Facile Electrochemical Characterization of Core/Shell Nanoparticles. Ag Core/Ag2O Shell Structures

We report in this paper a facile approach for the formation and electrochemical characterization of silver−silver oxide core−shell nanoparticles (NPs). Thus, thermal treatment at temperatures between 200 and 360 °C of Ag NP, in the gas phase or in an organic solvent, has been used to achieve the formation Ag@Ag2O NP. The evidence of formation of such a core−shell structure was obtained by cyclic voltammetry using a Nafion modified electrode (where Nafion containing carbon particles is used as the matrix to encapsulate the core−shell NP). Initial positive scans measure free Ag. Initial negative scans measure Ag2O, with the following positive scan, compared to the initial one, providing a measure of “trapped” or core Ag. The results presented demonstrate the utility of this approach in characterizing core−shell structures, like Ag@Ag2O, which could be extended to other core−shell forms, such as bimetallic core−shell NP.