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- Title
Identification of a Critical Intermediate in Galvanic Exchange Reactions by Single-Nanoparticle-Resolved Kinetics.
- Authors
Smith, Jeremy G.; Yang, Qing; Jain, Prashant K.
- 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.
- Subjects
EXCHANGE reactions; METAL nanoparticles; NANOSTRUCTURES; ELECTROLYTIC corrosion; SCANNING transmission electron microscopy; VACANCIES in crystals
- Publication
Angewandte Chemie International Edition, 2014, Vol 53, Issue 11, p2867
- ISSN
1433-7851
- Publication type
Article
- DOI
10.1002/anie.201309307