A new preparation method of LaMnO sub 3 perovskite using electrochemical oxidation

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1016/0022-4596(91)90058-P· OSTI ID:5407823

Sasaki, Takeshi; Matsumoto, Yasumichi; Hombo, Jukichi; Ogawa, Yoriyuki ^[1]

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1. Kumamoto Univ. (Japan)

LaMnO{sub 3} perovskite was prepared by heat treatment of an oxide film which was electrochemically deposited on a Pt electrode in solutions containing both La{sup 3+} and Mn{sup 2+} ions. The La/Mn ratio in the deposited oxide films increased with an increase in the (La{sup 3+})/(Mn{sup 2+}) ratio in solution and with a positive shift of electrode potential. The maximum value in this ratio was about one, and was obtained in solution with (La{sup 3+})/(Mn{sup 2+}) > 500 and/or in a potential region more positive than about 1.9 V vs. Ag/AgCl. It was presumed from IR, TG, XRD, and XPS measurements that the incorporation of La{sup 3+} ion into the oxide film during electrochemical deposition is based on a specific adsorption of La{sup 3+} ions onto the surface of amorphous and hydrous {epsilon}-MnO{sub 2}, which has some oxygen deficiencies, and that the La{sup 3+} ion exists as a hydroxide in the oxide. A single phase of LaMnO{sub 3} perovskite was obtained by heat-treatment of the deposited oxide film with La/Mn = 1.0 at a temperature higher than about 750C, which was always lower than the preparation temperature in the ceramic technique (about 1,200C). The crystallization process in the heat treatment was also discussed from TG and XRD analysis.

• OSTI ID: 5407823
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 91:1; ISSN 0022-4596; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
COHERENT SCATTERING
CRYSTALLIZATION
DIFFRACTION
ELECTRON SPECTROSCOPY
GRAVIMETRIC ANALYSIS
HEAT TREATMENTS
INFRARED SPECTRA
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MANGANESE COMPOUNDS
MANGANESE OXIDES
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITE
PEROVSKITES
PHASE TRANSFORMATIONS
PHOTOELECTRON SPECTROSCOPY
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTH COMPOUNDS
SCATTERING
SPECTRA
SPECTROSCOPY
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION