Effect of alkali metal cations on the structure of Mo(VI)/SiO[sub 2] catalysts and its relevance of the selective oxidation of methane and methanol

Journal Article · Tue Mar 01 04:00:00 EST 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(94)90023-X· OSTI ID:6798231

Banares, M A; Wachs, I E ^[1]; Spencer, N D; Jones, M D ^[2]

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1. Lehigh Univ. Bethlehem, PA (United States)
2. W.R. Grace Co.-Conn, Columbia, MD (United States)

The effect of alkali metal additives on both the structure of MoO[sub 3]/SiO[sub 2] and its behavior as a catalyst for selective oxidation of methane and methanol to formaldehyde was investigated. The structure of the silica-supported molybdenum oxide catalysts was determined by in situ Raman spectroscopy and the amount of reducible oxygen in the catalyst was determined by temperature-programmed reduction. In the absence of alkali metal, only an isolated surface molybdenum oxide species was present on the silica support. Addition of alkali metals decreased the number of isolated surface molybdenum oxide species and formed new alkali-molybdate compounds due to the weak interaction of the Mo species with the silica surface. The oxygen associated with the alkali-molybdate compounds are generally not available for oxidation reactions. Consequently, the addition of alkali metal decreased the catalytic activity for the oxidation of both methane and methanol. The activity for methane oxidation was found to correlate with the number of remaining isolated Mo species and the activity for methanol oxidation was found to correlate with the amount of reducible oxygen present in the catalyst. 32 refs., 8 figs., 1 tab.

• OSTI ID: 6798231
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 146:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALCOHOLS
ALKALI METALS
ALKANES
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
ELEMENTS
HETEROGENEOUS CATALYSIS
HYDROCARBONS
HYDROXY COMPOUNDS
LASER SPECTROSCOPY
METALS
METHANE
METHANOL
MINERALS
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
ORGANIC COMPOUNDS
OXIDATION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
RAMAN SPECTROSCOPY
REDUCTION
REFRACTORY METAL COMPOUNDS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SPECTROSCOPY
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS