Methane hydrogenation and confirmation of CH_x intermediate species on NaY encapsulated cobalt clusters and Co/SiO₂ catalysts: EXAFS, FTIR, UV characterization and catalytic performances

Abstract

The adsorption of Co₂(CO)₈ onto dehydrated NaY powder under an N₂ atmosphere predominantly yielded supported Co₄(CO)₁₂. The molecular cobalt carbonyl clusters and their decarbonylated products have been structurally characterized by in situ IR, extended X-ray absorption fine structure (EXAFS) and diffuse reflectance spectroscopies. The IR spectrum assigned to the species Co₄(CO)₁₂/NaY is shifted significantly from that observed for externally supported analogues on NaY and for this cluster in solution, which indicates that the cobalt carbonyl clusters occurring on the NaY are similar to those occurring in weakly basic solution. EXAFS coordination numbers (N) show that the successively decarbonylated samples maintain small cluster sizes, which depend on the temperature-programmed oxidation of the precursor. Methane hydrogenation was carried out on intrazeolitic cobalt clusters using a two-step process. It showed a relatively higher activity and selectivity to C₂₊ hydrocarbons in comparison with Co/SiO₂ catalysts. On the basis of IR (ν_C-H 2960, 2880 cm^-1 and δ_C-H 1520, 1393 cm^-1) spectroscopy, mass spectrometry and reaction studies, one can conclude that CH_x (x=0, 1 or 2) surface carbonaceous species were generated by CH₄ dissociation on the activated cobalt catalyst; the CH₂ species was quite reactive, and propagated higher hydrocarbons.

