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1.
以冷冻干燥获得的多孔胡萝卜为炭源,经过600℃氮气氛围下炭化和KOH活化,获得了多孔结构的炭材料。采用红外光谱、X-射线粉末衍射、扫描电镜、透射电镜、循环伏安、恒流充放电和交流阻抗对多孔炭进行了微结构和电容性能研究。结果表明:通过活化处理,多孔炭的比表面积从7m2·g-1大幅提高到147m2·g-1。而且,活化后的多孔炭产生了414F·g-1的最大比电容,且电流增至4A·g-1时的电容保持率为74.5%。而未活化的多孔炭最大电容为253F·g-1,电容保持率仅为45.1%。此外,活化后的多孔炭还具有优异的电化学稳定性。在5A·g-1电流下循环8000圈后,其电容保持率高达94%。活化后的多孔炭在电容性能方面的极大改善与其比表面积的大幅提高及介孔的增多有密切关系。  相似文献   

2.
以冷冻干燥获得的多孔胡萝卜为炭源,经过600℃氮气氛围下炭化和KOH活化,获得了多孔结构的炭材料。采用红外光谱、X-射线粉末衍射、扫描电镜、透射电镜、循环伏安、恒流充放电和交流阻抗对多孔炭进行了微结构和电容性能研究。结果表明:通过活化处理,多孔炭的比表面积从7 m2·g-1大幅提高到147 m2·g-1。而且,活化后的多孔炭产生了414 F·g-1的最大比电容,且电流增至4 A·g-1时的电容保持率为74.5%。而未活化的多孔炭最大电容为253 F·g-1,电容保持率仅为45.1%。此外,活化后的多孔炭还具有优异的电化学稳定性。在5 A·g-1电流下循环8 000圈后,其电容保持率高达94%。活化后的多孔炭在电容性能方面的极大改善与其比表面积的大幅提高及介孔的增多有密切关系。  相似文献   

3.
以工业制糖的副产物糖蜜为新型碳源,替代传统多孔碳生产原料,制备出性能优异的多孔碳球超级电容器电极材料;探索了制备方法,优化了反应条件.利用全功能表面吸附仪、扫描电子显微镜及电化学方法对材料的结构、形貌和电化学性能进行了表征.结果表明,制得的多孔碳球比表面积高达2547 m~2/g,且展现出优异的双电层电容性(170.5 F/g).本研究可解决制糖企业对糖蜜无法大规模利用的问题,并为多孔碳的制备寻求新方法.  相似文献   

4.
基于羧甲基纤维素钠制备氮掺杂多孔炭及其电容性能研究   总被引:3,自引:0,他引:3  
以羧甲基纤维素钠(NaCMC)为碳源, 利用直接炭化工艺(无需进一步活化)制备多孔炭材料; 然后, 以CO(NH2)2为氮源, 形成了氮掺杂多孔炭材料. 氮的存在形式包括吡啶N、石墨N和吡咯N. 实验结果表明, 羧甲基纤维素钠与CO(NH2)2之间的配比可以有效控制氮存在形式、含量、样品的比表面积及孔的结构等. 样品的电化学性能测试表明, 氮掺杂后多孔炭材料的超电容性能得到了显著提升. 以carbon-N-1:20为例, 其比表面积可达858 m2·g-1, 远高于未经氮掺杂carbon-blank 的463 m2·g-1, 其质量比电容则由94.0 F·g-1提高到了156.7F·g-1.  相似文献   

5.
以廉价的椰壳为原料制备了高比表面积的多孔碳材料,然后在密闭的反应釜中以硝酸蒸汽对多孔碳材料进行了后处理,制备了亲水性更好的多孔碳材料。采用扫描透射电子显微镜(TEM)、物理吸附、X射线粉末衍射(XRD)、拉曼光谱(Raman)和接触角测试对材料的微观形貌、孔道结构、组成和亲水性进行了表征,探究了不同温度下硝酸蒸汽对多孔碳材料的形貌、结构的影响,并采用循环伏安法、恒电流充放电法和交流阻抗法考察了多孔碳材料的超级电容性能。结果表明,经过硝酸蒸汽处理后的多孔碳材料的比表面积和孔体积均有所降低,且随着处理温度的升高,降低得更加明显,而亲水性却越来越好。电化学测试结果表明,经过100℃硝酸蒸汽处理的多孔碳材料(CSC-100)具有最佳的超级电容性能。在以6 mol·L-1 KOH为电解液的三电极体系中,当电流密度为0.5 A·g-1时CSC-100的比电容可达452.9 F·g-1,而未经硝酸蒸汽处理的多孔碳材料(CSC)的比电容仅为350.4 F·g-1。电容贡献分析表明CSC-100良好的亲水性和表面官能团不仅提高了双电层电容,也提高了赝电容。  相似文献   

