21 times higher than those of single-components TiO2 and PyOT, respectively. Mechanistic study by XPS, M–S plots and hydroxyl radical detection tests revealed the p–n heterojunction characteristics of PyOT@TiO2 that contributed to the enhanced photocatalytic performance. Our work develops a promising strategy for the in situ construction of polymeric–inorganic soft–hard heterostructures via atom-economic C–H activation polymerization.

How to prompt higher photocatalytic hydrogen production (PHP) efficiency from water to achieve practical applications still remains a big challenge with conjugated porous polymers (CPP)-based photocatalysts. Herein, we developed a simple and efficient cosolvent-assisted strategy to significantly improve the photocatalytic efficiency of CPP-based photocatalysts by introducing water-soluble aprotic bipolar co-solvents, including N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methyl pyrrolidone (NMP). The PHP activity of the pyrene–bithiophene-based CPP (named CP-St) using ascorbic acid (AA) as a sacrificial electron donor could be excellently accelerated in the presence of an aprotic bipolar NMP solvent. CP-St dispersed in an NMP/H2O/AA mixed solution under visible-light (λ > 420 nm) irradiation without the aid of a Pt cocatalyst achieved an unprecedented hydrogen evolution rate (HER) of 190.7 mmol h−1 g−1. As a result, 6 mg CP-St amazingly produced 128.1 mL H2 (∼5.72 mmol) under visible-light irradiation for only 5 h. Excitingly, by introducing 0.5 wt% Pt cocatalyst into the NMP/H2O/AA system, the HER of CP-St could be further boosted to 303.7 mmol h−1 g−1 (1.82 mmol h−1/6 mg), which represents the highest photocatalytic HER ever reported. This outstanding photocatalytic performance is mainly ascribed to the enhanced dispersity, strong hydrogen-bond interactions, and exfoliation effect by the NMP solvent. This study provides us with some new design ideas and opportunities for effectively catering to the actual hydrogen production demand.

3,4-Ethylene dioxythiophene (EDOT), as a monomer of commercial conductive poly(3,4-ethylene dioxythiophene) (PEDOT), has been facilely incorporated into a series of new π-conjugated polymer-based photocatalysts

Correction for ‘EDOT-based conjugated polymers accessed via C–H direct arylation for efficient photocatalytic hydrogen production’ by Zhi-Rong Tan et al., Chem. Sci., 2022, DOI: 10.1039/d1sc05784g.