title: Rapid synthesis of hollow Ag-Au nanodendrites in 15 seconds by combining galvanic replacement and precursor reduction reactions.
abstract: Metallic nanomaterials displaying hollow interiors as well as sharp tips/branches at their surface (such as hollow nanodendrites) are attractive, because these features enable higher surface-to-volume ratios than their solid and/or rounded counterparts. This paper describes a simple strategy for the synthesis of Ag-Au nanodendrites in 15 s using Ag nanospheres prepared in a previous synthetic step as seeds. Our approach was based on the utilization of Ag nanospheres as seeds for Au deposition by a combination of galvanic replacement reaction between Ag and AuCl4(-)(aq) and AuCl4(-)(aq) reduction using hydroquinone in the presence of polyvinylpyrrolidone (PVP) as a stabilizer and water as the solvent. The produced Ag-Au nanodendrites presented monodisperse sizes, and their surface morphologies could be tuned as a function of growth time. Owing to their hollow interiors and sharp tips, the Ag-Au nanodendrites performed as effective substrates for surface-enhanced Raman scattering (SERS) detection of 4-MPy (4-mercaptopyridine) and R6G (rhodamine 6G) as probe molecules. We believe that the approach described herein can serve as a protocol for the fast and one-step synthesis of Ag-Au hollow nanondendrites with a wide range of sizes, compositions, and surface morphologies for applications in SERS and catalysis.
authors.affiliation: Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000, São Paulo-SP (Brazil).
authors.forename: Anderson G M
authors.initials: AG
authors.lastname: da Silva
authors.forename: Michele L
authors.initials: ML
authors.lastname: de Souza
authors.forename: Thenner S
authors.initials: TS
authors.lastname: Rodrigues
authors.forename: Rafael S
authors.initials: RS
authors.lastname: Alves
authors.forename: Marcia L A
authors.initials: ML
authors.lastname: Temperini
authors.forename: Pedro H C
authors.initials: PH
authors.lastname: Camargo
keywords: gold; nanostructures; silver; surface plasmon resonance; surface-enhanced Raman spectroscopy