Recent Advances in Low-Temperature Liquid Electrolyte for Supercapacitors.

As one of the key components of supercapacitors, electrolyte is intensively investigated to promote the fast development of the energy supply system under extremely cold conditions. However, high freezing point and sluggish ion transport kinetics for routine electrolytes hinder the application of supercapacitors at low temperatures. Resultantly, the liquid electrolyte should be oriented to reduce the freezing point, accompanied by other superior characteristics, such as large ionic conductivity, low viscosity and outstanding chemical stability. In this review, the intrinsically physical parameters and microscopic structure of low-temperature electrolytes are discussed thoroughly, then the previously reported strategies that are used to address the associated issues are summarized subsequently from the aspects of aqueous and non-aqueous electrolytes (organic electrolyte and ionic liquid electrolyte). In addition, some advanced spectroscopy techniques and theoretical simulation to better decouple the solvation structure of electrolytes and reveal the link between the key physical parameters and microscopic structure are briefly presented. Finally, the further improvement direction is put forward to provide a reference and guidance for the follow-up research.

A Ferricyanide Anion-Philic Interface Induced by Boron Species within Carbon Framework for Efficient Charge Storage in Supercapacitors.

Carbon materials with hierarchical porous structures hold great potential for redox electrolyte-enhanced supercapacitors. However, restricted by the intrinsic inert and nonpolar characteristics of carbon, the energy barrier of anchoring redox electrolytes on the pore walls is relatively high. As such, the redox process at the interface less occurs, and the rate of mass transfer is impaired, further leading to a poor electrochemical performance. Here, a ferricyanide anion-philic interface made of in situ inserted boron species into carbon rings is constructed for enhanced charge storage in supercapacitors. Profiting from the unique component-driven effects, the polar anchoring sites on the pore wall can be built to grasp the charged redox ferricyanide anion from the bulk electrolyte and promote the redox process; the dynamics process is fastened correspondingly. Especially, the boron atoms in BC2O and BCO2 units with higher positive natural bond orbital values in the carbon skeleton are pinpointed as intrinsic active sites to bind the negatively charged nitrogen atoms in the ferricyanide anion via electrostatic interaction, confirmed by density functional theoretical calculations. This will suppress the shuttle and diffusion effects of the ferricyanide anion from the surface of the electrode to the bulk electrolyte. Finally, the well-designed PC-3 with high content of BC2O and BCO2 units can reach 1099 F g-1 at 2 mV s-1, which is a more than 2-fold increase over boron-free units of carbon (428 F g-1). The work offers a novel version for designing high-performance carbon materials with unique yet reaction species-philic effects.

A multiple Kirkendall strategy for converting nanosized zero-valent iron to highly active Fenton-like catalyst for organics degradation.

Nanosized zero-valent iron (nZVI) is a promising persulfate (PS) activator, however, its structurally dense oxide shell seriously inhibited electrons transfer for O-O bond cleavage of PS. Herein, we introduced sulfidation and phosphorus-doped biochar for breaking the pristine oxide shell with formation of FeS and FePO4-containing mixed shell. In this case, the faster diffusion rate of iron atoms compared to shell components triggered multiple Kirkendall effects, causing inward fluxion of vacancies with further coalescing into radial nanocracks. Exemplified by trichloroethylene (TCE) removal, such a unique "lemon-slice-like" nanocrack structure favored fast outward transfer of electrons and ferrous ions across the mixed shell to PS activation for high-efficient generation and utilization of reactive species, as evidenced by effective dechlorination (90.6%) and mineralization (85.4%) of TCE. [Formula: see text] contributed most to TCE decomposition, moreover, the SnZVI@PBC gradually became electron-deficient and thus extracted electrons from TCE with achieving nonradical-based degradation. Compared to nZVI/PS process, the SnZVI@PBC/PS system could significantly reduce catalyst dosage (87.5%) and PS amount (68.8%) to achieve nearly complete TCE degradation, and was anti-interference, stable, and pH-universal. This study advanced mechanistic understandings of multiple Kirkendall effects-triggered nanocrack formation on nZVI with corresponding rational design of Fenton-like catalysts for organics degradation.

Processable Hydroxide Ink with Oriented Microstructure.

The intrinsic poor processability of hydroxide originating from the structural property greatly hinders their practical applications. Here, a processable highly-concentrated nickel/cobalt double hydroxide ink is reported to meet the practical demand. The inner nanoflakes in ink possess a high width/thickness ratio (>100), which endows the highly-concentrated ink (60 mg mL-1 ) with liquid-like rheology properties. Further, the elliptical diffusive arc in small-angle X-ray scattering pattern and porous and ordered alignment morphology in cryogenic temperature scanning electron microscopy confirms the locally oriented arrangement of nanoflakes in the ink. Benefiting from this interior-ordered structure, the ink can be processed into meter-level film, continuous yarn, and rigid and free-standing aerogel, respectively. In particular, the films can be used as electrodes directly in aqueous zinc ion batteries and deliver a favorable capacity (382 mAh g-1 @ 200 mA g-1 ) as well as long cycle stability (capacity retention rate of 88% @ 1000 mA g-1 after 400 cycles). Moreover, the enlarged-batched fabrication with the introduction of efficient thermal conduction in a 10 L reactor is also carried out successfully. These results clarify the inner relationship between microstructure-rheology and mechanical engineering for hydroxides, thus paving the way to develop hydroxide-based products for future practical applications.

