A Raman and ultraviolet diffuse reflectance spectroscopic investigation of alumina-supported molybdenum oxide

Journal Article · Wed Oct 30 23:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100175a068· OSTI ID:7252912

Williams, C C; Ekerdt, J G ^[1]; Jehng, Jihmirn; Hardcastle, F D; Wachs, I E ^[2]

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1. Univ. of Texas, Austin (United States)
2. Lehigh Univ., Bethlehem, PA (United States)

Laser Raman spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy were used to characterize alumina-supported molybdenum oxide at loadings ranging from 0.67 to 13.3 wt % Mo. The structure of the calcined Mo{sup 6+}/Al{sub 2}O{sub 3}, under ambient conditions, was found to be independent of the molybdenum precursor and the preparation pH. The hydrated surface molybdate structure was found to be governed by the inherent acid-base properties of the molybdena/alumina system and the molybdenum weight loading. At low Mo loadings (< 1 Mo atom/nm{sup 2}), isolated MoO{sub 4} tetrahedra dominate although a low degree of polymerization was observed. At 2-2.5 Mo atoms/nm{sup 2}, the majority of the molybdenum was incorporated into octahedrally coordinated molybdenum polyanions. Crystalline MoO{sub 3} was detected above monolayer coverage (5-6 Mo atoms/nm{sup 2}).

• OSTI ID: 7252912
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:22; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical &amp; Spectral Procedures
400201* -- Chemical &amp; Physicochemical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CALCINATION
CATALYST SUPPORTS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
DECOMPOSITION
EXPERIMENTAL DATA
HYDRATES
INFORMATION
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS
RAMAN SPECTRA
REFLECTION
REFRACTORY METAL COMPOUNDS
SPECTRA
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
ULTRAVIOLET SPECTRA