Insitu confocal microprobe Raman spectroscopy study of CeO2/BaF2 catalyst for the oxidative coupling of methane
Abstract
The adsorption of gaseous oxygen over
CeO
2
/BaF
2
, a catalyst for the oxidative coupling
of methane (OCM) and the reactions of surface oxygen species with
methane, ethane and ethene have been studied by in
situ confocal microprobe Raman spectra. Lattice
O
2-
, O
2
2-
, O
2
-
,
O
2
δ-
(0<δ<1) and adsorbed
O
2
were detected on the surface of O
2
-pretreated
CeO
2
/BaF
2
at room temperature. As the
temperature was increased, some oxygen species desorbed. At the OCM
reaction temperature (973–1023 K), lattice O
2-
and
O
2
-
species were found to exist on the catalyst
surface and these could convert C
2
H
4
,
C
2
H
6
and CH
4
at high temperature in
the absence of gaseous oxygen. The lattice O
2-
and
O
2
-
species were also observed on the working
CeO
2
/BaF
2
catalyst. These results suggest that
the lattice O
2-
and O
2
-
species might
be the active oxygen species for OCM over a
CeO
2
/BaF
2
catalyst.
Please wait while we load your content...
