The surface chemistry of molybdenum in states of lower oxidation on alumina

Journal Article · Mon May 01 04:00:00 EDT 1978 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(78)90337-8· OSTI ID:5714183

Brenner, A; Burwell, R L

The reactions of molybdenum(0) hexacarbonyl, Mo(CO)/sub 6/, on calcined (450/sup 0/C) alumina during heating in helium at -17/sup 0/ to 1000/sup 0/C were monitored with oxygen pulses to determine the molybdenum oxidation state, as well as by ESCA, ESR, and other techniques. Below 100/sup 0/C, adsorbed carbonyl species Mo(CO)/sub 6/, Mo(CO)/sub 5/, Mo(CO)/sub 4/, and Mo(CO)/sub 3/ formed reversibly. These species were probably molecularly dispersed. Above 200/sup 0/C, further irreversible decomposition occurred with complete loss of carbon monoxide; the molybdenum so formed was oxidized by surface hydroxyls with hydrogen evolution to an average oxidation state of 2 at 270/sup 0/C and of 5.6 at 500/sup 0/C. On alumina that had been dehydroxylated at 950/sup 0/C in helium, zero-valent molybdenum formed at 500/sup 0/C. Graphs and 28 references.

• Research Organization: Northwestern Univ., Evanston, IL
• OSTI ID: 5714183
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 52:3; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ANALYTICAL SOLUTION
CATALYSIS
CATALYST SUPPORTS
CHALCOGENIDES
CHEMICAL REACTIONS
ELECTRON SPIN RESONANCE
ELEMENTS
MAGNETIC RESONANCE
METALS
MOLYBDENUM
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC EFFECT
PHOTOELECTROMAGNETIC EFFECTS
RESONANCE
SPECTROSCOPY
TRANSITION ELEMENTS
VALENCE
X-RAY SPECTROSCOPY