Pt core confined within an Au skeletal frame: Pt@Void@Au nanoframes in a molecular dynamics Perspective

Abstract

Recently, nanoframe structures have attracted high amount of research interest due to their special properties such as open surface structure, high surface-to-volume ratio, large surface areas, and high densities of low-coordination surface atoms in various fields, especially in catalysis research. Since, stability of nanoparticles is an important factor for their application as catalysts, the present study aimed to evaluate the morphological effect of core and frame on the stability of Pt@void@Au nanoframes, where the Pt core is located inside an Au skeleton, using molecular dynamics simulation at room temperature. Hence, cuboctahedral, Marks-decahedral, decahedral, octahedral, icosahedral, cubic, and tetrahedral morphologies were considered for assessment. According to the simulation results, Au frame with various morphologies and coordination numbers from 3 to 6 was unstable at 300 K. In addition, the contraction and collapse of Au atoms in the frame along with the expansion of Pt atoms in the core, lead to void occupation, and increases the coordination number and formation of a more stable Pt@Au structure. The results also demonstrated that stability of the formed Pt@Au core-shell structure depends on initial morphology and obeys the following trend: Marks-decahedral > cubic > octahedral > icosahedral > decahedral > cuboctahedral > tetrahedral