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.
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.
The class of radical polymers is one of the most appealing electrode materials in organic radical batteries (ORBs). Herein, we report a series of copolymers poly(2,2,6,6-tetramethylpiperidinyloxyl-4-yl methacrylate)-poly(4-pinacolatoborylstyrene) (PTMA-PSBpin-n, n = 1, 2, and 3) and explore their electrochemical properties as cathodes for ORBs. At 50 wt % active material content, the PTMA-PSBpin electrodes are found to bear great capacity, long-term cycle life, and impressive rate performance. In addition, compared to the other two electrodes, the PTMA-PSBpin-3 electrode possesses the lowest voltage separation (ΔV), which owes much to the introduction of a higher content of the PSBpin unit that enhances the conductivity (in the range of 3.447 × 10 −3 to 5.219 × 10 −3 S cm −1 within the pressure range of 2.0−20 MPa) of the material and resultantly abases the ohmic resistance. Accordingly, the oxidation/ reduction mechanism during the discharge/charge process is revealed by electron paramagnetic resonance (EPR) spectra. This study will shed light on the development of advanced ORB cathodes with low cost and high performance.
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