Chemical and electronic characterization of cobalt in Lanthanumperovskites. Effects of Strontium substitution Page: 3 of 27
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
perovskites, others attribute them exclusively to the generation of oxygen vacancies
compensating the divalent charge of Sr atoms (9,16,17).
The aim of our research has been to clarify the chemical and electronic
modifications induced by this Strontium-substitution by means of X-ray absorption
spectroscopies. The combined study of the high energy Co K-edge (Extended X-ray
absorption spectroscopy, EXAFS, and X-ray absorption near-edge structure, XANES)
and the low energy O-K edge X-ray absorption spectroscopy (XAS) have shed some
light on the oxidation states, the spin configurations and the chemical reactivity of
LaCoO3 and Lao5SrosCoO3_, perovskites.
2. Experimental
2.1. Preparation method
The perovskite catalysts used for the present investigation, La& Sro.5CoO3_4 and
LaCoO3, were synthesized by spray pyrolysis (18,19). The preparation method involved
the uniform nebulisation of nitrate solutions containing La(NO3)36H2O (99.99%,
Aldrich), Co(NO3)r6H20 (>98%, Fluka), and Sr(NO3)2 (>99%, Fluka) prepared as a
0.1 M liquid solution of precursors. Two online furnaces, at 250 and 600"C, evaporated
the solvent (distilled water) with the dissolved nitrates and produced an initially
amorphous perovskite powder. The material was collected by a porous quartz rit
located at the outlet of the heating system. Then the amorphous powders were annealed
at 700"C for 4 h, thus obtaining LaCoO3 and LaO.5Sro.5CoO3. crystalline perovskites
with rhombohedral symmetry (19).2.2. Characterization techniques
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Hueso, Jose L.; Holgado, Juan P.; Pereniguez, Rosa; Mun, Simon; Salmeron, Miquel & Caballero, Alfonso. Chemical and electronic characterization of cobalt in Lanthanumperovskites. Effects of Strontium substitution, article, February 6, 2009; Berkeley, California. (https://digital.library.unt.edu/ark:/67531/metadc925912/m1/3/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.