Nabil A. Abdel Ghany1,, Shinsaku Meguro1, Naokazu Kumagai2, Katsuhiko Asami3 and Koji Hashimoto1,
1Tohoku Institute of Technology, Sendai 982-8588
In order to avoid chlorine evolution on the anode in hot seawater electrolysis, the oxygen evolution anodes were tailored. γ-MnO2-type Mn1-x-yMoxFeyO2+x-0.5y anodes consisting of Mn4+, Mo6+ and Fe3+ were prepared by anodic deposition. The anodes with the 100% oxygen evolution efficiency in the electrolysis of 0.5 kmol m-3 NaCl at pH 12, 353 K and a current density of 1000 Am-2 were prepared in solutions consisting of 0.003 kmol m-3 Na2MoO4, 0.1 kmol m-3 Fe(NH4)(SO4)2 and 0.2 kmol m-3 or higher concentrations of MnSO4 at pH 0.33-0.5, 363 K and a current density of 600 Am-2. In the outside of this range, generally because of lower deposition efficiency, the electrode surface was not completely covered with anodically deposited oxides with a consequent lower oxygen evolution efficiency.
hot seawater electrolysis, anode, oxygen evolution, manganese-molybdenum-iron oxide, 100% oxygen evolution efficiency, deposition efficiency
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