Photoluminescent and photocatalytic properties of layered caesium titanates, Cs₂Ti_nO_2n+1 (n=2, 5, 6)

Abstract

Photoluminescence and photocatalytic H₂ evolution reactions of layered caesium titanates, Cs₂Ti_nO_2n+1(n =2,5,6), have been studied to evaluate the photoactivity of these materials. Cs₂Ti₂O₅ showed a broad emission around 420 nm upon excitation at 270 nm at 77 K, while both Cs₂Ti₅O₁₁ and Cs₂Ti₆O₁₃ showed an emission around 490 nm upon excitation at 290 nm. Cs₂Ti₂O₅ showed a blue emission even at 300 K. The Raman spectrum of Cs₂Ti₂O₅ was similar to that of the well characterized K₂Ti₂O₅ . The results of the luminescence and the Raman spectrum suggested that Cs₂Ti₂O₅ consists of a layered structure with TiO₅ units, as observed in K₂Ti₂O₅ . Cs₂Ti₂O₅ with the five-coordinate structure showed higher photocatalytic activity for H₂ evolution from aqueous methanol solutions than Cs₂Ti₅O₁₁ and Cs₂Ti₆O₁₃ with ordinary six-coordinate structures.

References

1. T. Sakata, in Photocatalysis, ed. N. Serpone and E. Pelizzetti, Wiley, New York, 1989, p. 311.
2. D. E. Scaife, Sol. Energy, 1980, 25, 41.
3. K. Beneko and G. Lagaly, Z. Naturforsch., Teil B, 1978, 33, 564.
4. Y. Fujiki and T. Ohsaka, Yogyo Kyokai-shi (Ceramics), 1982, 90, 19; Y. Fujiki, Y. Komatsu and T. Sasaki, Ceramics, 1984, 19, 128.
5. M. Ogawa and K. Kuroda, Chem. Rev., 1995, 95, 399 and references therein.
6. A. Kudo and T. Sakata, J. Mater. Chem., 1993, 3, 1081.
7. M. Shibata, A. Kudo, A. Tanaka, K. Domen, K. Maruya and T. Onishi, Chem. Lett., 1987, 1017.
8. Y. Inoue, T. Kubokawa and K. Sato, J. Phys. Chem., 1991, 93, 4059.
9. S. Anderson and A. D. Wadsley, Nature (London), 1960, 187, 499; S. Anderson and A. D. Wadsley, Acta Chem. Scand., 1961, 15, 663.
10. T. Nakato, K. Kuroda and C. Kato, Catal. Today, 1993, 16, 471; T. Nakato, K. Kusunoki, K. Yoshizawa, K. Kuroda and M. Kaneko, J. Phys. Chem., 1995, 99, 17896.
11. Y. I. Kim, S. J. Atherton, E. S. Brigham and T. E. Mallouk, J. Phys. Chem., 1993, 97, 11802; Y. I. Kim, S. Salim, M. J. Huq and T. E. Mallouk, J. Am. Chem. Soc., 1991, 113, 9561.
12. I. E. Grey, I. C. Madsen, J. A. Watts, L. A. Bursill and J. Kwiatkowska, J. Solid State Chem., 1985, 58, 350; J. Kwiatkowska, I. E. Grey, I. C. Madsen and L. A. Bursill, Acta Crystallogr., Sect. B, 1987, 43, 258.
13. L. A. Bursill, D. J. Smith and J. Kwiatkowska, J. Solid State Chem., 1987, 69, 360.
14. T. Sasaki, Y. Komatsu and Y. Fujiki, Chem. Mater., 1992, 4, 894.
15. O. Schmitz-DuMont and A. H. Schulz, Monatsch. Chem., 1952, 83, 638; O. Schmitz-DuMont and H. Reckhard, Monatsch Chem., 1959, 90, 134.
16. F. A. Kröger, Some Aspects of the Luminescence of Solids, Elsevier, Amsterdam, 1948.
17. G. Blasse, Struct. Bonding, 1980, 42, 1; G. Blasse, Prog. Solid State Chem., 1988, 18, 79; J. Alarcon and G. Blasse, Phys. Status Solidi A, 1993, 135, 627; B. Bouma and G. Blasse, J. Phys. Chem. Solids, 1995, 56, 261.
18. G. Blasse and G. P. M. v. d. Heuvel, J. Solid State Chem., 1974, 10, 206; M. Wiegel, M. Hamoumi and G. Blasse, Mater. Chem. Phys., 1994, 36, 289; M. Hamoumi, M. Wiegel and G. Blasse, J. Solid State Chem., 1994, 108, 410.
19. A. Kudo and T. Sakata, J. Phys. Chem., 1995, 99, 15963; A. Kudo and E. Kaneko, J. Mater. Sci. Lett., 1997, 16, 224.
20. A. J. H. Macke, J. Solid State Chem., 1976, 18, 337; A. J. H. Macke, Phys. Status Solidi A, 1977, 39, 117.
21. K. Domen, A. Kudo, M. Shibata, A. Tanaka, K. Maruya and T. Onishi, J. Chem. Soc., Chem. Commun., 1986, 1706.
22. K. Domen, Y. Ebina, T. Sekine, A. Tanaka, J. Kondo and C. Hirose, Catal. Today, 1993, 16, 479.
23. M. Anpo, I. Tanahashi and Y. Kubokawa, J. Phys. Chem., 1982, 86, 1; M. Anpo, N. Aikawa, Y. Kubokawa, M. Che, C. Louis and E. Giamello, J. Phys. Chem., 1985, 89, 5689; M. Anpo, N. Aikawa, Y. Kubokawa, M. Che, C. Louis and E. Giamello, J. Phys. Chem., 1985, 89, 5017; M. Anpo, M. Sunamoto and M. Che, J. Phys. Chem., 1989, 93, 1187; M. Anpo, S. C. Moon, K. Chiba, G. Martra's and S. Coluccia, Res. Chem. Intermed., 1993, 19, 495.