静电纺丝纳米纤维基超级电容器电极材料的研究进展

静电纺丝纳米纤维具有比表面积大、孔隙率高及密度低等优势,是电化学储能材料的理想候选者之一.本文综述了近年来静电纺丝碳纳米纤维、金属氧化物/硫化物/氮化物、导电聚合物及其复合材料在超级电容器领域的研究及应用进展,探讨了材料组成、结构与电化学电容性能之间的关系,并对静电纺丝纳米纤维基电极材料的发展前景进行了展望.这将为新型高性能超级电容器电极材料的结构设计与可控制备提供新思路.     

静电纺纳米纤维基超级电容器无粘合剂电极材料的研究进展

对高性能超级电容器不断增长的需求促进了无粘合剂电极材料的快速发展。静电纺纳米纤维由于具有良好的柔性、大比表面积、高孔隙率、容易制备等优点引起了研究者们的强烈关注。本文综述了静电纺纳米纤维基无粘合剂电极材料在超级电容器领域的研究进展,阐述了不同材料的设计制备过程和提升电化学性能的诸多方法,并指明了静电纺纳米纤维基超级电容器无粘合剂电极材料的发展机遇与挑战,为性能优异的无粘合剂超级电容器电极材料的进一步开发与应用拓宽了思路。     

静电纺丝技术在新能源电池中应用的研究进展

简要介绍了五种新能源电池和静电纺丝技术,综述了静电纺丝技术用于锂电池的正负极材料和燃料电池电极材料的现状,以及应用静电纺丝技术制备电极隔膜材料。静电纺丝制备纳米纤维具有直径小、比表面积大、孔隙率高等特点,用于正负电极和隔膜材料将大大提高电池的比容量、充放电速率和充放电电流,从而提高电池的蓄电能力、循环性能、离子导电性、力学稳定性和化学稳定性。最后总结了静电纺丝技术产业化需要解决的问题,并展望了在新能源电池中的进一步应用。     

静电纺丝技术在锂离子动力电池中的应用

锂离子动力电池,作为动力源,要求其具有较高的比容量、倍率性能、热稳定性及优异的循环性能。静电纺丝技术是一种新型纳米纤维制备技术,因其制备的纳米纤维膜具有比表面积大和孔隙率高等特点,近年来在锂离子电池领域得到了广泛应用,有望成为大幅改善锂离子动力电池性能的关键技术。基于锂离子动力电池的特性,当前静电纺丝技术主要用于制备高孔隙率的纳米纤维膜、高分子共混膜及无机-高分子复合膜等隔膜材料以提高隔膜的机械性能和热稳定性;此外,静电纺丝技术还被用于改善磷酸铁锂等聚阴离子型正极材料及石墨负极材料的电化学性能。本文还针对上述研究中存在的问题,提出了未来静电纺丝技术在锂离子动力电池中应用的可改进的研究方案。     

静电纺丝制备石墨烯基复合纳米纤维研究进展

在静电纺丝纳米纤维中加入纳米填料——石墨烯(G),有助于提高纳米纤维的性能,扩展其应用领域。本文综述了近年来国内外静电纺丝制备石墨烯基复合纳米纤维的研究现状,重点介绍了石墨烯与聚酰胺(PA)、聚甲基丙烯酸甲酯(PMMA)、聚丙烯腈(PAN)、二氧化钛(TiO2)等复合纳米纤维制备的研究进展及其在光催化剂、超级电容器、染料敏化太阳能电池(DSSCs)、传感器、生物医学等方面的应用潜力,展望了石墨烯基复合纳米纤维的发展前景。     

静电纺丝技术在二次电池和电催化领域的应用进展

静电纺丝技术是一种简单、高效制备一维纳米纤维的方法,其制备的纳米纤维一般经过后期热处理得到含碳复合物,具有操作简单、方法可控、产量可观等优点,得到的材料具有良好的导电性和快速的电子、离子传输路径,因此可用来广泛制备电极及催化材料.基于此,静电纺丝技术在二次电池(如锂/钠离子电池)和电催化领域有着广泛的应用.本综述不仅介绍了静电纺丝技术的原理,并且总结了其在纳米电极材料及催化领域的优势和标志性成果,并针对相关领域的问题进行了合理的探讨.此外,本文简要总结了现有的发展进程并指出了未来的发展方向,可对静电纺丝技术在先进能源材料的设计与制备上提供指导.     

