Hydrogen adsorption on PdGa(100), (111) and () surfaces: A DFT study

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• 作者：P. Bechthold ; J.S. Ardenghi ; O. Nagel ; A. Juan ; E.A. Gonz谩lez ; P.V. Jasen
• 关键词：PdGa ; DFT ; Intermetallic compounds ; Hydrogen adsorption
• 刊名：International Journal of Hydrogen Energy
• 出版年：4 February, 2014
• 年：2014
• 卷：39
• 期：5
• 页码：2093-2103
• 全文大小：2203 K

文摘

Hydrogen adsorption on PdGa intermetallic compound is analyzed using density functional theory (DFT) calculations. Changes in the electronic structure of PdGa(100), (111) and surfaces and H bonding after adsorption are addressed. H interacts with Pd atoms with a tilted geometry on (100) and (111) surfaces. On the surface two possible forms for H adsorption are detected: one is observed atop perpendicular to the surface and the other one is subsuperficial, both with similar adsorption energies. The Ga-H interaction is energetically less stable and is only present on the (100) plane. Pd-Pd bond strength decreases up to 53.8% as the new Pd-H bond is formed. The Pd-H bond length differs less than 1%, compared to the gas phase value for the (100), (111) and atop . However in the subsurface-H bond length is about 2.17聽脜. The effect of H is limited to its first Pd neighbor. Analysis of orbital interaction reveals that the Pd-H bond mainly involves s-s and s-p orbitals with lower participation of Pd 4d orbitals. The computed H vibration frequencies after adsorption show values of 1786, 1289 and 633.5聽cm<sup>鈭?sup> that correspond to top, bridge and hollow sites respectively.