On the Possibility of Using Protonic Solid Electrolyte CsHSO<Subscript>4</Subscript> in Hydrogen Fuel Cells

Electrochemical parameters of an H₂|air fuel cell with a membrane of solid electrolyte CsHSO₄ or composites (1 − x)CsHSO₄/xSiO₂ (x = 0.1–0.3) and different electrodes are measured at 175 °C. The maximal power (3.5 mW/cm² at a voltage of 0.6 V) is obtained for a cell with platinum-black electrodes and an intermediate layer of a mixture of platinum black and the electrolyte material. In the absence of a platinum catalyst, CsHSO₄ and composites CsHSO₄/SiO₂ are chemically stable in hydrogen at the operating temperature of the fuel cell.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 556–559.Original Russian Text Copyright © 2005 by Lavrova, Russkikh, Ponomareva, Uvarov.     

Impact of Membrane Types and Catalyst Layers Composition on Performance of Polymer Electrolyte Membrane Fuel Cells

Performance of a low temperature polymer electrolyte membrane fuel cell (PEMFC) is highly dependent on the kind of catalysts, catalyst supports, ionomer amount on the catalyst layers (CL), membrane types and operating conditions. In this work, we investigated the influence of membrane types and CL compositions on MEA performance. MEA performance increases under all practically relevant load conditions with reduction of the membrane thickness from 50 to 15 μm, however further decrease in membrane thickness from 15 to 10 μm leads to reduction in cell voltage at high current loads. A thick anode CL is found to be beneficial under wet operating conditions assuming more pore space is provided to accommodate liquid water, whereas under dry operating conditions, an intermediate thickness of the anode CL is beneficial. When studying the impact of catalyst layer thickness, too thin a catalyst layer again shows reduced performance due to increased ohmic resistance ruled out the performance of the MEAs which have identical Pt crystallite sizes on the cathode CLs i. e. the thinnest the cathode CL, the highest the voltage were achieved at a defined current load. Adaptation of the operating conditions is highly anticipated to achieve the highest MEA performance.     

生物膜电极在以苯酚为燃料的微生物燃料电池中的应用

以苯酚为燃料, 生物膜电极为负极, Ti/SnO₂-Sb₂O₅/PbO₂电极为正极, 构建了双室微生物燃料电池. 利用微电流驯化法和自然驯化法分别制备了生物膜电极, 研究了微生物的挂膜方法、 挂膜时间和负极基底材料种类对微生物燃料电池产电能力的影响. 结果表明, 微电流驯化法优于自然驯化法, 微电流驯化法制备的生物膜电极更利于电池的产电; 微生物的挂膜时间为8 d时, 电池的产电能力最高, 其最大输出功率密度达到39 mW/m²; 不同基底材料生物膜电极所组建的微生物燃料电池产电能力高低顺序为碳毡>石墨>钛网>泡沫钛.     

固体电解质La2-xCaxMo1.7W0.3O9-δ(0≤x≤0.2)的合成、表征及电性能

在氧离子导体La₂Mo_1.7W_0.3O₉的基础上，采用固相法合成了La位掺杂的Ca系列新型氧化物La_2-xCa_xMo_1.7W_0.3O_9-δ(0≤x≤0.2)。通过XRD、Raman和XPS等手段对化合物结构进行表征，交流阻抗谱测试其电性能。结果表明：掺杂离子Ca²⁺的半径小于基质离子La³⁺的半径导致晶格收缩；Ca的掺杂在La₂Mo_1.7W_0.3O₉自身内置氧空位的基础上增加了额外的氧空位，提高了氧离子导体的电导率，550 ℃电导率由0.79 × 10^-4 S·cm^-1 (x=0.0)增加到1.5 × 10^-4 S·cm^-1 (x=0.16，0.2)，电导率增加89.9%。     

