Thiophene hydrodesulfurization over alumina-supported molybdenum carbide and nitride catalysts: Adsorption sites, catalytic activities, and nature of the active surface
- Western Washington Univ., Bellingham, WA (United States); and others
Mo{sub 2}C/Al{sub 2}O{sub 3} and Mo{sub 2}N/Al{sub 2}O{sub 3} catalysts have been synthesized and characterized by X-ray diffraction, pulsed chemisorption (CO and O{sub 2}) and infrared (IR) spectroscopy, and temperature programmed desorption (TPD) measurements. Thiophene hydrodesulfurization (HDS) activities were measured for alumina-supported Mo carbide and nitride catalysts as well as a sulfided Mo/Al{sub 2}O{sub 3} catalyst, all with a 10 wt% Mo loading. The HDS activities ({mu}mol Th/mol Mo/s) of the catalysts after 24 h at 693 K were found to increase according to the trend sulfided Mo <{gamma}-Mo{sub 2}N < {beta}-Mo{sub 2}C, and provide further evidence that carbide and nitride catalysts have the potential to replace sulfided Mo catalysts in commercial HDS reactors. X-ray diffraction analysis of fresh and tested 30 wt% Mo{sub 2}C/Al{sub 2}O{sub 3} and Mo{sub 2}N/Al{sub 2}O{sub 3} catalysts indicates that the bulk structure of the carbide ({beta}-Mo{sub 2}C) and nitride ({gamma}-Mo{sub 2}N) particles is retained, while IR spectroscopy of adsorbed CO indicates that the surface of the carbide and nitride particles becomes sulfided under reaction conditions. A model is proposed for the structure of the active catalytic surface of the alumina-supported Mo carbide and nitride catalysts in which a thin layer of highly dispersed sulfided Mo is present on the surfaces of the carbide and nitride particles. 38 refs., 10 figs., 4 tabs.
- OSTI ID:
- 486380
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 164; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
40 CHEMISTRY
ABSORPTION SPECTROSCOPY
ADSORPTION
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHEMISORPTION
DESORPTION
DESULFURIZATION
HETEROGENEOUS CATALYSIS
HYDROGENATION
MOLYBDENUM CARBIDES
MOLYBDENUM NITRIDES
SORPTIVE PROPERTIES
TEMPERATURE DEPENDENCE
THIOPHENE
X-RAY DIFFRACTION