Surface properties of molybdenum-impregnated ZSM-5 catalysts
- 1 January 1992
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions
- Vol. 88 (3) , 385-390
- https://doi.org/10.1039/ft9928800385
Abstract
Molybdena-containing H-ZSM5 zeolites have been prepared and used in the hydrodesulfurization of thiophene and dibenzothiophene model compounds. The catalysts containing 3 and 6% MoO3 were prepared by aqueous impregnation with ammonium heptamolybdate, followed by calcination at 383, 623 and 773 K. They have been characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), temperature-programmed reduction (TPR), and scanning electron microscopy (SEM). The set of data indicated that the zeolite crystallinity is mostly preserved for the high Mo-containing catalysts, and that most of the molybdena appears as MoO3 crystals on the external zeolite surface. The appearance of MoS2 structures produced by sulfidation has already been observed by X-ray photoelectron spectroscopy (XPS) and FTIR spectroscopy of an NO probe molecule. These also showed a better dispersion for the low Mo-containing catalysts. All these data and activity data are jointly discussed.Keywords
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