Transformation of tetragonal zirconia phase to monoclinic phase in the presence of Fe³⁺ ions as probes: an EPR study

Abstract

EPR was mainly used to study the morphological, textural and structural behavior of zirconium hydroxide [ZrO(OH)₂] with respect to calcination under air at different temperatures. For calcination temperatures less than 700°C, the tetragonal and monoclinic phases of the solid were present. In this range of temperatures an EPR signal with g_xx=1.9755, g_yy=1.9720 and g_zz=1.9562 was observed and attributed to Zr³⁺ ions located in octahedral sites with strong tetragonal distortion. The dehydration of OH^- groups from solids could be responsible for the Zr⁴⁺ reduction into Zr³⁺ ions. A second signal, centered at g=2.0018, was also observed and assigned to trapped single electrons located in oxygen vacancies of ZrO₂. A third signal with g_xx=2.0040, g_yy=2.0082 and g_zz=2.0334 was attributed to adsorbed O₂^- species. Finally, a fourth signal obtained at low magnetic field with different g values was attributed to Fe³⁺ ions located in sites with a purely rhombic field. For high calcination temperatures (>700°C), the tetragonal phase was completely transformed into monoclinic phase. In this phase, the trapped single electrons and the adsorbed O₂^- species disappeared whereas the number of Zr³⁺ ions increases when compared to that obtained at lower calcination temperatures. This increase could be related to the reduction of Zr⁴⁺ by the trapped single electrons and the formation of the monoclinic phase which stabilizes the Zr³⁺ ions. In this latter phase, the Fe³⁺ ions are located in sites which have the same environmental symmetry than in tetragonal phase but with specific EPR parameter values.

References

1. T. Yamaguchi, Catal. Today, 1994, 20, 199.
2. G. L. Clark and D. H. Reynolds, Z. Kristallogr., 1937, 98, 299.
3. E. D. Whitney, Trans. Faraday Soc., 1965, 61, 1991 and references therein.
4. R. C. Garvie, J. Phys. Chem., 1965, 69, 1238.
5. Y. Murase and E. Kato, Nippon Kagaku Kaishi, 1978, 367.
6. Handbook of Chemistry and Physics, ed. D. R. Lide, CRC Press, Boca Raton, Fl, 77th edn., 1996–1997, pp. 11–16.
7. R. T. Weber, W IN-EPR SIMFONIA manual, Ver. 1.2, Bruker Instruments, Inc., 1995, Billerica, MA and references therein.
8. L. M. Zaitsev, Zh. Neorg. Khim., 1966, 11, 1684.
9. A. Clearfield, G. P. D. Serrette and A. H. Khazi-Syed, Catal. Today, 1994, 20, 295 and references therein V. Parvulescu, S. Coman, P. Grange and V. I. Parvulescu, Appl. Catal., 1999, 176(1), 27.
10. R. C. Garvie and P. S. Nicholson, J. Am. Ceram. Soc., 1972, 55(6), 303.
11. T. Mitsuhashi, M. Ichihara and U. Tatsuke, J. Am. Ceram. Soc., 1974, 57(2), 97.
12. V. G. Keramidas and W. B. White, J. Am. Ceram. Soc., 1974, 57, 22.
13. M. J. Torralvo, M. A. Alario and J. Soria, J. Catal., 1984, 86, 473; C. Morterra, E. Giamello, E. Orio and M. Volante, J. Phys. Chem., 1990, 94, 3111.
14. F. R. Chen, G. Coudurier, J. F. Joly and J. C. Vedrine, J. Catal., 1993, 143, 616.
15. I. V. Bobricheva, I. A. Stavitsky, V. K. Yermolaev, N. S. Kotsarenko, V. P. Shmachkova and D. I. Kochubey, Catal. Lett., 1998, 56, 23.
16. G. L. Markaryan, L. N. Ikryannikova, G. P. Muravieva, A. O. Turakulova, B. G. Kostyuk, E. V. Lunina, V. V. Lunin, E. Zhilinskaya and A. Aboukaïs, Colloids Surf. A, 1999, 147, 435.
17. T. Lopez, F. Tzompantzi, J. Navarrete, R. Gomez, J. L. Boldu, E. Munoz and O. Novaro, J. Catal., 1999, 181, 285.
18. M. Che and A. Tench, J. Adv. Catal., 1983, 32, 1.
19. X. Zhang and K. Klabunde, J. Inorg. Chem., 1992, 31, 1706.
20. E. Abi-aad, R. Bechara, J. Grimblot and A. Aboukaïs, Chem. Mater., 1993, 5, 793.
21. V. I. Dimza, Phys. Status Solidi A, 1993, 140, 543.
22. M. D. Glinchuk, V. Skorokhod, I. P. Bykov, V. Dimza and E. Cernoskova, J. Phys. Condens. Matter, 1994, 6, 3421.
23. P. B. Ayscough, Electron Spin Resonance in Chemistry. Methuen & Co. Ltd., London, 1967.
24. E. A. Zhilinsaya, V. N. Lazukin, I. V. Chepeleva and V. V. Osiko, Phys. Status Solidi B, 1980, 98, 419.
25. K. K. Ermakovich, V. N. Lazukin, V. M. Tatarintsev and I. V. Chepeleva, Fiz. Tverd. Tela (S.-Peterburg), 1977, 19, 3488.
26. G. Bacquet, J. Dugas, C. Escribe and A. Rauanet, J. Solid State Chem., 1976, 19, 251.
27. G. Bacquet, J. Dugas and C. Escribe, Phys. Status Solidi B, 1971, 47, 177.
28. D. L. Griscom, J. Non-Cryst. Solids, 1980, 40, 211.
29. R. Aasa and T. Vänngård, Ark. Kemi, 1965, 24(18), 331.
30. R. Aasa, J. Chem. Phys., 1970, 52(8), 3919.
31. R. D. Dowsing and J. F. Gibson, J. Chem. Phys., 1969, 50(1), 294.
32. C. M. Brodbeck, J. Non-Cryst. Solids, 1980, 40(1-3), 305.
33. M. I. Scullane, L. K. White and N. D. Chasteen, J. Magn. Res., 1982, 47, 383.
34. J. M. Schreurs, J. Chem. Phys., 1978, 69, 211.