title: The surface structure of silver-coated gold nanocrystals and its influence on shape control.
abstract: Understanding the surface structure of metal nanocrystals with specific facet indices is important due to its impact on controlling nanocrystal shape and functionality. However, this is particularly challenging for halide-adsorbed nanocrystals due to the difficulty in analysing interactions between metals and light halides (for example, chloride). Here we uncover the surface structures of chloride-adsorbed, silver-coated gold nanocrystals with {111}, {110}, {310} and {720} indexed facets by X-ray absorption spectroscopy and density functional theory modelling. The silver-chloride, silver-silver and silver-gold bonding structures are markedly different between the nanocrystal surfaces, and are sensitive to their formation mechanism and facet type. A unique approach of combining the density functional theory and experimental/simulated X-ray spectroscopy further verifies the surface structure models and identifies the previously indistinguishable valence state of silver atoms on the nanocrystal surfaces. Overall, this work elucidates the thus-far unknown chloride-metal nanocrystal surface structures and sheds light onto the halide-induced growth mechanism of anisotropic nanocrystals.
authors.affiliation: Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2.
authors.forename: J Daniel
authors.initials: JD
authors.lastname: Padmos
authors.affiliation: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Personick
authors.affiliation: Department of Chemistry, University of California, Riverside, California 92521, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Tang
authors.affiliation: Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Duchesne
authors.affiliation: Department of Chemistry, University of California, Riverside, California 92521, USA.
authors.forename: De-en
authors.initials: DE
authors.lastname: Jiang
authors.affiliation: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Chad A
authors.initials: CA
authors.lastname: Mirkin
authors.affiliation: 1] Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2. [2] School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2.
authors.forename: Peng
authors.identifier: 0000000336030175
authors.initials: P
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D002712:Chlorides / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D012834:Silver / Q000737:chemistry*
chemical_list: D002712:Chlorides; D012834:Silver; D006046:Gold