Rapid Synthesis of Hollow Ag-Au Nanodendrites in 15 Seconds by Combining Galvanic Replacement and Precursor Reduction Reactions

• Published in: Chemistry : a European journal 2014-11, Vol.20 (46), p.15040-15046
• Main Authors: da Silva, Anderson G. M., de Souza, Michele L., Rodrigues, Thenner S., Alves, Rafael S., Temperini, Marcia L. A., Camargo, Pedro H. C.
• Format: Article
• Language: English
• Subjects: Chemistry; gold; Morphology; Nanospheres; Nanostructure; nanostructures; Raman scattering; Reduction; Seeds; Silver; surface plasmon resonance; surface-enhanced Raman spectroscopy; Tips
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201404739

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. Spiky and hollow: By using Ag nanospheres as seeds, hollow Ag–Au nanodendrites can be prepared in 15 s by a combination of a galvanic replacement reaction between Ag and AuCl4−(aq), and a AuCl4−(aq) reduction using hydroquinone in the presence of polyvinylpyrrolidone (PVP) in water. Owing to their sharp tips, the Ag–Au nanodendrites were effective substrates for surface‐enhanced Raman scattering (SERS) detection of 4‐mercaptopyridine and rhodamine 6G.