碳化聚丙烯腈多孔材料在电化学电容器中的应用研究

聚丙烯腈 (PAN)及其共聚物是常用的高分子材料 ,在纺织和膜技术方面倍受重视 .聚丙烯腈纤维经氧化、碳化后 ,可制成具有高强度、高模量、能导电的碳纤维 .随着电子、信息、环保事业的发展和对新能源需求的提高 ,电化学电容器的研究成了一个热点 ,聚丙烯腈及其共聚物也开拓了它们的新应用领域 .电化学电容器是一类新型电子元件 ,其能量密度及功率密度介于电池及普通电容器之间 ,在低负荷场合可广泛应用于移动电话、录像机和笔记本电脑等电子产品 ,在高的功率负荷场合可与电池匹配 ,用于电动汽车 .从上世纪 80年代中后期开始 ,相关研究活跃…     

导电聚合物的现场电导/电化学研究——聚(3-甲基噻吩)和聚噻吩

本文提出一种研究导电聚合物的现场电位、电导测量/电化学方法。该实验方法基于一种可重复使用的玻璃碳-碳纤维组双电极。用该方法研究了聚(3-甲基噻吩)和聚噻吩的现场电位、电导/电化学行为。     

聚3-甲基噻吩的光电化学研究

利用光电化学方法研究了聚3-甲基噻吩的光电化学性质.其禁带宽度为1.93 eV.同时确定了它的价带、导带位置.研究还发现聚3-甲基噻吩属于直接跃迁半导体,具有很好的光电流稳定性.得到的最高IPCE值近1.0%.     

聚噻吩的光电化学研究

导电聚合物是由一些具有共轭π键的聚合物经化学或电化学掺杂后形成的导电率可从绝缘体延伸到导体范围的一类高分子材料。其中噻吩及其衍生物具有导电率高、环境稳定性好、成膜性好、禁带宽度小等特点,是用做光伏电池的理想材料。相继报道的有聚3-甲噻吩[1]、聚3-己基噻吩[2],聚(3-十一烷基-2,2’-并噻吩)[3]等。对于聚噻吩的光电化学性质的研究,在国际上很少见报道,国内尚未见报道,本文对聚噻吩(PTh)的光电化学性质进行了研究。1实验部分1.1仪器与试剂光电化学实验采用带石英窗口的三电极电解池,工作电极为ITO/PTh膜电极,参比电极为饱和…     

BMIMPF_6-有机溶剂对聚噻吩电化学性能的影响

实验测试了纯离子液体BMIMPF6、BMIMPF6-乙腈、BMIMPF6-碳酸丙二醇脂混合体系的粘度和电导率.应用循环伏安法在玻碳电极表面合成了聚噻吩,并测试了聚噻吩修饰电极在上述各溶液中的电化学行为.结果表明,聚噻吩在纯离子液体中的惨杂电量较小,电化学反应的可逆性较差.聚噻吩的氧化参杂电量与混合溶液的电导率呈明显的线性关系,当离子液体的体积含量为25%时,溶液的电导率达到最大,同时聚噻吩惨杂电量也达到最大,反应可逆也得到了明显的改善.     

Ru(II)染料与聚3-甲基噻吩复合敏化纳米结构TiO_2电极的光电化学研究

利用光电流作用谱、循环伏安等光电化学方法研究了染料RuL2(SCN)2:2TBA(L=2,2'-bipydine-4,4'-dicarboxylicacid)与聚3-甲基噻吩(P3MT)复合敏化电极的光电化学性质.RuL2(SCN)2:2TBA/P3MT复合敏化TiO2纳米晶多孔膜电极比染料RuL2(SCN)2:2TBA敏化TiO2纳米结构电极的光电转换效率大幅度提高.复合敏化电极中存在p-n异质结有效地抑制了电子的反向复合,减少了电子的损失.     

Ru(II)染料与聚3-甲基噻吩复合敏化纳米结构TiO2电极的光电化学研究

利用光电流作用谱、循环伏安等光电化学方法研究了染料RuL₂(SCN)₂: 2TBA (L＝2,2'-bipydine-4,4'-dicarboxylic acid)与聚3-甲基噻吩(P3MT)复合敏化电极的光电化学性质. RuL₂(SCN)₂: 2TBA/P3MT复合敏化TiO₂纳米晶多孔膜电极比染料RuL₂(SCN)₂: 2TBA敏化TiO₂纳米结构电极的光电转换效率大幅度提高. 复合敏化电极中存在p-n异质结有效地抑制了电子的反向复合, 减少了电子的损失.     

