Electrochemistry and Electrocatalysis at Single Gold Nanoparticles Attached to Carbon Nanoelectrodes

Electrochemical experiments at individual metal nanoparticles (NPs) can provide new insights into their electrocatalytic behavior. In this Communication, we report the preparation of nanometer-sized carbon electrodes and their use as substrates for the immobilization of single gold NPs (AuNPs). In addition to its very small size, the surface of a carbon nanoelectrode is catalytically inert, which makes it an excellent substrate for studying electrocatalytic reactions. The activity of single AuNPs towards the hydrogen evolution reaction was investigated and compared to that of low-atomicity gold clusters. Three approaches to attaching AuNPs to either chemically modified or bare carbon nanoelectrodes, and the effects of immobilization on hydrogen adsorption and catalytic behavior of AuNPs are discussed. The developed methodology should be useful for studying the effects of NP size, geometry, and surface attachment on the electrocatalytic activity.