XAFS characterization of La1−xSrxMnO3±δ catalysts prepared by Pechini’s method
| Autor: | Patrícia Mendonça Pimentel, Marcus Antônio de Freitas Melo, Renato Canha Ambrosio, F. M. M. Borges, Carlos Neco da Silva Júnior, Dulce Maria de Araújo Melo |
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| Rok vydání: | 2006 |
| Předmět: |
Extended X-ray absorption fine structure
Chemistry Coordination number Doping Analytical chemistry General Physics and Astronomy Distortion Spectral line Characterization (materials science) Catalysis X-ray absorption fine structure La1−xSrxMnO3±δ catalysts Defect Oxygen desorption Physical and Theoretical Chemistry XAFSJT Perovskite (structure) |
| Zdroj: | Repositório Institucional da UFRN Universidade Federal do Rio Grande do Norte (UFRN) instacron:UFRN |
| ISSN: | 0301-0104 |
| Popis: | XAFS experiments at the Mn and Sr K-edges were carried out in order to investigate the short-range arrangement of Mn and Sr sites on La1−xSrxMnO3±δ highly doped perovskites (x = 0, 0.2, 0.4 and 0.6). The Mn K-edge EXAFS spectra show a static Jahn–Teller distortion of the MnO6 for x = 0 and 0.2, which is drastically reduced as x increases. The distortion of perovskite, characterized by the Mn–O–Mn tilt angle, progressively decreases with increasing Sr contents. Sr K-edge results indicated a decrease on the Sr–Mn coordination number upon Sr doping. Based on this and TPD results, a charge compensating mechanism is proposed suggesting a partial Mn oxidation and formation of Mn defect vacancies due to the introduction of Sr. |
| Databáze: | OpenAIRE |
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