Two-dimensional to three-dimensional structural transition of gold cluster Au 10 during soft landing on TiO 2 surface and its effect on CO oxidation

Authors

Hui Li, University of Nebraska-LincolnFollow
Yong Pei, University of Nebraska-Lincoln
Xiao Cheng Zeng, University of Nebraska-LincolnFollow

Date of this Version

2010

Citation

The Journal of Chemical Physics 133, 134707 (2010); doi: 10.1063/1.3485291

Comments

Copyright © 2010 American Institute of Physics. Used by permission.

Abstract

We investigate the possible structural transition of a planar Au₁₀ cluster during its soft landing on a TiO₂ (110) surface with or with no oxygen defects. The collision between the gold cluster and the oxide surface is simulated using the Car–Parrinello quantum molecular dynamics method. Both high-speed and low-speed conditions typically implemented in soft-landing experiments are simulated. It is found that under a high-speed condition, the gold cluster Au₁₀ can undergo a sequence of structural transitions after colliding with a defect-free TiO₂ (110) surface. When the TiO₂ (110) surface possesses oxygen vacancies, however, chemical bonds can form between gold and Ti atoms if gold atoms contact directly with the vacancies. As a consequence, one oxygen vacancy is capable of trapping one Au atom, and thus can split the Au₁₀ into two parts while bouncing back from the surface. In addition, we study reaction pathways for the CO oxidation based on three isomer structures of Au₁₀ observed in the soft-landing simulation: (1) the precollision two-dimensional structure, (2) a postcollision three-dimensional (3D) structure, and (3) an intermediate (transient) 3D structure that appeared in the midst of the collision. This study allows us to examine the structure-activity relationship using the Au₁₀ as a prototype model catalyst.