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首页> 外文期刊>Journal of Alloys and Compounds: An Interdisciplinary Journal of Materials Science and Solid-state Chemistry and Physics >Catalyzed alanates for hydrogen storage
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Catalyzed alanates for hydrogen storage

机译：催化丙氨酸盐用于储氢

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The discovery that hydrogen can be reversibly absorbed and desorbed from complex hydrides (the alanates) by the addition of catalysts has created an entirely new prospect for lightweight hydrogen storage. Unlike the interstitial intermetallic hydrides, these compounds release hydrogen through a series of decomposition/recombination reactions e.g.: NaAlH_4 reversible 1/3Na_3AlH_6 + 2/3Al + H_2 reversible NaH + Al + 3/2H_2. Initial work resulted in improved catalysts, advanced methods of preparation, and a better understanding of the hydrogen absorption and desorption processes. Recent studies have clarified some of the fundamental material properties, as well as the engineering characteristics of catalyst enhanced sodium alanate. Phase transitions were observed real-time through in situ X-ray powder diffraction. These measurements demonstrate that the decomposition reactions occur through long-range transport of metal species. SEM imaging and EDS analysis verified the segregation of aluminum to surface of the material during decomposition. The equilibrium thermodynamics of decomposition have now been measured down to room temperature. They show a plateau pressure for the first reaction of 1 bar at 33 deg C, which suggest that, thermodynamically, this material is ideally suited to on-board hydrogen storage for fuel cell vehicles. Room temperature desorption with slow but measurable kinetics has been recorded for the first time. Studies at temperatures approaching that found in the operation of PEM fuel cells (125-165 deg C) were performed on a scaled-up test bed. The bed demonstrated surprisingly good kinetics and other positive material properties. However, these studies also pointed to the need to develop new non-alkoxide based catalysts and doping methods to increase the capacity and reduce the level of hydrocarbon impurities found in the desorbed hydrogen. For this reason, new Ti-Cl catalysts and doping processes are being developed which show higher capacities and improved kinetics. An overview of the current state-of-the-art will be presented along with our own studies and the implications for the viability of these materials in on-board hydrogen storage applications.
机译：通过添加催化剂，氢可以从复杂的氢化物（铝酸盐）中可逆地吸收和解吸，这一发现为轻质储氢创造了全新的前景。与间隙金属间氢化物不同，这些化合物通过一系列分解/重组反应释放氢，例如：NaAlH_4可逆1 / 3Na_3AlH_6 + 2 / 3Al + H_2可逆NaH + Al + 3 / 2H_2。最初的工作导致了催化剂的改进，先进的制备方法以及对氢吸收和解吸过程的更好理解。最近的研究澄清了一些基本的材料性能，以及催化剂增强的丙二酸钠的工程特性。通过原位X射线粉末衍射实时观察到相变。这些测量结果表明，分解反应是通过金属物质的远距离传输发生的。 SEM成像和EDS分析验证了分解过程中铝在材料表面的偏析。现在已经测量到室温下分解的平衡热力学。它们显示了在33摄氏度下1 bar的第一反应的平稳压力，这表明，从热力学上讲，该材料非常适合燃料电池车辆的车载氢气存储。首次记录了室温下具有缓慢但可测量的动力学的解吸。在放大的试验床上进行了接近PEM燃料电池工作时发现的温度（125-165摄氏度）的研究。该床表现出令人惊讶的良好动力学和其他积极的材料性能。然而，这些研究还指出需要开发新的非基于醇盐的催化剂和掺杂方法以增加容量并降低在解吸的氢中发现的烃杂质的水平。因此，正在开发新的Ti-Cl催化剂和掺杂工艺，它们显示出更高的容量和改进的动力学。将概述当前的最新技术以及我们自己的研究，以及这些材料在车载氢存储应用中的可行性。

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