Synthesis of Sr0.9K0.1FeO3-delta electrocatalysts by mechanical activation
authors Monteiro, JF; Waerenborgh, JC; Kovalevsky, AV; Yaremchenko, AA; Frade, JR
nationality International
journal JOURNAL OF SOLID STATE CHEMISTRY
author keywords Mechanical activation; Strontium ferrite; Mossbauer spectroscopy
keywords OXIDE FUEL-CELLS; OXYGEN STOICHIOMETRY; CATHODE MATERIALS; SRFEO3-DELTA; CONDUCTIVITY; PEROVSKITES; PERMEATION; STABILITY; CERAMICS; SIZE
abstract Potassium-substituted SrFeO3-delta for possible application as oxygen evolution electrode in alkaline or molten salt media was prepared by mechanical activation and characterized by X-ray diffraction, dilatometric and thermogravimetric analysis, Mossbauer spectroscopy, and electrical conductivity measurements. Room temperature mechanical activation of a mixture of oxide precursors with subsequent thermal treatments at 700-900 degrees C results in the formation of Sr(0.9)Ka(0.1)FeO(3-delta) with tetragonal perovskite-like structure. Such allows to decrease the synthesis temperature, if compared to the conventional solid-state route, and to prevent possible volatilization of potassium. The results of Mossbauer spectroscopy studies indicate that the oxygen nonstoichiometry in the samples annealed in air at 900-1100 degrees C with subsequent rapid cooling vary in the range delta=0.30-0.32. The electrical conductivity in air exhibits a metal-like behaviour at temperatures above 400 degrees C and semiconductor behaviour in the low-temperature range, reaching 13-30 S/cm under prospective operation conditions for alkaline electrolyzers (<= 90 degrees C). (C) 2012 Elsevier Inc. All rights reserved.
publisher ACADEMIC PRESS INC ELSEVIER SCIENCE
issn 0022-4596
year published 2013
volume 198
beginning page 169
ending page 175
digital object identifier (doi) 10.1016/j.jssc.2012.10.009
web of science category Chemistry, Inorganic & Nuclear; Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000314320800026
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