The anodic characteristics of manganese dioxide electrodes prepared by thermal decomposition of manganese nitrate

✍ Scribed by M. Morita; C. Iwakura; H. Tamura

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 420 KB
• Volume: 22
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(77)85081-0

✦ Synopsis

Abatraet-Manganese dioxide electrodes were prepared by a thermal decomposition of manganese nitrate solution on a titanium or a platinum substrate, and their anodic characteristics were investigated mainly in IN H$O, and 1N KOH. The platinum-supported manganese dioxide electrode shows the good anodic characteristics with a relatively low overvoltage for oxygen evolution while the use of the titanium-supported one as an anode needs further modification to reduce its high resistivity resulting from the thick film of titanium dioxide in spite of good adhesion of the oxide film with the titanium substrate.

The primary water or hydroxide ion discharge step is rate-controlling in the anodic evolution of oxygen on the platinum-supported manganese dioxide electrode in both acidic and alkaline solutions. The oxygen overvoltage is raised and the mechanical strength of the catalytic oxide on the platinum substrate is weakened by the anodic polarization in acidic solutions. These phenomena are explicable on the basis of an increase in the oxygen content in the oxide. In conclusion, the presented results suggest that the manganese dioxide film is a practical usable material for the anodic evolution of oxygen as well as chlorine, especially in alkaline solutions.