超级电容器炭电极材料的研究

炭电极材料是超级电容器的核心,该领域的研究近年来相当活跃,活性炭粉、活性炭纤维、碳凝胶、碳纳米管、玻态炭、模板炭、碳化物衍生炭、石墨烯等各种多孔炭材料用作超级电容器电极材料的研究都有报道.本文概述了我们近年来在超级电容器炭电极材料方面的研究工作,主要介绍了强碱化学活化制备活性炭电极材料、纳米CaCO3模板法制备介孔炭电...     

静电纺丝制备碳纳米管基复合纳米纤维的研究进展

碳纳米管(CNTs)作为增强材料与聚合物复合制成纳米纤维,有助于提高纳米纤维性能,扩展其应用领域。本文综述了近年来国内外静电纺丝制备CNTs基复合纳米纤维的研究现状,重点介绍了CNTs/PAN复合纳米纤维、CNTs/PANI/PEO复合纳米纤维、CNTs/PVA复合纳米纤维、CNTs/PA复合纳米纤维、CNTs/TiO2复合纳米纤维的研究进展及其在纳米传感器、电磁干扰、超级电容器、染料敏化太阳能电池(DSSCs)、组织工程支架、药物控制释放等方面的应用潜力,展望了CNTs基复合纳米纤维的发展前景。     

双钙钛矿La2CoNiO6无机纳米纤维的制备及超级电容器性能

以聚乙烯吡咯烷酮/硝酸镧-乙酸钴-乙酸镍(PVP/LCN)为前驱体, 采用静电纺丝法, 经预氧化、碳化, 制得双钙钛矿La₂CoNiO₆无机纳米纤维超级电容器电极材料. 利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)对其形貌和结构进行表征. 结果表明, 纤维由菱形结构的La₂CoNiO₆纳米颗粒相互连接而成, 呈链状空间网状结构. 循环伏安(CV)、恒流充放电(CP)和循环寿命测试表明, La₂CoNiO₆纳米纤维电极材料在三电极体系中, 电流密度为0.25 A·g^-1时, 比电容值达335.0 F·g^-1; 在对称型双电极体系中, 电流密度为0.25 A·g^-1时, 比电容值可达到129.1 F·g^-1,表现出良好的电容性能.     

二维纳米片层孔洞化策略及组装材料在超级电容器中的应用

功率密度高、倍率性能优异和循环性能好等特性使得超级电容器在储能领域显示了巨大的应用前景。尽管二维层状材料剥离形成的纳米片层不仅可为电化学反应提供独特的纳米级反应空间,而且由其组装的层状纳米电极材料具有化学和结构上的氧化还原可逆性及纳米片层水平方向上离子或电子快速传输通道。但是,纳米片层组装电极材料在纳米片层垂直方向上离子或电子传输存在障碍,对于超级电容器功率密度和能量密度的提高及实现快速能量储存非常不利。因此,如何通过改善离子或电子的快速传输,实现超级电容器大功率密度下的高能量密度是超级电容器电极材料发展的方向之一。本文主要综述了二维层状材料剥离成纳米片层,纳米片层孔洞化策略及组装孔洞化材料在超级电容器电极材料中的应用。纳米层孔洞化技术是改善层状电极材料在纳米片层垂直方向离子或电子传输的有效手段,为实现高比电容下的高倍率性能超级电容器电极材料制备提供了方法学。最后,对开发大功率密度下的高能量密度超级电容器电极材料提出了展望。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.