Surface structure and catalytic activity of MoO/sub 3//Al/sub 2/O/sub 3/ catalysts in the hydrodesulfurization of thiophene studied by X-ray photoelectron spectroscopy
Catalysts containing 2.4-23.1% molybdenum trioxide on alumina were calcined and either tested for their activity for thiophene hydrodesulfurization without further pretreatment, or hydrogen-reduced or sulfided (CS/sub 2/ + H/sub 2/) before the activity tests. The catalysts were also characterized by pyridine adsorption, extraction of molybdenum with water and aqueous ammonia solution, and ESCA of the sulfided catalysts. The intrinsic hydrodesulfurization activity correlated with the sulfur-molybdenum ratio in a volcano-shaped plot with the peak at the 1:1 ratio, and it was independent of pretreatment and molybdenum content. At low molybdenum contents and for partial sulfidation, a 1:1 sulfur/molybdenum(IV) (S/Mo1) species formed; on fully sulfided catalysts an MoS/sub 2/ species was also present; and the S/Mo1 species had a much higher intrinsic activity than MoS/sub 2/. Apparently, the high anion vacancy concentration of the S/Mo1 promoted the reaction. The surface structure of the sulfided catalyst and the molybdenum redox cycle are discussed.
- Research Organization:
- Osaka Univ.
- OSTI ID:
- 6212247
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 84:14
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM OXIDES
CATALYTIC EFFECTS
STRUCTURAL CHEMICAL ANALYSIS
SULFIDATION
SURFACE PROPERTIES
DESULFURIZATION
REACTION INTERMEDIATES
MOLYBDENUM OXIDES
PYRIDINE
ADSORPTION
THIOPHENE
CHEMICAL PREPARATION
CORRELATIONS
EXPERIMENTAL DATA
HYDROGEN
MOLYBDENUM SULFIDES
PHOTOELECTRON SPECTROSCOPY
PROMOTERS
QUANTITY RATIO
TESTING
X-RAY SPECTROSCOPY
ALUMINIUM COMPOUNDS
AZINES
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
ELECTRON SPECTROSCOPY
ELEMENTS
HETEROCYCLIC COMPOUNDS
INFORMATION
MOLYBDENUM COMPOUNDS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYRIDINES
REFRACTORY METAL COMPOUNDS
SORPTION
SPECTROSCOPY
SULFIDES
SULFUR COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)