PEMFC催化层中PTFE和Nafion对催化剂利用率的影响

本文利用循环伏安法,结合透射电镜和扫描电镜研究了质子膜燃料电池催化层中加入的聚四氟乙烯（ＰＴＦＥ）和全氟磺酸枝脂对催化剂利用率的影响。ＰＴＦＥ对催化剂利用率的影响很小。但在亲水型电极中,催化剂颗粒之间的电子导通会受到Ｎａｆｉｏｎ的阻碍,并导致催化剂利用率降低,由于Ｎａｆｉｏｎ分子很小,因此与Ｐｔ／Ｃ中Ｐｔ颗粒的接触没有大问题。     

质子交换膜燃料电池Nafion/PTFE复合膜的研究

在聚四氟乙烯(PTFE)多孔膜内浸入Nafion树脂,制成Nafion/PTFE复合膜用于质子交换膜燃料电池(PEMFC).该复合膜的Nafion含量在50%左右,在干态和湿态时的拉伸强度及水化/脱水过程中,其尺寸稳定性比Nafion均有所提高.在80 ℃,H2/O2压力为0.2/0.2 MPa条件下,用25 μm厚复合膜组装的电池性能优于Nafion117膜组装电池的性能.测量了复合膜的O2渗透率和含水量并与Nafion膜的性能作了比较.     

Nafion汞膜修饰电极用于阳极溶出伏安法测定痕量铋的研究

本文报道了Nafion汞膜修饰电极及其用于阳极溶出伏安法测定未处理尿样,水样及土样中痕量铋的研究。样品中常共存的Pb(Ⅱ)、Sb(Ⅲ )等19种阳离子及尿样中共存的有机物在实验条件下不干扰。本法不仅选择性好,而且灵敏度也较高。线性范围为2×10~(-10)～1×10~(-7)mol/L。回收率为94～105％。     

Nafion修饰电极预富集-石墨炉原子吸收法测定痕量银的研究

本文报道了用Nafion修饰电极预富集-石墨炉原子吸收法测定痕量银的方法。采用不加电位的离子交换富集方法,将痕量银富集在Nafion修饰钨丝电极上,然后用石墨炉原子吸收法测定,检出限为0.04ng/ml,线性范围为0.08～12ng/ml,RDS为4.2%,回收率为88～100%。方法简便、灵敏,选择性好,适用于测定复杂体系中的痕量银。     

Co(salen)/Nafion修饰电极对天然海水中一氧化氮的催化氧化及其测定

用Co(salen)/Nafion修饰铂电极对天然海水介质中的一氧化氮进行了测定,在最佳实验条件下,确定了Co(salen)/Nafion修饰电极的检出限是0.1 μmol/L,线性范围分别为0.1～1.0和1.0～9.9 μmol/L,相对标准偏差为0.24%,并且探讨了Co(salen)对NO的催化机理.     

电化学浸渍法制备空间氢镍电池用镍电极的循环寿命研究

以空间储能电源4.5’镍极板为对象,研究了过充电、高倍率及极板孔径对电化学浸渍电极循环寿命的影响.结果表明,5C过充电70%,电极初始容量为2.7 Ah,150次循环后容量逐渐下降,300次循环,放电容量约为1.7 Ah(保持率约63%).5C无过充电,300次循环其容量保持率约100%,1000次循环,容量保持率仍可达76%.无过充电,极板孔径及小电流活化均可改善电极循环性能.     

