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Surface Oxygen Species Over Cerium Oxide and Their Reactivities with Methane and Ethane by Means of in situ Confocal Microprobe Raman Spectroscopy
Author(s) -
Long R. Q.,
Huang Y. P.,
Wan H. L.
Publication year - 1997
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199701)28:1<29::aid-jrs59>3.0.co;2-g
Subject(s) - microprobe , chemistry , oxygen , raman spectroscopy , cerium , cerium oxide , methane , oxide , analytical chemistry (journal) , atmospheric temperature range , inorganic chemistry , mineralogy , organic chemistry , physics , optics , meteorology
The activation of molecular oxygen on the surface of cerium oxide and the reactivities of surface oxygen species with methane and ethane were studied by means of in situ confocal microprobe Raman spectroscopy in the temperature range 298–1023 K. The results showed that O 2 2‐ , O 2 ‐ and O 2 δ‐ (0<δ<1) adspecies formed on the surface of an oxygen‐pretreated cerium oxide sample when the temperature was below 423 K. As the temperature was increased, some oxygen species desorbed from the sample surface. At 1023 K, only the CeO 2 F 2gpeak (at 449 cm ‐1 ) and O 2 ‐ species (at 1159 cm ‐1 ) were observed on the CeO 2 surface. In the absence of gaseous oxygen, ethane reacted with lattice oxygen species and diatomic oxygen adspecies, including O 2 2‐ , O 2 ‐ and O 2 δ‐ (0<δ<1) below 373 K. In contrast, the reactions of methane with superoxide and lattice oxygen species apparently did not take place until the temperature was increased to 1023 K. © 1997 by John Wiley & Sons, Ltd.