富镧混合稀土贮氢合金分离氢中Kr,Xe性能的研究

叙述Ｍ１Ｎｉ４．５Ａｌ０．５贮氢合金分离氢中氪、氙的基本原理，分了分离时氢中氪、浓度与分离温度的关系。结果表明，当Ｔ为２９８Ｋ时，贮氢合金Ｎ１Ｎｉ４．５Ａｌ０．５与ＴｉＦｅ０．８６Ｍｎ０．１的分离性能基本相似，分离浓度与放氢体积符合Ｎ＝ａｅ＾－ｂｒ方程。     

稀土储氢合金在有机氢化物中的吸氢行为和吸氢热力学性能

研究了富镧混合稀土－镍储氢合金（MlNi5)与有机化合物（C6H6）组成的浆液体系的吸氢行为和吸氢热力学性能。测定了不同温度（10，20，30，40℃）下两个不同系统的吸氢压力－成分等温（PCT）曲线，并分别计算出气固系统和气固液系统吸氢反应的热力学函数值ΔH,ΔS。     

MINi5—xSnx合金贮氢性能研究

研究了富镧混合稀土贮氢合金ＭＩＮｉ５及加Ｓｎ后对合金的结构、活化性能、吸氢容量和平衡氢压等性能的影响。通过Ｘ射线衍射分析进行物相分析,测试了２９８,３１３,３３３Ｋ温度下合金的吸、放氢Ｐ－Ｃ－Ｔ曲线。结果表明,ＭＩＮｉ５－ｘＳｎｘ合金（ｘ＝０～０．４）为六言晶体结构的单相组织。以Ｓｎ部分取代Ｎｉ改善了ＭＩＮｉ５的活化特性,并使平台压力降低、吸、放氢滞后减小。随着Ｓｎ含量增加,晶胞体积增大,平衡氢压     

甲基橙—溴化十六烷基三甲胺三元络合物分光光度法测定微量铜（Ⅱ）

本介绍了甲基橙与铜在ＰＨ３．８时与溴化十六烷基三甲胺形成三元胶束络合物增溶于聚乙烯醇体系中，其表观摩尔吸系数ε５８０为２．９５×１０＾６Ｌ．ｍｏｎ＾－１．ｃｍ＾－１，铜（Ⅱ）浓度在０．１－０．６μｇ／２５ｍＬ范围内与吸光度成线性关系。用此法分析人中铜含量，结果满意。     

硝酸镧对大鼠胃液分泌和胃粘膜的影响

报道了硝酸镧对大鼠胃液和胃粘膜的影响。硝酸镧对大鼠胃的分泌机能呈双重效应：１ｍｇ．ｋｇ＾－１时，极为明显地促进胃液、胃酸及胃蛋白酶的分泌；而１６ｍｇ．ｋｇ＾－１时则相反，胃液、胃蛋白酶的分泌都显著减少。但对大鼠胃粘液的分泌，１、１６ｍｇ．ｋｇ＾－１的硝酸镧都无明显的影响。１、１６ｍｇ．ｋｇ＾－１的硝酸镧对饥饿大鼠的胃粘膜无明显的损伤作用，对结扎幽门诱发的胃溃疡也无明显影响。     

乙醇在Ni-Mo合金电极上氧化的动力学模型

利用循环伏安以及稳态极化曲线等方法研究了在１ｍｏｌ．Ｌ＾－１ＫＯＨ溶液中,乙醇在电沉积Ｎｉ－Ｍｏ合金电极上氧化的电化学特性,提出了一个数学模型来预计乙醇在电沉积Ｎｉ－Ｍｏ合金电极上的电化学行为,在碱性溶液中,Ｎｉ（ＯＨ）２／ＮｉＯＯＨ电对的氧化还原过程是乙醇氧化的前期步骤,Ｎｉ（ＯＨ）２／ＮｉＯＯＨ）电对相应的速度常数（即ｋ１和ｋ－１）是电极电位的函数,乙醇氧化是通过一个速度常数为ｋｃ１的化学反应来完成,推导出了各个动力学方程并将实验数据与方程进行比较而获得各个动力学参数,电化学速度常数ｋ１（Ｅ）＝１．４１＊１０＾７ｅｘｐ（０．５ＦＥ／ＲＴ）ｍｍｏｌ．ｃｍ＾－２．ｓ＾－１以及ｋ－１（Ｅ）＝０．７１１ｅｘｐ（０．５ＦＥ／ＲＴ）ｍｍｏｌ．ｃｍ＾－２．ｓ＾－１,Ｅ是相对饱和甘汞电极（ＳＣＥ）的电极电位,而化学反应的速     

