Descripción
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Three nickel catalysts supported on carbon nanofibers (CNFs) have been prepared by deposition-precipitation (ca. 3%, w/w). The CNFs were prepared by catalytic chemical vapour decomposition of ethylene over a Ni/SiO 2 catalyst, and chemically activated with RbOH (CNF RbOH) and KOH (CNF KOH). The materials were characterized by transmission electron microscopy (TEM), N 2 adsorption-desorption, temperature-programmed oxidation, X-ray diffraction (XRD), acid-base titrations and temperature-programmed decomposition in helium. KOH was the most effective activating agent, developing carbon porosity, decreasing the crystalline character and increasing surface acidity to a higher extent. After nickel introduction, the catalysts were characterized by temperature-programmed reduction, XRD, TEM, N 2 adsorption-desorption and acid-base titrations. Surface-area weighted mean Ni particle diameters (post reduction at 400 °C) followed the sequence: Ni/CNF KOH (4.9 nm) < Ni/CNF RbOH (8.6 nm) < Ni/CNF (25.5 nm), where a further activation of the support led to smaller/better dispersed nickel particles. The surface acidity of the catalysts followed the sequence: Ni/CNF RbOH < Ni/CNF < Ni/CNF KOH. The gas phase hydrogenation of butyronitrile was used as a surface characterization test, where bigger nickel particles consistently developed higher catalytic activity. Selectivity, however, was not sensitive to metal particle size, but increased towards condensation products with increasing catalyst acidity. | |
Internacional
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Si |
JCR del ISI
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Título de la revista
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Applied Catalysis A: General |
ISSN
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0926860X |
Factor de impacto JCR
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0 |
Información de impacto
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Volumen
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DOI
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Número de revista
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Desde la página
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78 |
Hasta la página
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87 |
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