The Corrosion of Carbon Black Anodes in Alkaline Electrolyte: II . Acetylene Black and the Effect of Oxygen Evolution Catalysts on Corrosion

The effect of five different metal oxides on the corrosion rate of acetylene black during oxygen evolution in alkaline electrolyte was determined using the analytical methods described in Part I. All five metal oxides ( , , , , and Ru) catalyzed the corrosion processes of the acetylene black, resulting in corrosion rates accelerated by factors of 3–14. The mechanism of this catalytic effect remains unclear. Some results with have indicated direct contact with the oxide, and the carbon is not required to accelerate the corrosion, suggesting a redox mechanism involving dissolved species. However, the effects of and , which were significantly greater than with , are difficult to rationalize on this basis, as their redox potentials lie well below the oxygen evolution potential range.