Electrochemical oxidation of silver shells on gold nanorods in potassium chloride and phosphate buffer solutions

Electrochemical oxidation of silver shells on gold nanorods was examined using in situ spectroscopy and scanning electron microscopy. The oxidation, in a phosphate buffer solution, was suppressed because of the formation of Ag3PO4. In contrast, oxidation in a KCl solution occurred at the corners of the nanorods and proceeded until giving gold nanorods without silver shells. After the 10-s electrolysis, nanoparticles with different shapes were found on the electrode. The inhomogeneous oxidation was due to rapid oxidation of the silver shells and occasional contact of the nanorods with the electrode surfaces.