示波极谱法连续测定食品中微量锌铁锰铜铅镉砷

研究了三乙醇胺－乙二胺－硫氰酸钾－乙酸－碘经钾－盐酸－酒石酸锑钾体系示波极谱法在同一份食品试样中连续测定七种微量元素。在该体系中,七种微量元素可分别产生稳定的极谱二阶导数波,空白无峰出现。锌、铁、锰、铜、铅检出限为０．０ｍｇ．ｋｇ＾－１,砷、镉检出限为０．００５ｍｇ．ｋｇ＾－１。锌、铁、铜、铅０．０１～０．８０μｇ．ｍｌ＾－１,镉０．００５～０．８０μｇ．ｍｌ＾－１,锰０．０１～０．５０μｇ．ｍｌ     

MlNi5-xSnx合金贮氢性能研究

研究了富镧混合稀土贮氢合金ＭｌＮｉ５ 及加Ｓｎ 后对合金的结构、活化性能、吸氢容量和平衡氢压等性能的影响。通过Ｘ 射线衍射分析进行物相分析， 测试了２９８ ，３１３，３３３ Ｋ 温度下合金的吸、放氢ＰＣＴ曲线。结果表明，ＭｌＮｉ５ － ｘＳｎｘ 合金（ｘ＝０ ～０．４） 为六方晶体结构的单相组织。以Ｓｎ 部分取代Ｎｉ 改善了ＭｌＮｉ５ 的活化特性， 并使平台压力降低， 吸、放氢滞后减小。随着Ｓｎ 含量增加， 晶胞体积增大， 平衡氢压降低， 生成热减小， 氢化物稳定性提高。而少量的Ｓｎ 对吸氢能力降低较小， 是理想的替代元素。     

隐性亮绿作为过氧化物酶催化测定过氧化氢底物的研究

研究了以隐性亮绿作为氢供体底物的辣根过氧化物酶－过氧化氢催化体系。该体系在ＰＨ＝６．４－７．５的条件下所形成的亮绿于６４０ｎｍ处有最大吸收。测定过氧化氢的摩尔吸光系数为９．３×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１；工作曲线的线性范围为０．０３６ｍｇ／Ｌ。方法可应用于雨水中过氧化氢含量的测定。     

六氟磷酸二（4,4‘—二甲基—2,2’—联吡啶）.（2,2‘—联吡啶—4,4’—二羧？…

用＾１Ｈ ＮＭＲ和＾１３Ｃ ＮＭＲ谱研究了新型电化学发光探针六氟磷酸二（４,４’;－二甲基－２,２‘－联吡啶）．（４．４’－二羧酸－２,２‘－联吡啶）合钌的立体结构,通过＾１Ｈ ＾１Ｈ ＣＯＳＹ,＾１３Ｃ－＾１Ｈ ＨＥＴＣＯＲ谱对其氢谱和碳谱中的各谱峰进行了归属,并给出了氢谱和碳谱峰的化学位移值。     

Evaluation of oxidant media for the determination of lead in food slurries by hydride generation atomic absorption spectrometry