活性炭载体对聚合物电解质膜燃料电池中炭载铂电催化剂性能的影响

分别以松木炭和Vulcan XC-72炭为载体制得载铂电催化作用，在聚合物电解质膜燃料电池（PEMFC）中对其性能进行了比较。结果表明：Vulcan XC-72炭作载体的电催化剂性能显著优于松木炭作载体的电催化剂，利用多种分析对活性炭的物理和表面化学性质进行了系统的研究，发现活性炭的孔径、电导率和表面含氧基团和电催化剂性能有很大的影响。     

中温固体氧化物燃料电池复合阴极材料LaBiMn2O6-Sm0.2Ce0.8O1.9的制备与电化学性质

采用甘氨酸燃烧法合成了LaBiMn_2O_6粉体,并与Sm_(0.2)Ce_(0.8)O_(1.9)均匀混合制备了LaBiMn_2O_6-Sm_(0.2)Ce_(0.8)O_(1.9)(LBM-SDC)复合阴极材料。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对材料的物相及微观形貌进行分析,结果表明LBM与SDC在1 000℃下有良好的化学稳定性。SDC的复合增加了氧离子传导路径,进而使氧还原反应(ORR)速度加快。电化学阻抗谱(EIS)测试结果表明,复合阴极极化电阻(Rp)随SDC复合量的增加呈现先降低后升高的趋势,当复合量为30%(w/w)时,阴极材料的性能最优。在700℃空气气氛下的极化电阻为0.186Ω·cm~2,相对LBM(0.717Ω·cm~2)减少74%。氧分压测试结果表明阴极反应的速率控制步骤为氧分子的吸附-解离过程。以复合阴极构筑的电解质支撑单电池Ni-SDC/SDC/LBM-30%SDC在700℃的最大输出功率密度为234 mW·cm~(-2),连续测试90 h输出功率衰减约4%。     

酞菁钴催化剂载体表面含氮官能团对其在燃料电池中氧还原性能的影响

以酞菁钴为催化剂,纳米碳管为载体,分别通过超声法和四氢呋喃法混合分散,并在氮气氛围高温热处理制备了两种酞菁钴催化剂.热重分析（TGA）结果显示超声法制备的酞菁钴催化剂（CoPc-CNT-S）含钴的质量分数为8.1 wt%,四氢呋喃混合法制备的酞菁钴催化剂（CoPc-CNT-R）含钴的质量分数为7.0 wt%.X射线光电子谱（XPS）结果显示CoPc-CNT-R催化剂的含氮量是CoPc-CNT-S催化剂的两倍多,且两种催化剂含氮官能团的种类及比例不同.相比较而言,CoPc-CNT-S表面有更多的吡咯型氮.将两种催化剂应用于混合酸碱燃料电池中发现：CoPc-CNT-S对电催化氧还原有较高的活性和稳定性,将CoPc-CNT-S作为燃料电池的阴极催化剂分别工作5 h和15 h后,电荷转移电阻相对CoPc-CNT-R为阴极催化剂时均较低.原因可能是相近比例的吡啶型N和吡咯型N的协同作用有利于电催化氧还原.     

Kinetics and Mechanism of low-Temperature Oxidation of H2S with Oxygen in the gas Phase

The possibility of the formation of polysulfides during oxidation of H₂ S with oxygen on oxide catalysts has been checked, and the sequence of the reaction stages at temperatures below the sulfur dew point determined. The amount of polysulfides formed during H₂ S oxidation has been found to exceed significantly that obtained in the reaction of sulfur with H₂ S. Polysulfides are concluded to be intermediates in H₂ S oxidation to sulfur. The rate of formation of SO₂ from sulfur vapor is shown to be negligibly low at 100-200°C. A reaction scheme involving the formation of sulfur from polysulfides and the formation of sulfur dioxide by direct oxidation of H₂ S is suggested.     

