INCORPORATION OF REDOX-ACTIVE CATIONS INTO TUNGSTEN-OXIDE COATINGS ON ELECTRODES - ENHANCEMENT OF COATING STABILITY AND ELECTROCATALYTIC ACTIVITY

The electrochemical deposition of tungsten oxide onto the surface of glassy carbon electrodes produces a coating which exhibits significant cation exchange behavior. Catalysts such as the protonated form of cobalt meso-tetrakis(4-pyridyl)porphyrin (CoTPyP) or cis-[Ru(6,6'-Cl2bpy)2(OH2)2]2+ are efficiently bound to the oxide coatings where they serve to catalyze the reduction of O2 or various oxidation reactions respectively. The combination of the reduced tungsten oxide (hydrogen tungsten bronze) with CoTPyP leads to the reduction of O2 to H2O2 and subsequently to H2O under conditions where CoTPyP alone produces only a two-electron reduction of O2.