6.
以壳聚糖为原料在 600、700、800和900℃直接炭化制备多孔炭 C-600,C-700, C-800 和C-900,其BET比表面积分别为278、461、515和625 m2·g-1.用恒流充放电和循环伏安法表征了其电化学性能. 结果表明, 由 C-800 制备电极的循环伏安图形更接近矩形, 在恒电流充放电实验中阴极和阳极过程基本对称, 说明该电极具有较好的电容性能.在 50 mA·g-1 的电流密度下,C-600、C-700、C-800和C-900的电容分别为96、120、154 和 28 F·g-1.由 C-800 制备电极的循环充放电稳定性好, 电流密度为1 A·g-1循环1000次后电容损失小于2%,说明壳聚糖制备多孔碳具有作为超级电容器电极材料的潜在价值. 同时还考察了不同浓度的电解液对C-800电化学性质的影响,发现在KOH浓度为 30%时的电容最大.依据实验结果,对多孔炭制备及其电化学性质间的关系进行了探讨.  相似文献   

7.
在加热条件下采用氢化硅烷化反应对多孔硅表面进行改性, 通过扫描电子显微镜、 红外光谱及元素分析等手段表征了多孔硅改性前后的结构和组成, 研究了不同反应时间对其性能的影响. 结果表明, 反应3 h后制得了超疏水表面的多孔硅, 其在碱性及空气环境中具有良好的稳定性.  相似文献   

8.
一种新型氧化还原电解液电化学电容器体系   总被引:1,自引:0,他引:1  
以含有Fe3+/Fe2+离子对的H2SO4溶液为电解液, 以多孔炭做电极材料, 就Fe3+/Fe2+离子对在多孔炭纳米孔隙中的电化学行为及准电容效应进行了探讨. 循环伏安测试结果表明, Fe3+/Fe2+离子对在多孔炭电极纳米孔隙中发生了可逆的电化学反应. 恒流充放电结果发现, 加入Fe3+/Fe2+使得充放曲线出现对称的充放电平台, 有效地提高了电化学电容器(EC)的电能存储容量, 其单电极比电容最高达174 mAh•g−1, 比单纯的H2SO4电解液的比电容高109 mAh•g−1, 且有着良好的循环稳定性. 根据实验现象及结果, 探讨了Fe3+/Fe2+离子对在EC电极上的充放电机理, 并提出了一种新的概念——氧化还原电解液电化学电容器.  相似文献   

9.
氧化钌/活性炭超电容器复合电极的电化学行为   总被引:19,自引:4,他引:15  
电化学超电容器作为一种新一代储能系统具有广泛的应用领域. 直流充放电、循环伏安以及交流阻抗等实验显示了本文制备的活性碳材料以及复合电极材料具有良好的电化学性能.活性碳材料的质量比容量为172 F•g-1,采用无定形RuO2与上述活性碳复合制成的新型电极材料具有359 F•g-1以上的比容量和良好的功率特性,并对上述材料的双电层电容和法拉第准电容等电化学特性进行了详细的讨论.  相似文献   

10.
采用水热法硼磷改性椰壳多孔炭,并对其电化学性能进行研究。通过X射线衍射、红外光谱以及氮气吸脱附表征改性前后多孔炭的结构和性能;将多孔炭制作电化学电容器负极,通过恒流充放电、循环伏安以及交流阻抗测试分析其电化学性能。结果表明,水热法硼磷改性使多孔炭的微观结构及组成发生了一定变化,比电容等电化学性能有明显的提高。渗硼剂为氧化硼,渗硼量为15(wt)%时,比电容达108 F/g,比原始样增长了92%;渗硼剂为硼酸,渗硼量为25(wt)%时,比电容达到98 F/g,比原始样增长了83%。  相似文献   

