表面处理对储氢合金电化学性能的影响研究

通过电化学方法,研究了储氢合金碱化处理及碱液中加入KBH4对合金电极的电催化活性和高倍率放电性能的影响.结果表明:处理后合金颗粒分布均匀,表面变得粗糙.两种处理方法均增加了合金表面的电催化活性,降低了合金电极的极化电阻,从而提高了高倍率放电能力.尤其在900mA/g放电时,处理前合金电极不能放电,单一碱处理合金电极和加入还原剂碱处理合金电极仍具有较高的高倍率放电能力,分别为69.2%和83.4%.在单一碱溶液中加入还原剂KBH4处理后,合金电极的电化学性能明显高于单一碱处理合金电极.     

钒电池中石墨基复合电极的制备及性能

以V2O5为原料,电解制取VOSO4溶液.用炭黑和石墨粉压制电极,与导电铜网和炭毡构成石墨基复创合电极.炭毡经过热处理和化学处理,其电化学活性有所提高.此外,研究了复合电极在2 mol/LVOSO4和3mol/LH 2SO4溶液中的电化学行为,实验结果表明:这种复合电极对钒离子氧化还原反应的催化活性较好.     

表面处理对镧镨铈贮氢合金电极电化学性能的影响

研究了硼氢化钾、次磷酸钠、热碱溶液处理等表面处理方法对镧镨铈(LPC)贮氢合金电极电化学性能影响.结果表明,在研究范围内,各种表面处理方法均明显改善电极的活化性能,提高初始放电容量;热碱处理的时间和温度对电化学性能影响很大;KBH4处理能明显改善循环稳定性,但降低最大容量;NaH2PO4处理能提高最大放电容量,但不利于循环稳定性的提高;综合比较,热碱处理的综合电化学性能最好,且工艺简单,成本低廉.     

Si/BDD电极在酸/碱电解条件下的电化学氧化性能变化

目的 探究Si/BDD电极在酸性、碱性2种电解条件下的性能变化特征,阐明BDD电极在酸、碱溶液中电化学氧化性能的变化与失效机理。方法 通过HFCVD技术制备Si/BDD电极,分别在1 mol/L H₂SO₄、1 mol/L NaOH溶液中进行加速寿命实验,以活性蓝19(RB-19)模拟染料废水,进行电化学氧化降解实验。使用扫描电子显微镜、拉曼光谱、接触角测试仪、紫外分光光度计及电化学工作站对电极的表面形貌、成分及电化学性能进行表征。结果 在1 mol/L NaOH溶液中,当电解时间为195 h时,电极表面部分区域发生了明显的脱落现象;在1 mol/L H₂SO₄溶液中,当电解时间达到600 h时,电极表面仍未出现明显的脱落现象,电极表面形貌由清晰转为模糊,晶粒尺寸细化,且在晶界处存在明显的腐蚀现象;在酸溶液中,BDD电极对RB-19的降解效果随着电解时间的延长而提高,而在碱溶液中,其降解效果与电解10 h的降解效果基本一致。结论 与酸溶液相比,Si/BDD电极更易在碱溶液中发生腐蚀。     

爆炸复合Pt/Ti电极的电化学性能

Pt/Ti电极作为一种优良的耐腐蚀复合材料,被广泛应用于海洋工业、氯碱工业及电子工业。根据铂层厚度及性能的差异,电镀与爆炸复合工艺均被广泛应用于Pt/Ti复合电极的工业化生产。采用SEM对爆炸复合Pt/Ti电极的表面及扩散层形貌进行了研究;采用PARSTAT4000型电化学分析仪对爆炸复合Pt/Ti电极试样的极化曲线(Tafel曲线)及循环伏安特性曲线(CV曲线)进行了测试,对比了电镀工艺Pt/Ti电极的电化学性能。结果表明,Pt/Ti复合电极的表面形貌对其电化学活性具有重要影响,爆炸复合工艺制备的Pt/Ti电极表面十分致密,沿着轧制方向具有明显的加工流线,抗腐蚀性能较佳;电镀工艺制备的Pt/Ti复合电极表面铂层呈颗粒状分布,增大了与溶液的实际接触面积,表面活性较好。     

