MlNi4Co0.6Al0.4储H2合金表面吸H2的TDS研究

用热脱附谱(TDS)对不同表面处理的富La混合储H2合金MlNi4Co0.6Al0.4粉末样品进行H2气吸附和脱附特性的比较和研究。未经表面处理的粉末样品,只测到一个H2脱附峰(α峰),脱附温度在400K左右;经6molKOH溶液,在80℃下处理6h的MlNi4Co0.6Al0.4粉末样品,有2个H2热脱附峰(β峰和γ峰),脱附温度分别在540和630K处;而用6molKOH+0.02molKBH4溶液处理后,则有3个H2热脱附峰(α峰,β峰和γ峰),脱附温度分别在400,530和640K处。TDS研究表明,热碱加还原的处理使材料表面对H2气吸附的活性和容量提高,并使各个吸附态的扩散和转变更加容易。     

MINi4Co0.6Al0.4储H2合金表面吸H2的TDS研究

用热脱附谱（TDS）对不同表面处理的富La混合储H2合金MINi4Co0.6Al0.4粉末样品进行H2气吸附和脱附特性的比较和研究,未经表面处理的粉末样品,只测到一个H2脱附峰（α峰）,脱附 度在400K左右,经6mol KOH溶液,在80度下处理6h的MINi4Co0.6Al0.4粉末样品,有2个H2热脱附峰（β峰和γ峰）,脱附温度分别在540和630K处,而且6mol KOH 0.02mol KBH4溶液处理后,则有3个H2热脱附峰（α峰,β峰和γ锋）,脱附温度分别在400,530和640K处,TDS研究表明,热碱加还原的处理使表面对H2气吸附的活性和容量提高,并使各个吸附态的扩散和转变更加容易。     

程序升温热脱附法表征SmMnO_3及SmFeO_3的表面

本文用程序升温热脱附谱(TDS)及程序升温表面反应谱(TPRS),研究了SmMnO_3及SmFeO_3表面上CO与O_2的吸附与反应。实验表明,在SmMnO_3表面上,室温时就存在能与CO反应生成CO_2的氧物种,而对SmFeO_3来说,在温度为620K以前检测不到能与CO反应生化CO_2的氧物种。当CO与O_2先后吸附于SmMnO_3及SmFeO_3表面,则它们的TPRS都出现CO_2,但两者仍有区别。对SmMnO_2在室温以上的TPRS谱都有两个CO_2脱附峰,而对SmFeO_3则只有在较高温度吸附时才出现CO_2的第二个峰,且第二个峰的峰高在333K与451K间有一个极大值,表明在SmFeO_3上O_2在第二吸附中心的吸附是一个活化吸附过程。     

H_2O在多晶铜表面的热脱附研究

利用热脱附技术研究了80K下H_2O在多晶铜表面的吸附特性,结合程序升温脱附技术、高倍数光学显微镜、扫描电子显微镜和表面粗糙度因子对经三种不同方法(机械清洗、电抛光、化学清洗)处理的多晶铜表面进行了综合考察,得到了一些新的结果。     

Co_3O_4/介孔SiO_2复合体的制备及其介观结构的调控

以合成的螯合型表面活性剂N-月桂酰基乙二胺三乙酸(LED3A)为模板剂,利用其与Co2+的配位作用,一步法制备了Co3O4/介孔SiO2复合体。借助紫外光谱验证了LED3A与Co2+间的配位作用,热重分析仪测定样品合适的煅烧温度,通过傅里叶变换红外光谱、X射线衍射、高分辨透射电子显微镜以及N2吸附-脱附等方法对制备的Co3O4/介孔SiO2复合体进行了组分分析和结构表征。发现所形成的Co3O4纳米颗粒分布于SiO2孔道中,并可通过调节Co2+的加入量来控制LED3A极性头电负性,分别得到Pm3n立方相、p6mm二维六方相和Ia3d立方相等不同的介观结构。     

