On the ability of ruthenium to stabilize polynuclear hexacyanometallate film electrodes

A novel procedure that yields extremely stable ruthenium-modified inorganic film electrodes is presented. The following prussian blue (PB) analogues w ere investigated: indium(III)-hexacyanoferrate (InHCF), nickel(II)-hexacyan oferrate (NiHCF), cobalt(II)-hexacyanoferrate (CoHCF), and iron(III)-hexacy anorutenate also known as ruthenium purple (RP). The process includes elect rochemical film deposition and subsequent voltammetric conditioning in a Ru (III)-containing solution at pH 2. Electrochemical and spectroscopic proper ties of each resulting modified film are better defined, redox and switchin g rates improved, and stability strongly enhanced. XPS supports the conclus ions that the incorporation of ruthenium imparts an extensive crosslinking between hydrate microparticles through dinuclear [Fe, Ru] oxo (-O-) and cya nide (-CN-) bridges. (C) 1998 Elsevier Science S.A. All rights reserved.