University of Illinois Urbana-Champaign

Identification Of A Critical Intermediate In Galvanic Exchange Reactions By Single-nanoparticle Resolved Kinetics

Smith, Jeremy George

Content Files
TH09_Abstract.pdf
TH09_Abstract.txt
TH09_Presentation.pptx

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https://hdl.handle.net/2142/50813

Description

Title
Identification Of A Critical Intermediate In Galvanic Exchange Reactions By Single-nanoparticle Resolved Kinetics
Author(s)
Smith, Jeremy George
Contributor(s)
Jain, Prashant
Issue Date
2014-06-17
Keyword(s)
Mini-symposium: Spectroscopy in Kinetics and Dynamics
Date of Ingest
  • 2014-09-17T16:55:01Z
  • 2015-04-14T18:40:47Z
Abstract
\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.25]{Graph2.eps} \end{wrapfigure} The realization of common materials transformations in nanocrystalline systems is fostering the development of novel nanostructures and allowing a deep look into the atomistic mechanisms involved. Galvanic corrosion is one such transformation. We studied galvanic replacement within individual metal nanoparticles by using plasmonic spectroscopy. This proved to be a powerful approach to studying materials transformations in the absence of ensemble averaging. Individual nanoscale units act as domains that can be interrogated optically in isolation, whereas the averaging of all such domains provides a bulk reaction trajectory. Single-nanoparticle reaction trajectories showed that a Ag nanoparticle exposed to Au$^{3+}$ makes an abrupt transition into a nanocage structure. The transition is limited by a critical structural event, which we identified by electron microscopy to comprise the formation of a nanosized void, similar to the pitting process commonly observed in the corrosion of metals. Trajectories also revealed a surprisingly strong nonlinearity of the reaction kinetics, which we explain by a model involving the critical coalescence of vacancies into a growing void. The critical void size for galvanic exchange to spontaneously proceed was found to be 20 atomic vacancies. In the future we hope to extend this approach to examine a wide variety of materials transformations and chemical reactions.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
English
Permalink
http://hdl.handle.net/2142/50813
DOI
https://doi.org/10.15278/isms.2014.TH09
Copyright and License Information
Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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Abstracts & Presentations - 2014 International Symposium on Molecular Spectroscopy PRIMARY