11.
Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of four Linkage Isomeric Trichlorotrirhodanoosmates(IV) By treatment of fac-[OsCl3I3]2? with (SCN)2 in dichloromethane the linkage isomers fac-[OsCl3(NCS)3]2? ( 1 ), mer-[OsCl3(NCS)2c(SCN)]2? ( 2 ), mer-[OsCl3(NCS)(SCN)2t]2? ( 3 ), and mer-[OsCl3(NCS)(SCN)2c]2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. X-Ray structure determinations have been performed on single crystals of fac-(Ph4As)2[OsCl3(NCS)3] (triclinic, space group P1 , a = 12.142(5), b = 13.233(5), c = 19.300(5) Å, α = 98.642(5)º, β = 100.509(5)º, γ = 112.514(5)º, Z = 2), mer-(Ph4As)2[OsCl3(NCS)2c (SCN)] · acetone (triclinic, space group P1 , a = 11.707(5), b = 13.238(5), c = 19.048(5) Å, α = 75.960(5)º, β = 88.981(5)º, γ = 69.999(5)º, Z = 2), mer-(Ph4As)2[OsCl3(NCS)(SCN)2 t] (triclinic, space group P1, a = 10.6861(12), b = 11.6587(5), c = 12.5232(5) Å, α = 112.069(8)º, β = 95.052(8)º, γ = 92.559(7)º, Z = 1) and mer-(Ph4As)2[OsCl3(NCS)(SCN)2 c] · 2acetone (triclinic, space group P1 , a = 11.444(5), b = 14.661(5), c = 15.830(5) Å, α = 75.790(5)º, β = 80.273(5)º, γ = 75.205(5)º, Z = 2). The complex anions are completely ordered. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 169.1º, 171.5º, 175.7º ( 1 ), 175.6º, 178.6º ( 2 ), 172º ( 3 ), and 173.1º ( 4 ) and Os? S? C angles of 106.2º ( 2 ), 106.1º, 106.6º ( 3 ), 105.1º, and 108.2º ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu4N) salts of all four linkage isomers have been assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are fd(OsN) = 1.71 ( 1 ), 1.46 and 1.62 ( 2 ), 1.69 ( 3 ), and 1.61 ( 4 ), fd(OsS) = 1.27 ( 2 ), 1.36 ( 3 ), 1.32, and 1.49 mdyn/Å ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.  相似文献   

12.
Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of Four Linkage Isomeric Tetrachlorodirhodanoosmates(IV) By treatment of cis- or trans-[OsCl4I2]2? with (SCN)2 in dichloromethane the linkage isomers cis-[OsCl4(NCS)2]2? ( 1 ), trans-[OsCl4(NCS)(SCN)]2? ( 2 ), cis-[OsCl4(NCS)(SCN)]2? ( 3 ) and trans-[OsCl4(SCN)2]2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-Ray structure determinations on single crystals of cis-(Ph4As)2[OsCl4(NCS)2] (triclinic, space group P1 , a = 10.019(5), b = 11.702(5), c = 21.922(5) Å, α = 83.602(5)°, β = 85.718(5)°, γ = 73.300(5)°, Z = 2), trans-(Ph4As)2[OsCl4 · (NCS)(SCN)] (monoclinic, space group P21/c, a = 18.025(5), b = 11.445(5), c = 23.437(5) Å, β = 94.208(5)°, Z = 4), cis-(Ph4As)2[OsCl4(NCS)(SCN)] (triclinic, space group P1 , a = 10.579(5), b = 11.682(5), c = 22.557(5) Å, α = 81.073(5)°, β = 85.807(5)°, γ = 87.677(5)°, Z = 2) and trans-(Ph4As)2 · [OsCl4(SCN)2] (triclinic, space group P1 , a = 10.615(5), b = 11.691(5), c = 11.907(5) Å, α = 111.314(5)°, β = 96.718(5)°, γ = 91.446(5)°, Z = 1) reveal the complete ordering of the complex anions. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 171.2° and 174.3° ( 1 ), 162.3° ( 2 ), 172° ( 3 ) and Os? S? C angles of 108.3° ( 2 ), 105.7° ( 3 ) and 105.5° ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu4N) salts of all four linkage isomers are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are fd(OsN) = 1.59 ( 1 ), 1.67 ( 2 ), 1.60 ( 3 ) and fd(OsS) = 1.27 ( 2 ), 1.31 ( 3 ) and 1.32 mdyn Å?1 ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.  相似文献   

