IN-SITU SCANNING-TUNNELING-MICROSCOPY STUDIES OF NANOMETER-SIZE PALLADIUM PARTICLES ON HIGHLY ORIENTED PYROLYTIC-GRAPHITE

A special electrodeposition process of palladium was studied by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS) and in situ scann ing tunneling microscopy (STM). A kind of palladium(IV) complex was at tached to the highly oriented pyrolytic graphite (HOPG) electrode surf ace by electro-oxidation of palladium(II) complex first, and was then reduced to palladium particles. The surface complexes and particles of palladium were both characterized by in situ STM and XPS. The Pd part icles are in the nanometer range of size and exhibit electrocatalytic activity towards the oxidation of hydrazine and hydroxylamine.