- Title
- Oxidative dehydrogenation of isobutane to isobutene by pyrovanadates, M₂V₂O₇, where M(II) = Mn, Co, Ni, Cu and Zn, and Co₂VO₄ and ZnV₂O₄: the effect of gold nanoparticles
- Creator
- Almukhlifi, Hanadi A.; Burns, Robert C.
- Relation
- Journal of Molecular Catalysis A: Chemical Vol. 408, Issue November 2015, p. 26-40
- Publisher Link
- http://dx.doi.org/10.1016/j.molcata.2015.07.010
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2015
- Description
- The pyrovanadates M₂V₂O₇, where MII = Mn, Co, Ni, Cu and Zn, have been investigated for the oxidative dehydrogenation of isobutane from 300 to 450 °C, both with and without 5 wt% gold nanoparticles. Reduction of the pyrovanadate compounds was generally observed, yielding products that contained V(IV) and/or V(III), and depended on both M(II) and the presence of gold nanoparticles. The most stable pyrovanadate was Ni₂V₂O₇. Products identified by XRD were M₂VO₄, MVO₃, MV₂O₄, or V₂O₃. The conversion of isobutane always increased with temperature, reaching 11% and 16% in the absence and presence of gold nanoparticles, respectively, at 450 °C. Selectivities to isobutene were as high as 40–50%. Vanadium 2p3/2 XPS studies indicated that all catalysts exhibited surface V(V) and V(IV), while V(III) was present in those catalysts that generated V(III)-containing products. This suggests that catalytic activity depends on the rate of reoxidation of the lower oxidation states to V(V). Gold 4f7/2 XPS studies always indicated the presence of Au(0) and Au(I), and for some catalysts Au(III). The highest yields of isobutene correlate with the lowest Au(I) content. The reduction products Co₂VIVO₄ and ZnVIII₂O₄ were compared in their activities with Co₂V₂O₇ and α-Zn₂V₂O₇. The reduced phase Co₂VO₄ proved to be a good catalyst, comparable to the best 5 wt% Au/M₂V₂O₇ compositions.
- Subject
- oxidative dehydrogenation; isobutane; isobutene; pyrovanadates; gold nanoparticles
- Identifier
- http://hdl.handle.net/1959.13/1330946
- Identifier
- uon:26511
- Identifier
- ISSN:1381-1169
- Language
- eng
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