Establishing the occupation of supercage sites by silver ions using the response of partially silver-exchanged zeolite X- and Y-modified electrodes

Abstract

Exclusive occupancy of the sodalite cage and hexagonal-prism (small-channel network) sites of zeolites X and Y by silver ions results in an attenuated electrochemical response of zeolite-modified electrodes (ZMEs) compared with the case where silver ions occupy supercage sites. When silver ions located in the small-channel network, the initial redox current was a minimum, and grew slowly as the electrode was repeatedly cycled. Electrodes showed the reverse behavior when silver ions resided in the supercages, in that the initial redox current was a maximum and decayed rapidly. The maximum current due to silver ions in the small-channel network, computed using the peak current for the oxidation recorded in NaNO₃, is less than 10 µA per Ag⁺ ion per unit cell (uc). In contrast, modified electrodes in which silver ions occupy supercage sites produced maximum peak currents of ca. 200 µA per Ag⁺ ion per uc in the same electrolyte. In this paper we use this information to identify the general locations of silver ions in X and Y zeolites. At less than 5 Ag⁺ ions uc^-1, silver ions preferentially occupy supercage sites in zeolite Y. In zeolite X silver ions exclusively locate in the small-channel network at loadings of less than 5 Ag⁺ ions uc^-1.

References

1. R. M. Barrer, Pure Appl. Chem., 1980, 52, 2143.
2. H. S. Sherry, in Ion Exchange, ed. J. A. Marinsky, Marcel Dekker, 1969, vol. 2, pp. 89–133.
3. R. M. Barrer, L. V. C. Rees and M. Shamsuzzoha, J. Inorg. Nucl. Chem., 1966, 28, 629.
4. H. S. Sherry, J. Colloid Interface Sci., 1968, 28, 288.
5. H. S. Sherry, J. Phys. Chem., 1968, 72, 4086.
6. R. M. Barrer, J. A. Davies and L. V. C. Rees, J. Inorg. Nucl. Chem., 1969, 31, 2599.
7. A. Dyer, R. B. Gettins and J. G. Brown, J. Inorg. Nucl. Chem., 1970, 32, 2389.
8. M. L. Constenoble, W. J. Mortier and J. B. Uytterhoeven, J. Chem. Soc., Faraday Trans. 1, 1976, 72, 1877.
9. M. Brown and H. S. Sherry, J. Phys. Chem., 1971, 75, 3855.
10. E. Hoinkis and H. W. Levi, Ion Exch. Process Ind., Pap. Conf. 1969, 1970, 339.
11. H. S. Sherry, in Advances in Chemistry Series 101, ed. E. M. Flanigen and L. B. Sand, American Chemical Society, Washington DC, 1971.
12. L. M. Brown, H. S. Sherry and F. J. Krambeck, J. Phys. Chem., 1971, 75, 3846.
13. H. S. Sherry, J. Phys. Chem., 1966, 70, 1158.
14. B. K. G. Theng, E. Vansant and J. B. Uytterhoeven, Trans. Faraday Soc., 1968, 64, 3370.
15. W. H. Baur, Am. Mineral., 1964, 49, 697.
16. C. Senaratne and M. D. Baker, J. Phys. Chem., 1994, 98, 13687.
17. M. D. Baker and C. Senaratne, Anal. Chem., 1992, 64, 697.
18. A. Dyer and R. B. Gettins, Ion Exch. Process Ind., Pap. Conf. 1969, 1970, 357.
19. A. Dyer and R. B. Gettins, J. Inorg. Nucl. Chem., 1970, 32, 2401.
20. C. Senaratne and M. D. Baker, J. Electroanal. Chem., 1992, 332, 357.
21. C. Senaratne, J. Zhang, M. D. Baker, C. A. Bessel and D. R. Rolison, J. Phys. Chem., 1996, 100, 5849.
22. H. S. Sherry, J. Colloid Interface Sci., 1968, 28, 288.
23. M. D. Baker and C. Senaratne, US Patent 5,733,437, March 31, 1998.
24. M. D. Baker and C. Senaratne, US Patent 5,730,857, March 24, 1998.
25. S. Leutwyler and E. Schumacher, Chimia, 1977, 31, 475.
26. K. R. Franklin, R. P. Townsend, S. J. Whelan and C. J. Adams, Proceedings of the Seventh International Conference on Zeolites, Tokyo, 1986, ed. Y. Murakami, A. Ijima and J. M. Ward, Elsevier, Amsterdam, 1986.
27. R. Harjula, J. Lehto, J. H. Pothuis, A. Dyer and R. P. Townsend, J. Chem. Soc., Faraday Trans., 1993, 89, 971.
28. M. D. Baker, C. Senaratne and J. Zhang, J. Chem. Soc., Faraday Trans., 1992, 88, 3187.
29. P. Allongue and E. Souteyrand, J. Electroanal. Chem., 1990, 286, 217.
30. B. R. Shaw, K. Creasy, C. L. Lanczycki, J. Sargeant and M. Tirhado, J. Electrochem. Soc., 1988, 135, 869.
31. D. R. Rolison, R. J. Nowak, T. A. Welsh and C. G. Murray, Talanta, 1991, 38, 27.
32. A. J. Bard and T. E. Mallouk, in Molecular Design of Electrode Surfaces, ed. R. W. Murray, John Wiley & Sons, New York, 1992.
33. M. D. Baker and C. Senaratne, in Frontiers of Electrochemistry, Electrochemistry of Novel Materials, ed. P. N. Ross and J. Lipkowski, VCH, vol. 33, 1994.
34. D. R. Rolison, in Advanced Zeolite Science and Applications, ed. J. C. Jansen, M. Stocker, H. G. Karge and J. Weitkamp, Elsevier, Amsterdam, Stud. Surf. Sci. Catal., 1994, 85, 543.
35. A. Walcarius, Electroanalysis, 1996, 8, 971.
36. D. H. Brouwer and M. D. Baker, J. Phys. Chem., 1997, 101, 10390.
37. M. L. Constenoble and A. Maes, J. Chem. Soc., Faraday Trans. 1, 1978, 74, 131.
38. A. Maes and A. Cremers, J. Chem. Soc., Faraday Trans. 1, 1978, 74, 136.
39. E. Vansant and J. B. Uytterhoeven, Adv. Chem. Ser., 1971, 101, 426.