Novel electrochemical fingerprinting methods for the precise determination of Pt(shell) coverage on Ru(core) nanoparticles.

The surface composition of nanoparticles is critical in defining their chemical and electrochemical properties. However, there are a limited number of tools that can rapidly and reliably establish these important characteristics at this small scale. In the present work, a series of Rucore@Ptshell nanoparticles (2 or 3 nm diameter Ru core, 0 to 2 monolayers of Pt in the shell layer) were synthesized and several novel electrochemical fingerprinting methods were developed to determine the Pt shell characteristics. These involved tracking the charge associated with the reduction of the oxide film formed on the exposed Rucore, as well as the potential and charge associated with COads stripping, giving the precise coverage of the first and second Pt monolayer, respectively.