Nafion膜电极对氧的催化还原的研究(I)──CoTSPc和CoTMAP的循环伏安对比

制备了两组Nafion膜电极(膜中分别分布有带正、负电荷的过渡金属大环配离子),并用循环伏安法研究比较了这两组电极对氧催化还原性能,探讨了配离子和Nafion膜之间的静电作用对电极催化性能影响的规律,同时对其它因素的影响及电荷在Nafion膜中传递的机理也进行了讨论。     

Nafion修饰铂电极电化学还原法测定溶液中的一氧化氮

采用电化学还原法对溶液中一氧化氮（ＮＯ）进行测定，研究对比了电化学氧化和电化学还原对ＮＯ检测的选择性和灵敏度，同时研究了工作电极表面修饰膜厚度、工作电极在被测溶液中的吸附时间，扫描速度对峰电流及峰电位的影响，证明电化学还原法选择性好，方法检出限为６μｍｏｌ／Ｌ，线性范围１０￣８００μｍｏｌ／Ｌ。     

熔融浸渍法合成单晶锰酸锂作为锂离子电池阴极材料

以二氧化锰和氢氧化锂为原料,通过熔融浸渍法合成具有尖晶石构型的单晶锰酸锂。前驱体β-MnO₂以乙酸锰和过硫酸钠为原料通过水热反应合成。基于TGA/DTA测试,确定了单晶锰酸锂的煅烧温度为470℃预烧5h,再升温至750℃保温12h。XRD,FTIR和SEM结果表明,合成的单晶锰酸锂具有均一的棒状结构以及良好的结晶性。电化学性能测试结果表明材料在0.1C倍率下充放电时,其首次放电比容量可达126mAh·g^-1,且在一百次循环之后容量保持率为91%。     

熔融浸渍法合成单晶锰酸锂作为锂离子电池阴极材料(英文)

以二氧化锰和氢氧化锂为原料,通过熔融浸渍法合成具有尖晶石构型的单晶锰酸锂。前驱体β-MnO2以乙酸锰和过硫酸钠为原料通过水热反应合成。基于TGA/DTA测试,确定了单晶锰酸锂的煅烧温度为470℃预烧5 h,再升温至750℃保温12h。XRD,FTIR和SEM结果表明,合成的单晶锰酸锂具有均一的棒状结构以及良好的结晶性。电化学性能测试结果表明材料在0.1C倍率下充放电时,其首次放电比容量可达126 mAh·g-1,且在一百次循环之后容量保持率为91%。     

Nafion Schiff碱化学修饰电极的研究

研制了Nafion-N,N′-双(3-羧基邻羟亚苄基)三亚甲基二胺(Schiff碱)化学修饰电极;研究了电极的伏安特性,探讨了电极反应机理;用红外光谱证实了Hg(Ⅱ)与Schiff碱的可配位性,该电极用于微分脉冲阳极溶出伏安法测定未处理的尿样中痕量汞,较玻碳电极具有更高的灵敏度和较好的抗表面活性物质干扰的能力。     

以Nafion修饰的镀铂玻碳电极为基底的半乳糖传感器的制备

在镀铂的玻碳电极表面,修饰一层全氟代磺酸酯(Nafion)膜,制成基底电极。用化学交联法将半乳糖氧化酶(GAD)固定在基底电极表面,即制成半乳糖传感器。和光亮铂相比,镀铂电极对过氧化氢有更高的响应,而Nafion膜可以消除抗坏血酸,尿酸等电活性物质对测定的影响,提高了酶电极测定的选择性。D-半乳糖测定的线性范围为0.25～4.25 mmol/L,响应时间小于30s。电极连续使用300次,没有明显的电流变化。该电极具有快速、准确,选择性高的特点。     

碳的热处理对PEMFC氧电极性能的影响

氧还原反应;碳黑;碳的热处理对PEMFC氧电极性能的影响;聚合物燃料电池;氧电极     

Graphene‐Nafion Composite Film Modified Electrode for Voltammetric Sensor for Determination of Dihydromyricetin

A simple but highly snesitive electrochemical sensor for the determination of dihydromyricetin (DMY) based on graphene‐Nafion nanocomposite film modified Glassy carbon electrode (GCE) was reported. The characteristic of the sensor was examined by scanning electron microscopic (SEM) and electrochemical impedance spectroscopy (EIS). Compares with bare GCE, pre‐anodized glassy carbon electrode (GCE(ox)) and Nafion modified electrode, the sensor exhibited the more superior ability of detecting DMY, due to the synergetic graphene and Nafion. Other, the dependence of the current on pH, instrumental parameters, accumulation time and potential were investigated to optimize the experimental conditions in the determination of DMY. Under the selected conditions, the response peak currents were linear relationship with the DMY concentrations in the range of 8.0 × 10^?8 ～ 2.0 × 10^?5 mol L^?1 with a detection limit of 2.0 × 10^?8 mol L^?1. And, the method was also applied successfully to detect DMY in Ampelopsis grossedentata samples.     

