Fig. 3
From: Active site localization of methane oxidation on Pt nanocrystals
Reactive molecular dynamics (RMD) simulation of Pt catalytic activity. Images of a Pt nanocrystal colored by displacement from RMD simulation results and expanded views of the region marked out in the upper image. a Pt in an environment of pure H2. b Pt in an environment of pure O2. Surficial Pt atoms are displaced from their original position by oxidation of the edge and corner sites; those on faces of the particle show only weak displacements. c Oxidized Pt nanocrystals in the presence of CH4. d Analysis of the RMD of the ratio of adsorbed methane molecules to adsorbed oxygen atoms on the Pt nanocrystal. Only a fraction of the absorbed oxygen atoms are active for final product formation owing to steric hindrance. The solid line is a fit to A × [1 − exp(−t/B)] with t in ps, A and B are fitting constants. Extrapolating to infinite time yields an adsorption ratio of 0.398 ± 0.003 at any given time
