Low-temperature oxidation of Mn3O4 hausmannite

被引：71

作者：

Fritsch, S

Sarrias, J

Rousset, A

Kulkarni, GU ^{[1
]}

机构：

[1] Jawaharlal Nehru Ctr Adv Sci Res, Chem & Phys Mat Unit, Bangalore 560064, Karnataka, India

[2] Univ Toulouse 3, Lab Chim Mat Inorgan, ESA 5070, F-31062 Toulouse, France

来源：

MATERIALS RESEARCH BULLETIN | 1998年 / 33卷 / 08期

关键词：

oxides; thermogravimetric analysis (TGA); XAFS; (EXAFS; XANES); X-ray diffraction;

D O I：

10.1016/S0025-5408(98)00108-1

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Hausmannite, Mn3O4, with a specific surface area of 10 m(2)/g has been oxidized at low temperatures (300 degrees C < T < 425 degrees C). In this temperature range both Mn2+ and Mn3+ cations are oxidized. The oxidation of Mn2+ to Mn3+ is governed by a diffusion process and the spinel structure is stable up to 425 degrees C. Oxidation of Mn3+ to Mn4+ leads to the crystallization of the Mn5O8 phase. Careful oxidation studies show the formation of two metastable manganese oxides, Mn5O8 and a defect spinel of the formula Mn2O2.78. The coordination numbers and the cation-anion distances in Mn3O4, gamma-Mn2O2.78 and alpha-Mn2O3 obtained by EXAFS (extended X-ray absorption fine structure) are compared. (C) 1998 Elsevier Science Ltd.

引用

页码：1185 / 1194

页数：10

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