The electrochemical response of manganese hydroxide–oxide films in slightly alkaline solutions. II. Voltammetric and ellipsometric studies

Autor:	M. López Teijelo, M. Hernández Ubeda, B.A. López de Mishima, H.T. Mishima, H. Herrera, H. M. Villullas
Rok vydání:	1998
Předmět:	General Chemical Engineering Inorganic chemistry Oxide chemistry.chemical_element Manganese Buffer solution Electrochemistry chemistry.chemical_compound chemistry Transition metal Ellipsometry Hydroxide Cyclic voltammetry
Zdroj:	Electrochimica Acta. 44:513-519
ISSN:	0013-4686
DOI:	10.1016/s0013-4686(98)00068-1
Popis:	The potentiodynamic behaviour of colloidal manganese hydroxide–oxide films obtained by chemical precipitation on a conducting substrate in alkaline solutions is described. The voltammetric response of cycled electrodes shows a main redox couple which is associated with the Mn(III)/Mn(IV) reaction occurring in solid state. The observed dependence of peak currents and peak potentials on sweep rate, charge and solution pH is similar to that reported for manganese and iridium oxides obtained by cycling the base metal. The optical response of cycled hydrous manganese oxide films is studied by in-situ ellipsometry. Data can be explained using an anisotropic single layer model. The optical anisotropy is related to the morphology of the hydrous oxide layer. The electroreduction process produces a decrease of the refractive indices and a pronounced diminution of the extinction coefficients yielding a practically transparent film.
Databáze:	OpenAIRE
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