Identification of a critical intermediate in galvanic exchange reactions by single-nanoparticle-resolved kinetics

Jeremy G. Smith, Qing Yang, Prashant K. Jain

Research output: Contribution to journalArticle

Abstract

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 a combination of plasmonic spectroscopy and scanning transmission electron microscopy. Single-nanoparticle reaction trajectories showed that a Ag nanoparticle exposed to Au3+ 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. 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.

Original languageEnglish (US)
Pages (from-to)2867-2872
Number of pages6
JournalAngewandte Chemie - International Edition
Volume53
Issue number11
DOIs
StatePublished - Mar 10 2014

Keywords

  • galvanic reactions
  • nanoparticles
  • nanostructures
  • nucleation
  • single-particle spectroscopy

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis

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