电纺法制备PAN基高比表面积活性纳米碳纤维

将聚丙烯腈(PAN)粉末配制为PAN/DMF溶液,通过静电纺丝工艺制备了PAN纳米纤维,然后依次进行预氧化、碳化处理得到纳米碳纤维;采用CO₂作为活化剂制备了超大比表面积活性碳纤维。使用扫描电镜、场发射透射电镜、拉曼光谱,傅里叶红外光谱和N₂吸附等手段对样品的形貌、成分和结构进行了全面表征,研究了聚合物溶液浓度和静电压对PAN纳米纤维形貌和直径的影响。活性碳纤维独特的孔结构使其作为电极材料在多种电解液中保持了较高的比容量。结果表明活化后的碳纤维的比表面积、总孔容和微孔孔容都明显增加,本研究所制备的活性碳纤维具有极高的比面积和良好的电导率,使其在超级电容器电极材料领域有着进一步的应用。     

碳纤维复合贴片的界面行为研究

采用低温等离子体法对碳纤维进行表面处理,并在微波固化条件下将碳纤维与环氧树脂复合成形,制得碳纤维复合贴片.采用X射线光电子能谱仪对碳纤维表面的元素组成进行了表征,采用扫描电镜和能量散射光谱(EDS)对碳纤维/树脂界面区的形貌和元素分布进行了表征.结果表明:碳纤维经处理后,其表面氨基官能团的含量增大,有利于纤维与树脂的化...     

Effec钛基IrO_2-Ta_2O_5涂层阳极形状对电化学性能的影响(英文)

钛基IrO2-Ta2O5涂层阳极的形状分别是板状和扩张网。采用涂覆了H2IrCl6.H2O的盐酸溶液和TaCl5乙醇溶液的混合溶液再进行热分解制备得到IrO2-Ta2O5涂层。分别采用SEM,EDX,CV和加速寿命测试对电极的微观结构和电化学性能进行分析。相对板状电极而言,由于较少的活性物质IrO2在电极表面结晶析出,扩张网状电极具有更低的电化学催化活性。但是由于表面的裂纹较为细密、表面活性元素分布也较为均匀,并且其纵截面的形状更有利于电解析出的气泡排出,扩张网状电极具有更长的加速寿命。     

上浆剂对国产碳纤维/聚酰亚胺复合材料界面性能的影响

采用2种高温型上浆剂（溶液型和乳液型）对国产CCF300（表面已去浆）碳纤维进行上浆处理。通过扫描电子显微镜、X射线光电子能谱和接触角测试等手段,研究上浆剂对碳纤维表面性能的影响。通过对层间剪切强度（ILSS）的测试,研究上浆剂对碳纤维增强聚酰亚胺复合材料界面性能的影响。结果表明：2种上浆剂均能在碳纤维表面引入大量含氧官能团,增加碳纤维的表面能,并改善碳纤维与树脂间的浸润性;溶液型上浆剂使复合材料的ILSS提高了17%,乳液型上浆剂使复合材料的ILSS提高了12%,在高温下溶液型上浆剂表现出更好的耐热性能。     

Effect of Different Shapes of the Titanium Based IrO2-Ta2O5 Coatings Anode on Electrochemical Properties

钛基IrO2-Ta2O5涂层阳极的形状分别是板状和扩张网。采用涂覆了H2IrCl6.H2O的盐酸溶液和TaCl5乙醇溶液的混合溶液再进行热分解制备得到IrO2-Ta2O5涂层。分别采用SEM,EDX,CV和加速寿命测试对电极的微观结构和电化学性能进行分析。相对板状电极而言,由于较少的活性物质IrO2在电极表面结晶析出,扩张网状电极具有更低的电化学催化活性。但是由于表面的裂纹较为细密、表面活性元素分布也较为均匀,并且其纵截面的形状更有利于电解析出的气泡排出,扩张网状电极具有更长的加速寿命。     

Effect of carbon fiber surface treatment on Cu electrodeposition: The electrochemical behavior and the morphology of Cu deposits