13.
Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

14.
Preparation and Crystal Structure of (n-Bu4N)3[Ir(NCS)(SCN)5] The evaporated ethanolic extrakt of the reaction product of K3[IrCl6] and HNO3, refluxed with an aqueous KSCN solution yields a mixture of the linkage isomers [Ir(NCS)n(SCN)6?-n]3?, n = 0? 2, and small amounts of linkage isomeric chloropentarhodanoiridates(III), from which [Ir(NCS)(SCN)5]3? has been isolated by ion exchange chromatography on DEAE-cellulose. The X-Ray structure determination on a single crystal of (n-Bu4N)3[Ir(NCS)(SCN)5] (monoclinic, space group P 21/a, a = 17.513(5), b = 32.607(5), c = 23.661(5) Å, β = 94.757(5)°, Z = 8) confirms the existance of a heteroleptic hexakis(thiocyanato(N)-thiocyanato(S))iridate(III) with an Ir? N distance of 2.03 Å and Ir? S bond lengths between 2.29 and 2.38 Å. The SCN groups with angles between 166 and 175° are nearly linear with Ir? S? C angles from 99.9 to 109.4°. The Ir? N? C angles of the two crystallographic independent anions are 166 and 174°.  相似文献   

15.
Abstract

The reaction, in water, of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with sodium ampicillinate at room temperature has allowed isolation of dimers with the following general formula [M(amp)Cl]2 × nH2O (n = 1.5?3.2). The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible). A dinuclear structure based on octahedrally coordinated metal ions is proposed.  相似文献   

16.
In this paper, we carry out the calculation on the system (X@C60)(X=Li, Na, K, Kb, Cs; F, Cl, Br, I), where the position of X changes along 5 typical symmetry directions. For the calculation of quantum chemistry we use EHMO/ASED method, for the calculation of molecular mechanics we use Buckingham potential (exp-6-1) function, and for the calculation of thermo-chemical cycle we use individually isolating the processes such as the structure variation, charge transfer and charge distribution, and their interactions etc. The calculation results show that (1) In the region of radius r≈0.2 nm of the Ceo cage, the potential field is nearly spherical; (2) Except for Li and Na, the systems are the most stable with minimum energies at the center of C60 cage. For Li and Na, the systems are the most stable with minimum energies at r≈0.16 nm and r≈0.13 nm, respectively. In view of the interactive region of chemical bonds, the interactions between X and the C60 cage do not belong to the classical chemical bonds; (  相似文献   

17.
高原  张茂根  王昉  王炳祥  沈健 《应用化学》2005,22(10):1096-1099
用廉价的均苯四甲酸二酐(PMDA)代替部分或全部3,3,′4,4′-联苯四羧酸二酐(BPDA),与3,3′-二羟基联苯胺(HAB)进行缩聚,然后脱水酰亚胺化,制备了5种聚酰亚胺(PI)。TGA分析显示,这些PI的DTG曲线为2个峰,可分为生成聚苯并唑(PBO)再发生PBO分解的2个阶段。PI膜在500℃通N2气1 h,所得聚合物膜的DTG曲线仅为1个峰,表明这些PI可充分转变成PBO。用FTIR表征了PI和PBO膜的结构。PBO的耐热性(用失重5%时的温度Td表示)比PI高100~170℃。PMDA-HAB PBO的耐热性高于BPDA-HABPBO。HAB-BPDA-PMDA PBO的耐热性优于二元PBO。当PMDA在二酐单体中所占的摩尔分数为75%时,PBO的Td高达643℃。  相似文献   

