Electrochemistry of Single Nanoparticles via Electrocatalytic Amplification

Recent experiments on the observation of colli- sions of single nanoparticles (NPs) with an electrode through amplification of the current by electrocatalysis are described. Systems in which the particles adhere to the elec- trode upon collision produce a step and staircase response, while those in which particles only interact for a short time with the electrode produce a spike or blip, with little change in the steady state current. Examples of both behaviors, e. g., Pt NPs on a Au electrode for hydrazine oxidation (staircase response) and IrOx NPs on a Pt electrode for water oxidation (blip response) are shown. Controlling the nature of the electrode surface is important in generating useful responses, for example, in the case of gold NPs on an oxidized Pt electrode for borohydride oxidation.