纳米气泡电化学研究进展

纳米气泡广泛存在于许多自然现象和工业生产过程,其自身具有独特的物理化学性质.由于涉及气体反应的纳米电催化及能源转化技术的迅速发展,有关纳米气泡的电化学研究越来越受研究者的关注.针对电极界面纳米气泡的研究不仅有助于实现对气泡行为的调控,指导催化剂电极界面的合理设计以提高电催化效率,也可以从科学上去了解纳米催化剂本征电催化...     

石墨烯的纳米摩擦与磨损性质

采用乙醇溶剂剥离的方法制备石墨烯. 通过对溶剂温度、超声时间、超声功率和溶剂离心速度及时间的控制, 从高定向热解石墨(HOPG)制备得到少层石墨烯. 用原子力显微镜(AFM)研究了云母基底上不同层数石墨烯在真空中的纳米摩擦过程, 发现从约4 个原子单层(4 ML)起, 摩擦系数基本不再变化, 但摩擦力仍随着厚度的增加而显著减小, 7 ML之后, 其摩擦系数基本接近于零. 在磨损实验中, 少层石墨烯表面存在刮坏的现象,且不同厚度的石墨烯的磨损现象明显不同, 其中2 ML石墨烯相比4 ML石墨烯表现出较好的耐磨损性能, 且不具有摩擦方向依赖性. 测试了真空下少层石墨烯和云母表面的粘附力, 发现不同层厚的石墨烯相差不大, 因此认为基底效应并不是磨损性质差异的主要原因. 相对于单层石墨烯, 少层石墨烯在抗磨损涂层等领域有着很大的潜在应用价值.     

镍电极上吡咯的电化学聚合及聚吡咯的热稳定性

吡咯在乙二醇/乙睛混合溶剂中以对甲苯磺酸四乙基胺为支持电解质,在恒电流或恒电位条件下进行在镍电极上的电化学氧化聚合。元素分析及红外光谱表明有少量乙二醇参加了反应。扫描电镜图表明,在其接触镍电极的一面呈纤维状堆积,与在铂电极上的形态不同。电导率为10s/cm数量级。热失重分析表明,氧化态的聚吡咯膜在300℃以下是稳定的。     

不同形貌聚吡咯的制备及其电化学性能研究

以吡咯为单体,用化学氧化法和电化学沉积法分别制备聚吡咯(PPy)纳米粒子和微球。实验表明,PPy-ED微球的比电容要优于PPy-CS纳米粒子,并且PPy微球表现出理想的赝电容行为,可以进行快速可逆的法拉第反应,其原因在于PPy微球分子链规整,具有较大的共轭程度,从而表现出优异的电化学储能性。     

聚吡咯-分级多孔碳纳米复合材料的制备及其电化学性能

以空心介孔硅球为模板,酚醛树脂乙醇溶液为碳源制得了分级多孔碳(HPCs).以酸化处理后的HPCs为载体、对甲苯磺酸(p-TSA)为掺杂剂、三氯化铁(FeCl3)为氧化剂,通过原位化学氧化聚合法制备了聚吡咯-分级多孔碳(PPy-HPCs)纳米复合材料.采用场发射扫描电镜(FESEM)、透射电镜(TEM)、傅里叶红外光谱仪(FT IR)、恒流充放电、循环伏安以及交流阻抗等测试技术对复合材料进行了形貌结构和电化学性能的研究.结果表明:聚吡咯成功地包覆在HPCs的表面,随着聚吡咯含量的增加,复合材料的比容量呈现先增大后减小的趋势.当聚吡咯的质量含量为34.9％时,复合材料在电流密度为0.1 A/g时达到最大比容量(316 F/g),在1 A/g的电流密度下循环1 000次后,比容量保持率为95.8％,聚吡咯的引入有效地提高了HPCs电极材料的电化学性能.     