Ru(II)染料与聚3-甲基噻吩复合敏化纳米结构TiO2电极的光电化学研究

利用光电流作用谱、循环伏安等光电化学方法研究了染料RuL₂(SCN)₂: 2TBA (L＝2,2'-bipydine-4,4'-dicarboxylic acid)与聚3-甲基噻吩(P3MT)复合敏化电极的光电化学性质. RuL₂(SCN)₂: 2TBA/P3MT复合敏化TiO₂纳米晶多孔膜电极比染料RuL₂(SCN)₂: 2TBA敏化TiO₂纳米结构电极的光电转换效率大幅度提高. 复合敏化电极中存在p-n异质结有效地抑制了电子的反向复合, 减少了电子的损失.     

2-苯基噻吩的电化学聚合

聚噻吩及其衍生物是一类重要的导电高分子材料,它们具有良好的导电性、高度稳定性以及易于调控的分子链结构．因此,自从人们发现聚噻吩以来,噻吩类化合物,尤其是3-取代噻吩的聚合和表征一直受到人们的广泛关注[1,2]．相对而言,关于2-取代噻吩的聚合几乎还是空白,以往人们对其进行电化学聚合的尝试是不成功的[3]．     

聚3-甲基噻吩及聚3-己基噻吩修饰钛酸盐纳米管的光电化学性能研究

采用水热法制备了钛酸盐纳米管, 并将钛酸盐纳米管制备成纳米结构电极进行光电化学研究. 钛酸盐纳米管产生阳极光电流, 具有n-型半导体特性. 结果表明, 聚3-甲基噻吩[poly(3-methylthiophene), PMeT]、聚3-己基噻吩[poly(3-hexylthiophene), P3HT]修饰钛酸盐纳米管后产生的光电流均较纯钛酸盐纳米管的光电流高, 且使产生光电流的波长向长波区移动. 钛酸盐纳米管/PMeT、钛酸盐纳米管/P3HT的光电转换效率分别达11.40%, 0.91%(未校正光子损失). 钛酸盐纳米管/PMeT的光电转换效率较钛酸盐纳米管/P3HT的光电转换效率高10.5%. 钛酸盐纳米管/PMeT、钛酸盐纳米管/P3HT中存在p-n异质结, 在一定条件下p-n异质结的存在有利于光生电子/空穴的分离.     

Electrochemical Evaluation of Titanium (IV) Oxide/Polyacrylonitrile Electrospun Discharged Battery Coals as Supercapacitor Electrodes

The TiO₂ nanoparticles are electrospun with polyacrylonitrile (PAN) polymer solution onto the discharged battery coal (DBC) electrode and the results are evaluated as a supercapacitor. The morphology and chemical composition of the synthesized TiO₂ nanoparticles and PAN+TiO₂ nanocomposite fibers were characterized by Scanning electron microscopy, thermogravimetry and FTIR analysis. Supercapacitor measurements and electrochemical characterizations of the electrodes examined by cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical measurements showed that the best current value was obtained from PAN and TiO₂ coated DBC. The performances of both PAN and PAN+TiO₂ coated DBC electrodes were investigated as supercapacitors. PAN+TiO₂/DBC showed the best specific capacitance value of 156.00 F g⁻¹ and PAN/DBC showed 74.93 F g⁻¹. In addition, PAN+TiO₂/DBC exhibited reliable stability performance over 2000.00 cycles.     

Electrochemical polymerization of 1-(4-nitrophenyl)-2,5-di(2-thienyl)-1 H-pyrrole as a novel immobilization platform for microbial sensing

Two types of bacterial biosensor were constructed by immobilization of Gluconobacter oxydans and Pseudomonas fluorescens cells on graphite electrodes modified with the conducting polymer; poly(1-(4-nitrophenyl)-2,5-di(2-thienyl)-1 H-pyrrole) [SNS(NO₂)]. The measurement was based on the respiratory activity of cells estimated by the oxygen consumption at − 0.7 V due to the metabolic activity in the presence of substrate. As well as analytical characterization, the linear detection ranges, effects of electropolymerization time, pH and cell amount were examined by using glucose as the substrate. The linear relationships were observed in the range of 0.25–4.0 mM and 0.2–1.0 mM for G. oxydans and P. fluorescens based sensors, respectively.     

