Influence of Phase Composition of Bulk Tungsten Vanadium Oxides on the Aerobic Transformation of Methanol and Glycerol
[EN] A series of W-V-O catalysts with different m-WO3 and h-WO3 phase contents were hydrothermally synthesized by employing different tungsten, vanadium, and ammonium precursors and characterized by powder XRD, N-2 adsorption, SEM, X-ray energy-dispersive spectroscopy, thermogravimetric analysis, Ra...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2018 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/146160 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/146160 |
| Access Level: | acceso abierto |
| Palabra clave: | Heterogeneous catalysis Oxydehydration Hydrothermal synthesis Vanadium Tungsten Oxidation |
| Sumario: | [EN] A series of W-V-O catalysts with different m-WO3 and h-WO3 phase contents were hydrothermally synthesized by employing different tungsten, vanadium, and ammonium precursors and characterized by powder XRD, N-2 adsorption, SEM, X-ray energy-dispersive spectroscopy, thermogravimetric analysis, Raman and FTIR spectroscopy, NH3 temperature programmed desorption, H-2 temperature-programmed reduction, and XPS. Finally, the acid/redox properties were analyzed by using aerobic transformation of methanol as a characterization reaction. A correlation between phase composition as well as acid and redox properties was observed, which were correlated to the catalytic performance of the title materials in a one-pot oxydehydration reaction of glycerol. The hexagonal tungsten bronze (h-WO3) phase shows a significantly higher concentration of acid sites than monoclinic m-WO3, so that the acid properties of W-V-O oxides are directly related to the presence of h-WO3 crystals. The presence of a higher concentration of acid sites in V-containing h-WO3 crystals is a key factor to achieve high selectivity to both acrolein and acrylic acid during one-pot glycerol oxydehydration. Also, V sites in h-WO3 show higher selectivity in the consecutive reaction (partial oxidation of acrolein to acrylic acid), while V sites in the m-WO3 phase fundamentally lead to the formation of carbon oxides. |
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