激光诱导吡咯和邻苯二胺的电化学聚合

激光诱导吡咯和邻苯二胺的电化学聚合高劲松蔡雄伟田中群＊（厦门大学固体表面物理化学国家重点实验室，化学系，物理化学研究所厦门３６１００５）关键词激光诱导，电化学聚合，微加工，聚吡咯，聚邻苯二胺１９９６－０８－１２收稿，１９９６－１１－１８修回国家自然科...     

以膨胀石墨为基底的聚吡咯电化学免疫传感器

用恒电位法在膨胀石墨基底表面合成聚吡咯,聚吡咯上的亚氨基与戊二醛发生交联,制备成稳定的膨胀石墨/聚吡咯/戊二醛传感器界面.以此界面固定人IgG抗体,戊二醛作为交联剂,发展了一种新型的电化学免疫传感器.该传感器在IgG溶液中温育后,其表面结合的IgG和随后加入的辣根过氧化氢酶(HRP)标IgG二抗以及传感器表面的IgG抗...     

纳米石墨薄片/聚吡咯复合材料的制备及导电性能

膨胀石墨经过超声处理制备了纳米石墨薄片。以其为导电填料，对甲苯磺酸为掺杂剂，FeCl₃·6H₂O为氧化剂，引发吡咯单体发生原位聚合，制备出纳米石墨薄片/聚吡咯(NanoGs/PPy)复合材料。利用红外光谱(FTIR)、扫描电镜(SEM)和透射电镜(TEM)表征了材料的组成和结构。结果表明，石墨薄片被聚吡咯完全包覆；并且以纳米级尺寸分散在聚吡咯基体中。热失重(TG)分析和电导率测试结果表明，复合材料的耐热性能和导电性能较纯聚吡咯有所提高。     

聚合电流对锂/聚吡咯电池正极电化学行为的影响

在Pt微盘电极上用恒电流技术在电流密度为0.05-10 mA·cm-2范围合成了1 滋m厚度的聚吡咯(PPy)膜. 采用循环伏安(CV)、计时电势、交流阻抗(EIS)技术考察了不同聚合电流下得到的聚吡咯的电化学行为. 结果表明, 最佳聚合电流区间为1-5 mA·cm-2, 对应的电势一般在3.9-4.1V (vs Li/Li+)之间, PPy的掺杂度为30%左右. 在这一聚合电流密度范围得到的PPy具有较大的电化学容量, 较佳的电化学反应可逆性能、较高的氧化还原电势数值和稳定性能. 处于氧化态的聚吡咯具有优良的导电性. 上述条件下得到的PPy适合于作为锂离子二次电池的正极材料. 适当选择电流, 可以得到有相对完整的共轭仔键的长链结构的PPy 膜.     

不同形貌聚吡咯对SnO_2负极电化学性能的改善

在预先原位合成的聚吡咯溶液中通过简单沉淀得到SnO2/聚吡咯负极材料,对材料的结构、形貌进行了表征并对材料的电化学性能进行了研究.发现不同形貌的聚吡咯对负极材料的电化学性能存在一定影响:SnO2负极材料在球状聚吡咯体系中比在管状聚吡咯体系中的电化学性能优越,首次库仑效率提高至77.6%,60次循环后仍剩余600 mA·h/g的可逆比容量.     

聚吡咯涂层的电化学合成及对神经微电极电性能的影响

通过改变掺杂剂种类、反应时间、电流密度等合成条件, 在神经微电极表面通过电化学沉积一系列厚度及形貌不同的导电高分子聚吡咯(PPy)涂层. 通过X射线光电子能谱及扫描电子显微镜对所得涂层化学组成及形貌进行表征.研究了PPy涂层对神经微电极电性能的影响. 电化学阻抗谱表明, 在神经信号相关的1 kHz频率处, 神经微电极阻抗值可降低至原来的1/55. 循环伏安曲线表明, 随PPy合成时间加长或电流密度提高, 电极总电容量随之增大.     

