Reactivity of Nanostructured MnO2 in Alkaline Medium Studied with a Microcavity Electrode: Effect of Oxidizing Agent - Sorbonne Université Access content directly
Journal Articles J. Mater. Sci. Technol. Year : 2011

Reactivity of Nanostructured MnO2 in Alkaline Medium Studied with a Microcavity Electrode: Effect of Oxidizing Agent

Abstract

The synthesis of MnO2 powders by hydrothermal method with different oxidizing agents has been successfully achieved. The characterizations by scanning electron microscopy, energy-dispersive X-ray analyses, transmission electron microscopy, and X-ray diffraction techniques confirm the synthesis of nanostructured gamma--MnO2 powders. The electrochemical reactivity of these powders in 1 mol/l KOH is investigated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) by using microcavity electrode. The results reveal that the MnO2 synthesized with Na2S2O8 shows the highest electrochemical reactivity in the test medium. This is due both to its large expanded surface area and its crystallographic variety gamma-MnO2 formed in the matrix of ramsdellite, which is largely used as cathodic material for primary batteries. However, the presence of pyrolusite in the structure of -gamma--MnO2 synthesized with (NH4)(2)S2O8 decreases its electrochemical reactivity due to its narrow 1x1 size tunnel, which hinders the protons insertion.

Dates and versions

hal-00818876 , version 1 (29-04-2013)

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Lynda Benhaddad, Laid Makhloufi, Bouzid Messaoudi, Kamal Rahmouni, Hisasi Takenouti. Reactivity of Nanostructured MnO2 in Alkaline Medium Studied with a Microcavity Electrode: Effect of Oxidizing Agent. J. Mater. Sci. Technol., 2011, 27 (7), pp.585-593. ⟨10.1016/S1005-0302(11)60112-6⟩. ⟨hal-00818876⟩
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