Conjugated porous polymers (CPPs) have recently emerged as prospective materials for photocatalytic hydrogen evolution. In the design of CPP photocatalysts, one of the challenges is to find ways to inhibit backward charge recombination and promote forward charge transfer/separation. Conjugated donor–acceptor polymers are capable of favoring forward intramolecular charge separation; however, they often suffer from backward charge recombination simultaneously, which causes a decrease of the quantum efficiency for solar-energy conversion. Herein, a photoinduced electron-transfer system via constructing D–A1–A2 conjugated polymers for photocatalytic hydrogen evolution is developed. Such a D–A1–A2 system can not only boost charge separation but also suppress charge recombination owing to the cascade energy levels of the comprised units and large charge delocalization structures. Therefore, an apparent quantum yield up to 22.8% at 420 nm is achieved, and the highest hydrogen evolution rate can be up to 966 μmol h–1 (19.3 mmol g–1 h–1) under visible light irradiation. These values are comparable to the state-of-the-art CPPs as well as part of inorganic photocatalysts. This work provides an alternative strategy and insight for the design of CPP photocatalytic systems for photocatalytic applications in high efficiency.

Engineering heteroatoms that precisely positioned in covalent triazine frameworks (CTFs) can dramatically enhance the photocatalytic hydrogen evolution rate of CTFs and is thus an effective strategy to improve the photocatalysis performance for porous organic polymers (POPs).

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The structural characteristics of hyper-cross-linked polymers (HCPs) make them interesting for a wide variety of applications.

The development of cost-effective, functional materials that can be efficiently used for sustainable energy generation is highly desirable. Herein, a new molecular precursor of bismuth (tris(selenobenzoato)bismuth(III), [Bi(SeOCPh) 3 ]), has been used to prepare selectively Bi or Bi 2 Se 3 nanosheets via a colloidal route by the judicious control of the reaction parameters. The Bi formation mechanism was investigated, and it was observed that the trioctylphosphine (TOP) plays a crucial role in the formation of Bi. Employing the vapor deposition method resulted in the formation of exclusively Bi 2 Se 3 films at different temperatures. The synthesized nanomaterials and films were characterized by p-XRD, TEM, Raman, SEM, EDX, AFM, XPS, and UV–vis spectroscopy. A minimum sheet thickness of 3.6 nm (i.e., a thickness of 8–9 layers) was observed for bismuth, whereas a thickness of 4 nm (i.e., a thickness of 4 layers) was observed for Bi 2 Se 3 nanosheets. XPS showed surface oxidation of both materials and indicated an uncapped surface of Bi, whereas Bi 2 Se 3 had a capping layer of oleylamine, resulting in reduced surface oxidation. The potential of Bi and Bi 2 Se 3 nanosheets was tested for overall water-splitting application. The OER and HER catalytic performances of Bi 2 Se 3 indicate overpotentials of 385 mV at 10 mA cm –2 and 220 mV, with Tafel slopes of 122 and 178 mV dec –1 , respectively. In comparison, Bi showed a much lower OER activity (506 mV at 10 mA cm –2 ) but a slightly better HER (214 mV at 10 mA cm –2 ) performance. Similarly, Bi 2 Se 3 nanosheets were observed to exhibit cathodic photocurrent in photoelectrocatalytic activity, which indicated their p-type behavior.