无纺布基聚吡咯柔性电极的储锂性能

高性能的柔性锂离子电池对可穿戴电子设备的发展具有重要意义。采用化学氧化法在聚对苯二甲酸乙二醇酯(PET)无纺布基材上原位聚合聚吡咯(PPy),并通过控制反应条件得到不同形貌的聚吡咯电极材料。当反应体系中剪切力较小时,得到纳米线状聚吡咯(PPy-NW/PET),反之,为纳米颗粒形貌的聚吡咯(PPy-NP/PET)。PPy纳米线的平均直径为460 nm,在包覆PET纤维的同时相互交叠,形成了三维网状导电通道。该PPy/PET可以直接作为无粘结剂的柔性电极材料。电化学测试结果表明,PPy-NW/PET电极材料的性能更优异,其首次放电和充电的比容量分别为124和98 mA[DK1]·h/g,且具有良好的柔性和稳定性。本文对柔性、轻质电极材料的制备及其在储能领域的应用提供了很好的思路。     

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.     

纳米结构ZnO/染料/聚吡咯光阳极的光电化学性质

用光电化学方法研究了染料RuL2 (NCS) 2 (L =2 ,2′ bipydine 4,4′ dicarboxylicacid) (简写为Dye)、聚吡咯 (PPy)敏化氧化锌 (ZnO)纳米晶电极以及用RuL2 (NCS) 2 和PPy复合敏化ZnO纳米晶膜电极的光电化学行为 .实验表明 ,ZnO/PPy纳米多孔膜电极为双层n 型半导体结构 .PPy和RuL2(NCS) 2 都可对ZnO纳米晶膜产生敏化作用 ,ZnO/RuL2 (NCS) 2 /PPy复合多孔膜电极产生的光电流远大于ZnO/PPy纳米多孔膜电极和ZnO/Dye多孔膜电极产生的光电流 .讨论了该电极的光生电子的机理 ,初步测定了ZnO/RuL2 (NCS) 2 /PPy电极作为光阳极的光电化学电池的工作特性曲线 ,测得该电池的光电转换效率为 1 .3% ,填充因子为 0 .75 .     

导电聚吡咯纳米线的电化学无模板法可控合成与表征

以β-萘磺酸(NSA)为掺杂剂,采用电化学无模板法制备了聚吡咯(PPy)纳米线.研究了NSA浓度、吡咯(Py)单体浓度及反应温度对PPy纳米线形貌的影响.分别采用场发射扫描电子显微镜(FE-SEM)和拉曼光谱对PPy纳米线的结构形貌和化学结构进行了表征.结果表明,利用电化学无模板法可得到中空的PPy纳米线;NSA浓度会影响PPy纳米线的取向性;增大Py单体浓度,可制得圆锥状PPy纳米线;低温有利于合成形状细长、紧密堆积的PPy纳米线.PPy纳米线形貌受游离Py浓度及Py-NSA胶束数量影响,通过调节NSA浓度、Py浓度及反应温度改变游离Py浓度及Py-NSA胶束数量,可制得不同形貌的PPy纳米线.     

9,10-蒽醌-2-磺酸钠盐掺杂对导电聚吡咯电容性能的促进作用

用恒电位法制成以9,10-蒽醌-2-磺酸钠盐(AQS)为掺杂阴离子的导电聚吡咯(PPy)电化学电容器电极材料,并采用循环伏安(CV)、充放电测试、电化学阻抗(EIS)等方法表征电容性质.结果表明,与高氯酸阴离子(ClO4-)掺杂的PPy相比,PPy/AQS电极材料不仅单位质量电容和电极稳定性得到提高,工作电压范围也得以扩大.在1mol·L-1的氯化钾中,工作电压为-0.6至0.6V,扫描速率为50mV·s-1时其单位质量电容达到491F·g-1,比PPy/ClO4-电极材料提高1.5倍.这是由于AQS自身良好的氧化还原活性和AQS掺杂有利于聚吡咯膜形成疏松多孔的纳米及亚微米颗粒结构而导致的.     

肝素钠掺杂球状聚吡咯的合成及其电化学电容

以生物制剂肝素钠为掺杂剂,由自组装方法合成出平均粒径为100 nm的球状聚吡咯(PPy),用作超级电容器电极材料.透射电镜(TEM)、循环伏安、恒流充放电和电化学交流阻抗测试表明,肝素钠掺杂聚吡咯呈现较好的形貌和电容性质,在电流密度3 mA/cm2下充放电,单电极比电容达到338 F/g.     

