Preparation of α-MnO2 with an open tunnel

被引：52

作者：

Muraoka, Y

Chiba, H

Atou, T

Kikuchi, M

Hiraga, K

Syono, Y

Sugiyama, S

Yamamoto, S

Grenier, JC

机构：

[1] Tohoku Univ, Inst Mat Res, Aoba Ku, Sendai, Miyagi 9808577, Japan

[2] Mitsui Chem Inc, Performance Mat R&D Ctr, Sakae Ku, Yokohama, Kanagawa 2478567, Japan

[3] CNRS, Inst Chim Mat Condensee BOrdeaux, F-33608 Pessac, France

来源：

JOURNAL OF SOLID STATE CHEMISTRY | 1999年 / 144卷 / 01期

关键词：

alpha-MnO2; hollandite structure; ammonium ion; quench; 440 degrees C;

D O I：

10.1006/jssc.1999.8133

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

A single-phase alpha-MnO2 without any large stabilizing cations was successfully prepared by starting from hollandite-type (NH4)(x)Mn8O16 and quenching from 440 degrees C during heating in flowing Ar. The unit-cell dimension was determined by XRD analysis to be a 10.308(2) Angstrom and c = 2.854(1) Angstrom. In comparison with that of the starting material (a = 9.896(1) Angstrom and c = 2.859(1) Angstrom), the a dimension increased while the c dimension changed little. No presence of ammonium ions in the structure of this specimen was shown by IR spectroscopy, the Kjeldahl analysis, or temperature-programmed-desorption (TPD) measurement. The structural change from the hollandite phase to Mn2O3 was observed at 540 degrees C. TPD analysis indicates the presence of nitrogen other than ammonium ions in the hollandite material we prepared, and also suggests that this nitrogen might have a strong chemical interaction to the hollandite structure, (C) 1999 Academic Press.

引用

页码：136 / 142

页数：7

共 16 条

[1] CATIONIC SHORT-RANGE ORDER IN HOLLANDITE K1.54MG0.77T7.23O16 - EVIDENCE FOR IMPORTANCE OF ION-ION INTERACTIONS IN SUPERIONIC CONDUCTORS [J].