Recent progress in surface NMR-electrochemistry

Abstract

NMR spectroscopy is one of the newer spectroscopic techniques for investigating the static, dynamic and electronic structures of molecules adsorbed onto metal catalyst surfaces. We review recent progress in the application of solid-state NMR methods to the investigation of molecules adsorbed onto metal surfaces in an electrochemical environment: in the presence of electrolyte, and at an electrified interface under external potentiostatic control. While at a very early stage of development, the NMR-electrochemistry approach has considerable potential for investigating otherwise inaccessible aspects of electrode and adsorbate structure, and should enable a comparison of results obtained from different spectroscopies, in particular from IR spectroscopy. We present a brief review of the development of the subject, followed by details of the instrumentation necessary for NMR-electrochemistry studies. We show how spin–spin relaxation can give information on surface structure and surface diffusion, how spin–lattice relaxation can give information on the presence of conduction electron spillover onto the adsorbate, and how the NMR of surface species responds to an externally applied electric field. The ¹³C-NMR of CO on Pt in an electrochemical environment is compared with the ¹³C-NMR of CO on Pt catalysts in vacuum, which are well characterized. In the case of CN on Pt, we show large spectral shifts of the resonance as the electrode potential is varied, providing an independent measurement of the effects of the electrified interface on the chemisorption bond. Spectral sensitivity is also now adequate to observe nuclei which produce even weaker signals than ¹³C, such as ¹⁵N. The NMR-electrochemistry method thus opens up a broad new array of possibilities for probing static structures (from T₂), surface diffusion (from the temperature dependence of T₂) as well as electronic properties of the chemisorption bond (from T_l, and from electrode potential effects) at electrochemical interfaces, and for studying reactive intermediates and poisons on high-surface-area catalysts, such as those utilized in hydrogen and organic fuel cells.

References

1. M. Mehring, Principles of High Resolution NMR in Solids, Springer, New York, 1983.
2. C. P. Slichter, Surf Sci., 1981, 106, 382.
3. C. P. Slichter, Annu. Rev. Phys. Chem., 1986, 37, 25.
4. J. P. Burger, N. J. Poulis and W. P. A. Haas, Physica, 1961, 27, 514.
5. T. Ito, T. Kadowski and T. Toya, Jpn. J. Appl. Phys., 1974, Suppl. 2, Part 2, p. 257.
6. T. Ito and T. Kadowski, Jpn. J. Appl. Phys., 1975, 14, 1673.
7. T. Ito, T. Kumagai and T. Kadowski, Jpn. J. Appl. Phys., 1977, 16, 1919.
8. H. Pfeifer, in NMR Basic Principles and Progress, ed. P. Diehl, E. Fluck and R. Kosfeld, Springer, Berlin, 1972, vol. 7, p. 53.
9. T. M. Duncan and C. Dybowski, Surf Sci. Rep, 1981, 1, 157.
10. J.-Ph. Ansermet, C. P. Slichter and J. H. Sinfelt, Prog. NMR Spectrosc., 1990, 22, 401.
11. P. K. Wang, J.-Ph. Ansermet, S. L. Rudaz, Z. Wang, S. Shore, C. P. Slichter and J. H. Sinfelt, Science, 1986, 234, 35.
