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The article is devoted to methodological problems of investigation of the pressure-concentration-temperature (PCT) phase diagrams of hydrogen-absorbing materials that are used in metal hydride systems for storage and purification of hydrogen based on intermetallic compounds of the AB5-type. The problem is discussed with an example of the PCT-diagram of the LaFe0.1Mn0.3Ni4.8 alloy, which is promising for creation of metal hydride systems for storage and purification of hydrogen integrated with power plants (with a power of up to 5 kW) based on fuel cells with a solid-polymer electrolyte. 相似文献
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The development of hydrogen‐storage alloys used in high‐power nickel/metal hydride batteries has become an important research field. Various methods of improving the high‐rate dischargeability of the metal‐hydride negative electrode are discussed. Our recent investigations show that optimization of rare‐earth composition, combined with appropriate amounts of B or Mo additive, significantly improves the high‐rate capability of hydrogen‐storage alloys, which may be suitable for use in high‐power Ni/MH batteries. 相似文献
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本文系浙江大学自1978年以来对贮氢合金研究开发的总结,由于开拓了在氢的超纯净化、氢压缩,热泵和氢化物电极等多方面应用,贮氢合金的研究得到迅速发展。 相似文献
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The rapid and extensive development of advanced nanostructures and nanotechnologies has driven a correspondingly rapid growth of research that presents enormous potential for fulfilling the practical requirements of solid state hydrogen storage applications. This article reviews the most recent progress in the development of nanostructured materials for hydrogen storage technology, demonstrating that nanostructures provide a pronounced benefit to applications involving molecular hydrogen storage, chemical hydrogen storage, and as supports for the nanoconfinement of various hydrides. To further optimize hydrogen storage performance, we emphasize the desirability of exploring and developing nanoporous materials with ultrahigh surface areas and the advantageous incorporation of metals and functionalities, nanostructured hydrides with excellent mechanic stabilities and rigid main construction, and nanostructured supports comprised of lightweight components and enhanced hydride loading capacities. In addition to highlighting the conspicuous advantages of nanostructured materials in the field of hydrogen storage, we also discuss the remaining challenges and the directions of emerging research for these materials. 相似文献
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The adsorption and desorption of hydrogen on Ir/SiO(2) catalyst were studied by using in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) combined with curve-fitting analysis. The results indicate that there are three different surface species formed on the catalyst that correspond to the peaks at 1950, 2010, and 2035 cm(-1), respectively, when exposed in H(2) flow at 130 °C. These surface species display different adsorption and desorption trends. Surface hydride forms after the catalyst is cooled to 80 °C and it disappears after the catalyst is heated to 130 °C again. This study may help us understand the interaction between hydrogen and noble metals and thus give more insights to heterogeneous catalytic mechanism involving hydrogen and hydrogen storage using metal materials. 相似文献
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《Materials Research Bulletin》2006,41(6):1118-1126
Of all the materials presently being investigated to safely store high volumes of hydrogen for mobile applications; magnesium remains the most attractive. Magnesium is a light, low cost metal with high capacity for hydrogen storage but its (de)hydriding kinetics have to be improved for practical applications. Recently, hydrogen kinetics in magnesium have been significantly improved by mechanically milling magnesium hydride with catalyst transition metals or metal oxides. Here, we report that similar improvements can be achieved without using a catalyst. Our results demonstrate that magnesium hydride milled with magnesium oxide exhibits dehydriding and hydriding kinetics as fast as those obtained with catalyst transition metals or metal oxides. 相似文献
