Atomistic investigation on the diffusion mechanism of Pt nanoclusters on well-aligned multi-walled carbon nanotubes

Platinum (Pt) particle agglomeration and detachment from the carbon support significantly decreases their durability and reduces the performance of fuel cell, finding ideal support materials may increase the binding energy and catalytic activity of Pt particles. In this work, we mainly investigated the support material of well-aligned carbon nanotubes (WACNTs), and the influence of the number of walls on the diffusion process of Pt particles. Molecular dynamic (MD) simulations were employed to analyze the Pt nanocluster diffusion mechanism. It was found that Pt/WACNT structures had higher binding energies between the Pt clusters and carbon supports than the Pt/graphene and Pt/well-aligned single-walled CNT structures, and the binding energies increased with the number of walls of carbon nanotube. However, the influence of wall number on the binding energy would become less than that of the diameter of carbon nanotube when the number of walls was larger than two. Moreover, WACNT substrates yield a lower aggregation probability and diffusion coefficient for Pt clusters. Pt loading is calculated at a suggested magnitude of mu g/cm(2) on WACNT substrates for a reduced occurrence of Pt agglomeration. (C) 2015 Elsevier B.V. All rights reserved.