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A 121Sb Mössbauer Study of the Chemical State of Antimony in V–Sb–O Mixed-Oxide Catalysts for the Ammoxidation of Propane.

A 121Sb Mössbauer Study of the Chemical State of Antimony in V–Sb–O Mixed-Oxide Catalysts for the Ammoxidation of Propane.

Authors :
Stievano, L.
Wagner, F.
Zanthoff, H.
Calogero, S.
Source :
Hyperfine Interactions; Jun2002, Vol. 141 Issue 1-4, p397-402, 6p
Publication Year :
2002

Abstract

The structural changes of two representative samples of a group of V-Sb-oxide catalysts, a vanadium-rich and an antimony-rich specimen, are investigated by <superscript>121</superscript>Sb Mössbauer spectroscopy after treatment under propene or hydrogen at 673 K. The as-prepared catalysts contain both Sb(V) and Sb(III) as crystalline and microcrystalline α-Sb<subscript>2</subscript>O<subscript>4</subscript> and VSbO<subscript>4</subscript>, as well as an additional amorphous V<superscript>5+</superscript> oxide phase. The oxidation state of antimony does not change upon exposure to propene, whereas a partial reduction can be obtained by a more intense reduction under hydrogen. The Mössbauer results indicate that the antimony in VSbO<subscript>4</subscript> can be reduced more easily than that in α-Sb<subscript>2</subscript>O<subscript>4</subscript>, which appears to be more stable. These results are discussed in view of the observed depletion of vanadium at the surface of the catalyst particles under reaction conditions. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
03043843
Volume :
141
Issue :
1-4
Database :
Complementary Index
Journal :
Hyperfine Interactions
Publication Type :
Academic Journal
Accession number :
50224702
Full Text :
https://doi.org/10.1023/A:1021200808596