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surface molybdena sites for propane ODH. The surface mo-
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the edges are active3 ) are approximately 3 times as active as
the surface molybdena sites present on the Nb2O5 or MoxNb2-xO5
bulk oxides. The surface molybdena sites are more than an order
of magnitude more active than the surface niobia sites on bulk
Nb2O5 for propane ODH. The surface telluria sites are even
less active than the surface niobia sites. So the general specific
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The determination of the number of surface active sites of
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Raman spectroscopy. The structural models of the surface
species present on the bulk mixed metal oxides of V-Nb-O
and Mo-Nb-O were proposed from comparative studies with
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dena.
2000, 61, 333.
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(
(
(
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the active surface sites in the bulk V-Nb-O and Mo-Nb-O
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(4) This is the first study to quantitatively determine the
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number of surface active sites present on bulk mixed metal
oxides from a comparative study with the corresponding model
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TOF values and a reliable comparison of the catalytic behavior
of different bulk mixed metal oxides.
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(
(
(
(
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2
s-1) for the oxidative
(5) The reaction rate (µmol m
(
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dehydrogenation of propane follows the pattern: V-NbOx >
Mo-NbOx . Nb2O5 > Te-NbOx. Tellurium oxide is inactive
for propane activation.
(
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Acknowledgment. This work was supported by the U.S.
Department of Energy, Basic Energy Sciences, Grant DE-FG02-
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0, 194.
9
3ER14350.
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