Electrode materials for the electrolysis of metal oxides

Abstract

Carbon, tungsten, platinum, and iridium were examined as candidate anode materials for an electrolytic cell. The materials were pre-selected to endure high process temperatures and were characterized for inertness and high current density during electrolysis using voltammometric techniques. Inertness is viewable through current discrepancies dependent on voltage scan direction at low voltage, consumption of current by metal oxide formation, and ease of surface oxide electro-stripping. Conductivity during electrolytic oxidation is observable as current density maximization at high voltages. While carbon, tungsten, and platinum formed surface oxides, iridium remained quite inert. In addition, the voltage hold-time was found to affect the leading current density, as platinum performed best during cyclic voltammometry, but iridium performed best during potentiostatic electrolysis. The intermediate potentiodynamic scan-rate displays the transition from platinum to iridium dominated current density.