Thin Film Coating of Mg-Intercalated Layered MnO2 to Suppress Chlorine Evolution at an IrO2 Anode in Cathodic Protection
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Titanium-supported electrocatalysts composed of novel metal oxides have exclusively been utilized as anodes in the cathodic protection (CP) of steel structures. These types of anodes have a small overpotential toward the chlorine evolution reaction (CER) in impressed-current cathodic protection (ICCP) systems and vigorously evolve chlorine (Cl2) in electrolytes containing Cl−, such as seawater. Cl2 has a negative impact on the ecosystem because of its intrinsic toxicity and corrosivity. We present herein a thin film coating that can effectively suppress the CER without prevention of the oxygen evolution reaction (OER) at the underlying iridium oxide (IrO2) layer coated on a titanium substrate in 0.5 M NaCl solution. The thin film consists of buserite-type layered manganese dioxide (MnO2), the interlayer of which accommodates Mg2+ cations and two layers of H2O molecules, and is uniformly deposited via an electrochemical route and subsequent ion-exchange. The CER efficiency of the electrode modified with the Mg-buserite layer was as small as 11% at + 1.7 V vs. Ag/AgCl.
KeywordsCathodic protection Chlorine evolution Oxygen evolution Buserite Magnesium Iridium oxide
This present work is under the support by the following organizations: Japan Society for the Promotion of Science (grant no. 16 K05938) and Yamaguchi University Blue Energy center for SGE Technology (BEST).
- 2.H.H. Uhlig, R.W. Revie, Corrosion and Corrosion Control: An Introduction to Corrosion Science and Engineering, 4th edn. (Wiley, Hoboken, 2008)Google Scholar
- 3.A. Bahadori, Cathodic Corrosion Protection Systems: A Guide for Oil and Gas Industries (Gulf Professional Publishing, Oxford, 2014)Google Scholar
- 4.C.F. Schrieber, in Designing Cathodic Protection Systems for Marine Structures and Vehicles, ed. by H. P. Hack. (ASTM International, West Conshohocken, 1999), p. 39Google Scholar
- 5.H. Bohnes, D. Funk, in Handbook of Cathodic Corrosion Protection Theory and Practice of Electrochemical Protection Processes, ed. by W. V. Baeckmann, W. Schwenk, W. Prinz. (Gulf Professional Publishing, Houston, 1997), p. 207Google Scholar
- 6.B.V. Tilak, C.P. Chen, in Chlor-Alkali and Chlorate Technology: R.B. Macmullin Memorial Symposium: Proceedings of the Symposium, ed. by H. S. Burney, N. Furuya, F. Hine, K. I. Ota. (The Electrochemical Society, Pennington, 1999), p. 8Google Scholar
- 12.E.P. Anderson, U.S. Patent 3, 303, 118 (1967)Google Scholar
- 13.M. Saleem, M.H. Chakrabarti, D.B. Hasan, M.S. Islam, R. Yussof, S.A. Hajimolana, M.A. Hussain, G.M.A. Khan, B.S. Ali, Int. J. Electrochem. Sci. 7, 3929 (2012)Google Scholar
- 35.J.E. Post, D.R. Veblen, Am. Mineral. 75, 477 (1990)Google Scholar
- 37.H. Sato, A. Morita, K. Ono, H. Nakano, N. Wakabayashi, A. Yamaguchi, Templating effects on the mineralization of layered inorganic compounds: (1) density functional calculations of the formation of single-layered magnesium hydroxide as a brucite model. Langmuir 19(17), 7120–7126 (2003)CrossRefGoogle Scholar