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1.
用离子散射谱(ISS)、俄歇电子能谱(AES)及低能电子衍射(LEED)技术对Ni3Ti(0001)表面结构与组成进行考察后,主要采用高分辨电子能量损失谱(HREELS),以CO为探针分子,研究了清洁及部分氧化的Ni3Ti(0001)表面上Ni,Ti间的相互作用及对CO吸附态的影响.结果表明:(1)在最表层几乎完全为Ni的Ni3Ti(0001)清洁规整表面上,CO没有发生解离;(2)次表层Ti原子与最表层Ni原子间的电子相互作用,使初始吸附的CO伸缩振动与Ni(111)相比向低频位移约60cm-1;(3)适量CO暴露后,CO氧端与近邻Ti原子的成键作用产生了一种新的Nix-C-O-Tiy物种.Ni3Ti(0001)表面部分氧化后,上述(2)和(3)作用消失 相似文献
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对聚砜(PSF)、聚二甲基硅氧烷(PDMS)和聚对羟基苯乙烯(PHS)的三元多嵌段共聚物[PSF-PDMS-PHS]n的形态和表面组成进行了研究,结果表明溶液成膜后,组成不同的聚合物样品的表面都有有机硅(PDMS)的富集.在用溶剂处理后,富集于膜表面的有机硅含量与所用溶剂的溶度参数有关,一般均下降,但是用水处理后,表面层有机硅的含量却增加 相似文献
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TiO_2纳米粒子的表面修饰研究 总被引:22,自引:0,他引:22
利用表面修饰法合成了油酸(OA)修饰的TiO_2纳米粒子,采用红外光谱(IR )、透射电子显微镜(TEM)和X射线光电子能谱(XPS)对表面修饰的TiO_2纳米粒 子进行了结构表征,并研究了油酸浓度对TiO_2表面覆盖量及在油中分散性能的影 响。研究结果表明通过油酸表面修饰,成功合成了具有油分散性能的纳米TiO_2, 并且获得了油酸修饰量与TiO_2的最佳配比。 相似文献
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采用第一性原理的方法对ZrC(111)清洁和氢吸附表面的电子结构进行了研究 。构型优化结果表明,从表面深入到体相一定深度,层间距存在交替“收缩”和“ 扩张”的现象,其紧邻E_F以下的DOS峰对应于活性表面态,主要成分为表面Zr原子 4d_(xz)/d_(yz)轨道;与理想表面相比,表面弛豫对该表面态影响不大。对于氢吸 附表面,计算结果表明氢原子倾向于吸附在表面孔洞上方位置(正对着第三层Zr原 子),此时H的1s态从体相的电子态中分离出来。此外,本文中H/ZrC(111)和 H/NbC(111)体系的H 1s诱导态变化进行了解释,并对清洁的吸附表面的芯能级位 移以及功函的变化进行了探讨。 相似文献
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利用X射线光电子能谱(XPS)和紫外光电子能谱(UPS)等表面分析方法,表征了甲酸和乙酸在ZrO2表面 的反应和吸附态。室温下,甲酸在ZrO2表面以HCOO-(a)的形态被吸附,部分HCOO-(a)进一步分解产生O~(2-)(a), HCO(a)和CH_x(a),加热有利于表面甲酸根的分解。乙酸在ZrO2表面的反应与甲酸相似。甲酸和乙酸在ZrO2表面 的吸附实质就是表面酸碱中和反应。 相似文献
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采用MNDO(UHF)方法计算了金刚石(100)-(1×1):2H双氢化表面和(100)-(2×1):H单氢化表面的脱氢势垒,论证了决定金刚石附氢表面脱氢势垒大小的主要因素是气相-表面吸附氢原子间的相互排斥大小,得出(100)面两种表面结构脱氢势垒的理论预言值分别为71和59kJ·mol-1,均大于(111)面脱氢势垒的理论预言值42kJ·mol-1.揭示了在同等生长条件下金刚石(111)面可供成核和生长的反应基多于(100)面,与实验上得到的同等生长条件下(111)面的相对生长率大于(100)面的结论是一致的。 相似文献
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TiO_2-K_2SiO_3无机涂层对空间材料Ag的防护行为研究 总被引:1,自引:0,他引:1
在微波电离型原子氮(AO)源地面模拟设备中对空间材料Ag及TiO_2- K_2SiO_3无机涂层进行原子氧剥蚀效应试验。用扫描电镜(SEM)、光电子能谱( XPS)、红外光谱(FT-IR)、X射线衍射光谱(XRD)和LAMBDA-9分光光度计,对在 模拟原子氧(AO)环境中Ag及在其表面涂覆的无机涂层,所发生的侵蚀与防护作用 进行了表征研究。AO对Ag表现了较严重的侵蚀作用,原来光亮如镜的表面形貌变得 粗糙,且失去光泽。而所施用的TiO_2-K_2SiO_3无机涂层,经AO辐照后,表面形貌 则变化甚少。实验表明,该涂层对AO辐照有较强的防护效果、较好的空间稳定性( AO辐照前后Δα ≈ 0.024),能阻止AO对基材的侵蚀。 相似文献
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Electrochemical behavior of metal hydrides 总被引:1,自引:0,他引:1
J. Kleperis G. Wójcik A. Czerwinski J. Skowronski M. Kopczyk M. Beltowska-Brzezinska 《Journal of Solid State Electrochemistry》2001,5(4):229-249
Metal hydride electrodes are of particular interest owing to their potential and practical application in batteries. A large
number of hydrogen storage materials has been characterized so far. This paper deals with the effect of the chemical nature
and stoichiometry of specific alloy families (AB5, A2B, AB/AB2 and AB2) on the hydride stability, hydrogen storage capacity and kinetics of hydrogen sorption-desorption in the solid phase/gas
and solid phase/electrolyte solution systems. Special attention has been paid towards the electrochemical properties of metal
hydrides in terms of their performance in Ni-MH rechargeable alkaline cells.