Preparation and characterization of sulfated zirconia (SO4/ZrO2)/Nafion composite membranes for PEMFC operation at high temperature/low humidity

Fine particle superacidic sulfated zirconia (SO₄²⁻/ZrO₂, S-ZrO₂) was synthesized by ameliorated method, and composite membranes with different S-ZrO₂ contents were prepared by a recasting procedure from a suspension of S-ZrO₂ powder and Nafion solution. The physico-chemical properties of the membranes were studied by ion exchange capacity (IEC) and liquid water uptake measurements, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, thermogravimetry–mass spectrometry (TG–MS) and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the IEC of composite membrane increased with the content of S-ZrO₂, S-ZrO₂ was compatible with the Nafion matrix, the incorporation of the S-ZrO₂ could increase the crystallinity and also improve the initial degradation temperature of the composite membrane. The performance of single cell was the best when the S-ZrO₂ content was 15 wt.%, and achieved 1.35 W/cm² at 80 °C and 0.99 W/cm² at 120 °C based on H₂/O₂ and at a pressure of 2 atm, the performance of the single cell with optimized S-ZrO₂ was far more than that of the Nafion at the same condition (e.g. 1.28 W/cm² at 80 °C, 0.75 W/cm² at 120 °C). The 15 wt.% S-ZrO₂/Nafion composite membrane showed lower fuel cell internal resistance than Nafion membranes at high temperature and low relative humidity (RH).     

一种降低质子交换膜燃料电池不锈钢集流板与石墨单极板接触电阻的方法

建立一种降低质子交换膜燃料电池金属集流板与石墨单极板接触电阻的新方法.电学方法(电压降法)测试-数学模型分析表明,在不锈钢集流板和石墨单极板间嵌入金属拉伸网-碳胶聚合物复合体可消除金属集流板与石墨单极板间的接触电阻,从而能够有效降低燃料电池的内阻,提高燃料电池的性能.     

A Highly Sensitive and Selective Multiwall Carbon Nanotubes/Nafion/Au Microarrays Electrode for Dopamine Determination

This work presents the fabrication of Nafion (Nf) or Nafion/Multiwalled Carbon Nanotubes (Nf/MWCNTs) modified gold microarray (Au‐µA) and macro‐(Au‐M)electrode biosensors. The surface morphologies of the above electrodes were examined using SEM. The catalytic properties of the above electrodes towards dopamine were tested using square wave voltammetric technique. The Nf/MWCNT/Au‐µA electrode exhibited a wide range (0.1–1000 nM) of linearity among the other electrodes. The LOD of Nf/MWCNT/Au‐µA electrode was 50 pM for dopamine in the presence of 5000 µM ascorbic acid. Therefore, the Nf/MWCNT/Au‐µA biosensor was applied for the determination of dopamine in human serum.     

多巴胺在聚茶碱/Nafion双层修饰玻碳电极上的电化学行为

研究聚茶碱／Nafion双层修饰玻碳电极的制备和其电化学性质,并用于测定多巴胺（DA）。在pH7．4的PBS缓冲溶液中,DA在聚茶碱／Nafion双层修饰玻碳电极上产生一灵敏的氧化峰。峰电流与DA浓度在1×10－7～4×10-4mol/L范围内呈良好线性关系,检出限为5×10－8mol/L。该双层膜对DA有增敏作用,对抗坏血酸（AA）有排斥作用,重现性良好,可用于DA的测定。