Bulletin of the Korean Chemical Society

Korean Chemical Society (대한화학회)
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Carbon-13 Nuclear Magnetic Resonance Spectroscopic Studies of $^{13}CO$ Adsorbed on Platinum Particles in L-Zeolites

  • Published : 1998.09.20
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Abstract

$^13CO$ chemisorbed on platinum particles in L-zeolite has been investigated by static and magic angle spinning NMR spectroscopy. The representative spectra are composed of a broad asymmetric peak with a center of gravity at 230±30 ppm and a sharp symmetric peak at 124±2 ppm which is tentatively assigned to physisorbed $CO_2$, on inner walls of L-zeolite. Overall, the broad resonance component is similar to our previous results of highly dispersed (80-96%) CO/Pt/silica or CO/Pt/alumina samples, still showing metallic characters. The principal difference is in the first moment value. The broad peak in the spectra is assigned to CO linearly bound to Pt particles in the L-zeolites, and indicates a distribution of isotropic shifts from bonding site to bonding site. The NMR results reported here manifest that the Pt particles inside of the L-zeolites channels are not collectively the same with the ones supported on silica or alumina with similar dispersion in terms of Pt particle shape and/or ordering of Pt atoms in a particle. As a result, Pt particles of CO/Pt/L-zeolite were agglomerated accompanying CO desorption upon annealing. There were no definite changes in the NMR spectra due to differences of exchanged cations. Comparison of our observation on CO/Pt/L-zeolite with Sharma et al.'s reveals that even when the first moment, the linewidtb, and the relaxation times of the static spectra and the dispersion measured by chemisorption are similar, the properties of Pt particles can be dramatically different. Therefore, it is essential to take advantage of the strengths of several techniques together in order to interpret data reliably, especially for the highly dispersed samples.

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References

  1. J. Phys. Chem v.94 Zilm, K. W;Bonneviot, L;Hamilton, D. M;Gretchen, W. G;Haller, G. L
  2. J. Phys. Chem v.94 Zilm, K. W;Bonneviot, L;Haller, G. L;Han, O. H;ermarec, M
  3. Phys. Rev. Lett. v.55 Rudaz, S. L;Ansermet, J. P;Wang, P. K;Slichter, C. P;Sinfelt, J. H
  4. J. Chem. Phys v.88 Ansermet, J. P;Slichter, C. P;Sinfelt, J. H
  5. Phys. Rev. (B) v.37 Ansermet, J. P;Wang, P. K;Slichter, C. P;Sinfelt, J. H
  6. J. Phys. Chem. v.92 Duncan, T. M;Root, T. W
  7. Phys. Rev. Lett. v.63 Duncan, T. M;Thayer, A. M;Root, T. W
  8. J. Phys. Chem. v.93 Duncan, T. M;Zilm, K. W;Hamilton, D. M;Root, T. W
  9. J. Chem. Phys v.73 Duncan, T. M;Yates Jr., J. T;Vaughan, R. W
  10. Ann. Rev. Phys. Chem v.37 Slichter, C. P
  11. Science v.234 Wang, P. K;Ansermet, J. P;Rudaz, S. L;Wang, Z;Shore, S;Slichter, C. P;Sinfelt, J. H
  12. Colloids Surf. v.45 Duncan, T. M
  13. Ph. D. thesis, university of illinois urbana-champaign Ansermet, J. P
  14. Ph. D. Thesis, University of illinois urbana-champaign Rudaz, S. L
  15. Phys. Rev. Lett v.55 Wang, P. K;Ansermet, J. P;Slichter, C. P;Sinfelt, J. H
  16. J. Chem. Soc. Chem. Commun Bradley, J. S;Millar, J;Hill, E. W;Melchior, M
  17. J. of Catal v.150 Sharma, S. B;Laska, T. E;Balaraman, P;Root, T. W;Dumesic, J. A
  18. J. Chem. Soc. Farday Trans. I v.84 Takaish, T
  19. Catal. Letters v.3 Larsen, G;Haller, G. L
  20. J. Phys. Chem v.94 McHugh, B. J;larsen, G. L
  21. Catalytic Sci. and Technol v.1 Larsen, G;Haller, G. L;Yoshida, S(et al ed.)
  22. Advances in Infrared and Raman Spectroscopy Sheppard, N;Nguyen, T. T;Clark, R. J. H(ed.);Hester, R. E(ed.)
  23. J. Catal v.40 Parra, C. F;Ballivet, D;Barthomeuf, D
  24. J. Catal v.124 Umansky, B. S;Hall, W. K
  25. J. Magn. Reson v.58 Gay, I. D
  26. J. Magn. Reson v.14 Stejskal, E. O;Schaefer, J
  27. J. Chem. Phys v.70 Maricq, M. M;Waugh, J. S
  28. J. Chem. Phys v.81 Olejiniczak, E. T;Vega, S;Griffin, R. G
  29. Principles of High Resolution NMR in Solids(2nd Ed.) Mehring, M
  30. J. magn v.29 Morris, G. A;Freeman, R.
  31. J. Chem. Phys v.92 Duncan, T. M;Thayer, A. M;Root, T. W
  32. J. Chem. Phys v.77 Dixon, W. T
  33. J. magn. Reson v.49 Dixon, WT;Schaefer, J;Sefcik, M. D;Stejskeal, E. O;Mckay, R. A
  34. J. Magn. Reson v.72 Raleigh, D. P;Olejniczak, E. T;Vaga, S;Griffin, R. G
  35. J. Chem. Phys v.89 Raleigh, D. P;Olejniczak, E. T;Griffin, R. G
  36. J. Am. Chem. Soc. v.106 Raleigh, D. P;Olejniczak, E. T;Vega, S;Griffin, R. G
  37. Appl. Catal v.25 Maesen, T. L. M;Botman, M. J. P;Slaghek, T. M;She, L. Q;Zhang, J. Y;Ponec, V
  38. The Principles of Nuclear Magnetism Abragam, A
  39. Principles of Magnetic Resonance (Third Edition) Slichter, C. P
  40. J. Chem. Phys v.61 Stejskal, e. O;Schaefer, J;Henis, J. M. S;Tripod, M. K