Abstract
Despite the large number of reports on colloidal nanocrystals, very little is known about the mechanistic details in terms of nucleation and growth at the atomistic level. Taking bimetallic core-shell nanocrystals as an example, here we integrate in situ liquid-cell transmission electron microscopy with first-principles calculations to shed light on the atomistic details involved in the nucleation and growth of Pt on Pd cubic seeds. We elucidate the roles played by key synthesis parameters, including capping agent and precursor concentration, in controlling the nucleation site, diffusion path, and growth pattern of the Pt atoms. When the faces of a cubic seed are capped by Br−, Pt atoms preferentially nucleate from corners and then diffuse to edges and faces for the creation of a uniform shell. The diffusion does not occur until the Pt deposited at the corner has reached a threshold thickness. At a high concentration of the precursor, self-nucleation takes place and the Pt clusters then randomly attach to the surface of a seed for the formation of a non-uniform shell. These atomistic insights offer a general guideline for the rational synthesis of nanocrystals with diverse compositions, structures, shapes, and related properties.
| Original language | English |
|---|---|
| Article number | 3215 |
| Journal | Nature Communications |
| Volume | 12 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2021 |
Funding
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, Catalysis Science Program. Electron Microscopy was performed at the Center for Nano-phase Materials Sciences at Oak Ridge National Laboratory (ORNL), which is a DOE Office of Science User Facility. W.G. and X.P. are supported by National Science Foundation with the grant number CBET-2031494 and the School of Engineering at University of California, Irvine. Theoretical work at UW-Madison was supported by DOE-BES, Division of Chemical Sciences, Catalysis Science program, grant # DE-FG02-05ER15731. A.O.E. and L.T.R. thank Drs. Benjamin Chen and Tibor Szilvási for helpful discussions. Calculations were performed using supercomputing resources at the National Energy Research Scientific Computing Center (NERSC), supported by the U.S. Department of Energy, Office of Science, under contract DE-AC02-05CH11231. Z.D.H. gratefully acknowledges a Graduate Research Fellowship award from the National Science Foundation (DGE-1148903) and the Georgia Tech-ORNL Fellowship. Copyright Notice is missing. Please add: “Copyright notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).