原子氢在Si(100)表面吸附的FI-STM研究

高性能的场离子-扫描隧道显微镜(field ion-scanning tunneling microscope简称FI-STM)已成功地用于原子氢在Si(100)2×1表面的化学吸附过程的研究。结果表明,在小于6L低的氢暴露量下,氢原子通常是吸附在Si的二聚原子列(dimer rows)的顶部。随着氢暴露量的增加,先后出现Si(100)2×1:H单氢化物相(monohydride)和Si(100)1×1::2H双氢化物相(dihydride)两种表面结构。氢饱和的Si表面的热脱附研究表明,当样品被加热到590K时,表面结构并无明显变化;而到达670K时,则表面的(1×1)双氢化物相消失;当温度升高到730K时,(2×1)结构的二聚原子列又重现于表面,而且在Si衬底的台阶上出现许多错列的吸附原子链。这些原子链垂直于原先的Si的二聚原子列的方向,因此被认为是由Si的氢化物热解产生的Si原子在Si(100)表面的有序化排列。     

用闪烁脱附谱方法研究氧在电解银催化剂表面的吸附

本文报道了在超高真空下用四极质谱计来测量粉末样品热脱附谱的实验方法,并用它得列了电解银催化剂表面吸附氧以后的热脱附谱。实验表明,氧的热脱附谱峰位发生在300℃附近,且随升温速率β增大而增加。由谱峰形状的对称性和峰位随初始覆盖度增大而下降,可判断它是二级脱附,计算得到的脱附活化能为42 kcal/mol。     

Ce_(1-x)Y_xO_(2-δ)(x=0,0.15,0.25)纳米粉体的氧化-还原性能研究

为了研究氧化铈(YDC)材料的氧化还原性能,通过水溶液体系中沉淀反应平衡的计算,研究了Y3+、Ce3+在水溶液体系中共沉淀的pH值条件,并制备了Ce1-xYxO2-δ(x=0,15%,25%)纳米粉体,平均晶粒尺寸在12 nm左右。通过O2-TPD研究了Ce1-x YxO2-δ纳米粉体在室温~1 000℃的氧气的脱附行为,发现随着Y2O3掺杂量增加,氧脱附峰面积增大,但脱附氧的起始温度提高,说明Y2O3的掺杂使样品中的氧空位增加,增加了氧的脱附量。通过H2-TPR研究了Ce1-xYxO2-δ纳米粉体在200~1 000℃条件下的氢气还原能力,发现随着Y2O3掺杂量增加,在450~650℃,Ce1-xYxO2-δ纳米粉体消耗H2峰强度逐渐增大,说明Ce1-xYxO2-δ的抗还原性能提高;在750~950℃,CeO2纳米粉体的消耗H2峰强度逐渐减小,说明CeO2抗还原的能力逐渐降低。通过O-1s和Ce3d XPS能谱分析结果可知,随着Y2O3掺杂量增加,Ce1-xYxO2-δ纳米粉体的晶格氧峰和吸附氧峰的强度降低,证明了在加热过程中,Ce1-xYxO2-δ的氧气脱附量逐渐增大;相对在空气条件下加热处理的样品,在10%H2/Ar混合气体条件下加热处理后,Ce1-xYxO2-δ纳米粉体中有部分的Ce4+被还原为Ce3+。     

Co3O4纳米线的模板合成及其电化学性能

以三甲基氯硅烷(TMCS)和氨丙基三乙氧基硅烷(APTS)进行外内表面修饰的SBA-15为模板,Co(NO3)2·6H2O为原料,成功地合成了Co3O4纳米线.采用透射电子显微镜(TEM)、N2吸附-脱附、X-射线衍射(XRD)等多种手段对修饰后的SBA-15和Co3O4纳米线进行表征.结果证明:内外表面修饰后的SBA...     

CeO_2、TiO_2及Ce_(0.5)Ti_(0.5)O_2催化载体的制备及性能研究

采用热分解法、溶胶-凝胶法、沉淀法和水热法制备了CeO_2载体,SEM、XRD表征、N_2低温吸脱附和氢气程序升温还原(H2-TPR)实验和结果分析显示,溶胶-凝胶法制备样品具有更优的比表面积、孔容、孔径和氧化还原性能,故选择溶胶-凝胶法制备Ti_(0.5)Ce_(0.5)O_2混合氧化物催化载体。使用XRD、SEM、N2低温吸脱附、H2-TPR等分析手段对产物的物相特征、吸附性能和氧化还原性能进行了表征。Ti_(0.5)Ce_(0.5)O_2的H2-TPR在261、529和749℃处出现耗氢峰,分别归属于表面吸附氧的还原、表面晶格氧的还原和体相晶格氧的还原,TEM结果表明Ti4+离子进入CeO_2晶格形成TiO_2-CeO_2填隙固溶体,固溶体的形成有利于载体氧化还原能力的增强。     