质子导体固体氧化物燃料电池的Ba_2Co_9O_(14)阴极材料

Ba2Co9O14(BCO)是一种新型的电子-氧离子混合导体,在氧离子导体的固体氧化物燃料电池(SOFC)中,其作为阴极材料的应用可能性已经得到证实,本工作探索BCO在质子导体SOFC中的应用可能性。采用固相反应法制备BCO粉体,研究BCO与质子导体电解质BZCY(Ba Zr0.1Ce0.7Y0.2O3-δ)之间的化学相容性,分析BCO-BZCY复合阴极在BZCY电解质上的电化学性能。当复合阴极中BCO的质量含量为70%时,阴极性能最佳,界面阻抗活化能为1.26 e V。以BCO-BZCY为阴极,Ni-BZCY为阳极,BZCY为电解质的阳极支撑型单电池,700℃时,单电池的极化阻抗为0.15Ω·cm2,最大功率密度为400 m W·cm-2。     

质子导体固体氧化物燃料电池的Ba2Co9O14阴极材料

Ba₂Co₉O₁₄（BCO）是一种新型的电子-氧离子混合导体,在氧离子导体的固体氧化物燃料电池（SOFC）中,其作为阴极材料的应用可能性已经得到证实,本工作探索BCO在质子导体SOFC中的应用可能性。采用固相反应法制备BCO粉体,研究BCO与质子导体电解质BZCY （BaZr_0.1Ce_0.7Y_0.2O_3-δ）之间的化学相容性,分析BCO-BZCY复合阴极在BZCY电解质上的电化学性能。当复合阴极中BCO的质量含量为70%时,阴极性能最佳,界面阻抗活化能为1.26 eV。以BCO-BZCY为阴极,Ni-BZCY为阳极,BZCY为电解质的阳极支撑型单电池,700℃时,单电池的极化阻抗为0.15 Ω·cm²,最大功率密度为400 mW·cm^-2。     

Composite film of carbon nanotubes and chitosan for preparation of amperometric hydrogen peroxide biosensor

A new amperometric biosensor for hydrogen peroxide was developed based on cross-linking horseradish peroxidase (HRP) by glutaraldehyde with multiwall carbon nanotubes/chitosan (MWNTs/chitosan) composite film coated on a glassy carbon electrode. MWNTs were firstly dissolved in a chitosan solution. Then the morphology of MWNTs/chitosan composite film was characterized by field-emission scanning electron microscopy. The results showed that MWNTs were well soluble in chitosan and robust films could be formed on the surface. HRP was cross-linked by glutaraldehyde with MWNTs/chitosan film to prepare a hydrogen peroxide biosensor. The enzyme electrode exhibited excellent electrocatalytic activity and rapid response for H₂O₂ in the absence of a mediator. The linear range of detection towards H₂O₂ (applied potential: −0.2 V) was from 1.67 × 10⁻⁵ to 7.40 × 10⁻⁴ M with correction coefficient of 0.998. The biosensor had good repeatability and stability for the determination of H₂O₂. There were no interferences from ascorbic acid, glucose, citrate acid and lactic acid.     

Performance of H2/O2 fuel cell using membrane electrolyte of phosphotungstic acid-modified 3-glycidoxypropyl-trimethoxysilanes

Proton-conducting membranes based on phosphotungstic acid (PWA) and 3-glycidoxypropyl-trimethoxysilane (GPTMS) was investigated as the electrolyte for low temperature H₂/O₂ fuel cell. Parameters determining the conductivity and elastic modulus of the membranes were characterized by thermogravimetry/differential thermal analysis and infrared spectroscopic measurements. The composite containing 5% of PWA exhibited an elastic modulus below 100 MPa at room temperature and a high proton conductivity of 1.0 × 10⁻² S/cm at 80 °C and 100% RH. Low elastic modulus of the membrane was found to be useful for both the reduction of the membrane thickness and the better contact with the electrodes. The performance of the membrane electrode assemblies (MEA) was systematically studied as an effect of preparation conditions. A maximum power density of 45 mW/cm² and the current density of 175 mA/cm² at 0.2 V were achieved at 90 °C and 100% RH for the membrane of 5PWA·95GPTMS composition and 0.2 mm thickness.     

