title: In Situ Single-Nanoparticle Spectroscopy Study of Bimetallic Nanostructure Formation.
abstract: Bimetallic nanostructures (NSs), with utility in catalysis, are typically prepared using galvanic exchange (GE), but the final catalyst morphology is dictated by the dynamics of the process. In situ single nanoparticle (NP) optical scattering spectroscopy, coupled with ex situ electron microscopy, is used to capture the dynamic structural evolution of a bimetallic NS formed in a GE reaction between Ag and [PtCl6 ](2-) . We identify an early stage involving anisotropic oxidation of Ag to AgCl concomitant with reductive deposition of small Pt clusters on the NS surface. At later stages of GE, unreacted Ag inclusions phase segregate from the overcoated AgCl as a result of lattice strain between Ag and AgCl. The nature of the structural evolution elucidates why multi-domain Ag/AgCl/Pt NSs result from the GE process. The complex structural dynamics, determined from single-NP trajectories, would be masked in ensemble studies due to heterogeneity in the response of different NPs.
authors.affiliation: Dept. of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL, 61801, USA.
authors.forename: Jeremy G
authors.initials: JG
authors.lastname: Smith
authors.affiliation: Dept. of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL, 61801, USA.
authors.forename: Indranath
authors.identifier: 0000-0003-4195-9384
authors.initials: I
authors.lastname: Chakraborty
authors.affiliation: Dept. of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL, 61801, USA. jain@illinois.edu.|Materials Research Lab, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, IL, 61801, USA. jain@illinois.edu.
authors.forename: Prashant K
authors.identifier: 0000-0002-7306-3972
authors.initials: PK
authors.lastname: Jain
keywords: alloys; catalysis; nanoscience; plasmon; single-molecule spectroscopy