Redox Nature of Fe-Incorporated Magnesium ortho-Vanadate as a Catalyst for the Oxidative Dehydrogenation of Propane

In order to improve the catalytic activity of magnesium ortho-vanadate (Mg3V2O8) for the oxidative dehydrogenation of propane, Mg3V2O8 doped with Fe3+ (Fe–Mg3V2O8) was prepared. The improvement of the conversion of propane from 4.8% on Mg3V2O8 to 8.2% on 5% Fe–Mg3V2O8 together with the rather similar selectivity to propylene on un-doped and doped catalysts (62.3 and 61.0%, respectively). To evaluate the redox nature of Fe–Mg3V2O8 during the oxidative dehydrogenation, the catalysts used for the conversion of propane with and without gaseous oxygen were analyzed by XRD, solid state 51V MAS NMR, XAFS, and XPS. After the propane conversion without oxygen, complete conversion of Fe–Mg3V2O8 to Mg2VO4 and MgO together with a small amount of Fe2O3 was observed by XRD, while the reduction of V5+ to V4+ was detected by 51V MAS NMR and V K-edge XAFS from the catalyst. However XPS analysis showed that such a reduction was not observed over the surface of Fe–Mg3V2O8 since oxygen was supplied from bulk to the surface of the catalyst to keep V5+ over the surface. After the treatment of the reduced catalysts with gaseous oxygen, the complete regeneration of Fe–Mg3V2O8 from the reduced phase was confirmed by those analyses.

[1]  T. Ressler,et al.  In situ investigations of the bulk structural evolution of vanadium-containing heteropolyoxomolybdate catalysts during thermal activation , 2005 .

[2]  N. Shigemoto,et al.  Effects of the enhancement of the abstraction of lattice oxygen from magnesium vanadates incorporated with copper(II) cations on the oxidative dehydrogenation of propane , 2005 .

[3]  N. Shigemoto,et al.  Effects of calcium cations incorporated into magnesium vanadates on the redox behaviors and the catalytic activities for the oxidative dehydrogenation of propane , 2004 .

[4]  N. Shigemoto,et al.  Redox Behaviors of Magnesium Vanadate Catalysts During the Oxidative Dehydrogenation of Propane , 2003 .

[5]  H. Hayashi,et al.  Effect of the phase transition of iron (III) oxide on the oxidative dehydrogenation of propane in the presence and absence of tetrachloromethane , 2001 .

[6]  M. Seah,et al.  Practical Surface Analysis , 1992 .

[7]  J. Volta,et al.  Oxidative dehydrogenation of propane over VMgO catalysts , 1990 .

[8]  J. Volta,et al.  Oxidative dehydrogenation of propane over VMgO catalysts , 1990 .

[9]  J. Lunsford,et al.  Catalytic partial oxidation of methane over barium metaplumbate BaPbO3: possible involvement of peroxide ion , 1989 .

[10]  N. Bremer,et al.  Fundamental study of the oxidation of butane over vanadyl pyrophosphate , 1985 .

[11]  D. H. Maylotte,et al.  A Study of the K-edge Absorption Spectra of Selected Vanadium Compounds. , 1984 .

[12]  T. Nash,et al.  Energy shift and structure of the K-absorption edge of vanadium in some vanadium compounds , 1978 .

[13]  SugiyamaShigeru,et al.  Characterization of Calcium, Strontium, Barium and Lead Hydroxyapatites: X-ray Diffraction, Photoelectron, Extended X-ray Absorption Fine Structure and MAS NMR Spectroscopies , 2001 .

[14]  H. Kung.  Oxidative Dehydrogenation of Light (C2 to C4) Alkanes , 1994 .

[15]  Satohiro Yoshida,et al.  X-ray absorption (EXAFS/XANES) study of supported vanadium oxide catalysts. Structure of surface vanadium oxide species on silica and γ-alumina at a low level of vanadium loading , 1988 .