三维还原氧化石墨烯/聚苯胺复合材料的制备及其超级电容性能

以制备的氧化石墨凝胶和聚苯胺纳米线为原料, 将二者按一定的质量比进行混合超声分散, 再以混合分散液为前驱体采用一步水热法制备得到三维还原氧化石墨烯(RGO)/聚苯胺(PANI) (RGP)复合材料, 采用扫描电镜(SEM), 透射电镜(TEM), X射线衍射(XRD), 傅里叶变换红外(FT-IR)光谱, X射线光电子能谱(XPS)和电化学测试等分析研究了复合材料的形貌、结构和超级电容性能. 结果表明, 复合材料既保持了还原氧化石墨烯的基本形貌, 又能使聚苯胺较好地镶嵌在还原氧化石墨烯的网状结构中; 且当氧化石墨与聚苯胺的质量比为1:1时复合材料在0.5 A·g^-1电流密度下比电容可高达758 F·g^-1, 即使在大电流密度(30 A·g^-1)下其比容量仍高达400 F·g^-1,在1A·g^-1电流密度下循环1000次后比容量保持率为86%, 表现出了良好的倍率性能和循环稳定性, 其超级电容性能远优于单纯的还原氧化石墨烯和聚苯胺, 其优异的超级电容性能可归咎于二者的相互协同作用.     

氮掺杂部分石墨化碳/钴铁氧化物复合材料的制备及电化学性能

以甲壳胺（CTS）和钴、铁盐作有机前体与反应物,采用共沉淀法制备了CTS/钴铁层状双金属氢氧化物复合物.样品经过氩气氛、空气氛煅烧,生成氮掺杂部分石墨化碳/钴铁氧化物复合材料（N-PGC/CoFe-TMOs）.CTS热解且被过渡金属催化生成部分石墨化碳,同时原位氮掺杂,氮/碳原子比例约为1/18.N-PGC/CoFe-TMOs具有大孔和介孔结构,用作超级电容器电极材料兼有双电层电容与赝电容特征.在2 A·g^-1电流密度下,复合物比电容达到671.1 F·g^-1,远大于纯钴铁氧化物比电容283.3 F·g^-1,复合物具有典型的协同效应.电流密度增加到10 A·g^-1时,N-PGC/CoFe-TMOs比电容为573.3 F·g^-1,经过5000次充放电循环,复合物比电容保留率为66.4%.制备方法简便、通用,煅烧过程可一步制备氮掺杂的部分石墨化碳并与过渡金属氧化物复合,产物电化学性能优异.     

氢氧化镍纳米线/三维石墨烯复合材料的制备及其电化学性能

采用水热法制备了氢氧化镍纳米线/三维石墨烯复合材料及作为比较的三维石墨烯、氢氧化镍纳米线、还原氧化石墨烯和氢氧化镍纳米线/还原氧化石墨烯, 通过X射线衍射、扫描电镜、热失重分析和氮气吸脱附表征了材料的形貌、结构和组成, 并采用循环伏安法和恒电流充放电测试了复合材料的电化学性能. 结果表明: 氢氧化镍纳米线/三维石墨烯复合材料中直径为20-30 nm的氢氧化镍纳米线和三维结构的石墨烯紧密结合, 相互交联形成网状结构, 其比表面积达到136 m²·g^-1, 孔径分布20-50 nm, 氢氧化镍纳米线的含量达到88% (w,质量分数). 在6 mol·L^-1的KOH电解液中, 复合材料的比电容在1 A·g^-1电流密度下达到1664 F·g^-1, 在1 A·g^-1电流密度下循环3000 次后的比电容保持率为93%. 将复合材料的比电容和循环性能与氢氧化镍纳米线、氢氧化镍纳米线/还原氧化石墨烯、三维石墨烯和还原氧化石墨烯的性能进行比较, 发现三维石墨烯较还原氧化石墨烯具有更高的比表面积和三维多孔结构, 可以更大地提高活性物质的利用率, 进而提高复合材料的比电容和稳定性.     

石墨烯/钴镍双金属氢氧化物复合材料的制备及电化学性能研究

采用微波辐射与高温裂解相结合的二步还原法制备石墨烯。二步还原使氧化石墨被充分还原和剥离,所得到的石墨烯有较好的传导性,其比表面达675.4 m2.g-1。以此石墨烯为原料,水热法合成出石墨烯/钴镍双金属氢氧化物复合材料,并考察了复合材料作为超级电容电极材料的电化学性能。研究发现,褶皱的石墨烯纳米片均匀分散在钴镍双金属氢氧化物中,这改善了钴镍双金属氢氧化物的传导性和结构稳定性。在0.25 A.g-1电流密度下,复合材料的比电容量是800.2 F.g-1。当电流密度增加至10 A.g-1,比电容量为386.5 F.g-1,恒电流充-放电500次后比电容量仍能保持99%以上,这些呈示该复合材料具有优良的电化学性能。     