On-line microdialysis system with poly(amidoamine)-encapsulated Pt nanoparticles biosensor for glutamate sensing in vivo

In this work, an amine-terminated poly (amidoamine) dendrimer containing Pt nanoparticles (PAMAM/Pt) nanocomposite was synthesized and a novel amperometric H(2)O(2) biosensor based on PAMAM/Pt and MWCNTs was developed. The resulting film of MWCNTs/PAMAM/Pt was characterized by transmission electron microscopy (TEM), linear sweep voltammetry (LSV) and amperometric i-t curve. It demonstrates excellent electrocatalytic responses toward the reduction of H(2)O(2) at -200 mV (vs.SCE) without HRP participation. Immobilized with glutamate oxidase (GlutaOx), an effective glutamate biosensor, was fabricated, and the in vivo detection for glutamate was realized combining with the on-line microdialysis system. The glutamate biosensor showed good linear range from 1.0 μM to 50.0 μM with the detection limit of 0.5 μM (S/N=3). The basal level of glutamate in the striatum of rat was detected continuously with this on-line system and was calculated to be 5.80±0.12 μM (n=3). This method was proved to be sensitive and selective and may be feasible in the further application of physiology and pathology.     

梯度Cu-CeO2-Ni-YSZ复合阳极直接甲烷SOFC的制备与性能

采用三层共压-共烧结法, 并涂覆La_0.8Sr_0.2MnO₃ (LSM)阴极, 制备了梯度Ni-YSZ阳极结构的固体氧化物燃料电池(SOFC)(大孔Ni-YSZ|微孔Ni-YSZ|YSZ|LSM) (YSZ: Y₂O₃稳定的ZrO₂; LSM: Sr 掺杂的LaMnO₃).通过浸渍法在大孔Ni-YSZ 基底中沉积占总重量约1%的Cu-CeO₂抗积碳催化剂, 形成梯度Cu-CeO₂-Ni-YSZ复合阳极. 分别以CH₄和H₂为燃料, 空气为氧化剂, 测定了构造的SOFC输出电性能和长期稳定性. 结果表明,三层共压-共烧结法制备的梯度阳极SOFC, 层间结合紧密无缺陷, 阳极梯度孔结构明显, YSZ膜致密无缺陷.在850℃下操作, 以梯度Ni-YSZ 阳极制备的SOFC, 燃料由H₂切换为甲烷时, 最大功率密度由284 mW·cm^-2下降到143 mW·cm^-2; 而以Cu-CeO₂-Ni-YSZ 复合阳极构造的SOFC出现相反趋势, H₂切换为甲烷后最大输出由176 mW·cm^-2增加到196 mW·cm^-2. 在250 mA·cm^-2负荷下, 梯度Ni-YSZ阳极支撑的直接甲烷SOFC仅稳定运转10 h 便出现明显衰减, 阳极中积碳严重; 但Cu-CeO₂-Ni-YSZ 复合阳极支撑SOFC连续运转50 h, 输出电压与输出功率密度基本不变, 电镜观察不到积碳.     

Design and Preparation of NiFe2O4@FeOOH Composite Electrocatalyst for Highly Efficient and Stable Oxygen Evolution Reaction

Rational design and constructing earth-abundant electrocatalysts for efficient electrocatalytic water splitting is a crucial challenge. Herein, we report a simple and efficient one-step electrochemical synthetic route of the NiFe₂O₄@FeOOH composite electrocatalyst for the oxygen evolution reaction. The unique morphology of the NiFe₂O₄ nanoflowers loaded on FeOOH nanosheets allows more active sites to be exposed and promote charge transfer as well as gas release, and the resulting electrode enables a current density of 10 mA cm⁻² at a low overpotential of 255 mV with outstanding stability at a current density of 100 mA cm⁻² for 300 h.     

