Cobalt-Iron red-ox behavior in nano-structured La0.4Sr0.6Co0.8Fe0.2O3-d cathodes

A. SOLDATI; L. BAQUÉ; F. NAPOLITANO; A. SERQUIS

JOURNAL OF SOLID STATE CHEMISTRY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2013 vol. 198 p. 253 - 261

0022-4596

Nano-sizedLa0.4Sr0.6Co0.8Fe0.2O3d (LSCF) perovskite samples(prepared by a conventional acetate route and a novel acetates synthesis with HMTA additives), were tested simulating are d?oxcycle. The crystallography was studied by X-ray Powder Diffraction(XPD)and the changes in the oxidation state of the perovskite B-site were evaluated by synchrotron X-ray Absorption Near Edge Spectroscopy (XANES).After a reducing treatment, LSFC particles show the appearance of a new phase that coexists with the original one. The structural change is accompanied by a Co and Fe formal oxidation states decrease, although Fe remains always closer to 4 þ and Co closerto 3þ. The treatment produces a B-site valence average reduction from3.52þ to 3.26þ and the formation of oxygen vacancies. A re-oxidation treatment under O2 rich atmosphere at 800 1C for 10h shows that the change is reversible and independent of the two chemical methods used to synthesize the LSCF nano-particles.