Thermal stability of Pt nanoparticles supported on WOx/Al 2O3 for n-heptane hydroconversion

J. L. Contreras, G. A. Fuentes, J. Salmones, B. Zeifert

Producción científica: Capítulo del libro/informe/acta de congresoContribución a la conferenciarevisión exhaustiva

3 Citas (Scopus)

Resumen

The thermal stabilization of γ-Al2O3 using W+6 ions has been found useful to the synthesis of Pt/Al 2O3 catalysts. The sequential impregnation method was used to study the effect of W6+ upon Pt/ γ-Al2O 3 reducibility, Pt dispersion, Raman spectroscopy and ç-heptane hydroconversion. The W/Pt atomic ratios varied from 3.28 to 75. We found that the W6+ ions delayed reduction of a fraction of Pt+4 atoms beyond 773 K. At the same time, W6+ inhibited sintering of the metallic crystallites once they were formed on the surface. For the sample with a W/Pt atomic ratio of 3.28, W6+ did not inhibit the H2 reduction of Pt oxides even below of 773 K, the Pt oxides were reduced completely, however, the Pt dispersion decreased for this sample with respect to the Pt/γ-Al2O3 catalyst. After reduction at 1073 K, sequential samples impregnating Pt on WOx/γ-Al 2O3 were more active and stable during n-heptane hydroconversion than monometallic Pt/γ-Al2O3 catalyst. Selectivities for dehydrocyclization, isomerization and Hydrocracking changed significantly when the W/Pt atomic ratio and reduction temperature increased. Initial and final reaction rates were more sensitive to reduction temperature. W6+ ions promoted high thermal stability of Pt crystallites when sequential catalysts were reduced at 1073 K and deactivation of bimetallic catalysts reduced at 773 K and 1073 K was less than the deactivation of Pt/Al2O3 catalyst.

Idioma originalInglés
Título de la publicación alojadaNew Catalytic Materials
EditorialMaterials Research Society
Páginas123-141
Número de páginas19
ISBN (versión impresa)9781605112565
DOI
EstadoPublicada - 2010

Serie de la publicación

NombreMaterials Research Society Symposium Proceedings
Volumen1279
ISSN (versión impresa)0272-9172

Huella

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