A novel method to deposit continuous platinum shells of ~5 atomic layers onto preformed gold seeds is reported. The plating process consists in reducing hexachloroplatinic acid with ascorbic acid in aqueous medium. A rigorous control of the reduction kinetics of Pt(IV) species and core particles with suitable properties are necessary to achieve epitaxial deposition of platinum atoms. The compactness and uniformity of platinum shell were confirmed by electron microscopy and its continuity by electrochemical (CV) evaluations. The mass specific oxygen reduction activity of platinum in the AuPt core-shell structures was found to be four times higher than that of platinum black and comparable to that of polycrystalline bulk metal. The core/shell AuPt nanoparticles prepared represent a viable replacement of pure Pt nanoparticles in proton exchange membrane fuel cells (PEMFC) applications.

Epitaxial deposition of thin platinum shells on gold nanocrystals

244th National Meeting (2012)

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