As a class of the efficacious photocatalysts for watersplitting, 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 C 3 N 3 -SO photocatalysts in an A 1 −π−A 2 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 C 3 N 3 -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.

A series of linear conjugated organoborane oligomers are synthesized here by introducing electron-deficient borole units to the well-explored thiophene unit of variable length. It is found that the photophysical properties, particularly the band structures of products, alter regularly with the extension of thiophene. Interestingly, such oligomers exhibit high activity for photocatalytic hydrogen evolution under visible light (λ > 420 nm), outperforming most of the reported linear polymers. The enhanced performance is possibly attributed to the strong electron-accepting nature of the borole group, as well as the good electron donor and light-harvesting properties of the thiophene group. The combination of these two units facilitates charge separation of oligomers, thus allowing the participation of as many photogenerated charge carriers as possible in the desired water reduction reaction. The results indicate the success of our strategy and the importance of rational molecular design for developing conjugated (oligo)polymers for efficient photocatalytic hydrogen evolution.

Poor charge separation is the main factor that limits the photocatalytic hydrogen generation efficiency of organic conjugated polymers. In this work, a series of linear donor–acceptor (D–A) type oligomers are synthesized by a palladium‐catalyzed Sonogashira–Hagihara coupling of electron‐deficient diborane unit and different dihalide substitution sulfur functionalized monomers. Such diborane‐based A unit exerts great impact on the resulting oligomers, including distinct semiconductor characters with isolated lowest unoccupied molecular orbital (LUMO) orbits locating in diborane‐containing fragment, and elevated LUMO level higher than water reduction potential. Relative to A‐A type counterpart, the enhanced dipole polarization effect in D–A oligomers facilitates separation of photogenerated charge carriers, as evidenced by notably prolonged electron lifetime. Owing to π–π stacking of rigid backbone, the oligomers can aggregate into an interesting 2D semicrystalline nanosheet (≈2.74 nm), which is rarely reported in linear polymeric photocatalysts prepared by similar carbon–carbon coupling reaction. Despite low surface area (30.3 m2 g−1), such ultrathin nanosheet D–A oligomer offers outstanding visible light (λ > 420 nm) hydrogen evolution rate of 833 µmol g−1 h−1, 14 times greater than its A‐A analogue (61 µmol g−1 h−1). The study highlights the great potential of using boron element to construct D–A type oligomers for efficient photocatalytic hydrogen generation.

Covalent organic frameworks (COFs) are attractive organic polymers as promising photocatalysts for water reduction. Herein, two novel arylboron functional TAB-TFB-COF and TAB-TFP-COF were synthesized and their photocatalytic hydrogen evolution ability...

Although excellent photocatalytic activity of donor–acceptor (D–A) polymers has been widely proved, different D/A ratios in the polymer skeleton affect their electronic properties and microstructure, which may limit their photocatalytic activity. To understand the relationship between the D/A ratio and photocatalytic activity, in this paper, a series of random conjugated polymers were synthesized by adjusting the molar ratio of D/A using pyrene as the electron D unit and dibenzothiophene sulfone as the electron A unit and applied to the study of photocatalytic hydrogen evolution from water reduction. When the molar ratio of D/A was 1:20, the PySO-2 polymer showed the highest photocatalytic hydrogen production activity of 23.3 mmol g–1 h–1, which was probably caused by the increase of the photo-induced carrier separation efficiency, indicating that the photocatalytic performance depended on the molar ratio of D/A in the skeleton. In addition, the hydrogen evolution rate (HER) of PySO-2 was nearly two times higher than that of PySO-6 under the same reaction conditions, suggesting that the photocatalytic performance relies on the molar ratio of D/A in the skeleton. All results indicate that adjusting the molar ratio of D/A in the polymer skeleton can influence the separation and migration efficiency of photogenerated charge carriers, which in turn accelerates the performance of photocatalytic hydrogen production.