References

1. J. C. Mackie, Catal. Rev. Sci. Eng., 1969, 33, 169.
2. H. Zanthoff and M. Baerns, Ind. Eng. Chem. Res., 1990, 29, 2.
3. G. J. Hutchings, M. S. Scurrell and J. R. Woodhouse, Chem. Soc. Rev., 1989, 18, 251.
4. T. Tashiro, T. Ito and K. Toi, J. Chem. Soc., Faraday Trans. 1, 1985, 81, 2835.
5. M. Nakamoea, H. Mitsuhasi and N. Takezawa, J. Catal., 1992, 138, 572.
6. Q. Y. Yang, A. D. Johnson, K. J. Maynard and S. T. Ceyer, J. Am. Chem. Soc., 1989, 111, 8748.
7. T. Koerts and R. A. Van Santen, J. Chem. Soc., Chem. Commun., 1991, 1281.
8. (a) J. G. Goodwin, Jr., J. Mol. Catal., 1982, 14, 259; (b) R. Pierantozzi, E. G. Valagene, A. F. Nordquist and P. Dyer, J. Mol. Catal., 1983, 21, 189.
9. (a) E. Mantovani, N. Palladino and A. Zanobi, J. Mol. Catal., 1977/1978, 3, 285; (b) P. Gelin, Y. Ben. Taarit and C. Naccache, J. Catal., 1979, 59, 537; (c) L.-F. Rao, A. Fukuoka, N. Kosugi, H. Kuroda and M. Ichikawa, J. Phys. Chem., 1990, 94, 5317.
10. (a) L. L. Sheu, H. Knözinger and W. M. H. Sachtler, Catal. Lett., 1989, 2, 129; (b) L. L. Sheu, H. Knözinger and W. M. H. Sachtler, J. Mol. Catal., 1989, 57, 61; (c) L. L. Sheu, H. Knözinger and W. M. H. Sachtler, J. Am. Chem. Soc., 1989, 111, 8125.
11. (a) S. Kawi and B. C. Gates, J. Chem. Soc., Chem. Commun., 1991, 994; (b) S. Kawi, J.-R. Chang and B. C. Gates, J. Catal., 1993, 142, 585; (c) T. Beutel, S. Kawi, K. Purnell, H. Knözinger and B. C. Gates, J. Phys. Chem., 1993, 97, 7284.
12. (a) A. De. Mallmann and D. Barthomeuf, Catal. Lett., 1990, 5, 293; (b) G.-J. Li, T. Fujimoto, A. Fukuoka and M. Ichikawa, Catal. Lett., 1992, 12, 171.
13. A. Fukuoka, L.-F. Rao, N. Kozugi and M. Ichikawa, Appl. Catal., 1989, 50, 295.
14. M. Ichikawa, L.-F. Rao, T. Ito and A. Fukuoka, Faraday Discuss., Chem. Soc., 1989, 87, 232.
15. F.-S. Xio, A. Fukuoka and M. Ichikawa, J. Catal., 1992, 138, 206.
16. P. A. Jacobs, in Metal Clusters in Catalysis, ed. B. C. Gates, L. Guczi and H. Knözinger, Elsevier, Amsterdam, 1986, p. 357.
17. G.-C. Shen, A.-M. Liu, T. Shido and M. Ichikawa, Top. Catal., 1995, 2, 141.
18. J. B. A. D. van Zon, D. C. Koningsberger, H. F. J. van't Blik and D. E. Sayers, J. Chem. Phys., 1985, 12, 5742.
19. N. Kosugi and H. Kuroda, Program EXAFS 2, Research Center for Spectrochemistry, University of Tokyo, 1988.
20. Y.-C. Xie and Y.-Q. Tang, Adv. Catal., 1990, 37, 1.
21. S. Qui, R. Ohnishi and M. Ichicawa, J. Chem. Soc., Chem. Commun., 1992, 1425.
22. F. A. Cotton and R. R. Monchamp, J. Chem. Soc., 1960, 1882.
23. (a) R. L. Schneider, R. F. Howe and K. L. Watters, Inorg. Chem., 1984, 23, 4600; (b) M. C. Connaway and B. E. Hanson, Inorg. Chem., 1986, 25, 1445.
24. Y. Iwasawa, M. Yamada, Y. Sato and H. Kuroda, J. Mol. Catal., 1984, 23, 95.
25. R. A. Friedel, I. Wender, S. L. Shufler and H. W. Sternberg, J. Am. Chem. Soc., 1995, 77, 3951.
26. M. P. Georeg, N. R. Avery, W. H. Weinberg and F. N. Tebbe, J. Am. Chem. Soc., 1983, 105, 1393.
27. (a) J. E. Demuth and H. Ibach, Surf. Sci., 1978, 78, 1238; (b) I. A. Oxton, D. B. Powell, N. Sheppard, K. Burgess, B. F. G. Johnson and J. Lewis, J. Chem. Soc., Chem. Commun., 1982, 719.
28. M. B. Lee, Q. Y. Yang, S. L. Tang and S. T. Ceyer, J. Chem. Phys., 1986, 85, 1693.
29. (a) V. Albano, P. Chini and V. Scatturin, Chem. Commun., 1968, 163; (b) P. Chini, Chem. Commun., 1967, 440.
30. D. F. Shriver, J. Organoment. Chem., 1975, 94, 259.
31. H. H. Lamb, B. C. Gates and H. Knözinger, Angew. Chem., Int. Ed. Engl., 1988, 27, 1127.
32. G. A. Ozin, Materials Chemistry, ed. L. V. Interrante, L. A. Casper and A. B. Ellis, Am. Chem. Soc., Washington, DC, 1995, pp. 335–371.
33. S. Kawi, J.-R. Chang and B. C. Gates, J. Am. Chem. Soc., 1993, 115, 4830.
34. Z. Zhang, Y. D. Zhang, W. A. Hines, J. I. Budnick and W. M. H. Sachtler, J. Am. Chem. Soc., 1992, 114, 4843.
35. S. D. Maloney, M. J. Kelley, D. C. Koningsberger and B. C. Gates, J. Phys. Chem., 1991, 95, 9406.
36. M. S. Tzou, B. K. Teo and W. M. H. Sachtler, Langmuir, 1986, 3, 773.
37. J. H. Lansford, P. J. Hutta, M. J. Lin and K. A. Windhorst, Inorg. Chem., 1978, 17, 606.
38. K. A. Windhorst and J. H. Lansford, J. Am. Chem. Soc., 1975, 97, 1407.
39. C. Naccache and Y. B. Taarit, J. Chem. Soc., Faraday Trans. 1, 1973, 69, 1475.
40. P. J. Feibeman, J. Phys. Rev. B, 1982, 26, 5347.
41. H. Yang and J. L. Whitten, Surf. Sci., 1991, 255, 193.