Characterization of an AgCl/Al₂O₃ catalyst for lean NO conversion

Abstract

An AgCl/Al₂O₃ catalyst calcined at 873 K in air is highly active for the conversion of lean NO with ethanol even in the presence of SO₂. The chemical and physical characteristics of the AgCl/Al₂O₃ catalyst were studied using X-ray diffraction, X-ray photoelectron spectroscopy and ultraviolet-visible (UV-VIS) spectroscopy. Crystallized AgCl particles were formed for the AgCl/Al₂O₃ catalyst calcined above 393 K in air. AgCl particles began to disperse on the Al₂O₃ surface upon calcination at 773 K. Dispersion of the AgCl particles progressed upon calcination at 873 K. UV–VIS spectra also showed an intense absorption band at ∽250 nm for the AgCl/Al₂O₃ catalyst calcined at 873 K which can be attributed to the AgCl on Al₂O₃. Surface silver content in the AgCl/Al₂O₃ catalyst calcined at 873 K is ∽4.2 times that of the AgCl/Al₂O₃ catalyst calcined at 773 K. These results suggest that effective NO conversion over the AgCl/Al₂O₃ catalyst calcined at 873 K in air is ascribed to the AgCl particles being well dispersed by interaction with Al₂O₃.

References

1. A. Fritz and V. Pitchon, Appl. Catal. B, 1997, 13, 1.
2. T. Miyadera and K. Yoshida, Chem. Lett., 1993, 1483.
3. T. Miyadera, Appl. Catal. B, 1993, 2, 199.
4. T. Miyadera, A. Abe, G. Muramatsu and K. Yoshida, Adv. Mater., '93/V: Ecomater., 1994, 405.
5. N. Aoyama, K. Yoshida, A. Abe and T. Miyadera, Catal. Lett., 1997, 43, 249.
6. S. Sumiya, M. Saito, H. He, Q. Feng, N. Takezawa and K. Yoshida, Catal. Lett., 1998, 50, 87.
7. A. Abe, N. Aoyama, S. Sumiya, N. Kakuta and K. Yoshida, Catal. Lett., 1999, 51, 5.
8. C. E. Moore, Atomic Energy Levels, National Bureau of Standards, Washington, DC, 1971, vol. 3, p. 48.
9. J. Texter, R. Kellerman and T. Gonsiorwski, J. Phys. Chem., 1986, 90, 2118.
10. Y. Okamoto, Nachrichten der Akademie Wissenshaften in Goettingen Mathematisch- Physikalishe Klasse, No. 14 1956, 275.
11. J. S. Wong, M. Shluster and M. L. Cohen, Phys. Status. Solidi B, 1976, 77, 295.