Anodically deposited manganese-molybdenum oxide anodes with high selectivity for evolving oxygen in electrolysis of seawater

K. Fujimura, K. Izumiya, A. Kawashima, Eiji Akiyama, H. Habazaki, N. Kumagai, K. Hashimoto

Research output: Contribution to journalArticlepeer-review

52 Citations (Scopus)

Abstract

Manganese-molybdenum oxide electrodes were prepared by anodic deposition on an IrO2-coated titanium substrate at a constant current density of 600 A m-2 from baths containing 0.2 M MnSO4 and 0-0.1 M Na2MoO4 at 90 °C and pH 0.5. These electrodes were characterized for oxygen evolution in the electrolysis at 1,000 A m-2 in 0.5 M NaCl solution at 30 °C and pH 8 or 12. The most active and stable oxygen evolving anode exhibited 100% efficiency for oxygen evolution, and an efficiency of 98.5% for over 1,500 h at pH 12 and of 96.5% for over 2,800 h at pH 8 of continuous electrolysis. X-ray diffraction measurement and XPS analysis indicated that the deposits consist of a nanocrystalline single γ-MnO2 type phase, and manganese and molybdenum in the deposits are in the Mn4+ and Mo6+ states. The electrochemical studies showed that the manganese-molybdenum oxide electrodes drastically reduced the electrocatalytic activity for chlorine evolution to the undetectable level, resulting in 100% efficiency for oxygen evolution, although the addition of molybdenum slightly increased the oxygen overpotential.

Original languageEnglish
Pages (from-to)765-771
Number of pages7
JournalJournal of Applied Electrochemistry
Volume29
Issue number6
Publication statusPublished - 1999 Jan 1

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry
  • Materials Chemistry

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