Electrosyntheses of freestanding poly (3-(4-fluorophenyl)thiophene) films in boron trifluoride diethyl etherate

High quality free-standing poly (3-(4-fluorophenyl)thiophene) (PFPT) films with conductivity of 10⁻¹ S/cm were electrosynthesized in boron trifluoride diethyl etherate (BFEE) by direct anodic oxidation of the monomer 3-(4-fluorophenyl)thiophene (FPT) on stainless steel sheet. As-formed flexible and shiny PFPT films can be cut into various shapes by a knife or a pair of scissors. The structure, thermal stability and morphology of PFPT films were studied by FT-infrared, UV-vis, Raman spectroscopy thermogravimetric analysis and scanning electron microscopy, respectively.     

柔性复合织物电极Graphene/Cotton和MnO2/Graphene/Cotton的合成及在电化学电容器中的应用

通过热还原法成功地制备出了柔性复合织物电极石墨烯/棉布(graphene/cotton)。热还原条件对电极的导电性能具有较大的影响。导电柔性织物电极graphene/cotton特有的多级结构使其既有利于进一步负载膺电容材料,又有利于电子和电解质离子的传输与扩散。通过电化学沉积方法,利用导电柔性织物电极graphene/cotton进一步制备出了电极MnO₂/graphene/cotton。利用扫描电子显微镜(SEM),傅里叶变换红外(FTIR)光谱,四探针测试法等表征技术对电极的结构进行了较为详细的表征。结果表明电极MnO₂/graphene/cotton的比电容可以达到536 F·g^-1。良好的电化学性能和柔性使得此类电极在柔性储能材料应用中具有极大的应用前景。     

Cu/C-Nafion复合电极上硝基苯的电化学还原

制备性电解的结果表明，硝基苯在Cu／C－Nafion膜复合电极上的还原产物只有苯胺，可能与电极／Nafion界面的弱酸性环境和其还原中间产物本羟胺在界面的扩散较仅有关．生成苯胺的电流效率随电流密度的增大而减小，随反应液中硝基苯浓度的增大出现一个最大值．这可能是硝基苯的电化学还原过程受某种粒子的扩散控制、峰电流取决于硝基苯在Nafion膜中的溶解度所致．     

Electrosynthesis and characterization of poly(hydroxy-methylated-3,4-ethylenedioxythiophene) film in aqueous micellar solution and its biosensing application

A new and efficient synthetic route to hydroxymethylated-3,4-ethylenedioxylthiophene（EDOT-MeOH） was developed by a simple four-step sequence,and its global yield was approximately 41.06%.The poly（hydroxymethylated-3, 4-ethylenedioxylthiophene）（PEDOT-MeOH） film was electrosynthesized in aqueous sodium dodecylsulfate micellar solutions and characterized by different methods.The EDOT-MeOH possessed better water solubility,and lower onset oxidation potential than EDOT.The as-obtained PEDOT-MeOH film displayed good reversible redox activity,stability and capacitance properties in a monomer-free electrolyte,especially the good solubility of PEDOT-MeOH film in strong polar organic solvents such as dimethyl sulfoxide and tetrahydrofuran created a potential application in many different fields. Fluorescent spectra indicated that PEDOT-MeOH was a yellow-green-light-emitter with maximum emission at 568 nm.The as-formed PEDOT-MeOH film had good biocompatibility and was used for fabricating the electrochemical vitamin C biosensor.The proposed biosensor showed a linear range of 3×10^-6 mol/L to 1.2×10^-2 mol/L with the detection limit of 1μmol/L,a sensitivity of 95.6μA（mmol/L）^-1 cm^-2,and a current response time less than 10 s and a fairly good stability (The relative standard deviation was 0.43%for 20 successive assays,the proposed biosensor still retained 93.5%of bioactivity after 15 days storage.This result indicated that the prepared PEDOT-MeOH film as immobilization matrix of biologically-active species could be a promising candidate for the design and application of biosensor.     

PEO基纳米复合聚合物电解质电化学性质的研究

以PEO8 LiClO4作母体,纳米SiO2为填料,制成PEO8 LiClO4 SiO2(x%)系列复合聚合物电解质,测定这该电解质的电导率、锂离子迁移数和电化学稳定窗口,并对其晶态结构作差热分析表征.结果表明,纳米SiO2的引入,显著提高了电解质的电导率,在22℃时达到4.3×10-5S·cm-1.此外,还探讨了填料对复合聚合物电解质电导率提高的影响机理.     