One-step self-assembly of Fe-biochar composite for enhanced persulfate activation to phenol degradation: Different active sites-induced radical/non-radical mechanism.

Persulfate (PS) activation by nanoscale zerovalent iron (nZVI) is promising for water purification, while is limited due to its easy agglomeration and oxidation. Herein, nZVI encapsuled in carbon matrix shell was synthesized via one-step carbothermal reduction. The core-shell structure effectively inhibited oxidation and agglomeration of nZVI core, and graphitized porous structures facilitated phenol binding with maximal adsorption capacity of 117.10 mg/g achieved by nZVI0.6-BC800. Both reactive oxygen species (SO4•-, O•H, O2•- and 1O2) and electron transfer process resulted in phenol decomposition. Owing to diversified active sites, the nZVI0.6-BC800/PS system could completely degrade phenol degradation within short time, and exhibited great adaptation to extensive pH range (3.0-9.0) and coexisting substances. Additionally, the nZVI0.6-BC800/PS system could maintain over 85% removal of phenol after three recycles or 50 days of storage, and was highly-efficient to different water environments, thus proposing rational design of iron-carbon catalyst with potential in water treatment.

Polyethylenimine-grafted nitrogen-doping magnetic biochar for efficient Cr(VI) decontamination: Insights into synthesis and adsorption mechanisms.

Herein, polyethylenimine (PEI)-grafted nitrogen (N)-doping magnetic biochar (PEIMW@MNBCBM) was synthesized, and characterization results showed that the microwave-assisted PEI grafting and ball milling-assisted N doping introduced abundant amino, pyridine N and pyrrole N structures onto biochar, which possessed high affinity to Cr(VI) in the anion form. The as-prepared PEIMW@MNBCBM displayed pH-dependence adsorption performance and high tolerance to co-existing ions with maximum uptake capacity of Cr(VI) identified as 183.02 mg/g. Furthermore, PEIMW@MNBCBM could bind Cr(VI) through electrostatic attraction, complexion, precipitation, reduction and pore filling. Especially, effective reduction of Cr(VI) was ascribed to cooperative electron transfer of partial oxygen-containing functional groups, intramolecular pyridine/pyrrole N, protonated amino and Fe2+ on the adsorbent, while oxygen-containing and amino functional groups from N-doping biochar and PEI synergistically complexed Cr(III) via providing lone pair electrons to form coordinate bonds. Furthermore, the stable precipitation was formed between Fe3+ and Cr(III). Additionally, the Cr(VI) elimination efficiency could maintain 95.83% even after four adsorption-desorption cycles, suggesting PEIMW@MNBCBM as a high-performance adsorbent for Cr(VI) contaminated water remediation.

One-step preparation of Fe/N co-doped porous biochar for chromium(VI) and bisphenol a decontamination in water: Insights to co-activation and adsorption mechanisms.

Herein, magnetic nitrogen doped porous biochar (Fe/N-PBC) was prepared by mixing KHCO3, K2FeO4 and CO(NH2)2 through one-step pyrolysis, and was employed for adsorbing Cr(VI) and BPA in water. The whole co-activated process was accompanied with pore-forming, carbon thermal reduction and element doping. Specifically, the developed microporous structures and high surface area of Fe/N-PBC (1093.68 m2/g) were achieved under synergistic activation of KHCO3 and K2FeO4. Meanwhile, carbon thermal reduction process successfully converted K2FeO4 to Fe0 with introduction of heterocyclic-N (pyrrolic N and pyridinic N) structures by CO(NH2)2 doping. Fe/N-PBC exhibited outstanding uptake for Cr(VI) (340.96 mg/g) and BPA (355.14 mg/g), and possessed favorable regeneration properties after three cycles. Notably, the high-performance Cr(VI) removal was associated to reduction, electrostatic interaction, complexation, pore filling and ion exchange, while pore filling, hydrogen-bonding interaction and π-π stacking were responsible for BPA binding. This work presents reasonable design of Fe/N-carbon materials for Cr(VI)/BPA polluted water remediation.

Interleukin-23-induced interleukin-23 receptor subunit expression is mediated by the Janus kinase/signal transducer and activation of transcription pathway in human CD4 T cells.

Interleukin (IL)-23 plays a critical role in the development of the T helper (Th) cell response and is responsible for the maintenance of the IL-17 producing subset of Th cells, Th17. IL-23 is a heterodimeric cytokine composed of IL-23p19 and IL-12p40 subunits, and the signaling pathway for IL-23 involves 2 receptor chains: IL-12Rß1 and IL-23Rα. The IL-23 receptor complex is expressed on a number of cells, including natural killer cells, monocytes, macrophages, dendritic cells, and CD4 T cells. Currently, the molecular mechanisms governing expression of the IL-23 receptor chains, IL-23Rα and IL-12Rß1, are not well understood. Our results show that IL-23 induces upregulation of IL-23Rα and IL-12Rß1 expression in human CD4 T cells. Further, we demonstrate that inhibition of the Janus kinase/signal transducer and activation of transcription (JAK/STAT) pathway by SD-1029, a JAK2 inhibitor, 5'-deoxy-5'-(methylthio) adenosine, a STAT1 inhibitor, and STAT3 VII, a STAT3 inhibitor, were able to block IL-23-induced expression of IL-23 receptor subunits in the human SUPT-1 T cell line and in primary CD4 human T cells. Taken together, our results suggest a positive feedback regulation of the IL-23 receptor via IL-23-mediated activation of the JAK/STAT pathway.