Insitu confocal microprobe Raman spectroscopy study of CeO₂/BaF₂ catalyst for the oxidative coupling of methane

Abstract

The adsorption of gaseous oxygen over CeO₂/BaF₂, 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-, O₂^2-, O₂^-, O₂^δ- (0<δ<1) and adsorbed O₂ were detected on the surface of O₂-pretreated CeO₂/BaF₂ at room temperature. As the temperature was increased, some oxygen species desorbed. At the OCM reaction temperature (973–1023 K), lattice O^2- and O₂^- species were found to exist on the catalyst surface and these could convert C₂H₄, C₂H₆ and CH₄ at high temperature in the absence of gaseous oxygen. The lattice O^2- and O₂^- species were also observed on the working CeO₂/BaF₂ catalyst. These results suggest that the lattice O^2- and O₂^- species might be the active oxygen species for OCM over a CeO₂/BaF₂ catalyst.

References

1. J. H. Lunsford, Angew. Chem. Int. Ed. Engl., 1995, 34, 970.
2. K. D. Campbell, H. Zhang and J. H. Lunsford, J. Phys. Chem., 1988, 92, 750.
3. J. H. Lunsford, Catal. Today, 1990, 6, 3.
4. E. Inamatsu and K. Aika, J. Catal., 1989, 117, 416.
5. P. F. Nelson, C. A. Lukey and N. W. Cant, J. Phys. Chem., 1988, 92, 6176.
6. Y. Tong, M. P. Rosynek and J. H. Lunsford, J. Phys. Chem., 1989, 93, 2896.
7. J. H. Lunsford, in Natural Gas Conversion II, ed. H. E. Curry-Hyde and R. F. Howe, Elsevier, Amsterdam, 1994, p. 1.
8. H. Yamashita, Y. Machida and A. Tomita, Appl. Catal. A, 1991, 79, 203.
9. J. X. Wang and J. H. Lunsford, J. Phys. Chem., 1986, 90, 5883.
10. Y. Osada, S. Koike, T. Fukushima and S. Ogasawara, Appl. Catal., 1990, 59, 59.
11. Y. D. Liu, H. B. Zhang, G. D. Lin, Y. Y. Liao and K. R. Tsai, J. Chem. Soc., Chem. Commun., 1994, 1871.
12. R. Q. Long, S. Q. Zhou, Y. P. Huang, H. Y. Wang, H. L. Wan and K. R. Tsai, Chin. Chem. Lett., 1995, 6, 727.
13. X. P. Zhou, Z. S. Chao, W. Z. Weng, W. D. Zhang, S. J. Wang, H. L. Wan and K. R. Tsai, Catal. Lett., 1994, 29, 177.
14. R. Q. Long, S. Q. Zhou, Y. P. Huang, W. Z. Weng, H. L. Wan and K. R. Tsai, Appl. Catal. A, 1995, 133, 269.
15. R. Q. Long, Y. P. Huang and H. L. Wan, Chinese Pat. Application, 1996, 96200851.6.
16. S. Sharonov, I. Nabiev, I. Chourpa, A. Feofanov, P. Valisa and M. Manfait, J. Raman Spectrosc., 1994, 25, 699.
17. J. Shamir, J. Binenboym and H. W. Classen, J. Am. Chem. Soc., 1968, 90, 6223.
18. A. A. Davydov, M. P. Komarova, V. F. Anufrienko and N. G. Maksimov, Kinet. Catal., 1973, 14, 1342.
19. E. Giamello, Z. Sojka, M. Che and A. Zecchina, J. Phys. Chem., 1986, 90, 6084.
20. A. Zecchina, G. Spoto and S. Coluccia, J. Mol. Catal., 1982, 14, 351.
21. A. Metcalfe and S. Ude Shankar, J. Chem. Soc., Faraday Trans. 1, 1980, 76, 630.
22. J. L. Gland, B. A. Sexton and G. B. Fisher, Surf. Sci., 1980, 95, 587.
23. R. F. Howe, J. P. Liddy and A. Metcalfe, J. Chem. Soc., Faraday Trans. I, 1972, 68, 1595.
24. F. Al-Mashta, N. Sheppard, V. Lorenzelli and G. Busca, J. Chem. Soc., Faraday Trans. 1, 1982, 78, 979.
25. J. Z. Shyu, W. H. Weber and H. S. Gandhi, J. Phys. Chem., 1988, 92, 4964.
26. M. Che and A. J. Tench, Adv. Catal., 1983, 32, 1.
27. M. Breysse and M. Steinberg, J. Solid State Chem., 1972, 4, 370.
28. M. Setaka and T. Kwan, Bull. Chem. Soc. Jpn., 1970, 43, 2727.
29. A. S. Sass, V. A. Shvets, G. A. Saveleva, N. M. Popova and V. B. Kazanskii, Kinet. Catal., 1985, 26, 799.
30. C. Li, K. Domen, K. Maruya and T. Onishi, J. Am. Chem. Soc., 1989, 111, 7683.