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Spatial Distribution of the Vanadium Atomic Species in MoVTeO and MoVTeNbO Oxide Catalysts as Revealed by High‐Angle Annular Dark‐Field Scanning Transmission Electron Microscopy
Author(s) -
Epicier Thierry,
Aouine Mimoun,
Nguyen Thi Thao,
Millet JeanMarc M.
Publication year - 2017
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201601542
Subject(s) - vanadium , dark field microscopy , scanning transmission electron microscopy , niobium , transmission electron microscopy , vanadium oxide , catalysis , analytical chemistry (journal) , oxide , niobium oxide , alkane , complex oxide , chemistry , materials science , crystallography , microscopy , inorganic chemistry , nanotechnology , optics , physics , biochemistry , chromatography , organic chemistry
High‐angle annular dark‐field scanning transmission electron microscopy (STEM–HAADF) was used to characterize a light‐alkane mild‐oxidation catalyst corresponding to two different MoVTe(Nb)O M1 phases. For that purpose a semiautomatic integration routine was developed, which allows the analysis of several hundred atomic columns with a normalization procedure to quantitatively determine the vanadium content of mixed (V, Mo) crystallographic sites with a low statistical variability. The obtained results were compared with data previously obtained on other M1 phases with different compositions. The comparison showed that the V distribution over the sites was not strongly influenced by the presence or absence of niobium, the method of synthesis used, and the nature of the Te or Sb cations in the hexagonal channels, but depended mainly on the total V content of the phases. Extrapolation to low V content enabled a discussion on the possible location of the vanadium active sites.