The relationship between surface functional groups and electrochemical behaviors of polyacrylonitrile (PAN)-based carbon fibers (CFs) differentiated by oxidation treatment in air was studied. The chemical character of the CFs surface was estimated by X-ray photoelectron spectroscopy (XPS) and the electrochemical behavior of treated CFs in CuSO₄ plating solution was studied by electrochemical setup. The influence of functional groups on the morphology of copper deposits was characterized by field-emission scanning electron microscopy (FESEM). It was found that the O/C atomic ratio rose rapidly from 23.05% (as-received carbon fibers) to 42.83% as the oxidation temperature was increased to 400 °C and the content of -CO was the highest. Concentrations and types of the functional groups on CFs surface showed a close connection with the electrochemical response of CFs in CuSO₄ plating bath. It was showed that Cu electrodeposition was the interaction of applied voltage and the reduction of surface functional groups. With the functional groups increased, the quantities of the Cu nuclei increased, further the morphology of deposited Cu was affected.     

In-situ processing of carbon coatings on the surface of SiC-based fibers

Carbon coatings have been formed on the surface of free carbon containing Tyranno ZMI and Nicalon SiC-based fibers by reaction with chlorine gas (chlorination) in the temperature range 550-675 °C. The kinetics and growth mechanisms have been investigated for both fibers. Results have shown that, for similar experimental conditions, the reactivity of both fibers displayed noticeable discrepancies. It has thus been observed that the Nicalon fiber was more prone to chlorine-based treatment and displayed a thicker carbon coating than the ZMI fiber. These results have also revealed that, in both cases, these thicknesses can be closely monitored by physical parameters such as temperature and aging duration. The nature of the obtained coating has also been investigated by various experimental devices. AES, SEM and TEM analyses have thus evidenced that these carbon coatings were uniform and well adherent whereas AFM showed that the chlorine-based treatments resulted in a nanometer-range roughness at the fiber surface. Adsorption gas analyses also revealed a microporosity coupled with a high specific surface area. The chemical composition of the final products was determined by XPS and Mass Spectroscopy. Finally, the oxidation behavior which was investigated by thermogravimetric analysis revealed that oxidation occurs at a quite low temperature (225 °C).     

Preparation and mechanism of calcium phosphate coatings on chemical modified carbon fibers by biomineralization

In order to prepare HA coatings on the carbon fibers, chemical modification and biomineralization processes were applied. The phase components, morphologies, and possible growth mechanism of calcium phosphate were studied by infrared spectrosenpy（IR）, X-ray diffractometry（XRD） and scanning electron microsenpy（SEM）. The results show that calcium phosphate coating on carbon fibers can be obtained by biomineralization. But the phase components and morphologies of calcium phosphate coatings are different due to different modification methods. Plate-like CaHPO4·2H2O （DCPD） crystals grow from one site of the active centre by HNO3 treatment. While on the para-aminobenzoic acid treated fibers, the coating is composed of nano-structural HA crystal homogeneously. This is because the -COOH functional groups of para-aminobenzoic acid graft on fibers, with negative charge and arranged structure, accelerating the HA crystal nucleation and crystallization on the carbon fibers.     

碳纤维表面生长纳米碳管及其增强的炭/炭复合材料

采用化学气相沉积工艺在碳纤维表面生长了纳米碳管,将此种碳纤维作为增强材料,以中间相沥青为基体炭前驱体采用浸渍炭化工艺制备了炭/炭复合材料.观察了所得复合材料断口的微观形貌,测试了抗弯强度及热物理性能.结果表明,碳纤维表面的纳米碳管可以有效地提高纤维与基体的粘结力,复合材料的抗弯性能提高了50%,而对复合材料的导热性能影响较小.     

STUDY OF MICROSTRUCTURE ON PAN-ACFS PREPARED BY DIFFERENT ACTIVATION METHODS

1. IntroductionPorous solids play an important role in the fields of separation and purification. Ac-tivated carbon fiber (ACF) is a kind of typically ndcroporous carbonaceous adsorbent,which developed from organic precursors either by physical activation or chemical activa-tion. There are many advant8ges for ACFs comparing with conventional activated carbons(AC), including very faSt adsorption/desorption rates. ACFs can be used in the fOrm ofcloth, paPer or felt and so on. Furthermore A…     

Untersuchungen zur Bestimmung des Einflusses funktioneller Gruppen in N-haltigen Inhibitoren auf die Korrosionsschutzwirkung

