INVESTIGADORES
BRIAND Laura Estefania
artículos
Título:
Methodological Aspects in the Surface Analysis of Supported Molybdena Catalysts
Autor/es:
LAURA E BRIAND; OLGA P. TKACHENKO.; MONICA GURAYA ; ISRAEL E. WACHS; WOLFGANG GRUENERT
Revista:
SURFACE AND INTERFACE ANALYSIS
Editorial:
JOHN WILEY & SONS LTD
Referencias:
Año: 2004 vol. 36 p. 238 - 245
ISSN:
0142-2421
Resumen:
Supported molybdena catalysts, with TiO2, CeO2 and Al2O3 supports were studied with XPS and ISS. It was found that reliable results are obtained only when samples are calcined and transferred into the ultrahigh vaccum system without further contact with the ambient atmosphere . This applies also to catalysts that were previously calcined but had been stored in the ambient atmosphere.Supported Mo oxide becomes reduced under x-ray irradiation under during extended XPS data acquisition.A slight decrease of the Mo/support cation intensity ratio as a consequence of this reduction was detected by ISS in MoO3/TiO2 and MoO3/CeO2 , therefore ISS analysis should be performed on freshly calcined samples without prior extended exposure to X-rays. Because ISS spectra change rapidly with due to sputtering a corrent analysis of the surface properties of supported Mo catalysts requires extrapolation of the trend to the start of the experiment.