12. T. M. Duncan, Colloids Surf., 1990, 45, 11.
13. T. M. Duncan, J. T. Yates Jr. and R. W. Vaughan, J. Chem. Phys., 1980, 73, 975.
14. T. M. Duncan and T. W. Root, J. Phys. Chem., 1988, 92, 4426.
15. T. M. Duncan, A. M. Thayer and T. W. Root, J. Chem. Phys., 1990, 92, 2663.
16. T. M. Duncan, A. M. Thayer and T. W. Root, Phys. Rev. Lett., 1989, 63, 62.
17. L. R. Becerra, C. P. Slichter and J. H. Sinfelt, J. Phys. Chem., 1993, 97, 10.
18. S. L. Rudaz, J.-Ph. Ansermet, P. K. Wang, C. P. Slichter and J. H. Sinfelt, Phys. Rev. Lett., 1985, 54, 71.
19. P. K. Wang, J.-Ph. Ansermet, C. P. Slichter and J. H. Sinfelt, Phys. Rev. Lett., 1985, 55, 2731.
20. J.-Ph. Ansermet, P. K. Wang, C. P. Slichter and J. H. Sinfelt, Phys. Rev. B, 1988, 37, 1417.
21. J.-Ph. Ansermet, C. P. Slichter and J. H. Sinfelt, J. Chem. Phys., 1988, 88, 5963.
22. S. E. Shore, J.-Ph. Ansermet, C. P. Slichter and J. H. Sinfelt, Phys. Rev. Lett., 1987, 58, 953.
23. T. M. Duncan, K. W. Zilm, D. M. Hamilton and T. W. Root, J. Phys. Chem., 1989, 93, 2583.
24. K. W. Zilm, L. Bonneviot, D. M. Hamilton, G. G. Webb and G. L. Haller, J. Phys. Chem., 1990, 94, 1463.
25. P. K. Wang, Ph.D. Thesis, University of Illinois at Urbana-Champaign, 1984.
26. P. K. Wang, C. P. Slichter and J. H. Sinfelt, Phys. Rev. Lett., 1984, 53, 82.
27. P. K. Wang, C. P. Slichter and J. H. Sinfelt, J. Phys. Chem., 1990, 94, 1154.
28. A. Wieckowski, S. D. Rosasco, G. N. Salaita, A. T. Hubbard, B. Bent, F. Zaera, D. Godbey and G. A. Somorjai, J. Am. Chem. Soc., 1985, 111, 7653.
29. K. W. H. Chan and A. Wieckowski, J. Electrochem. Soc., 1990, 137, 367.
30. P. J. Slezak and A. Wieckowski, J. Electroanal. Chem., 1992, 339, 401.
31. P. J. Slezak and A. Wieckowski, J. Magn. Reson. A, 1993, 102, 166.
32. P. J. Slezak, Ph.D. Thesis, University of Illinois at Urbana-Champaign, 1992.
33. R. R. Ernst, G. Bodenhausen and A. Wokaun, Principles of Nuclear Magnetic Resonance in One and Two Dimensions, Oxford University Press, 1987.
34. A. C. Kunwar, G. L. Turner and E. Oldfield, J. Magn. Reson., 1986, 69, 124.
35. H. Angerstein-Kozlowska, B. E. Conway and W. B. A. Sharp, J. Electroanal. Chem., 1973, 43, 9.
36. H. Tamura, T. Arikado, H. Yoneyama and Y. Matsuda, Electrochim. Acta, 1974, 19, 272.
37. C. D. Makowka, C. P. Slichter and J. H. Sinfelt, Phys. Rev. Lett., 1982, 49, 379; J. J. van der Klink, J. Buttet and M. Graetzel, Phys. Rev. B, 1984, 29, 6352.
38. C. D. Makowka, C. P. Slichter and J. H. Sinfelt, Phys. Rev. B, 1985, 31, 5663; J. P. Bucher and J. J. van der Klink, Phys. Rev. B, 1988, 38, 11038.
