Ruthenium effect on formation mechanism and structural characteristics of LaCo1-xRuxO3 perovskites and its influence on catalytic performance for hydrocarbon oxidative reforming
This work deals with the formation mechanism of LaCo1-xRuxO3 perovskites (x = 0, 0.05, 0.1, 0.2 and 0.4). In situ characterization of perovskite during formation were monitored with X-ray diffraction and Raman spectroscopy techniques, revealing that perovskite formation occurs via an oxo-lanthanum c...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/127247 |
| Acceso en línea: | http://hdl.handle.net/10261/127247 |
| Access Level: | acceso abierto |
| Palabra clave: | perovskite ruthenium reforming hydrocarbon hydrogen production |
| Sumario: | This work deals with the formation mechanism of LaCo1-xRuxO3 perovskites (x = 0, 0.05, 0.1, 0.2 and 0.4). In situ characterization of perovskite during formation were monitored with X-ray diffraction and Raman spectroscopy techniques, revealing that perovskite formation occurs via an oxo-lanthanum carbonate intermediate phase. Structural characterization of perovskites showed structural changes in the perovskite as the Ru inserted in the structure increases. It was observed that the insertion of Ru affects the bulk structure by creating rotational and Jahn-Teller distortions in the perovskite structure. Raman spectroscopy completed the description, proving the strong distortions of the lattice oxygen and the La-O coordination induced by the presence of ruthenium. Such distorted configuration gave rise to a weakening of metal-oxygen bonds, maximizing anionic mobility and reactants adsorption. Surface changes were also observed with the insertion of Ru in the perovskite structure. XPS showed that there are cobalt spinel species, unaltered by ruthenium, and lanthanum oxide species that become more carbonated when Ru is present. The formation of carbonate-like structures is enhanced by ruthenium, which must be interacting with lanthanum entities, loosening La-O bonds in order to facilitate the adsorption of CO2. Relating these structural effects with catalytic performance in hydrocarbons reforming, we can conclude that the structural distortion induced by ruthenium favours catalytic stability, probably by stabilizing metallic Co and Co-Ru sites, increasing metal dispersion and by making oxygen mobility easier in the disturbed La2O3 support |
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