中空纳米结构在表界面化学能源存储中的应用

中空纳米结构因具有有效比表面积大、传输路径短、缓冲性能好等优势,在能源转换和存储领域受到人们的广泛关注,本综述详细总结了中空纳米结构材料在以超级电容器为代表的表界面化学能源存储领域的研究进展.首先介绍了表界面化学能源存储的机理和挑战;其次详细讨论了中空材料的微观结构参数对表界面化学能源存储装置性能的影响;然后系统概述了近年来研究者如何利用中空纳米结构解决表界面化学能源存储中的问题并优化电容器性能;最后,展望了中空纳米结构在表界面化学能源存储中面临的挑战和未来的发展方向.     

Application of Rhamnolipids as Dispersing Agents for the Fabrication of Composite MnO2-Carbon Nanotube Electrodes for Supercapacitors

The high theoretical capacitance of MnO₂ renders it a promising material for the cathodes of asymmetric supercapacitors. The good dispersion of MnO₂ and conductive additives in a nanocomposite electrode is a key factor for efficient electrode performance. This article describes, for the first time, the application of rhamnolipids (RL) as efficient natural biosurfactants for the fabrication of nanocomposite MnO₂-carbon nanotube electrodes for supercapacitors. RL act as co-dispersants for MnO₂ and carbon nanotubes and facilitate their efficient mixing, which allows for advanced capacitive properties at an active mass of 40 mg cm⁻² in Na₂SO₄ electrolytes. The highest capacitance obtained from the cyclic voltammetry data at a scan rate of 2 mV s⁻¹ is 8.10 F cm⁻² (202.6 F g⁻¹). The highest capacitance obtained from the galvanostatic charge–discharge data at a current density of 3 mA cm⁻² is 8.65 F cm⁻² (216.16 F g⁻¹). The obtained capacitances are higher than the capacitances of MnO₂-based electrodes of the same active mass reported in the literature. The approach developed in this investigation is simple compared to other techniques used for the fabrication of electrodes with high active mass. It offers advantages of using a biocompatible RL biosurfactant.     

Effect of Manganese Valence on Specific Capacitance in Supercapacitors of Manganese Oxide Microspheres

Manganese oxides have attracted great interest in electrochemical energy storage due to high theoretical specific capacitance and abundant valence states. The multiple valence states in the redox reactions are beneficial for enhancing the electrochemical properties. Herein, three manganese microspheres were prepared by a one-pot hydrothermal method and subsequent calcination at different temperatures using carbon spheres as templates. The trivalent manganese of Mn₂O₃ exhibited multiple redox transitions of Mn³⁺/Mn²⁺ and Mn⁴⁺/Mn³⁺ during the intercalation/deintercalation of electrolyte ions. The possible redox reactions of Mn₂O₃ were proposed based on the cyclic voltammetry and differential pulse voltammogram results. Mn₂O₃ microsphere integrated the advantages of multiple redox couples and unique structure, demonstrating a high specific capacitance and long cycling stability. The symmetric Mn₂O₃//Mn₂O₃ device yielded a maximum energy density of 29.3 Wh kg⁻¹ at 250 W kg⁻¹.     

Novel Two‐Dimensional Porous Materials for Electrochemical Energy Storage: A Minireview

