In situ Study of Structural Transformations of the Active Phase of VMoNbTeO Catalysts under Reduction Conditions

VMoNbTeO catalysts show high activity in the reactions of selective oxidation of ethane and propane. Time-resolved X-ray diffraction is used to study structural transformations of a mixed oxide with the composition (TeO) 0.18 (Mo 0.7 V 0.22 Nb 0.08 ) 20 O 56 and the structure of the active M1 phase...

Full description

Saved in:
Bibliographic Details
Published in:Journal of structural chemistry 2019-10, Vol.60 (10), p.1599-1611
Main Authors: Kardash, T. Yu, Marchuk, A. S., Ishchenko, A. V., Simanenko, A. A., Lazareva, E. V., Svintsitskiy, D. A.
Format: Article
Language:English
Subjects:
Atomic
Atomic/Molecular Structure and Spectra
Catalysts
Chemistry
Chemistry and Materials Science
Composition
Crystallization
Ethane
Inorganic Chemistry
Molecular
Molybdenum
Niobium
Optical and Plasma Physics
Oxidation
Oxides
Photoelectrons
Physical Chemistry
Reducing agents
Reduction
Solid State Physics
Sublimation
Tellurium
Transformations
Vanadium
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:VMoNbTeO catalysts show high activity in the reactions of selective oxidation of ethane and propane. Time-resolved X-ray diffraction is used to study structural transformations of a mixed oxide with the composition (TeO) 0.18 (Mo 0.7 V 0.22 Nb 0.08 ) 20 O 56 and the structure of the active M1 phase upon heating in a hydrogen atmosphere (1% H 2 in helium). It is shown that the structure of the M1 phase is destroyed in the presence of a reducing agent above 480 °C. The process is accompanied by structural distortions, diminishing of the size of crystalline blocks, elimination of tellurium (due to the reduction and sublimation), and the reduction by molybdenum and vanadium cations. As a result, VMoNb oxides with a disordered structure are formed and rapidly crystallized at T > 480 °C into the rutile-type monoclinic oxide (Mo,V,Nb)O 2 with a variable composition. X-ray photoelectron spectroscopy and transmission electron microscopy data confirm heterogeneous compositions of oxides formed by the decomposition of the initial phase. The surface of the formed particles is enriched with vanadium and niobium present in the composition of the oxides with disordered structure.
ISSN:0022-4766
1573-8779
DOI:10.1134/S0022476619100056