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水解制氢是一种常温常压下的现场制氢方式。由于水解制氢材料氢含量高, 储存容易, 运输方便, 安全可靠, 一直受到研究者们的关注。本文综述了近年来水解制氢材料的总体发展情况, 介绍了三类主要的水解制氢材料, 包括硼氢化物(NaBH4, NH3·BH3)、金属(Mg, Al)以及金属氢化物(MgH2), 对不同材料的制氢原理、主要问题、催化剂与材料设计进行了详细介绍, 比较了不同体系的特点与制氢成本, 并对水解制氢及水解制氢材料的现状和商业化面临的困难做了评价, 最后对未来的发展方向进行了展望。 相似文献
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Ping DU Wei CAO Manqi LU Jiangping CHEN Ke YANGInstitute of Metal Research Chinese Academy of Sciences Shenyang China 《材料科学技术学报》2004,(4)
Investigation has been carried out to find the effects of Nd substitution and Cu addition on the hydrogen storage properties of AB5-type alloy with a multicomponent La0.6M0.4Ni4.8Mn0.2 (M=Y, Nd) system. La0.6Y0.4Ni4.8Mn0.2, which was used in an air-conditioning system, showed poor hysteresis and sloping characteristics, which led to a decrease concerning the coefficient of performance of the system. By the substitution of Nd for Y, the hydrogen storage capacity increased, and the plateau pressure decreased a little, but the hydrogen absorption kinetics decreased dramatically. Cu addition can effectively improve the kinetics of hydride formation without changing the hydrogen storage capacity of La0.6Nd0.4Ni4.8Mn0.2. It has been found that La0.6Nd0.4Ni4.8Mno0.2Cu0.1 alloy showed good hydrogen storage characteristics for metal hydride air-conditioning system. The results showed that, for each component of La0.6M0.4Ni4.8Mn0.2. the effective hydrogen storage capacity increased with decrease of the unit cell 相似文献
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Complex light metal hydrides possess many properties which make them attractive as a storage medium for hydrogen, but typically catalysts are required to lower the hydrogen desorption temperature and to facilitate hydrogen uptake in the form of a reversible reaction. The overwhelming focus in the search for catalysing agents has been on compounds containing titanium, but the precise mechanism of their actions remains somewhat obscure. A recent experiment has now shown that fullerenes (C(60)) can also act as catalysts for both hydrogen uptake and release in lithium borohydride (LiBH(4)). In an effort to understand the involved mechanism, we have employed density functional theory to carry out a detailed study of the interaction between this complex metal hydride and the carbon nanomaterial. Considering a stepwise reduction of the hydrogen content in LiBH(4), we find that the presence of C(60) can lead to a substantial reduction of the involved H-removal energies. This effect is explained as a consequence of the interaction between the BH(x)( - ) complex and the C(60) entity. 相似文献
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Investigation has been carried out to find the effects of Nd substitution and Cu addition on the hydrogen storage properties of AB5-type alloy with a multicomponent La0.6M0.4Ni4.8Mn0.2 (M=Y, Nd) system. La0.6Y0.4Ni4.8Mn0.2,which was used in an air-conditioning system, showed poor hysteresis and sloping characteristics, which led to a decrease concerning the coefficient of performance of the system. By the substitution of Nd for Y, the hydrogenstorage capacity increased, and the plateau pressure decreased a little, but the hydrogen absorption kinetics decreased dramatically. Cu addition can effectively improve the kinetics of hydride formation without changing the hydrogen storage capacity of La0.6Nd0.4Ni4.8Mn0.2. It has been found that La0.6Nd0.4Ni4.8Mn0.2Cu0.1 alloy showed good hydrogen storage characteristics for metal hydride air-conditioning system. The results showed that, for each component of La0.6Mo.4Ni4.8Mn0.2, the effective hydrogen storage capacity increased with decrease of the unit cell parameter c/a and the hydrogen absorption plateau pressure increased with decrease of the parameter a. 相似文献
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基于机械反应球磨技术在氢气气氛下成功合成了Mg2NiH4及Cu掺杂Mg2NiH4储氢体系,并采用XRD、SEM、DSC及TGA检测手段对其组织结构与解氢性能进行表征。结果显示,适当提高氢压、延长球磨时间均有助于2Mg-Ni混合物氢化反应的完全化及产物结构的纳米化;Cu掺杂可进一步加快混合物的氢化反应速率,但其产物结构的团聚现象却因MgCu2相的出现而趋于严重;综合热分析表明Cu掺杂不仅降低了Mg2NiH4的解氢温度,还加快了体系的解氢速率;研究结果很好地证实Cu元素是改善Mg2NiH4储氢体系解氢性能最理想的合金化元素之一。 相似文献