高功率型和低温型镍氢电池用掺硼贮氢合金的研究

Ni/MH电池负极的高倍率性能和低温放电性能的提高应当受到重视，采用廉价的硼镍合金（B-Ni)作为掺硼添加剂，有效地改善常用MlNi3.55Co0.75Mn0.4Al0.3贮氢合金的高倍率性能和低温放电性能，实验结果表明，掺硼合金由于形成含CeCo4B相的复相结构可显著提高合金的电化学动力学性能，掺硼的MlNi3.55Co0.75Mn0.4Al0.3B0.3合金能够满足高功率型Ni/NH电池的高倍率性能和低温型Ni/MH电池在低温-35℃下的小倍率放电（≤120mA/g)的要求。     

一种新型稀土贮氢合金MlNi_(4.7)Al_(0.3)的贮氢性能

研究了新型稀土合金MlNi_(4.7)Al_(0.3)的PCT性能、动力学特性、活化性能、循环性能、抗O_2毒化性能.并与LaNi_5合金进行了比较,结果表明,MlNi_(4.7)Al_(0.3)活化性能、循环稳定性、抗O_2毒化性能均优于LaNi_5,是一种具有应用前景的稀土贮氢合金。     

Electrode Characteristics of MmNi_5-based Alloys for Nickel-Metal Hydride Batteries

Negative electrodes of the Ni-metal hydride battery were made from hydrogen storage alloy Mm0.9Ti0. 1Ni3. 9Mn0.4Co0.4Al0.3 mod fied by coating with Ni or mixing with Co powder. The cell volume expansion of hexagonal structure was about 12 % after coating with 11 % Ni on the alloy Surface,When this alloy was mixed with Co powder. the discharge capacity and the utilization efficiency of the hydrogen storage alloy increased. When the alloy was coated with 11 wt-% Ni and also mixed with 10 wt-% Co powder. the capacity decay for a small sealed cylindrical cell (AA size. 1 Ah) was only about 4 % after 200 cycles     

Study on Fine Structure of Gas Atomized LaNis-based Alloys

The fine structure of hydrogen storage alloy powders MlNi4.3-xCoxMn0.4Al0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis method. Two sets of CaCus-type crystal constants were observed in the studied alloys and one set was larger than the other. With decreasing powder radius the solidification rate of powder increased, and so did the percentage of a particle part with larger crystal constants. The reason why there were two sets of crystal constants might be the difference of solidification rate between the outside and inside of a particle.     

MlNi5-x （CoMnAl）x吸放氢性能及其催化聚合物双键加氢研究

为了探索新型聚合物双键加氢催化材料,采用XRD和自制吸氢装置等对贮氢合金MlNi5-x(CoMnAl)x的组成、吸放氢性能及其催化加氢活性等进行了研究.MlNi5-x(CoMnAl)x的P-C-T曲线表明,合金具有较低的平台压力,稳定性好;对比合金表面处理前后的吸氢动力学曲线发现:MlNi5-X(CoMnAl)x吸氢初期速度较快,后期则随时间延长吸氢量缓慢增加,而经过[6M KOH+1%KBH4]处理或Pd修饰后则可迅速达到吸氢平衡.催化聚合物双键加氢性能研究表明,未处理合金对NBR溶液加氢氢化度为零,经过[6M KOH+1%KBH4]处理和钯修饰后的合金可对NBR、SBS、NR等聚合物双键加氢,氢化度分别为33.5%、32.3%、31.1%.说明合金表面组成及结构对其吸放氢性能和催化活性均有明显影响.     

