氢与氧化铈表面的相互作用：一项量子力学计算研究。

Interaction of hydrogen with cerium oxide surfaces: a quantum mechanical computational study.

作者信息

Vicario Gianpaolo, Balducci Gabriele, Fabris Stefano, de Gironcoli Stefano, Baroni Stefano

机构信息

Department of Chemical Sciences, INSTM-Trieste Research Unit and Center of Excellence for Nanostructured Materials, Universita degli Studi di Trieste, via L.Giorgieri 1, I-34127 Trieste, Italy.

出版信息

J Phys Chem B. 2006 Oct 5;110(39):19380-5. doi: 10.1021/jp061375v.

DOI:10.1021/jp061375v

PMID:17004795

Abstract

The interaction of the (110) and (111) surfaces of ceria (CeO(2)) with atomic hydrogen is studied with ab initio calculations based on density functional theory. A Hubbard U term added to the standard density functional allows to accurately describe the electronic structure of the two surfaces. The minimum energy configuration for the adsorbed H on each of the two surfaces is obtained. An O-H-O bridge is formed on the (110) surface, whereas an axial tricoordinated OH group results on the (111) surface. For both surfaces, the adsorption of an H atom is accompanied by the reduction of a single Ce ion (which is one of the nearest neighbors of the adsorbed atom) and by a substantial outward protrusion of the O atom(s) directly bound to H. The adsorption of atomic H on the (110) and (111) surfaces is energetically favored by -150.8 and -128.3 kJ/mol, respectively, with respect to free molecular H(2). The calculated frequencies for the OH stretching vibrational mode are 3100 cm(-1) for the (110) surface and 3627 cm(-1) for the (111) surface. The latter value is in excellent agreement with experimental data reported in the literature.

摘要

基于密度泛函理论，通过从头算研究了二氧化铈（CeO₂）（110）和（111）表面与氢原子的相互作用。在标准密度泛函中添加哈伯德U项可准确描述这两个表面的电子结构。得到了氢原子在这两个表面上吸附的最低能量构型。在（110）表面形成了O-H-O桥，而在（111）表面形成了轴向三配位的OH基团。对于这两个表面，氢原子的吸附都伴随着单个铈离子（被吸附原子的最近邻之一）的还原以及直接与氢相连的氧原子的显著向外突出。相对于自由分子氢（H₂），氢原子在（110）和（111）表面上的吸附在能量上分别有利-150.8和-128.3 kJ/mol。（110）表面OH伸缩振动模式的计算频率为3100 cm⁻¹，（111）表面为3627 cm⁻¹。后一个值与文献报道的实验数据非常吻合。