New Nanocrystalline Manganese-Molybdenum-Tin Oxide Anodes for Oxygen Evolution in Seawater Electrolysis

Abstract

IrO2/Ti supported g-MnO2 type Mn-Mo-Sn oxide electrodes were prepared by electrodeposition from MnSO4-Na2MoO4-SnCl4 solutions of pH -0.1~0.5 at 600 Am-2 and 90oC for 60~90 min. The electrodes consist of Mn3+, Mn4+, Mo6+ and Sn4+ in the form of nanocrystalline single phase triple oxide. The performance of electrodes for oxygen evolution reaction during electrolysis of 0.5 M NaCl of pH 8.7 was examined at 1000 Am-2. Anodic deposition in 0.2 M Mn2+-0.003 M Mo6+-0.006 M Sn4+ electrolyte of pH -0.1 for 60 min guaranteed the stable electrode performance of 100 and 94% oxygen evolution efficiencies before and after electrolysis for more than seven months. Durability of the electrode was further improved by repeated deposition.