用离子吸附法制备银/聚吡咯同轴纳米电缆

以多元醇还原反应法制备出直径为40~50 nm的纳米银线, 采用醋酸铜水溶液对银纳米线表面进行处理, 通过离子吸附在纳米银线表面吸附铜离子. 以吸附在银纳米线表面上的铜离子作为活性单元, 氧化吡咯单体聚合, 制得Ag/PPy同轴纳米电缆. 采用TEM, FTIR和XPS等表征手段对产物进行表征和检测, 并通过表面增强拉曼光谱进一步证实产物中聚吡咯层紧密地吸附在银线表面. 结果表明, 利用醋酸铜作为氧化剂, 通过离子吸附法制备的Ag/PPy同轴纳米电缆, 可以在较大范围内有效地控制聚吡咯层厚度, 避免银纳米线被刻蚀.     

聚吡咯对Cu(II)的催化还原作用

以对甲苯磺酸钠为掺杂剂在不锈钢(SS)电极表面恒电位合成聚吡咯(PPy)修饰膜, 采用恒电位和动电位对Cu(II)的还原效果进行了研究, 并与不锈钢电极进行了对比. 结果表明, 由于聚吡咯的催化作用, 聚吡咯修饰电极对Cu(II)还原效率高于不锈钢电极; 聚吡咯膜对析氢有明显的抑制作用, 因此电流效率远远高于不锈钢电极, 这是采用聚吡咯进行电化学还原的明显优势. 通过在不同浓度Cu(II)酸性溶液中的循环伏安行为讨论了聚吡咯对Cu(II)的还原作用机理.     

聚吡咯／多壁碳纳米管修饰电极对多巴胺的测定

制备了聚吡咯/多壁碳纳米管(PPy/MWNT)复合膜修饰电极。研究了神经递质多巴胺(DA)在该修饰电极上的电化学行为。实验表明,PPy/MWNT复合膜修饰电极对DA的电催化作用优于PPy修饰电极。在pH=4.10的0.2mol/L醋酸-醋酸钠缓冲溶液中,DA在该修饰电极上的CV曲线于0.31V和0.28V处出现一对灵敏的氧化还原峰,峰电位差△Ep比裸玻碳电极降低58mV,比PPy修饰电极降低28mV,峰电流显著增加。氧化峰电流ipa与DA浓度在1.0×10-4~7.8×10-8mol/L范围内呈良好的线性关系,线性回归方程为ip(μA)=0.2512 1.2300C(×10-5mol/L),相关系数r=0.9992,检出限为3.9×10-8mol/L。常见物质对DA的检测无干扰,DA注射液样品检测回收率为94%~104%。     

不同状态下聚吡咯膜的电化学阻抗

用恒电流法分别聚合了掺杂对甲苯磺酸根(pTS-)和十二烷基磺酸根(DS-)的聚吡咯膜(PPy/pTS和PPy/DS),通过循环伏安法(CV)和电化学阻抗法(EIS)测试了聚吡咯膜在NaCl溶液中‘过电位’电化学过程前后及不同电位下聚吡咯膜的电化学性能.同时,通过嵌入和脱出Na+和Cl-离子的聚吡咯膜在特定溶液中电化学阻抗图谱,研究了离子的嵌入对聚吡咯膜电化学性能的影响.结果表明‘过电位’现象可以提高聚吡咯膜的离子电导率和膜电容,Cl-离子的嵌入能提高PPy/pTS的电导率,而Na+离子的嵌入对聚吡咯膜的电导率影响不大.另外,嵌入离子对聚吡咯膜形貌的改变会对聚吡咯膜的离子传导率有一定影响,从而导致膜的电化学阻抗的变化.     

Electrochemical preparation of effective and low cost catalyst for electrooxidation of ethanol

A nanocatalyst coating was prepared at surface of a glassy carbon electrode by electropolymerization of pyrrole by cycling the electrode potential between ?0.8 and 0.8 V (vs. Ag/AgCl). Then, polypyrrole film was potentiostatically coated with platinum nanoparticles at constant potential of ?0.2 V (vs. Ag/AgCl). The resulting electrode was denoted as GCE/PPy/Pt. This modified electrode was characterized by IR, SEM, TEM and EDX. The electrocatalytic oxidation of ethanol at the GCE/PPy/Pt has been investigated using cyclic voltammetric and chronoamperometric methods. The effects of various parameters on electrocatalytic oxidation of the ethanol, such as the thickness of PPy film, the amount of platinum nanoparticles, ethanol concentration, potential scan rate and working potential limit in anodic direction, were investigated. The kinetic of the ethanol oxidation is discussed on the GCE/PPy/Pt. The stability and reproducibility of this modified electrode were also studied.     

