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Redox Processes in Polynary Copper Oxides and Copper Oxide / Mesoporous Silica Composites

Published online by Cambridge University Press:  16 February 2011

A. Reller ,
S. Ebbinghaus ,
R. Köhn ,
M. Fröba ,
U. Sazama  and
P. Fortunato
A. Reller
Affiliation:
Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany; reller@xray.chemie.uni-hamburg.de
S. Ebbinghaus
Affiliation:
Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany; reller@xray.chemie.uni-hamburg.de
R. Köhn
Affiliation:
Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany; reller@xray.chemie.uni-hamburg.de
M. Fröba
Affiliation:
Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany; reller@xray.chemie.uni-hamburg.de
U. Sazama
Affiliation:
Institute of Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany; reller@xray.chemie.uni-hamburg.de
P. Fortunato
Affiliation:
Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 ZUrich, Switzerland
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Abstract

Dynamic redox processes in different complex copper oxides and oxide / mesoporous silica composites are characterized. In the spinel-type CuxMn3.xO4 the atomic and electronic structures are described with respect to the reversible process Cu2+ + Mn3+ ⇒ Cu3+ + Mn4+, the crucial dynamic equilibrium for the catalytic oxidation of CO to CO2 at ambient temperatures. A comparison with the perovskite-type LaCu1-xMnxO3-δ is presented. In the K2NiF4-type La2-xSrxCu1-yRuyO4-δ the electronic structure is characterized with respect to the equilibrium Cu2+ + Ru5+ ⇒ Cu3+ + Ru4+. Analogous redox processes are characterized in composite compounds made up of copper oxides inserted in mesoporous MCM-type silica. Due to their structural order in the nanoscopic range, the investigation of these materials required multiple, complementary characterization methods, i.e. X-ray diffractometry, thermal analysis, scanning and transmission electron microscopy, magnetic measurements, XPS, and particularly X-ray absorption spectroscopy (EXAFS / XANES) measurements.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 547: Symposium DD – Solid-State Chemistry of Inorganic Materials II , 1998 , 75
Copyright
Copyright © Materials Research Society 1999

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