A novel strategy for the synthesis of main-chain Azo polymers directly from bisnitroaromatic compounds by the photocatalytic process has been achieved under mild conditions. This approach avoids the tedious synthesis of Azo monomers and proceeds with a high monomer conversion (∼100%) and excellent selectivity (∼100%) but without generating a significant amount of inorganic wastes and impurities (Cu2+ or azoxy groups) existing in main-chain Azo polymers compared to previous methods. The polymerization was monitored by UV–vis, FT-IR, and MALDI-TOF-MS, indicating that the reaction process proceeded with formation of the azoxy repeating units from the corresponding bisnitroaromatic monomers and the reduction of corresponding azoxy repeating units to the azo repeating units. Furthermore, the recyclable heterogeneous photocatalysts represent an attractive green process for production of main-chain Azo polymers.
A circularly polarised photon hand, l- and r-, was not a deterministic factor for the induced chiroptical sign of π-conjugated polymer aggregates. This anomaly originates from circular dichroism inversion characteristics between shorter and longer π–π* bands.
TiO 2 /Bi 2 WO 6 (TB) heterojunction photocatalyst was successfully synthesized and characterized by XRD, SEM, TEM, UV–vis and photoluminescence measurement. The heterojunction interface structure of TB heterojunction photocatalyst was optimized via adjusting the ethylene glycol/water (EG/W) ratio. Based on XRD, SEM and TEM, the crystal size of Bi 2 WO 6 reduced from 14.6 nm to 8.8 nm, and the interface structure between Bi 2 WO 6 nanosheets and TiO 2 particle significantly changed with increasing EG concentration. Furthermore, the photocatalytic activity and the related mechanism of TB heterojunction photocatalyst were systematically discussed. Among them, TB EG /W sample shows the highest normalized apparent rate constant, which is attributed to its highest electron–hole pairs separation ability driven by optimized heterojunction interface between two semiconductors.
The preferred supramolecular chirality in aggregates of achiral azobenzene-containing polymers by limonene as a chiral transducer is achieved for the first time.
The nickel‐rich ternary‐layered oxide LiNi x Co y Mn (1− x − y ) O 2 (NCM) cathode exhibits high reversible capacity and low cost; however, severe capacity fade and aggravated air degradation prohibit its widespread commercialization. Herein, the hydrophobic fluoroalkylsilane‐modified NCM811 cathode materials are reported. To better understand the effects of electrochemical properties of lithium‐ion batteries, a variety of characterization techniques and electrochemical methods are utilized to study the surface chemistry at the cathode/electrolyte interphase. The hydrophobic fluoroalkylsilanes‐grafted NCM811 cathode materials suppress the formation of residual lithium even after 30 days in humid air. The fluoroalkylsilanes layer can also provide chemical stabilization to the NCM811 cathode materials by anchoring transition metals (TM) and suppressing TM dissolution during long immersion times in electrolytes. Moreover, the degree of improvement depends on the structure of the fluoroalkylsilanes, such as the number of F groups and the length of carbon chains. As a result, FAS17‐modified NCM811 cathode materials after 30‐day humid air exposure (humidity 70%) exhibit the greatest overall capacity retention of 74.2% after 200 charge/discharge cycles.
An “odd–even” effect for the chiral β-phase of polydialkylfluorene/limonene aggregates was first observed, depending on the odd–even alkyl side chain length.
Charge recombination and transfer at the TiO2/dye/electrolyte interface play a crucial role in dye-sensitized solar cells (DSSCs). Here, a fine-controlled gold nanoparticle (Au NP) via electrodeposition incorporated into a porous TiO2 photoanode and dodecanethiol molecules as an assembled monolayer capping on Au NPs was designed and prepared. The "fence-like" structure of gold thiol molecules at the TiO2/dye/electrolyte interface can not only insulate the electrolyte to suppress recombination but also make full use of the plasmon-enhanced light absorption of Au NPs. The photoanodes were characterized by X-ray photoelectron spectroscopy, UV-vis absorption, and Mott-Schottky analyses. Compared to pure TiO2, the DSSC with an interface "fence" structure achieved an efficiency (η) of 8.17%, increasing by 10.4%. The enhancement results are essentially attributed to the increase of the light-harvesting and electron collection properties, accompanying a slight promotion in the Fermi level. Furthermore, after dodecanethiol molecule treatment, the Au NPs with an intensified near-field effect also acted as electron sinks to store more electrons and exhibited a well electron-transport performance from electrochemical impedance spectroscopy analysis.
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