Electrochemical synthesis and characterization of poly(3,4-ethylenedioxythiophene) in ionic liquids with bulky organic anions

The electrochemistry of poly(3,4-ethylenedioxythiophene) (PEDOT) was studied in two ionic liquids with bulky organic anions, i.e., 1-butyl-3-methylimidazolium (BMIM) diethylene glycol monomethyl ether sulfate (MDEGSO₄) and BMIM octyl sulfate (OctSO₄). BMIM-MDEGSO₄ is a liquid, while BMIM-OctSO₄ is in solid form at room temperature. Electrosynthesis of PEDOT in BMIM-MDEGSO₄ with an EDOT concentration of 0.1 M and in BMIM-MDEGSO₄/EDOT 1/1 (w/w) solution resulted in no polymer at all or a very limited amount of polymer on the electrode surface, as determined by cyclic voltammetry in 0.1 M KCl(aq) solution. In contrast, electrosynthesis of PEDOT in BMIM-OctSO₄/EDOT 1/1 (w/w) resulted in a high yield of electroactive material on the electrode surface. Furthermore, electrosynthesis of PEDOT in ionic liquid–water solution (C_{ionic liquid}=1.5 M) containing 0.1 M EDOT was also found to give a relatively high yield of electroactive material on the electrode surface, both for 1.5 M BMIM-MDEGSO₄(aq) and 1.5 M BMIM-OctSO₄(aq). The PEDOT electrodes showed an anionic potentiometric response in 10^–5–10^–1 M KCl(aq) solution, indicating a predominant anion transfer at the polymer–solution interface despite the relatively bulky anions (MDEGSO₄^– or OctSO₄^–) incorporated as counterions in PEDOT during electropolymerization. On the basis of electrochemical impedance spectroscopy, the charge (ion) transport properties of the polymer film were strongly influenced by the water content of the ionic liquid (C_{ionic liquid}=0.05–2.0 M).Dedicated to Zbigniew Galus on the occasion of his 70th birthday     

Electrochemical and morphological characterization of poly[(R)-(−)-3-(l-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate] films deposited on ITO electrodes

Poly[(R)-(–)-3-(l-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate] films were deposited on ITO electrodes using potentiodynamic and galvanostatic methods. Polymerization occurred as a charge dependent process at 1.0 V vs. Ag/Ag⁺(CH₃CN) and was not affected by the presence of nitro groups in the monomer. The surface morphology of the film and its electrochemical properties were studied as a function of deposition charge (Q_dep) and deposition method. Film thickness increased in a quasi-linear manner with respect to Q_dep within the range 40–80 mC cm². The galvanostatic method provided easier control of Q_dep compared with potentiodynamic deposition, and produced a more adherent film with homogeneous grain geometry. Cyclic voltammetry revealed a well defined redox couple at the anodic region, attributable to polymer p-doping, and a poorly defined redox pair at the cathodic region, attributable to the reduction of the nitro group.     

Synthesis and characterization of poly(vinyl phosphonic acid) (PVPA)-Fe3O4 nanocomposite

Poly(vinyl phosphonic acid) (PVPA)-Fe₃O₄ nanocomposite is synthesized by the precipitation of Fe₃O₄ in the presence of PVPA. Structural, surface, morphological, thermal properties and conductivity characterization/evaluation of the nanocomposite were performed by XRD, FT-IR, TEM, TGA and conductivity measurements respectively. The capping of PVPA around the Fe₃O₄ nanoparticles was confirmed by FT-IR spectroscopy, the interaction being via bridging oxygens of the phosphate and the nanoparticle surface. The crystallite and particle size were obtained as 6 ± 2 and 8.7 ± 0.1 nm from XRD line profile fitting and TEM image analysis respectively, which reveal nearly single crystalline nature of the Fe₃O₄ nanoparticles. Magnetic characterization of the bulk magnetite and (PVPA)-Fe₃O₄ nanocomposite reveals that both are in the superparamagnetic state at room temperature. The average magnetic domain size of the nanoparticles has been calculated using the Langevin function, which was fitted to the measured M-H hysteresis curves as 7.6 nm for the nanocomposite. In the nanocomposite, the reduction is due to the adsorption of PVPA onto the magnetite surface, which cancels some of the free spins at the surface causing a magnetically dead layer. Analysis of the conductivity and permittivity measurements revealed the coupling of ionic and polymer segmental motions and strong temperature dependency in the nanocomposite.