An ellipsometric study of manganese oxide films: In situ characterization of the deposition and electroreduction of MnO2

• Autor(a) principal: Ubeda, M. Hernández
• Data de Publicação: 2005
• Outros Autores: Pérez, M. A., Mishima, H. T., Villullas, H. M. [UNESP], Zerbino, J. O., De Mishima, B.A. López, Teijelo, M. López
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1149/1.1825951; http://hdl.handle.net/11449/68134
• topic: Anisotropy; Computer simulation; Crystal structure; Crystallography; Diffusion; Electrochemistry; Electrodeposition; Electrolytes; Ellipsometry; Mathematical models; Precipitation (chemical); Raman spectroscopy; Reduction; Refractive index; X ray photoelectron spectroscopy; Electrochemical films; Manganese oxide films; Optical response; Step potential electrochemical spectroscopy (SPES); Manganese compounds

The electrodeposition of manganese oxide films onto a platinum substrate was investigated by means of in situ ellipsometry. In the thickness range from 0 to 150 nm, the anodic oxide behaves as an Isotropic single layer with optical constants that are independent of thickness. Deviations at higher thickness are explained in terms of anisotropic properties of the film. The electroreduction of thin films (up to ca. 150 nm) in an alkaline electrolyte leads to a decrease in both the refractive index and the extinction coefficient and is accompanied by a thickness increase of ca. 10%. The Mn(IV) to Mn(III) conversion takes place from the oxide/electrolyte interface inwards. © 2004 The Electrochemical Society. All rights reserved.