Institut Jean Lamour (UMR7198 CNRS, Université de Lorraine), Parc de Saurupt, 54011 Nancy Cedex, France.
Department of Earth and Environmental Sciences, Crystallography Section, Ludwig-Maximilians-Universität München, Theresienstrasse 41, D-80333 München, Germany.
Phys Rev Lett. 2013 Feb 15;110(7):076102. doi: 10.1103/PhysRevLett.110.076102.
We have investigated the structure of the Al(13)Fe(4)(010) surface using both experimental and ab initio computational methods. The results indicate that the topmost surface layers correspond to incomplete puckered (P) planes present in the bulk crystal structure. The main building block of the corrugated termination consists of two adjacent pentagons of Al atoms, each centered by a protruding Fe atom. These motifs are interconnected via additional Al atoms referred to as "glue" atoms which partially desorb above 873 K. The surface structure of lower atomic density compared to the bulk P plane is explained by a strong Fe-Al-Fe covalent polar interaction that preserves intact clusters at the surface. The proposed surface model with identified Fe-containing atomic ensembles could explain the Al(13)Fe(4) catalytic properties recently reported in line with the site-isolation concept [M. Armbrüster et al., Nat. Mater. 11, 690 (2012)].
我们使用实验和从头算计算方法研究了 Al(13)Fe(4)(010) 表面的结构。结果表明，最顶层的表面层对应于体相晶体结构中存在的不完全褶皱（P）面。波纹终止的主要构建块由两个相邻的 Al 原子五边形组成，每个五边形的中心都有一个突出的 Fe 原子。这些图案通过称为“胶水”原子的附加 Al 原子相互连接，这些原子在高于 873 K 时部分解吸。与体相 P 面相比，较低原子密度的表面结构由强烈的 Fe-Al-Fe 共价极性相互作用解释，该相互作用在表面上保持完整的簇。所提出的表面模型与最近报道的 Al(13)Fe(4)催化性能一致，符合位阻隔离概念[M. Armbrüster 等人，Nat. Mater. 11, 690 (2012)]。