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R. E. Ricker G. R. Myneni 《Journal of research of the National Institute of Standards and Technology》2010,115(5):353-371
During the fabrication of niobium superconducting radio frequency (SRF) particle accelerator cavities procedures are used that chemically or mechanically remove the passivating surface film of niobium pentoxide (Nb2O5). Removal of this film will expose the underlying niobium metal and allow it to react with the processing environment. If these reactions produce hydrogen at sufficient concentrations and rates, then hydrogen will be absorbed and diffuse into the metal. High hydrogen activities could result in supersaturation and the nucleation of hydride phases. If the metal repassivates at the conclusion of the processing step and the passive film blocks hydrogen egress, then the absorbed hydrogen or hydrides could be retained and alter the performance of the metal during subsequent processing steps or in-service. This report examines the feasibility of this hypothesis by first identifying the postulated events, conditions, and reactions and then determining if each is consistent with accepted scientific principles, literature, and data. Established precedent for similar events in other systems was found in the scientific literature and thermodynamic analysis found that the postulated reactions were not only energetically favorable, but produced large driving forces. The hydrogen activity or fugacity required for the reactions to be at equilibrium was determined to indicate the propensity for hydrogen evolution, absorption, and hydride nucleation. The influence of processing conditions and kinetics on the proximity of hydrogen surface coverage to these theoretical values is discussed. This examination found that the hypothesis of hydrogen absorption during SRF processing is consistent with published scientific literature and thermodynamic principles. 相似文献
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NaAlH4空间约束体系的构建及其脱/加氢行为 总被引:1,自引:0,他引:1
配位氢化物具有较高的质量储氢密度,已成为国内外储氢材料的研究热点,但尚未解决的脱/加氢温度过高、速率慢和可逆性差等问题是制约其实际应用的主要原因.利用孔性材料的结构特点来构建纳米尺度的空间约束体系,可有效地改善配位氢化物的脱/加氢性能.以NaAlH4为例,介绍了孔性材料的制备和表面修饰,分析了配位氢化物/孔性介质空间约束体系的构建及其且兑/加氢行为.这种空间约束体系为改善配位氢化物的储氢性能提供了一条新途径.进一步构建配位氢化物/孔性介质/催化剂的空间约束体系,实现对配位氢化物的复合催化,将是今后努力的方向. 相似文献
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文中对四肽封端的聚异戊二烯的合成方法和流变性能进行了初步探索。首先采用新癸酸钕/二异丁基氢化铝/二氯二甲基硅稀土催化剂体系催化异戊二烯聚合,得到了相对分子质量可控,窄分布(1.09~1.4),顺1,4结构含量高(96%)的聚异戊二烯。聚合4 h后用二氧化碳封端得到端羧基聚异戊二烯(PI-COOH)。非水滴定结果表明羧基封端率高(100%)。然后PI-COOH与四肽(Boc-(ala)_4-NH_2)缩合形成端基为四肽的聚异戊二烯(PI-4A)。流变测试结果表明,与PI-COOH相比,PI-4A中四肽的分子间氢键作用使得储能模量提高了约1000倍;并且在升温过程中氢键被逐渐破坏,模量快速下降,在50℃时大部分氢键断裂。 相似文献
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We present a review of the experimental and theoretical methods used in the discovery of new metal–hydrogen materials systems for hydrogen storage applications. Rather than a comprehensive review of all new materials and methods used in the metal hydride community, we focus on a specific subset of successful methods utilizing theoretical crystal structure prediction methods, computational approaches for screening large numbers of compound classes, and medium-throughput experimental methods for the preparation of such materials. Monte Carlo techniques paired with a simplified empirical Hamiltonian provide crystal structure candidates that are refined using density functional theory. First-principle methods using high-quality structural candidates are further screened for an estimate of reaction energetics, decomposition enthalpies, and determination of reaction pathways. Experimental synthesis utilizes a compacted-pellet sintering technique under high-pressure hydrogen at elevated temperatures. Crystal structure determination follows from a combination of Rietveld refinements of diffraction patterns and first-principles computation of total energies and dynamical stability of competing structures. The methods presented within are general and applicable to a wide class of materials for energy storage. 相似文献