39. M. Weinert and A. J. Freeman, Phys. Rev. B, 1983, 28, 6262.
40. J. J. van der Klink, J. Phys. Condens. Matter, 1996, 8, 1845.
41. R. Hofmann, Rev. Mod. Phys., 1988, 60, 601; P. Feibelman and D. R. Hamann, Surf. Sci., 1985, 149, 48.
42. J. Andzelm and D. R. Salahub, Int. J. Quantum Chem., 1986, 29, 1091.
43. J-Ph. Ansermet, Ph.D. Thesis, University of Illinois at Urbana-Champaign, 1985.
44. D. B. Zax, C. A. Klug, C. P. Slichter and J. H. Sinfelt, J. Phys. Chem., 1989, 93, 5009.
45. C. A. Klug, C. P. Slichter and J. H. Sinfelt, J. Phys. Chem., 1991, 95, 2119.
46. D. Zurawski, M. Wasberg and A. Wieckowski, J. Phys. Chem., 1990, 94, 2076.
47. C. K. Rhee, J. M. Feliu, E. Herrero, P. Mrozek and A. Wieckowski, J. Phys. Chem., 1993, 97, 9730.
48. I. Oda, J. Inukai and M. Ito, Chem. Phys. Lett., 1993, 203, 99.
49. L. R. Becerra, C. A. Klug, C. P. Slichter and J. H. Sinfelt, J. Phys. Chem., 1993, 97, 12014.
50. P. Zelenay and A. Wieckowski, in Electrochemical Interfaces Modern Techniques for In-Situ Interface Characterization, ed. H. D. Abruña, VCH, New York, 1991, p. 479.
51. J. Day, P. A. Vuissoz, E. Oldfield, A. Wieckowski and J.-Ph. Ansermet, J. Am. Chem. Soc., 1996, 118, 13046.
52. C. P. Slichter, Principles of Magnetic Resonance, Springer-Verlag, New York, 1990, p. 156.
53. S. E. Shore, Ph.D. Thesis, University of Illinois at Urbana-Champaign, 1986.
54. Y. Y. Tong, G. A. Martin and J. J. van der Klink, J. Phys. Condens. Matter, 1994, 6, L533.
55. G. Blyholder, J. Phys. Chem., 1964, 68, 2772.
56. J. N. Miller, I. Lindau and W. E. Spicer, Surf. Sci., 1981, 111, 595.
57. E. W. Plummer and W. Eberhardt, in Angle-Resolved Photoemission as a Tool for the Study of Surface, ed. I. Prigogine and S. A. Rice, Advances in Chemical Physics, Wiley, New York, 1982, vol. 49.
58. K. R. Naba and A. B. Anderson, Surf. Sci., 1982, 119, 35.
59. M. Trenary, S. L. Tang, R. J. Simonson and F. R. McFeely, Surf. Sci., 1983, 124, 555.
60. J. Rogozik and V. Dose, Surf. Sci., 1986, 176, L847.
61. S. C. Chang, L. W. H. Leung and M. J. Weaver, J. Phys. Chem., 1989, 93, 5341.
62. S. C. Chang and M. J. Weaver, Surf. Sci., 1990, 238, 142.
63. Y. T. Wong and R. Hoffmann, J. Phys. Chem., 1991, 95, 859.
64. J. O'M. Bockris and A. K. N. Reddy, Modern Electrochemistry, Plenum, New York, 1970.
65. C. Korzeniewski, S. Pons, P. P. Schmidt and M. W. Severson, J. Chem. Phys., 1986, 85, 4153.
66. C. Stuhlmann, I. Villegas and M. J. Weaver, Chem. Phys. Lett., 1994, 219, 319.
67. P. S. Bagus, C. J. Nelin, W. Muller, M. R. Philpott and H. Seki, Phys. Rev. Lett., 1987, 58, 559.
68. M. F. Baba, C. Mijoule, N. Godbout and D. R. Salahub, Surf. Sci., 1994, 316, 349.
69. C. Bureau, M. Defranceschi, J. Delhalle, G. Lecayon and D. R. Salahub, J. Mol. Struct. (Theochem.), 1995, 330, 279.
70. R. J. Nichols, in Adsorption of Molecules at Metal Electrode, ed. J. Lipkowski and P. N. Ross, VCH, Weinheim, 1992, p. 347.
71. E. Oldfield, J. Magn. Reson. A, 1994, 107, 255.
72. NMR Techniques in Catalysis, ed. A. T. Bell and A. Pines, Dekker, New York, 1994.