Several oxidant media were evaluated for the generation of lead hydride from slurry samples and their application to the determination of lead in vegetables and fish by hydride generation atomic absorption spectrometry. Three oxidant - acid media were compared: hydrogen peroxide - nitric acid, ammonium persulphate - nitric acid and potassium dichromate - lactic acid. The powdered samples were suspended in Triton X-100 and shaken with 10.0 g of blown zirconia spheres until a slurry was formed. The potassium dichromate - lactic acid medium was the most satisfactory for the determination of lead in fish and vegetables, providing the lowest detection limits as a result of its high sensitivity and low blank values. The ammonium persulphate - nitric acid medium gave good accuracy, precision and selectivity for vegetables (1-2 p.p.m. of lead); however, with fish (0.1-1 p.p.m. of lead) it was only a semi-quantitative medium for the determination of lead owing to its lack of sensitivity and selectivity. The hydrogen peroxide - nitric acid medium was unsatisfactory for the generation of lead hydride from slurry samples because of decomposition of hydrogen peroxide by the organic matter in the sample.     

Problem of hydrogen storage and prospective uses of hydrides for hydrogen accumulation

Merits and demerits of existing methods of hydrogen storage are discussed. Special attention is given a metal hydride technology based on the ability of metals, intermetallic compounds, and alloys for reversible reaction with hydrogen. It is noted that the basic advantages of metal hydrides are a high volumetric hydrogen content, operational safety, technological flexibility, and low power inputs on hydrogen absorption and desorption.     

Influence of surface contaminations on the hydrogen storage behaviour of metal hydride alloys

Hydrogen storage in metal hydrides is a promising alternative to common storage methods. The surface of a metal hydride plays an important part in the absorption of hydrogen, since important partial reaction steps take place here. The development of surface contaminations and their influence on hydrogen absorption is examined by means of absorption experiments and surface analysis, using X-ray photoelectron spectroscopy (XPS), thermal desorption mass spectrometry (TDMS) and secondary neutral mass spectrometry (SNMS), in this work. All investigations were carried out on a modern AB₂ metal hydride alloy, namely Ti_0.96Zr_0.04Mn_1.43V_0.45Fe_0.08. Surface analysis (SNMS, XPS) shows that long-term air storage (several months) leads to oxide layers about 15 nm thick, with complete oxidation of all main alloy components. By means of in situ oxygen exposure at room temperature and XPS analysis, it can be shown that an oxygen dose of about 100 Langmuirs produces an oxide layer comparable to that after air storage. Manganese enrichment (segregation) is also clearly observed and is theoretically described here. This oxide layer hinders hydrogen absorption, so an activation procedure is necessary in order to use the full capacity of the metal hydride. This procedure consists of heating (T = 120° C) in vacuum and hydrogen flushing at pressures like p = 18 bar. During the activation process the alloy is pulverized to particles of ∼20 μm through lattice stretches. It is shown that this pulverization of the metal hydride (creating clean surface) during hydrogen flushing is essential for complete activation of the material. Re-activation of powder contaminated by small doses of air (p ≈ 0.1 bar) does not lead to full absorption capacity. In ultrahigh vacuum, hydrogen is only taken up by the alloy after sputtering of the surface (which is done in order to remove oxide layers from it), thus creating adsorption sites for the hydrogen. This is shown by TDMS measurements with and without sputtering and oxygen exposure. Figure Investigated metal hydride before and after activation     

Tuning metal hydride thermodynamics via size and composition: Li-H, Mg-H, Al-H, and Mg-Al-H nanoclusters for hydrogen storage

Nanoscale Li and intermetallic Al-Mg metal hydride clusters are investigated as a possible hydrogen storage material using the high-level quantum Monte Carlo computational method. Lower level methods such as density functional theory are qualitatively, not quantitatively accurate for the calculation of the enthalpy of absorption of H(2). At sizes around 1 nm, it is predicted that Al/Mg alloyed nanoparticles are stable relative to the pure compositions and the metal composition can be tuned in tandem with the size to tune the hydrogen absorption energy, making this a promising route to a rechargeable hydrogen storage material.     