In situ FTIR spectroscopy study of the break-in phenomenon observed for PPy/PVS films in acetonitrile

The in situ Fourier transform infrared (in situ FTIR) technique was used for the first time to investigate the break-in phenomenon observed for polypyrrole/poly(vinyl sulfonate) (PPy/PVS) films in acetonitrile containing 0.1 M LiClO(4). Consecutive potential scans provided a continuous increase of the infrared band intensities, simultaneous to an increase observed in the charge involved in the voltammetric peaks, suggesting a rise in the number of the polymeric chains participating in the infrared signal at the same time as the electroactive participants increase in the redox process. Moreover, in situ FTIR spectra evidence that the new infrared-activated chains in each voltammetric cycle adopt the same polymeric structure achieved by the chains activated in the initial cycles. However, if we achieve a cathodic potential limit of -2.1 V (vs Ag/AgCl), a restructuring of the polymeric morphology is observed. In situ FTIR spectra obtained for PPy/ClO(4) films under the same conditions pointed to a steady-state behavior from the very early voltammetric scans. Moreover, the intensities of FTIR bands obtained for PPy/ClO(4) films in the early voltammetric cycles are much higher than those obtained for PPy/PVS films after several potential scans. Only when high cathodic and high anodic potential limits were used for the consecutive cycles did the FTIR band intensities from PPy/PVS become similar to those obtained from PPy/ClO(4), indicating that in both films a similar number of polymeric chains were infrared active. Polarization at a high anodic potential (+1.3 V vs Ag/AgCl) produced overoxidation of the polymer appearing characteristic 1725 cm(-1) band assigned to the formation of carbonyl groups. Furthermore, the approximately 1540 cm(-1) band shifted to higher wavenumbers, indicating that overoxidation reduced the length of conjugated chains in the polypyrrole.     

氟尿嘧啶的电化学控制释放

本文探讨了抗癌药物氟尿嘧啶在聚吡咯膜修饰玻碳电极上的电化学控制释放，结果表明药物自膜中的释放是聚吡咯膜的电化学氧化还原过程决定的。其释放量可由还原电位进行控制，并与还原电量和膜厚呈现良好的线性关系。     

A polypyrrole-based amperometric ammonia sensor

An ammonia sensor is described in this work. The sensing membrane is a thin layer of oxidized polypyrrole (PPy) on a platinum substrate. This sensor is used as the working electrode in a conventional three-electrode system for amperometric measurement of ammonia in aqueous solutions in the potential range of + 0.2 to + 0.4 V (vs. Ag/AgCl). Contact with ammonia causes a current to flow through the electrode. This current is proportional to the concentration of free ammonia in the solution and ammonium ions do not contribute to the measured signal. The signal is due to reduction of PPy by ammonia with subsequent oxidation of PPy by the external voltage source. The sensor is able to detect ammonia reproducibly at the muM level. The main interference is the doping effect of small anions such as Cl(-) and NO(3)(-), also giving a response on PPy at the mM level. This anionic response can, to a certain degree, be reduced by covering the polymer surface with dodecyl sulfate. The sensor gradually loses its activity when exposed to ammonia concentrations greater than 1 mM. The sensor has been tested by the flow injection analysis technique.     

Polypyrrole/Co-tetraphenylporphyrin modified carbon fibre paper as a fuel cell electrocatalyst of oxygen reduction

A thin-layer of polypyrrole (PPy) film, immobilized with neutral 5,10,15,20-tetraphenylporphyrinato cobalt (II) (Co-TPP), was successfully and uniformly deposited onto mesoporous carbon fibre paper (CFP) via vapor-phase polymerization. The resulting PPy/Co-TPP-modified carbon fibre paper (PPy/Co-TPP-CFP) electrode was characterized by cyclic voltammetry, SEM and EDX-ray mapping. Its electrochemical stability and long-term electrocatalytic performance were investigated in a half-fuel cell testing system. The electrode displayed significant electrocatalytic performance for oxygen reduction at 0.0 V (vs. Ag/AgCl), with notable long-term stability.     

Synthesis and characterization of a p-type boron arsenide photoelectrode

A p-type boron arsenide photoelectrode was prepared from a material consisting of a thin layer of boron arsenide on a boron substrate. The structure of the material was identified using X-ray diffraction and scanning electron microscopy, and the surface composition was determined by means of X-ray photoelectron spectroscopy. The electrode was found to be photoactive under both visible light and UV-vis irradiation and displayed a photocurrent of ~0.1 mA/cm(2) under UV-vis irradiation at an applied potential of -0.25 V vs Ag/AgCl. Mott-Schottky plots for this boron arsenide electrode displayed an estimated flat-band potential near the onset photopotential. The estimated indirect band gap, as determined from incident photon-to-electron conversion efficiency plots, is 1.46 ± 0.02 eV.     

