resumo
Graphene sheets, which possess unique nanostructure and a variety of fascinating properties, are considered as promising nanoscale building blocks of new nanocomposites, namely as a support material for the dispersion of metal nanoparticles. One of the methodologies used to prepare graphene sheets is the chemical exfoliation of graphite in aqueous medium, which produces oxygen functionalized graphene sheets. Here, we show that the presence of oxygen functionalities at the graphene surface provides reactive sites for the nucleation and growth of gold nanoparticles. Gold nanoparticles are effectively grown at functionalized graphene surfaces using a simple chemical method in aqueous medium. The nucleation and growth mechanism depends on the degree of oxygen functionalization at the graphene surface sheets, no gold nanoparticles are obtained at totally reduced graphene surfaces. Additionally, our studies indicate that the graphene/gold nanocomposites are potential substrates for SERS (surface enhanced Raman scattering) in particular for single gold nanoparticle SERS studies.
palavras-chave
ENHANCED RAMAN-SCATTERING; CARBON NANOTUBES; GRAPHITE OXIDE; FILMS; SERS; NANOCOMPOSITES; SPECTROSCOPY; DISPERSIONS; EXFOLIATION; COMPOSITES
categoria
Chemistry; Materials Science
autores
Goncalves, G; Marques, PAAP; Granadeiro, CM; Nogueira, HIS; Singh, MK; Gracio, J
nossos autores
Carlos Miguel Cardeal Enes Granadeiro
Bolseiro de pós-Doutoramento
Helena Isabel Seguro Nogueira
Professor Auxiliar com Agregaçãoagradecimentos
G.G. thanks the INL (International Iberian nanotechnology laboratory) for the Financial support of this work. Thanks are also due to Fundacao para a Ciencia e a Tecnologia (Portugal) for a post graduation grant to C.M.G. (SFRH/BD/30137/2006).