Oxygen depletion of bismuth molybdates

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

DOI:https://doi.org/10.1016/0021-9517(78)90363-9· OSTI ID:5750243

Yong, L K; Howe, R F; Keulks, G W; Hall, W K

Pure ..cap alpha..-phase bismuth molybdate (Bi/sub 2/Mo/sub 3/O/sub 12/), which is known to be weakly active for selective oxidation, and pure ..gamma..-phase bismuth molybdate (Bi/sub 2/MoO/sub 6/), which has good activity, were subjected to oxidation-reduction cycles with known amounts of hydrogen and oxygen, at 300/sup 0/-570/sup 0/C and with evacuation steps between treatments. The volume of oxygen consumed during reoxidation was equal to half the hydrogen consumed during the reduction on the ..cap alpha..-phase, which indicated that no hydrogen was retained during reduction. For the ..gamma..-phase, the oxygen consumption was greater than half of the hydrogen consumption and it increased with extent of reduction. The excess oxygen was apparently consumed by filling anion vacancies formed during outgassing subsequent to the reduction step. ESR spectroscopy and temperature-programed oxidation-reduction indicated that lattice oxide ions which bridge between bismuth and molybdenum layers of the koechlinite structure become more labile when the catalyst is in a partially reduced state, and that this effect is greater in the ..gamma..- than the ..cap alpha..-phase. Table and 15 references.

• Research Organization: Univ. of Wisconsin, Milwaukee
• OSTI ID: 5750243
• 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

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ANALYTICAL SOLUTION
ANIONS
BISMUTH COMPOUNDS
CATALYSTS
CHARGED PARTICLES
CHEMICAL REACTIONS
DESORPTION
ELECTRON SPIN RESONANCE
IONS
MAGNETIC RESONANCE
MOLYBDATES
MOLYBDENUM COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REDUCTION
RESONANCE
SORPTION
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS