Accessible Unlicensed Requires Authentication Published by Oldenbourg Wissenschaftsverlag February 17, 2012

Development of the local and average structure of a V–Mo–Nb oxide catalyst with Mo5O14-like structure during synthesis from nanostructured precursors

Tatyana Kardash, Ludmilla M. Plyasova, Dmitry I. Kochubey, Valentina M. Bondareva and Reinhard B. Neder
From the journal

Abstract

A combination of X-ray and neutron PDF measurements with powder diffraction and EXAFS data was used to determine the structures of a V—Mo—Nb-oxide catalyst and its poorly crystallized precursors that exhibit the strongest catalytic activities. The crystalline material belongs to space group P-4 21m, a = 22.8, c = 4.002, and is build up of pentagonal MeO7 bipyramids surrounded by edge sharing Me-octahedrons (Me = Mo, V, Nb). In the average structure all MeO7 units are at the same z-level, while the local structure analysis shows systematic shifts along [001]. Samples synthesized at 300 °C and 400 °C exhibit a nanostructure, whose local structure predates the final crystalline structure. Initial nanoparticles are spherical and grow predominantly along the c-axis. The successful analysis required a reverse analysis that took the crystalline material as starting model for the samples synthesized at lower temperatures.


* Correspondence address: Boreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090 Novosibirsk, Russische Föderation,

Published Online: 2012-02-17
Published in Print: 2012-05

© by Oldenbourg Wissenschaftsverlag, Novosibirsk, Germany