Oxygen depletion of bismuth molybdates

Journal Article · Mon May 01 00:00:00 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), Vol. 52:3
• Country of Publication: United States
• Language: English

Related Subjects

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