title: Correlating catalytic activity of Ag-Au nanoparticles with 3D compositional variations.
abstract: Significant elemental segregation is shown to exist within individual hollow silver-gold (Ag-Au) bimetallic nanoparticles obtained from the galvanic reaction between Ag particles and AuCl4(-). Three-dimensional compositional mapping using energy dispersive X-ray (EDX) tomography within the scanning transmission electron microscope (STEM) reveals that nanoparticle surface segregation inverts from Au-rich to Ag-rich as Au content increases. Maximum Au surface coverage was observed for nanoparticles with approximately 25 atom % Au, which correlates to the optimal catalytic performance in a three-component coupling reaction among cyclohexane carboxyaldehyde, piperidine, and phenylacetylene.
authors.affiliation: School of Materials, The University of Manchester , Manchester, M13 9PL, United Kingdom.
authors.forename: Thomas J A
authors.initials: TJ
authors.lastname: Slater
authors.forename: Alexandra
authors.initials: A
authors.lastname: Macedo
authors.forename: Sven L M
authors.initials: SL
authors.lastname: Schroeder
authors.forename: M Grace
authors.initials: MG
authors.lastname: Burke
authors.forename: Paul
authors.initials: P
authors.lastname: O'Brien
authors.forename: Pedro H C
authors.initials: PH
authors.lastname: Camargo
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Haigh