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Probing the Structural Changes and Redox Behavior of Mixed Molybdate Catalysts under Ammoxidation Conditions: An Operando Raman Spectroscopy Study
Author(s) -
Engeldinger Jana,
Radnik Jörg,
Kreyenschulte Carsten,
Devred François,
Gaigneaux Eric M.,
Fischer Achim,
Zanthoff HorstWerner,
Bentrup Ursula
Publication year - 2016
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.201501276
Subject(s) - ammoxidation , molybdate , catalysis , raman spectroscopy , redox , acrylonitrile , chemistry , inorganic chemistry , materials science , organic chemistry , physics , optics , copolymer , polymer
Mixed model molybdate catalysts that contain CoMoO 4 , Bi 2 Mo 3 O 12 , and Fe 2 Mo 3 O 12 were investigated in the ammoxidation reaction of propene to acrylonitrile to study the redox behavior of the iron molybdate component. The flexible changes of the oxidation state of the Fe component during ammoxidation were followed by examining the intensity changes of the characteristic bands of Fe 2 Mo 3 O 12 and FeMoO 4 in the Raman spectra and could be correlated with the catalyst performance examined by simultaneous MS analysis. Depending on the catalyst composition and the oxygen content in the feed, Fe 2 Mo 3 O 12 is reduced to a different extent, and consequently, FeMoO 4 is formed, which is accompanied by a restructuring of the catalyst and the formation of nanostructured MoO x species. In accordance with previous investigations, operando Raman studies revealed that CoMoO 4 and Bi 2 Mo 3 O 12 influence the redox behavior of Fe 2 Mo 3 O 12 in different ways.