American Chemical Society
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Thiol-Capped Gold Nanoparticles on Graphite:  Spontaneous Adsorption and Electrochemically Induced Release

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journal contribution
posted on 2007-05-17, 00:00 authored by D. Grumelli, C. Vericat, G. Benitez, M. E. Vela, R. C. Salvarezza, L. J. Giovanetti, J. M. Ramallo-López, F. G. Requejo, A. F. Craievich, Y. S. Shon
Gold nanoparticle-(AuNP)-modified carbon graphite surfaces have been prepared by simple immersion of highly oriented pyrolytic graphite (HOPG) in hexane solutions containing 3 nm diameter butanethiol- or nonanethiol-capped nanoparticles. The AuNP adsorb on the HOPG surface free of unbounded thiols, remaining unchanged with time. The amount of adsorbed thiol-protected AuNP depends on concentration and time. The reductive desorption of thiols from the AuNP produces an efficient release of more than 90% of the AuNP from the carbon surface to the aqueous solution. The remaining thiol-free Au nanoparticles do not sinter on the HOPG, forming stable and electrochemically active islands. These results could open interesting possibilities for easy transfer of thiol-capped metallic NP from one environment to another, for controlled release of biomolecules from metallic NP, and for the preparation of catalytic or decontamination systems on large area C surfaces.