| IN situ Confocal Microprobe Raman Spectroscopic Studies on Defective La-based Complex Oxides |
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| 基金项目： | Supported by the National Natural Science Foundation of China. |
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| 摘 要： | ＩＮｓｉｔｕＣｏｎｆｏｃａｌＭｉｃｒｏｐｒｏｂｅＲａｍａｎＳｐｅｃｔｒｏｓｃｏｐｉｃＳｔｕｄｉｅｓｏｎＤｅｆｅｃｔｉｖｅＬａ－ｂａｓｅｄＣｏｍｐｌｅｘＯｘｉｄｅｓＣＨＥＮＤｕ－ｈｕｉ，ＣＡＩＪｕｎ－ｘｉｕ，ＬＩＡＯＹｕａｎ－ｙｉａｎ，ＷＡＮＨｕｉ－ｌ...
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| 收稿时间： | 1996-07-27 |
IN SITU Confocal Microprobe Raman SpectroscopicStudies on Defective La-based Complex Oxides |
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| CHEN Du-hui,CAI Jun-xiu,LIAO Yuan-yian,WAN Hui-lin. IN SITU Confocal Microprobe Raman SpectroscopicStudies on Defective La-based Complex Oxides[J]. Chemical Research in Chinese University, 1997, 13(3): 249-255 |
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| Authors: | CHEN Du-hui CAI Jun-xiu LIAO Yuan-yian WAN Hui-lin |
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| Affiliation: | Chemistry Department of Xiamen University, State Key Laboratory of Physical Chemistry for Solid Surface, Xiamen 361005 |
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| Abstract: | The adsorption of O2 over defective La2O3-based OCM catalysts with anionic vacancies, and the reaction of surface oxygen species with CH4 were studied by means of in situ confocal microprobe Raman spectra. The partially reduced oxygen species O2-, O22-, O2δ- (O<δ<1 ) and even the lattice oxygen ion O2-can be detected on the surface of O2-pretreated La2O3-based catalysts. At lower temperatures (< 573 K) it is peroxide species O22- or O- that is more essential for the coupling of methane,while at higher temperature. the superoxide O2- and lattice oxygen species O2-are rather important. It is easier for fluoride-containing La2O3-based catalysts to induce the oxygen species with fewer negative charges and the basicity of the cat- alyst surface is weakened, so that the C2 selectivity for OCM reaction is improved. |
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| Keywords: | Methane oxidative coupling Oxygen adspecies Defective La2O3-based |
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