Two dimensional (2D) porous materials have great potential in electrochemical energy conversion and storage. Over the past five years, our research group has focused on Simple, Mass, Homogeneous and Repeatable Synthesis of various 2D porous materials and their applications for electrochemical energy storage especially for supercapacitors (SCs). During the experimental process, through precisely controlling the experimental parameters, such as reaction species, molar ratio of different ions, concentration, pH value of reaction solution, heating temperature, and reaction time, we have successfully achieved the control of crystal structure, composition, crystallinity, morphology, and size of these 2D porous materials including transition metal oxides (TMOs), transition metal hydroxides (TMHOs), transition metal oxalates (TMOXs), transition metal coordination complexes (TMCCs) and carbon materials, as well as their derivatives and composites. We have also named some of them with CQU‐Chen (CQU is the initialism of Chongqing University, Chen is the last name of Lingyun Chen), such as CQU‐Chen‐Co?O‐1, CQU‐Chen‐Ni?O?H‐1, CQU‐Chen‐Zn?Co?O‐1, CQU‐Chen‐Zn?Co?O‐2, CQU‐Chen‐OA?Co‐2‐1, CQU‐Chen‐Co?OA‐1, CQU‐Chen‐Ni?OA‐1, CQU‐Chen‐Gly?Co‐3‐1, CQU‐Chen‐Gly?Ni‐2‐1, CQU‐Chen‐Gly?Co?Ni‐1, etc. The introduction of 2D porous materials as electrode materials for SCs improves the energy storage performances. These materials provide a large number of active sites for ion adsorption, supply plentiful channels for fast ion transport and boost electrical conductivity and facilitate electron transportation and ion penetration. The unique 2D porous structures review is mainly devoted to the introduction of our contribution in the 2D porous nanostructured materials for SC. Finally, the further directions about the preparation of 2D porous materials and electrochemical energy conversion and storage applications are also included.     

Recovery of Gallium-68 and Zinc from HNO3-Based Solution by Liquid–Liquid Extraction with Arylamino Phosphonates

The cyclotron production of gallium-68 via the ⁶⁸Zn(p,n)⁶⁸Ga nuclear reaction in liquid targets is gaining significant traction in clinics. This work describes (1) the synthesis of new arylamino phosphonates via the Kabachnik–Fields reaction, (2) their use for liquid–liquid extraction of ⁶⁸Ga from 1 M Zn(NO₃)₂/0.01 M HNO₃ in batch and continuous flow, and (3) the use of Raman spectroscopy as a process analytical technology (PAT) tool for in-line measurement of ⁶⁸Zn. The highest extraction efficiencies were obtained with the extractants functionalized with trifluoromethyl substituents and ethylene glycol ponytails, which were able to extract up to 90% of gallium-68 in batch and 80% in flow. Only ppm amounts of zinc were co-extracted. The extraction efficiency was a function of pKa and the aqueous solubility of the extractant and showed marked concentration, solvent, and temperature dependence. Raman spectroscopy was found to be a promising PAT tool for the continuous production of gallium-68.     

Our Contributions in Nanochemistry for Antibiosis,Electrocatalyst and Energy Storage Materials

This account mainly introduces and reviews our recent progress in three projects: antibacterial nanomaterial, electrocatalyst for detecting and electrode nanomaterial of energy storage device, especially the supercapacitor. Besides, our thought and idea about the design, fabrication and application of corresponding nanomaterials are sketched throughout the whole article in order to reveal the structure‐function relationship and corresponding mechanism. In the end, we tend to attach importance to the bottleneck of nanomaterial's development and put forward our understanding in this field.     

铅炭电池负极炭材料的作用机制研究进展

传统铅酸电池主要应用于汽车及各种内燃机的起动和无线通信基站,但其在部分荷电态下负极易硫酸盐化而失效,降低了电池的受充能力及循环寿命. 铅炭电池是将高比表面、高导电的炭材料掺入铅负极的新型铅酸电池,具有优异的高倍率充放电性能及较高的部分荷电态下的循环寿命,在储能与混合动力车方面有很好的应用前景. 近年来国内外竞相开展了炭材料作用机制的研究,本文从构建导电网络、增加双电层电容储能、改善孔洞结构以及提高电化学反应动力等方面对炭材料在铅炭电池上的作用机制进行阐述,并结合作者课题组在铅炭电池领域的研发工作进行展望.     

