Metal nanoparticles have interesting size-dependent optical, electronic, thermal, chemical, and magnetic properties. They are used for several important applications, including catalysis, nanoelectronics, sensing, plasmonics, separations, drug delivery, medical diagnosis, and therapeutics. The size of the nanoparticle is crucial for these applications, especially in catalysis. Smaller-sized nanoparticles are often the most effective and the nanoparticle needs to be attached to a solid substrate for certain applications. The stability of metal nanoparticles against oxidation is a crucial issue for these applications. We recently showed by voltammetry that the oxidation potential of Ag and Au nanoparticles decreases as the size of the nanoparticle decreases. The decrease is about 200 mV from bulk to 4 nm average diameter for Au nanoparticles.

O.S. Ivanova; F.P. Zamborini. “Electrochemical Size Discrimination of Gold Nanoparticles Attached to Glass/Indium-Tin-Oxide Electrodes by Oxidation in Bromide-Containing Electrolyte” Anal. Chem. 2010, In press.

 O.S. Ivanova; F.P. Zamborini. “Size-Dependent Electrochemical Oxidation of Silver Nanoparticles” J. Am. Chem. Soc. 2010, 132, 70-72.