Oxygen evolution on (Mn1-xMox)O2+x anodes with a sublayer of iridium and platinum oxides:: Distinguishing features of the process kinetics

The manganese dioxide anodes modified by molybdenum compounds exhibit selectivity with respect to the oxygen evolution reaction in a 0.5 M solution of sodium chloride at pH 7.0. When depositing an active material, at first a sublayer of a noble metal is created at the surface of titanium. The task of the sublayer is usually reduced to the creation of a conducting sublayer that would hinder the passivation of titanium. Such a sublayer can be created from both iridium dioxide and platinum oxides that are produced by thermolysis of proper salts. The kinetics of the oxygen evolution reaction in a 0.5 M solution of sodium sulfate on these oxides is substantially different. Specifically, the oxygen evolution process at IrO2 is characterized by a substantially lower overvoltage and more pronounced reversibility. Selective evolution of oxygen out of 0.5 M solutions of sodium chloride may be reached both on the basis of an anode with a sublayer of iridium dioxide and with a sublayer of platinum oxides. The surface of the obtained electrodes is enriched by molybdenum compounds.