Adsorption and desorption of CO on Ni decorated stepped Rh(553)

Vicinal surfaces are important in surface science, as they show interesting electronic structures and reactivities due to the steps. In this paper the adsorption and desorption of carbon monoxide on the stepped Rh(553) surface decorated with Ni is reported. With 0.1 to 0.3 monolayer Ni on Rh(553) one and two atoms broad Ni wires along the Rh steps are formed. The adsorption and desorption of carbon monoxide on these surfaces is investigated using thermal desorption spectroscopy (TDS) and reflection absorption infra red spectroscopy (RAIRS). TDS shows a marked change from just one broad TDS peak on pure Rh(553) to 4 distinct peaks with increasing Ni decoration. RAIRS shows that already at 0.1 monolayer Ni the CO adsorption states on bridge sites on the Rh step atoms are completely quenched. In addition it is shown that with Ni films up to 3 monolayer the on top adsorption sites for CO on Ni are preferred over the bridge and hollow adsorption sites in contrast to what is known from the Ni(111) surface.     

Adsorption and desorption of CO on Ni decorated stepped Rh(553)

Vicinal surfaces are important in surface science, as they show interesting electronic structures and reactivities due to the steps. In this paper the adsorption and desorption of carbon monoxide on the stepped Rh(553) surface decorated with Ni is reported. With 0.1 to 0.3 monolayer Ni on Rh(553) one and two atoms broad Ni wires along the Rh steps are formed. The adsorption and desorption of carbon monoxide on these surfaces is investigated using thermal desorption spectroscopy (TDS) and reflection absorption infra red spectroscopy (RAIRS). TDS shows a marked change from just one broad TDS peak on pure Rh(553) to 4 distinct peaks with increasing Ni decoration. RAIRS shows that already at 0.1 monolayer Ni the CO adsorption states on bridge sites on the Rh step atoms are completely quenched. In addition it is shown that with Ni films up to 3 monolayer the on top adsorption sites for CO on Ni are preferred over the bridge and hollow adsorption sites in contrast to what is known from the Ni(111) surface.     

机械合金化制备FeSiAl合金粉末的研究

采用机械合金化的方法制备了FeSiAl合金粉末样品。以硅钢粉和铝粉为原料,按摩尔分数Fe3Si0.4Al0.6配比,研究其机械合金化过程,并对机械合金化的机制进行探讨。用激光粒度仪、X射线衍射(XRD)和扫描电子显微镜分析材料的粒度、形貌和结构。研究表明,Fe3Si0.4Al0.6混合粉末球磨30h后,粉末粒径可达18μm;Fe3Si0.4Al0.6混合粉末经高能球磨20h后,形成具有bcc结构的α固溶体;球磨继续进行,合金化的粉末和晶粒不断细化。     

Synthesis of a nanostructured MgH2-Ti alloy composite for hydrogen storage via combined vacuum arc remelting and mechanical alloying

To improve the hydrogen kinetics of magnesium hydride, TiCr_1.2Fe_0.6 alloy was prepared by vacuum arc remelting (VAR) and the alloy was co-milled with MgH₂ to process nanostructured MgH₂-5 at.% TiCr_1.2Fe_0.6 powder. The hydrogen desorption properties of the composite powder were studied and compared with pure magnesium hydride. X-ray diffraction (XRD) analysis showed that the composite powder prepared by VAR/mechanical alloying (MA) procedure consisted of β-MgH₂, γ-MgH₂, bcc Ti-Cr-Fe alloy, and small amount of MgO. The average size of particles and their grain structure after 4 h MA were determined by a laser particle size analyzer and XRD method and found to be 194 nm and 11 nm, respectively. The hydrogen desorption temperature of magnesium hydride decreased from 426 °C to 235 °C by the bcc Ti alloy and the utilized processing method, i.e. combined VAR/MA.     

包覆钯和镍后MmNi5基贮氢合金的电极特性

Ｍｍ＿（０．９）Ｔｉ＿（０．１）Ｎｉ＿（３．９）Ｍｎ＿（０．４）Ｃｏ＿（０．４）Ａｌ＿（０．３）合金包覆１０ｗｔ％钯－镍后，电极循环寿命和快速充放电性能有明显提高。同时，钯是较好的吸氢元素，这也提高了负极贮氢合金的电容量利用率。包覆钯－镍的贮氢合金电极２００次循环后电容量仅下降３％。