Photoactive Nanostructures of Polypyrrole

The creation of nanostructures of the photoactive polymer polypyrrole (PPy) on glass substrates with the spin‐coating method is described. No additional post‐production treatment is necessary to obtain uniformly distributed photoactive nanostructures on macroscopically scaled substrates. Based on X‐ray reflectivity measurements, the critical solution concentration of PPy below which these nanostructures develop is determined. The PPy nanostructures are displayed with atomic force microscopy (AFM) measurements, which prove that the nanostructures form directly on the substrate. With UV/Vis spectroscopy the absorption behavior of the nanostructures is probed in comparison to PPy films and PPy solutions. A linear dependence of the absorption of the nanostructure on the surface coverage measured with AFM is detected. The influence of confinement on the conjugation length results in a modified absorption behavior of the nanostructures.     

Electrochemically Controlled Ion‐exchange Property of Carbon Nanotubes/Polypyrrole Nanocomposite in Various Electrolyte Solutions

The electrochemically controlled ion‐exchange properties of multi‐wall carbon nanotube (MWNT)/electronically conductive polypyrrole (PPy) polymer composite in the various electrolyte solutions have been investigated. The ion‐exchange behavior, rate and capacity of the electrochemically deposited polypyrrole with and without carbon nanotube (CNT) were compared and characterized using cyclic voltammetry (CV), chronoamperometry (CA), electrochemical quartz crystal microbalance (EQCM), X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It has been found that the presence of carbon nanotube backbone resulted in improvement in ion‐exchange rate, stability of polypyrrole, and higher anion loading capacity per PPy due to higher surface area, electronic conductivity, porous structure of thin film, and thinner film thickness providing shorter diffusion path. Chronoamperometric studies show that electrically switched anion exchange could be completed more than 10 times faster than pure PPy thin film. The anion selectivity of CNT/PPy film is demonstrated using X‐ray photoelectron spectroscopy (XPS).     

Synthesis and Electrochemical Characterization of Modified Graphene/Polypyrrole Nanocomposites

Nanocomposites based on both modified/unmodified graphene and polypyrrole, were investigated as electrode materials for supercapacitor application. All the nanocomposites were prepared by in-situ oxidative polymerization method using ammonium persulfate as oxidant. The amine functionalization of Graphene was confirmed by FTIR and X-ray Photo Electron Spectroscopy (XPS). Field Emission Scanning Electron Microscopy (FESEM) and High Resolution Transmission Electron Microscopy (HRTEM) analysis were performed to study the morphology of the nanocomposites. The maximum capacitance value was found as 240 F/g for unmodified graphene based composite. Though the capacitance value was found to be lower for modified graphene based composite, the cyclic stability was found to be higher as compared to unmodified graphene/polypyrrole nanocomposite.     

Controlled Growth of Porphyrin Wires at a Solid‐Liquid Interface

Bis(zinc porphyrin) scaffolds bearing C₈ or C₁₈ alkyl chains and imidazole end groups self‐assembled in a head‐to‐tail fashion into multi‐porphyrin assemblies on both HOPG and mica. Due to weaker molecule surface‐interactions, longer arrays formed on mica than on HOPG. In both cases, it was essential first to generate monomers that were drop casted on the surface, then to allow time for the bis(zinc porphyrins) to assemble. Although thicker fibrous assemblies were observed with the C₈ alkyl substituents than with the longer chains, noncovalent assemblies up to 1 μm long were observed for each molecule. These investigations provide a reproducible, noncovalent method to grow porphyrin arrays that may be of interest in molecular electronics for charge transport.     

Au(111)/咪唑基离子液体界面结构研究：阳离子侧链长度的影响

本文结合电化学方法与原子力显微镜力曲线技术,研究了两种烷基侧链长度不同的离子液体BMITFSA和OMITFSA在Au(111)电极表面附近的层状结构的数目和耐受力对电位的依赖性,探究了烷基侧链长度变化对界面层状结构的影响. 研究表明,不同烷基侧链长度的离子液体体系力-电位曲线形状基本相似. 在零电荷电位（the potential of zero charge,PZC）附近时,力值最小,因为此时电极表面荷电量较小,层状结构不稳定;电位偏离PZC的过程中,第一层层状结构力值呈现先增大后减小的趋势. 受到烷基侧链所处的不同位置影响,在PZC电位以负,短侧链离子液体的层状结构稳定性较好,而PZC电位以正,长侧链离子液体的稳定性较好.     