Investigations into the determination of the influence of functional groups in N-containing inhibitors on the corrosion protection efficiency 91 compounds, primarily from the class of benzimidazoles, were synthesized as model substances for establishing relationships between molecular structure and inhibitors efficiency. Gravimetric and electrochemical tests as well as surface analysis were used to determine the influence of various functional groups on the inhibition of corrosion according to the type and position of these groups in the N-containing heterocycles. The analyses were performed in 1 mole NaClO₄ and in drinking water with unalloyed steel, oxygen-free copper and aluminium 99.5 as the test materials. The gravimetric tests show the type and length of the side chain, substituents at the nucleus and the functional group have an appreciable influence on the inhibition of corrosion. The electrochemical measurements show that the model substances can be divided into two groups according to their inhibitive effect: the anodically active ones (containing phosphono groups) and the cathodically active ones. The surface analysis tests using ESCA show, for example, that with the 2-aminopentyl benzimidazole, monomolecular adsorbates up to three atom layers thick are deposited on oxygen-free copper.     

Synthesis of vertically-aligned carbon nanotubes on stainless steel by water-assisted chemical vapor deposition and characterization of their electrochemical properties

We demonstrate synthesis of carbon nanotubes on stainless steel by water-assisted chemical vapor deposition using an Al/Fe bimetallic catalyst. A forest of vertically-oriented carbon nanotubes with a length of a few hundreds of micrometers were grown on the substrates. Electrical measurement confirmed that the carbon nanotubes were electrically connected to the stainless steel. Owing to the carbon nanotubes, electrochemical properties such as faradaic current and electron transfer were considerably improved. Carbon nanotubes grown on the stainless steel substrates would potentially be useful for various applications including electrochemical energy conversion and storage.     

The Effect of Surface Modification on the Interfacial Feature of Polystyrene Composite Filled with Carbon Fiber

The quality of interfacial interaction is dictated by the surface chemistry of the carbon fibers and the composition of the matrix. The composition of polystyrene was modified by the addition of maleic anhydride-grafted polystyrene (MAH-g-polystyrene). The surface properties of various matrix formulations were characterized by contact angle measurements. Carbon fibers were modified by nitric acid oxidation. The surface composition of the carbon fibers was characterized. The interaction between modified polystyrene and the carbon fibers was studied by single-fiber pull-out tests. The best adhesion behavior was achieved between polystyrene-containing grafted MAH and nitric acid-oxidized carbon fibers. The addition of MAH-g-polystyrene to the unmodified polystyrene caused the interfacial shear strength to increase. The apparent interfacial shear strength of this fiber-matrix combination allowed for the utilization of 100% of the yield tensile strength of polystyrene.     

Electrodeposition of metals after cation-exchange on modified carbon fibre electrodes

Several metals, Ag, Cu, Pb, Hg and Au, have been electrodeposited on carbon fibre electrodes after cation exchange of their salts with the acidic functional groups of oxidized fibres.Oxidation of carbon fibres was performed by thermal, photochemical and electrochemical treatment. The uptake of the metal cations is greater in the case of anodically oxidized and partially re-reduced carbon fibres, since this procedure leads to the formation of functional groups not only on the carbon surface, as in the case of thermal or photochemical oxidation, but also in the bulk of the fibres.The above-mentioned metals are deposited on the carbon support in a highly dispersed state, which decreases the hydrogen overvoltage and catalyses the reduction of nitroalkanes. These reactions take place on the metal-modified carbon electrodes at much more positive potentials than on carbon and at slightly more positive potentials than on the respective plain metallic electrodes.     

Electrodeposition of Metals and Their Oxides on Electrochemically Modified Three-Dimensional Carbon Nanotubes

The change in the qualitative and quantitative composition of oxygen-containing surface groups on the fibers of carbon-fibrous and nanocarbon materials is studied as a result of their electrochemical modification in solutions of indifferent electrolytes. The effect of preliminary electrode treatment on the efficiency of electrodeposition of metals on carbon-fibrous and nanocarbon materials is shown by the example of electrodeposition of cadmium, copper, nickel, and platinum, and that of metal oxides by the example of precipitation of manganese oxide. Preliminary electrochemical treatment of these carbon materials allows obtaining precipitates in the form of nanosized particles and in the form of continuous coating with good adhesion to the surface of the fibers of carbon materials.