Rh-doped SrTiO3 photocatalyst electrode showing cathodic photocurrent for water splitting under visible-light irradiation

A Rh-doped SrTiO(3) (SrTiO(3):Rh) photocatalyst electrode that was readily prepared by pasting SrTiO(3):Rh powder onto a transparent indium tin oxide electrode gave a cathodic photocurrent under visible-light irradiation (λ > 420 nm), indicating that the SrTiO(3):Rh photocatalyst electrode possessed p-type semiconductor character. The cathodic photocurrent increased with an increase in the amount of doped Rh up to 7 atom %. The incident-photon-to-current efficiency at 420 nm was 0.18% under an applied potential of -0.7 V vs Ag/AgCl for the SrTiO(3):Rh(7 atom %) photocatalyst electrode. The photocurrent was confirmed to be due to water splitting by analyzing the evolved H(2) and O(2). The water splitting proceeded with the application of an external bias smaller than 1.23 V versus a Pt counter electrode under visible-light irradiation and also using a solar simulator, suggesting that solar energy conversion should be possible with the present photoelectrochemical water splitting.     

A photoelectronic switching device using a mixed self-assembled monolayer

A cathodic-anodic biway photoelectronic device has been successfully constructed using a self-assembled monolayer (SAM). The SAM consists of two kinds of photofunctional thiol derivatives, a ruthenium complex-viologen linked compound (RuVS) and a phthalocyanine derivative (PcS), on a gold electrode. Structural characterization of the SAM has been carried out by absorption spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Photocurrent responses were measured in the presence of methyl viologen (MV2+) and oxygen as electron acceptors and triethanolamine (TEOA) as a sacrificial reagent. For the SAM of RuVS alone, intramolecular electron transfer (ET) was superior to intermolecular ET, resulting in anodic photocurrents even in the presence of MV2+ and oxygen at 0 V vs Ag/AgCl. On the contrary, only cathodic photocurrents were observed at 0 V for the SAM of PcS alone. Photocurrents from the mixed SAM of RuVS and PcS were roughly the sum of individual photocurrents from RuVS and PcS. In fact, photocurrents from the mixed SAM of RuVS and PcS were observed in the anodic direction below approximately 550 nm, and in the cathodic direction above approximately 550 nm at 0 V vs Ag/AgCl. In the case of the mixed SAM of RuS (ruthenium complex disulfide) and PcS, only cathodic photocurrents were observed at 0 V vs Ag/AgCl, due to the lack of an intramolecular ET pathway. The results indicate that in the mixed SAM of RuVS and PcS both dyes can individually function for opposite photocurrent generation. We have also applied the mixed SAM as a photoelectronic logic device by using two LEDs (470 and 640 nm). The system clearly operated as an XOR logic device.     

银掺杂聚L-酪氨酸修饰电极同时测定多巴胺、肾上腺素和抗坏血酸

用循环伏安法制备银掺杂聚L-酪氨酸修饰玻碳电极,研究了多巴胺、肾上腺素和抗坏血酸在其电极上的电化学行为,建立了同时测定多巴胺、肾上腺素和抗坏血酸的新方法。当3种组分共存时,在磷酸盐缓冲溶液(pH6.0)中,扫描速率为140mV/s,多巴胺和肾上腺素在修饰电极上分别产生还原峰,峰电位分别为0.198和-0.205V,多巴胺和肾上腺素氧化峰重叠,峰电位为0.313V(vs.Ag/AgCl);抗坏血酸产生一个氧化峰,峰电位0.108V(vs.Ag/AgCl)。多巴胺和肾上腺素的ΔEpc=0.403V,抗坏血酸的氧化峰与多巴胺和肾上腺素的ΔEpa=0.205V,用还原峰和氧化峰可同时测定多巴胺、肾上腺素和抗坏血酸,3种组分同时测定的线性范围分别为5.0×10-6～1.0×10-4mol/L,8.0×10-6～1.0×10-4mol/L和3.0×10-5～1.0×10-3mol/L;检出限分别为5.0×10-7,8.0×10-7和5.0×10-6mol/L。本方法用于人尿液中多巴胺、肾上腺素和抗坏血酸的同时测定,结果满意。     

三种食用色素的电化学行为的理论计算与验证

用量子理论计算柠檬黄、日落黄、胭脂红的相对焓（Hm）、相对熵（Sm），计算柠檬黄、日落黄、胭脂红的还原电位分别为-0．969，-0．901，-0．854V（vs．Ag／AgCl／Cl）。探讨了琼脂对色素的电催化机理，采用循环伏安法在玻碳琼脂电极上研究了食用色素柠檬黄、日落黄、胭脂红的电化学行为，分别于-1．064，-0．910，-0．882V（vs．Ag／AgCl／Cl）产生还原峰，理论预测与试验结果基本一致。