阳极氧化/GCD新工艺法制备镍基超级电容器薄膜电极

采用磷酸阳极氧化法在金属镍表面形成阳极氧化复合膜,在1 mol·L^-1氢氧化钾溶液中进行大电流密度恒流充放电(GCD)处理, 使基体表面形成一层多孔纳米花瓣状膜. 采用扫描电镜(SEM), X射线光电子能谱(XPS), X射线衍射(XRD)仪, 对膜的形貌、组成和结构进行了表征, 使用电化学工作站、电池寿命测试仪对该膜的电容特性进行了测试. 结果表明, 所制氧化膜由三维多孔纳米花瓣状的NiO、α-Ni(OH)₂和β-Ni(OH)₂构成, 该膜具有优异的电容特性, 其在电流密度为6.7 A·g^-1时,比电容量达1509 F·g^-1, 而当电流密度为66.7 A·g^-1时,比电容量为1120 F·g^-1 (为6.7A·g^-1时的74%).在电流密度为66.7 A·g^-1时, 经过2000次循环测试后比电容量基本保持不变.     

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.     

Mn3O4/石墨烯复合材料的制备与电化学性能研究

本文以氧化石墨烯（GO）溶液为氧化剂,采用水热法使GO直接氧化Mn(Ac)₂制备Mn₃O₄/石墨烯复合材料,并通过在制备过程中加入氨水提高了复合材料中GO的还原程度与Mn₃O₄颗粒的分散性. 制得的Mn₃O₄/石墨烯复合材料表现出优异的电化学性能. 在0.5 A·g^-1的电流密度下复合材料质量比容量可达到850 mAh·g^-1,0.5 A·g^-1时充放电循环测试200周容量保持率为99%.     

硫化镍/三维网络石墨烯复合材料制备及其在高性能超级电容器的应用研究

本文在泡沫镍上生长三维网络状结构的石墨烯（3DG）,以此为模板合成石墨烯复合电极并将其应用于超级电容器. 采用一步水热法在3DG上合成得到Ni₃S₂纳米棒结构（Ni₃S₂/3DG）. 通过TEM、XRD、SEM和拉曼光谱等手段表征对Ni₃S₂/3DG复合材料的形态与结构进行表征. 电化学测试表明,Ni₃S₂/3DG复合材料具有高的比电容（在扫速为5 mV·s^-1下,具有1825.3 F·g^-1的比容量）和放电电容（在电流密度10 mA下电容高达516.7 F·g^-1）. 此外,在电流密度20 mA下具有良好的循环性能（循环1000周后仍能保留约100%的初始电容）. 本工作为得到高能量密度和良好的长期稳定性的复合材料提供了参考.     

钴铝双金属氢氧化物的制备及电化学性能研究

选用三种不同的结构导向剂,以硝酸钴(Co(NO₃)₂·6H₂O)为钴源、硝酸铝(Al(NO₃)₃·9H₂O)为铝源,通过简单的水热法制备了钴铝双金属氢氧化物,并对制备的双金属氢氧化物的形貌结构及其电化学性能进行表征,以分析研究结构导向剂种类对所得材料形貌结构及其电化学性能的影响。结果表明：不同的结构导向剂不仅影响着双金属氢氧化物的形貌结构,而且对其电化学性能也有一定的影响,其中以氟化铵(NH₄F)为结构导向剂时合成的钴铝双金属氢氧化物具有三维花朵状结构和优异的电化学性能,在电流密度为0.5 A·g^-1下,其比电容为572.2 F·g^-1,在4.0 A·g^-1电流密度下,进行500次充放电循环后电容保持率达84.9%,说明其具有良好的循环稳定性。     

离子液体辅助条件下由稻壳合成超级电容器用多孔炭

本文以稻壳为碳源,以离子液体1-丁基-3-甲基咪唑六氟磷酸盐(BMIMPF₆)为模板和辅助活化剂制备了多孔炭材料（PCs）. 多孔炭的比表面积达1438 m²·g^-1,总孔容达0.75 cm³·g^-1. 以PCs为超级电容器电极材料,6 mol·L^-1的KOH溶液为电解液组装成扣式电池,在0.05 A·g^-1的电流密度下,比电容高达256 F·g^-1;当电流密度增大至10 A·g^-1,其比电容仍保持在211 F·g^-1,展现出好的倍率性能. 所得的多孔炭电极均表现出优异的循环稳定性. 这一工作以BMIMPF₆作为模板和辅助活化剂,为合成生物质基超级电容器用多孔炭提供了一种新方法.     

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%.     

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.     

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.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.