Selective Solid–Liquid and Liquid–Liquid Extraction of Lithium Chloride Using Strapped Calix[4]pyrroles

LiCl is a classic “hard” ion salt that is present in lithium‐rich brines and a key component in end‐of‐life materials (that is, used lithium‐ion batteries). Its isolation and purification from like salts is a recognized challenge with potential strategic and economic implications. Herein, we describe two ditopic calix[4]pyrrole‐based ion‐pair receptors ( 2 and 3 ), that are capable of selectively capturing LiCl. Under solid–liquid extraction conditions, using 2 as the extractant, LiCl could be separated from a NaCl/KCl salt mixture containing as little as 1 % LiCl with circa 100 % selectivity, while receptor 3 achieved similar separations when the LiCl level was as low as 200 ppm. Under liquid–liquid extraction conditions using nitrobenzene as the non‐aqueous phase, the extraction preference displayed by 2 is KCl>NaCl>LiCl. In contrast, 3 exhibits high selectivity towards LiCl over NaCl and KCl, with no appreciable extraction being observed for the latter two salts.     

Stable Carbon Isotope Analysis of Hexachlorocyclohexanes by Liquid–Liquid Extraction Gas Chromatography Isotope Ratio Mass Spectrometry: Method Evaluation and Applications

Compound specific isotope analysis (CSIA) and enantiomer specific isotope analysis (ESIA) are powerful tools for assessing the fate of hexachlorocyclohexanes (HCHs) in the environment. However, there is no systematic study on the CSIA and ESIA analysis test methods of the carbon isotopes of HCHs in water and soil environments, in particular the isotope fractionation in the pre-concentration process. We endeavored to test the compatibility of CSIA and ESIA with the liquid–liquid extraction method of HCHs in water. The results showed that there were negligible changes in the δ¹³C of HCHs after extraction, indicating that liquid–liquid extraction can be used as a pre-concentration method for the determination of δ¹³C of HCHs in water. The optimized method was validated and then applied to differentiate three HCHs from different manufacturers, to identify in situ degradation of HCHs of groundwater from a contaminated site and to resolve the carbon isotope fractionation occurring in the α-HCH oxidation by CaO₂/Fe(II) Fenton system. The results showed that the same reagents from different manufacturers have different carbon isotope compositions, and different isomers from the same manufacturer also have different isotope compositions, showing useful evidence in identifying the source of HCHs. The more enriched δ¹³C in the down-gradient wells indicated that HCHs have undergone biodegradation or/and chemical reactions in the groundwater system of the site. Carbon isotopic enrichment factors (ε_C) of −1.90 ± 0.10‰ were obtained in the oxidation process. Hence, the method validated in this study has great potential as a method for identifying the degradation of HCHs in a water environment.     

石墨烯/聚3，4-乙烯二氧噻吩复合物的电化学制备及其在超级电容器中的应用

首次提出了一种在离子液体中在石墨烯表面用恒电流法聚合3,4-乙烯二氧噻吩(EDOT)单体制备石墨烯/聚3,4-乙烯二氧噻吩(石墨烯/PEDOT)复合物的方法。用原子力显微镜、扫描电镜等技术表征证明石墨烯/PEDOT复合物是由PEDOT纳米谷粒状颗粒分散在石墨烯片表面而组成的。将该复合物用作超级电容器电极材料时,在1.0 A.g-1的充放电比电流下得到的比电容值为181 F.g-1。同时,该材料还显现出较好的充放电可逆性和稳定性。     

Application of a Low Transition Temperature Mixture for the Dispersive Liquid–Liquid Microextraction of Illicit Drugs from Urine Samples

The use of psychoactive substances is a serious problem in today’s society and reliable methods of analysis are necessary to confirm their occurrence in biological matrices. In this work, a green sample preparation technique prior to HPLC-MS analysis was successfully applied to the extraction of 14 illicit drugs from urine samples. The isolation procedure was a dispersive liquid–liquid microextraction based on the use of a low transition temperature mixture (LTTM), composed of choline chloride and sesamol in a molar ratio 1:3 as the extracting solvent. This mixture was classified as LTTM after a thorough investigation carried out by FTIR and DSC, which recorded a glass transition temperature at −71 °C. The extraction procedure was optimized and validated according to the main Food and Drug Administration (FDA) guidelines for bioanalytical methods, obtaining good figures of merit for all parameters: the estimated lower limit of quantitation (LLOQ) values were between 0.01 µg L⁻¹ (bk-MMBDB) and 0.37 µg L⁻¹ (PMA); recoveries, evaluated at very low spike levels (in the ng-µg L⁻¹ range), spanned from 55% (MBDB) to 100% (bk-MMBDB and MDPV); finally, both within-run and between-run precisions were lower than 20% (LLOQ) and 15% (10xLLOQ).     