Controlled Exfoliation of Layered Silicate Heterostructures into Bilayers and Their Conversion into Giant Janus Platelets

Ordered heterostructures of layered materials where interlayers with different reactivities strictly alternate in stacks offer predetermined slippage planes that provide a precise route for the preparation of bilayer materials. We use this route for the synthesis of a novel type of reinforced layered silicate bilayer that is 15 % stiffer than the corresponding monolayer. Furthermore, we will demonstrate that triggering cleavage of bilayers by osmotic swelling gives access to a generic toolbox for an asymmetrical modification of the two vis‐à‐vis standing basal planes of monolayers. Only two simple steps applying arbitrary commercial polycations are needed to obtain such Janus‐type monolayers. The generic synthesis route will be applicable to many other layered compounds capable of osmotic swelling, rendering this approach interesting for a variety of materials and applications.     

氧在铁卟啉/聚吡咯膜修饰电极上的还原

用旋转环盘电极技术研究含中位四（ 对磺基苯基） 卟啉合铁（ＦｅＴＰＰＳ） 的聚吡咯膜覆盖的玻碳电极上的氧还原过程． 结果表明该修饰膜的存在降低了氧还原的过电位,还原产物中有Ｈ２Ｏ２ ,过程用异相氧化还原催化（ＥＣ） 机理解释． 与金或铂比较,碳是较好的电极基体材料,适合于产生破坏水中有机物所需的过氧化物． 在酸性介质中氧在该膜修饰电极上的还原速度比在中性介质中大,由ＫｏｕｔｅｃｋｙＬｅｖｉｃｈ 关系式求出修饰膜中催化剂和分子氧反应的表观速度常数值．     

纳米尺度扫描电化学显微镜的探针制备及在电催化氧和氢反应研究中的应用

扫描电化学显微镜是一种在检测样品表面物理形貌的同时能提供丰富的电化学信息的扫描探针技术,由于超微电极的引入,它可以高时空分辨率地探究各类样品的物理形貌和电化学性能之间的构效关系. 随着现代纳米科技的不断发展,扫描探针的尺寸也逐渐从亚微米发展到纳米级别. 与此同时,高效优选各类氧反应和氢反应电催化材料,明晰其电化学反应过程和性能是二十一世纪绿色新能源转换存储系统（如可再生燃料电池、金属空气电池等）的重要研究方向. 本文首先概括了可应用于扫描电化学显微镜的纳米级扫描探针的制备及发展,之后着重介绍了近四年纳米尺度扫描电化学显微镜在电催化氧反应和氢反应研究中的一些最新研究进展. 最后以点窥面,对未来纳米尺度扫描电化学显微镜的未来发展趋势作了展望.     

Evaluation of Structure,Nucleation and Growth Mechanism of Electropolymerized Polypyrrole on Highly Oriented Pyrolytic Graphite Electrode

Chronoamperometry (i–t) and atomic force microscopy (AFM) were used to study the nucleation and growth mechanism of electropolymerized polypyrrole formed on highly oriented pyrolytic graphite (HOPG) substrate surface. From i–t measurements it was found that the nucleation and growth mechanism was a 3‐D progressive after nuclei overlapping. However, before nuclei overlapping, it was not clear whether the mechanism was 2‐D instantaneous or 3‐D progressive. This ambiguity in the nucleation and growth mechanism was confirmed as 3‐D progressive from the results of AFM measurements. In addition to nucleation and growth mechanism, possible models were proposed for different structures observed on the AFM image of polypyrrole, obtained from very early stages of polymerization.