Hydrogenation of nanostructured alloys and composites based on magnesium

The capability of sorbing hydrogen was studied for the magnesium alloys and related composites. The microstructures of the Mg-Ni binary eutectic alloys and Mg-La-Ni and Mg-Mm-Ni ternary eutectic alloys were studied. Both the initial alloys and alloys modified by the method of equal channel angular pressing were used as objects of the study. Features of interaction of the alloys with hydrogen were revealed. Sorption of hydrogen by the metal hydride composites based on alloys and ??pseudoalloys,?? viz., alloys obtained by sintering of mechanochemically treated highly dispersed powders formed by the hydride dispersion of metallic phases, was studied. Metal??carbon composites based on highly dispersed magnesium alloys or pseudoalloys and carbon nanostructures were formed, and the absorption of hydrogen by these composites was examined.     

The Origin of the Catalytic Activity of a Metal Hydride in CO2 Reduction

Atomic hydrogen on the surface of a metal with high hydrogen solubility is of particular interest for the hydrogenation of carbon dioxide. In a mixture of hydrogen and carbon dioxide, methane was markedly formed on the metal hydride ZrCoH_x in the course of the hydrogen desorption and not on the pristine intermetallic. The surface analysis was performed by means of time‐of‐flight secondary ion mass spectroscopy and near‐ambient pressure X‐ray photoelectron spectroscopy, for the in situ analysis. The aim was to elucidate the origin of the catalytic activity of the metal hydride. Since at the initial stage the dissociation of impinging hydrogen molecules is hindered by a high activation barrier of the oxidised surface, the atomic hydrogen flux from the metal hydride is crucial for the reduction of carbon dioxide and surface oxides at interfacial sites.     

A high-temperature,high-pressure microbalance for the determination of the hydrogen sorption characteristics of metal hydrides

The use of hydrogen as a future complementary energy vector is essentially linked to the problem of its storage and transport. Apart from conventional techniques, the storage of hydrogen in metal hydrides is considered of interest for a number of applications. To make a metal hydride a suitable hydrogen storage material, it must exhibit certain characteristics concerning in particular: (i) the hydrogen storage capacity, (ii) the dissociation pressure—temperature relationship, (iii) the heat of reaction, and (iv) the kinetics of hydrogen absorption/desorption. All these data can be determined using a microbalance capable of operating at high temperatures and pressures.The principal item of the thermogravimetric installation developed at Battelle-Geneva consists of a Sartorius balance type 4406 equipped with a heatable autoclave. The attached pressure and temperature control systems allow measurements under conditions of constant pressure (10^?5 Torr to 60 bar) and temperature (15 to 600°C), as well as the execution of pressure and temperature cycling programs at various scanning speeds.The performance and versatility of the instrument is illustrated by measuring various hydrogen sorption characteristics of the known magnesium nickel hydride and iron titanium hydride.     

我国金属氢化物化学研究

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。     

络合氢化物Ti-NaAlH4的制备与储氢特性

采用Ti粉为催化剂前驱体、预处理Al粉和NaH为合成原料, 通过机械球磨-加氢方法合成出络合氢化物Ti-NaAlH4, 系统研究了球磨保护气氛、球磨时间和氢化加氢压力等制备参数对其储氢性能的影响. 结果表明, 制备方法对Ti-NaAlH4储氢特性有很大影响. 与氩气保护气氛相比, 在氢气气氛中球磨制备的复合物具有更高的吸放氢性能. 在氢气保护气氛下, 随着球磨时间从6 h增至24 h, 复合物的吸氢容量和吸氢速率先增后减, 12 h时达到最佳值, 而复合物的放氢容量和放氢速率则逐渐增高; 进一步延长球磨时间会使颗粒发生团聚, 从而导致吸氢性能下降. 随着氢化加氢压力从7.5 MPa升至13.5 MPa, 复合物的吸氢容量(质量分数)由2.83%逐渐增至4.21%. 复合物球磨后出现的Na3AlH6中间氢化物相表明, 在氢气下掺Ti球磨对NaH和Al的氢化反应起到很好的促进作用.     

Kinetic and thermodynamic studies of hydrogen storage alloys as negative electrode materials for Ni/MH batteries: a review

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.