Layered Al‐substituted Cobalt Hydroxides/GO Composites for Electrode Materials of Supercapacitors

In this work, Al‐substituted α‐Co(OH)₂/GO composites with supercapacitive properties were prepared by chemical co‐precipitated method in which cobalt nitrate and aluminum nitrate were used as the raw material, and graphite oxide was employed as carrier. The as‐prepared materials were characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and fourier transform infrared spectroscopy (FT‐IR). Cyclic voltammetry (CV) and galvanostatic charge/discharge measurements showed that the Al‐substituted α‐Co(OH)₂/GO electrode material had excellent electrochemical capacitance. The specific capacitance of 1137 F·g⁻¹ was achieved in 6 mol/L KOH solution at a current density of 1 A·g⁻¹ within a potential range of 0–0.5 V. Moreover, only 12% losses of the initial specific capacitance were found after 500 cycles at a current density of 1 A·g⁻¹.     

Miniaturized Salting-Out Assisted Liquid-Liquid Extraction Combined with Disposable Pipette Extraction for Fast Sample Preparation of Neonicotinoid Pesticides in Bee Pollen

As the main source of nutrients for the important pollinator honeybee, bee pollen is crucial for the health of the honeybee and the agro-ecosystem. In the present study, a new sample preparation procedure has been developed for the determination of neonicotinoid pesticides in bee pollen. The neonicotinoid pesticides were extracted using miniaturized salting-out assisted liquid-liquid extraction (mini-SALLE), followed by disposable pipette extraction (DPX) for the clean-up of analytes. Effects of DPX parameters on the clean-up performance were systematically investigated, including sorbent types (PSA, C18, and silica gel), mass of sorbent, loading modes, and elution conditions. In addition, the clean-up effect of classical dispersive solid-phase extraction (d-SPE) was compared with that of the DPX method. Results indicated that PSA-based DPX showed excellent clean-up ability for the high performance liquid chromatography (HPLC) analysis of neonicotinoid pesticides in bee pollen. The proposed DPX method was fully validated and demonstrated to provide the advantage of simple and rapid clean-up with low consumption of solvent. This is the first report of DPX method applied in bee pollen matrix, and would be valuable for the development of a fast sample preparation method for this challenging and important matrix.     

液膜萃取技术在环境样品前处理中的应用

膜分离技术是利用膜对混合物中各组分的选择渗透性能的差异来实现分离、提纯和浓缩的新型分离技术。近年来,随着人们环保意识的加强,环境中污染物的监测逐渐被重视。因环境样品基体的复杂性,在分析测定前必须进行净化处理。将膜分离技术与液液萃取技术相结合的液膜萃取技术因其     

盐析辅助均相液液萃取/分散固相萃取-超高效液相色谱串联质谱法测定蜂蜜中新烟碱类农药残留

以盐析辅助均相液液萃取结合分散固相萃取作为前处理方法,建立了超高效液相色谱串联质谱快速检测蜂蜜中吡虫啉、噻虫嗪、噻虫胺、噻虫啉、啶虫脒及氯噻啉6种新烟碱类农药残留的分析方法。样品用乙腈提取,氯化钠盐析分层,提取液经分散固相萃取法净化,采用超高效液相色谱串联质谱检测器进行分析。考察了萃取剂种类、体积及氯化钠质量对萃取效率的影响,评估了在优化实验条件下的基质效应和方法性能。结果表明:除吡虫啉外,其余5种新烟碱类农药的基质效应均大于10%。6种新烟碱类农药在0.2~100μg/L范围内线性关系良好,相关系数(r2)为0.998 1~0.999 7。加标浓度为1.0~50.0μg/kg时,6种新烟碱类农药的加标回收率为77.0%~106%,相对标准偏差为2.4%~19.8%。方法的检出限为0.2~0.4μg/kg,定量下限为1.0μg/kg。该方法前处理简单,分析时间短,准确度和灵敏度高,重现性好,适用于蜂蜜中6种新烟碱类农药微量残留的快速测定。     