Au/Al2O3纳米复合薄膜的制备和表征

用溶胶-凝胶法制备了Au/Al₂O₃纳米复合薄膜。利用X-射线衍射、X-射线光电子能谱、原子力显微镜以及紫外-可见光谱对薄膜的微观结构、表面形貌及光学性能进行了表征,研究表明:Au/Al₂O₃纳米复合薄膜是由纳米微晶组成的颗粒膜, 复合薄膜均匀、致密、无裂纹,Au以纳米晶核形式镶嵌于Al₂O₃基体中,纳米Au晶核的粒径为23～26nm;复合薄膜在可见光区有较强的吸收,吸收峰位置与烧结温度有关,吸收强度随烧结温度和金添加量增大而增大。     

致密的5%Al3+掺杂的SnP2O7-SnO2复合陶瓷在中温燃料电池中的应用

首先制备了未掺杂和5%(摩尔分数)Al³⁺掺杂SnO₂的多孔性基片, 然后将基片与85%的H₃PO₄在600℃下反应, 分别得到了致密的未掺杂和5%Al³⁺掺杂的SnP₂O₇-SnO₂复合陶瓷样品. 采用X射线衍射(XRD), 扫描电子显微镜(SEM)和X射线能量色散谱(EDS)测试方法对样品进行了表征, 采用电化学阻抗谱法(EIS)测试了样品在中温(100-250℃)下, 湿润空气和湿润氢气气氛中的电导率. 结果表明, 在湿润空气和湿润氢气中, 5%Al³⁺掺杂的SnP₂O₇-SnO₂复合陶瓷样品的电导率均高于未掺杂的SnP₂O₇-SnO₂复合陶瓷样品的电导率, 且该复合陶瓷样品在湿润空气和湿润氢气中250℃下, 电导率分别达到最大值: 4.30×10^-2和6.25×10^-2 S·cm^-1, 高于至今报道的SnP₂O₇-SnO₂基复合陶瓷及SnP₂O₇基陶瓷在类似条件下的电导率. 以5%Al³⁺掺杂的SnP₂O₇-SnO₂复合陶瓷样品(厚度: 1.45 mm)为电解质, 多孔性铂为电极组装成的氢气/空气燃料电池具有良好的中温电池性能, 175、200、250℃的最大输出功率密度分别为52.0、61.9、82.3 mW·cm^-2. 良好的中温电池性能与该复合陶瓷电解质较高的电导率和致密度及该燃料电池较低的界面极化电阻有关.     

Interaction of SO2 with O2 over mixed Pt, Pd, Pt?Pd and Pt?Ru oxidation catalysts and combined treatment of automobile exhaust gases

TPD, XPS IR methods were used to study how the composition of mixed Pt and Pd contacts over Al₂O₃ affects the nature of SO₂ complexes formed in the presence of O₂. Two types of sulfates of different structure and binding strength are formed in SO₂ oxidation by oxygen over Pt and Pd contacts. Introducing elements such as Co and Cr into the composition, one can significantly reduce the formation of weakly binding sulfate-1 as well as sulfate-2 too.     

NH4PO3-SiO2复合电解质的溶胶凝胶法制备和导电性能

用溶胶凝胶法制备了复合固体电解质xNH₄PO₃-SiO₂(x=1，2，4)，并研究了该电解质在125～250 ℃范围内的导电性能。复合电解质的相结构分析表明，NH₄PO₃和SiO₂在溶胶凝胶法制备过程中没有发生化学反应;复合电解质的电导率随着NH₄PO₃含量增大而提高，并与NH₄PO     

Cu-Sn-P-LiMn2O4纳米复合材料镀层的XPS和AES研究

采用化学复合镀技术，在Q₂₃₅碳钢片表面制备了Cu-Sn-P-LiMn₂O₄纳米复合材料镀层。用扫描电子显微镜(SEM)观察外貌；称重法测定厚度；通过5% NaCl溶液、1% H₂S气体加速腐蚀试验、抗粘性试验及室温氧化试验等多种手段测定其性能。用X-射线光电子能谱(XPS)及俄歇电子能谱(AES)测定其价态及组成。结果表明:Cu-Sn-P-LiMn₂O₄纳米复合材料镀层的性