18.
Kilian K  Pyrzyńska K 《Talanta》2003,60(4):669-678
The reaction of 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin (TCPP) with Cd(II), Pb(II), Hg(II) and Zn(II) was studied spectrophotometrically and kinetics, equilibrium constants as well as photodecomposition of complexes were determined. It was verified that these metal ions with large radius accelerate the incorporation reaction of zinc into TCPP. On the basis of the mechanism and kinetics of this reaction, a sensitive method for the spectrophotometric determination of trace amounts of Zn(II) has been developed. The molar absorptivity of examined Zn-TCPP complex and Sandell's sensitivity at 423 nm were 3.5×105 M−1 cm−1 and 18.3 ng cm−2. The detection limit for the recommended procedure was 1.4×10−9 M (0.9 ng ml−1) and precision in range 20-100 ng ml−1 not exceeds 2.7% RSD. The proposed method applied for zinc determination in natural waters and nutritional supplement was compared with AAS results and declared value.  相似文献   

19.
Three Stereoisomeric Square-Pyramidal Complexes [Ma3b2]: Investigations of the Existence and the Structures of Crystalline Dimethyl Sulfoxide Complexes of Antimony and Bismuth Trichlorides The formation of solid complexes MCl3 · n DMSO (M = Sb, Bi; n = 1–4) was reinvestigated. In each system, only two of four presumptive complexes could be isolated as crystalline solids: SbCl3 · DMSO ( 1 a ) was prepared for the first time, SbCl3 · 2 DMSO ( 1 b ), BiCl3 · 2 DMSO ( 2 b ) and BiCl · 3 DMSO ( 2 c ) were reproduced according to literature data. Evidence is presented as to the non-existence of BiCl3 · 4 DMSO, contrary to previous claims in the literature. A unit cell determination showed 2 c to be structurally identical with the monomeric fac-octahedral complex BiCl3(DMSO)3 obtained fortuitously and described elsewhere [Z. anorg. allg. Chem. 620 (1994) 1037]. The compounds 1 a (monoclinic, space group P21/c), 1 b (monoclinic, space group P21/n) and 2 b (monoclinic, space group C2) represent examples of each of the three possible geometric isomers of a square-pyramidal complex [Ma3b2]. In the formally 1/1 adduct 1 a , which is in fact [Sb(1)Cl3(DMSO)2 · Sb(2)Cl3], the Sb(1) atom of the complex unit displays square-pyramidal geometry with the DMSO ligands situated in the apical and one of the basal positions. These units are linked into chains by SbCl3 molecules acting as Cl-acceptors. Sb(2) forms two chelating chloro-bridges with cis-Cl atoms of one neighbouring complex and a third chloro-bridge with the remaining Cl of the symmetry-related second neighbour. The resulting Cl6-geometry around Sb(2) is distorted octahedral. 1 b consists of square-pyramidal molecules, in which the DMSO ligands occupy two basal cis-positions; the monomeric units are loosely linked through the apical Cl atoms to form a chain of octahedra sharing trans-vertices. The asymmetric unit of 2b is a square pyramid with trans-basal DMSO ligands. The pyramids are connected by symmetry-equivalent basal chlorine atoms into chains of octahedra sharing cis-vertices. 1a displays remarkably short Sb? O dative bonds (204.7/212.9 pm); the M? O bond distances of 1b and 2b are 223.0/234.6 and 234.5/238.7 pm, respectively.  相似文献   

20.
Cu以其优异的导电性、导热性和易加工性广泛用于工农业生产中.自然Cu的腐蚀和防腐成为人们很关注的问题.人们已经注意到,Cl-对Cu的腐蚀有影响,并进行过一些研究.但目前使用光电化学方法研究这一问题的文章尚不多见,特别是利用测量开路光电压及其瞬态波形这一现场的、无损的、灵敏的监测方法研究户对Cu电极腐蚀全过程的文章尚未见到.本文正是利用如上方法及XPS,AES方法,研究了Cl-对Cu电极腐蚀的全过程,取得了一些有意义的结果.1实验方法Cu电极用99.99%(质量分数)的Cu制成,面积约为39mm2;电极底部由Cu导线焊接引出,…  相似文献   

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