氮掺杂石墨烯的制备及其在化学储能中的研究进展

石墨烯独特的二维空间结构使其具有优异的导电性能、力学性能以及超大的比表面积,被认为是颇具潜力的新型储能材料,是目前储能研究的热点之一。 但是石墨烯易团聚、表面光滑且呈惰性而不利于与其它材料的复合,导致其应用受到限制。 石墨烯掺氮可改变其电子结构,增加表面的活性位,从而提高其应用于储能器件时的电化学性能。 本文综述了近几年氮掺杂石墨烯的制备方法以及其在超级电容器、锂离子电池、锂空电池以及锂硫电池等化学储能领域中的应用,指出了目前氮掺杂石墨烯在制备和储能应用中关注的核心问题,并对氮掺杂石墨烯的发展前景进行了展望。     

CVD 法制备三维石墨烯的电化学储能性能

维石墨烯是由二维石墨烯构成的三维网络结构,多孔的网络结构赋予了三维石墨烯超大的比表面积、超高的机械强度以及优异的电子传输通道. 因其优异的性能,三维石墨烯及其复合材料已经广泛地应用于能源、化学和生物等研究领域. 在三维石墨烯的合成方法中,化学气相沉积法由于制备的三维石墨烯具有高纯度、良好结晶性和优异的机械性能而备受推崇. 本文结合当前研究热点,综述了化学气相沉积法制备三维石墨烯及其复合材料在电化学储能领域（铝电池、锂离子电池、锂-硫电池、钠离子电池、金属-空气电池、超级电容器）中的应用,并简要评述当前化学气相沉积法制备三维石墨烯在应用中所面临的挑战及发展前景.     

Controllable Synthesis of Mesoporous Co3O4 Nanostructures with Tunable Morphology for Application in Supercapacitors

Flower power : Various mesoporous Co₃O₄ architectural structures (see figure) have been successfully prepared through a facile binary‐solution route and sequential thermal decomposition at atmospheric pressure. The electrochemical experiments showed that the specific capacitance of Co₃O₄ nanosheets was higher than that of Co₃O₄ microspheres in a KOH electrolyte.

     

Simultaneous Dispersive Liquid–Liquid Microextraction and Determination of Different Polycyclic Aromatic Hydrocarbons in Surface Water

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants of water, and their determination at trace levels in the aquatic ecosystems is essential. In this work, an ultrasound-assisted dispersive liquid–liquid microextraction (DLLME) procedure was suggested utilizing a binary dispersive agent for recovery of different molecular weight polycyclic aromatic hydrocarbons (PAHs) from waters. The detection was carried out by gas chromatography–mass spectrometry (GC-MS) as well as high-performance liquid chromatography with fluorescence and diode-array detection (HPLC-FD/PDA). The method was optimized for the extraction of analytes with respect to the mixture composition, ratios of components, ultrasonication time and centrifugation parameters. The analytical schemes for PAHs extraction from water samples using different ratios of extraction and dispersive solvents are reported. The mixture consisting of chloroform and methanol was applied for the extraction of PAHs containing two or three fused aromatic rings; the mixture of chloroform and acetonitrile is suitable for PAHs containing more than four aromatic rings. The mixture of chloroform:acetone + acetonitrile was applied in the universal scheme and allowed for the simultaneous extraction of 20 PAHs with different structures. The developed sample preparation schemes were combined with GC-MS and HPLC-FD/PDA, which allowed us to determine the analytes at low concentrations (from 0.0002 µg/L) with the recoveries exceeding 80% and relative standard deviations of about 8%. The developed methods for the determination of 20 PAHs were applied to the analysis of water samples from the Karasun Lake (Krasnodar), Azov Sea (Temryuk) and Black Sea (Sochi).