The shaping of Au particles induced by the curvature of the supporting SWCNT

¹ Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University - Shanghai 200433, China
² State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences Lanzhou 730000, China
³ Department of Mechanical and Science Engineering, Fudan University - Shanghai 200433, China
⁴ Department of Energy and Process Engineering, Norwegian University of Science and Technology Trondheim, Norway

^(a) yxwang@fudan.edu.cn

Received: 18 February 2013
Accepted: 22 May 2013

Abstract

The shaping of Au particles induced by the curvature of the supporting single-walled carbon nanotube (SWCNT) was studied using molecular-dynamics simulations. Statistic results showed that two possible structures can be formed on the inner wall of a SWCNT even at the same conditions. One is the layered structure with each layer in the form of a curved {111} plane of a fcc crystal, and the other is the faceted structure. Although there is no energetic advantage between the two structures, the former is generated with higher probability, especially for small curvature radius of the SWCNT. Moreover, the layered structure leads to lower interface energy and high strain among Au-Au bonds, where the strain increases with the curvature of the SWCNT. This indicates that the minimum of the interface energy, not the global energy, primarily influences the structural formation. To release the strain energy stored in the Au particles, the faceted structure can form but with a low probability. A large strain in Au-Au bonds is not induced when the Au particle is on the flat graphene or outside the SWCNT wall because the confinement of SWCNT does not work efficiently.