Abstract
The catalytic performance of nanoparticles is primarily determined by the precise nature of the surface and near-surface atomic configurations, which can be tailored by post-synthesis annealing effectively and straightforwardly. Understanding the complete dynamic response of surface structure and chemistry to thermal treatments at the atomic scale is imperative for the rational design of catalyst nanoparticles. Here, by tracking the same individual Pt 3 Co nanoparticles during in situ annealing in a scanning transmission electron microscope, we directly discern five distinct stages of surface elemental rearrangements in Pt 3 Co nanoparticles at the atomic scale: initial random (alloy) elemental distribution; surface platinum-skin-layer formation; nucleation of structurally ordered domains; ordered framework development and, finally, initiation of amorphization. Furthermore, a comprehensive interplay among phase evolution, surface faceting and elemental inter-diffusion is revealed, and supported by atomistic simulations. This work may pave the way towards designing catalysts through post-synthesis annealing for optimized catalytic performance.
| Original language | English |
|---|---|
| Article number | 8925 |
| Journal | Nature Communications |
| Volume | 6 |
| DOIs | |
| State | Published - Nov 18 2015 |
Funding
This research was performed at ORNL’s Center for Nanophase Materials Sciences, which is a US Department of Energy, Office of Science User Facility, and was supported by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office. G.F. Wang thanks the support from the US Department of Energy (Grant No. DE-FG02-09ER16093) and the National Science Foundation (Grant No. DMR-1410597). This synthesis of NPs was conducted at Argonne National Laboratory, a U.S. Department of Energy, Office of Science Laboratory, operated by UChicago Argonne, LLC, under contract no. DE–AC02–06CH11357.