title: Synthesis and colloidal polymerization of ferromagnetic Au-Co nanoparticles into Au-Co3O4 nanowires.
abstract: The preparation of cobalt oxide nanowires with gold nanoparticle (AuNP) inclusions (Au-Co(3)O(4) nanowires) via colloidal polymerization of dipolar core-shell NPs is reported. Polystyrene-coated ferromagnetic NPs composed of a dipolar metallic cobalt shell and a gold NP core (PS-AuCoNPs) were synthesized by thermolysis of octacarbonyldicobalt [Co(2)(CO)(8)] in the presence of AuNP seeds and polymeric ligands. The colloidal polymerization process of these dipolar PS-AuCoNPs comprises dipolar nanoparticle assembly and solution oxidation of preorganized NPs to form interconnected cobalt oxide nanowires via the nanoscale Kirkendall effect, with AuNP inclusions in every repeating unit of the one-dimensional mesostructure. Calcination of the polymer-coated nanowires afforded polycrystalline Au-Co(3)O(4) nanowires that were determined to be electroactive. Nanocomposite materials were characterized by transmission electron microscopy, field-emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and cyclic voltammetry. We demonstrate that the optical and electrochemical properties of Au-Co(3)O(4) nanowires are significantly enhanced in comparison with hollow Co(3)O(4) nanowires prepared via colloidal polymerization.
authors.affiliation: Department of Chemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85752, USA.
authors.forename: Bo Yun
authors.initials: BY
authors.lastname: Kim
authors.forename: In-Bo
authors.initials: IB
authors.lastname: Shim
authors.forename: Zeynep O
authors.initials: ZO
authors.lastname: Araci
authors.forename: S Scott
authors.initials: SS
authors.lastname: Saavedra
authors.forename: Oliver L A
authors.initials: OL
authors.lastname: Monti
authors.forename: Neal R
authors.initials: NR
authors.lastname: Armstrong
authors.forename: Rabindra
authors.initials: R
authors.lastname: Sahoo
authors.forename: Divesh N
authors.initials: DN
authors.lastname: Srivastava
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Pyun