Kim Ki Chul, Dai Bing, Karl Johnson J, Sholl David S
School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0100, USA.
Nanotechnology. 2009 May 20;20(20):204001. doi: 10.1088/0957-4484/20/20/204001. Epub 2009 Apr 23.
The reaction thermodynamics of metal hydrides are crucial to the use of these materials for reversible hydrogen storage. In addition to altering the kinetics of metal hydride reactions, the use of nanoparticles can also change the overall reaction thermodynamics. We use density functional theory to predict the equilibrium crystal shapes of seven metals and their hydrides via the Wulff construction. These calculations allow the impact of nanoparticle size on the thermodynamics of hydrogen release from these metal hydrides to be predicted. Specifically, we study the temperature required for the hydride to generate a H(2) pressure of 1 bar as a function of the radius of the nanoparticle. In most, but not all, cases the hydrogen release temperature increases slightly as the particle size is reduced.
金属氢化物的反应热力学对于将这些材料用于可逆储氢至关重要。除了改变金属氢化物反应的动力学外，使用纳米颗粒还可以改变整体反应热力学。我们利用密度泛函理论通过伍尔夫构造预测七种金属及其氢化物的平衡晶体形状。这些计算使得能够预测纳米颗粒尺寸对这些金属氢化物释放氢的热力学的影响。具体而言，我们研究了氢化物产生1巴氢气压力所需的温度作为纳米颗粒半径的函数。在大多数（但不是所有）情况下，随着颗粒尺寸减小，氢释放温度会略有升高。