Electronic Publication 相似文献
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M. Tliha C. Khaldi S. Boussami N. Fenineche O. El-Kedim H. Mathlouthi J. Lamloumi 《Journal of Solid State Electrochemistry》2014,18(3):577-593
This paper reviews the present performances of intermetallic compound families as materials for negative electrodes of rechargeable Ni/MH batteries. The performance of the metal-hydride electrode is determined by both the kinetics of the processes occurring at the metal/solution interface and the rate of hydrogen diffusion within the bulk of the alloy. Thermodynamic and electrochemical properties for each hydride compound family will be reported. The steps of hydrogen absorption/desorption such as charge-transfer and hydrogen diffusion for evaluating the electrochemical properties of hydrogen storage alloys are discussed. Exchange current density (I 0) and hydrogen diffusion coefficient (D H) are the two most important parameters for evaluating the electrochemical properties of metal hydride electrode. The values of the two parameters for a number of hydrogen storage alloys are compared. The relationship between alloy composition and electrochemical properties is noted and evaluated. 相似文献
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通过对Mm(NiMnCoAl)5电极的化学活化处理提高了金属氢化物电极的容量、电催化活性、活化性能和快速放电能力;讨论了化学活化处理对金属氢化物电极电化学性能的影响;在活化剂KBH4作用下,金属氢化物表面的氧化物技还原,在活化过程中一部分氢原子贮入合金之中,增加了电极的比表面,文中试验了这种活化方法对Ni/MH电池封口化成的作用,测试结果表明封口化成的AA型Ni-MH电池性能与开口化成电池的性能相当,其容量达到1050~1150mAh,1C、3C、SC信率下放电容量分别达到0.2C下的96.7%、89.0%、83.8% 相似文献
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Aluminum-cobalt co-substituted α-Ni(OH)2 was prepared by means of the titration method in a buffer solution, the structure was characterized by XRD analysis. With above mentioned α-Ni(OH)2 as the positive electrode of a nickel-metal hydride cell, the discharge performances were examined by constant-current charge-discharge experiments. In comparison with the electrodes made of aluminum substituted or cobalt substituted Ni(OH)2 materials, the aluminum-cobalt co-substituted composite electrodes possess an excellent electrochemical performance and are of practical significance. 相似文献
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我国金属氢化物化学研究 总被引:6,自引:0,他引:6
综述了我国金属氢化物化学的发展。我国是从50年代中期开始研究离子型金属氢化物的合成、性能和应用的,发展了一些合成方法,获得了多项中国专利。储氢合金的化学研究是70年代中期开始的。在储氢合金的化学合成、吸放氢热力学与动力学、储氢合金氢化催化和电化学方面都有较深入的研究,特别是储氢电极合金电化学及其在Ni/MH可逆电池中的应用研究,在国家863计划强有力的支持下,某些方面进入了国际先进行列。 相似文献
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Katsuhiko Shinyama Yoshifumi Magari Tadayoshi Tanaka Hiroshi Nakamura Toshiyuki Nohma Ikuo Yonezu 《Research on Chemical Intermediates》2006,32(5):419-429
The effects of electroless nickel plating of a hydrogen-absorbing alloy on the cycle characteristics of a nickel-metal hydride
battery were investigated. The cycle life was improved by employing an electroless nickel-plated hydrogen-absorbing alloy
for the negative electrode, which retained the same high-rate level and low-temperature characteristics compared to a cell
using a non-plated hydrogen-absorbing alloy. The electroless nickel-plated hydrogen-absorbing alloy provided better electrochemical
characteristics when its surface was partly and tightly covered by nickel particles under optimal electroless plating conditions. 相似文献
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A Ti-V-based bcc phase alloy for use as metal hydride electrode with high discharge capacity 总被引:2,自引:0,他引:2
The electrochemical characteristics of single bcc phase Ti-30V-15Cr-15Mn alloy were investigated. It was demonstrated that the single bcc phase alloy has high electrochemical discharge performance at high temperature. Its discharge capacity is closely related with temperature and discharge current. The first discharge capacities of 580-814 mAh g(-1) of the alloy powder were obtained at discharge current of 45-10 mA g(-1) in 6 M KOH solution at 353 K. Although the electrochemical cycle life of the alloy is unsatisfactory at present, it opens up prospects for developing a new hydrogen storage alloy with high hydrogen capacity for use as high performance metal hydride electrodes in rechargeable Ni-MH battery. 相似文献
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铂基Pb-Sb表面合金电催化剂的制备与结构表征 总被引:3,自引:1,他引:2
通过电化学方法,在玻碳载体表面制备以Pt、Pb、Sb为主要成分的铂基Pb Sb表面合金电催化剂.运用电化学循环伏安、石英晶体微天平(EQCM)和扫描隧道显微镜(STM)技术对催化剂电极进行表征.结果表明:酸性溶液中在所制备的表面合金电极上,析氢起始电位负移至-0.45 V,表面合金的起始氧化电位为0.15 V,其稳定性明显高于电催化还原中常用的铅、锑等金属电极.通过EQCM研究表面合金电极的形成过程,结合STM观察和XPS深度剖析,确定电催化剂表面是由粒度均匀的纳米颗粒构成的表面合金层. 相似文献