Abstract
A study has been carried out of the interactions of NH3 with TiO2, Nb2O5, and Nb2O5/TiO2. Raman spectroscopy was used to characterize the structure of the adsorbed NH3 and perturbations of species present at the surface of the adsorbent. On each oxide, NH3 adsorbs predominantly at Lewis acid sites. Hydrogen-bonding occurs between the adsorbed NH3 and OH groups present on the surface of TiO2. A small concentration of NH +4 is observed, consistent with the relatively low concentration of Brønsted acid sites compared to Lewis acid sites on each of the samples investigated. Exposure of Nb2O5/TiO2 to NH3 at temperatures up to 500°C does not result in partial reduction of the supported niobia.
Similar content being viewed by others
References
M. Nishimura, K. Asakura and Y. Iwasawa, J. Chem. Soc. Chem. Commun. (1986) 1660.
M. Shirai, N. Ichikuni, K. Asakura and Y. Iwasawa, Catal. Today 8 (1990) 57.
S. Yoshida, Y. Nishimura, T. Tanaka, H. Kanai and T. Funabiki, Catal. Today 8 (1990) 67.
Y. Wada and A. Morikawa, Bull. Chem. Soc. Japan 60 (1987) 3509.
S. Okazaki and T. Okuyama, Bull. Chem. Soc. Japan 56 (1983) 2159.
K. Tanabe, Catal. Today 8 (1990) 1.
S. Yoshida, T. Tanaka, T. Hanada, H. Hiraiwa, H. Kanai and T. Funabiki, Catal. Lett. 12 (1992) 227.
T. Tanaka, H. Nojima, H. Yoshida, H. Nakagawa, T. Funabiki and S. Yoshida, Catal. Today 16 (1993) 297.
P.A. Burke and E.I. Ko, J. Catal. 129 (1991) 38.
E.I. Ko, R. Bafrali, N.T. Nuhfer and N.J. Wagner, J. Catal. 95 (1985) 260.
J.G. Weissman, E.I. Ko and P. Wynblatt, J. Catal. 108 (1987) 383.
K. Asakura and Y. Iwasawa, Chem. Lett. (1986) 859.
N. Ichikuni and Y. Iwasawa, Catal. Today 16 (1993) 427.
I.E. Wachs, J.-M. Jehng, and F.D. Hardcastle, Solid State Ionics 32/33 (1989) 904.
J.-M. Jehng and I.E. Wachs, Catal. Today 8 (1990) 37.
J.-M. Jehng and I.E. Wachs, J. Mol. Catal. 67 (1991) 369.
J.-M. Jehng and I.E. Wachs, J. Phys. Chem. 95 (1991) 7373.
R.M. Pittman and A.T. Bell, J. Phys. Chem., in press.
G. Busca, H. Saussey, O. Saur, J.C. LaValley and V. Lorenzelli, Appl. Catal. 14 (1985) 245.
N.W. Cant and L.H. Little, Can. J. Chem. 42 (1964) 802.
R.A. Rajadhyaksha and H. Knözinger, Appl. Catal. 51 (1989) 81.
M. Primet, P. Pichat and M. Mathieu, J. Phys. Chem. 75 (1971) 1221.
N. Topsøe, J. Catal. 128 (1991) 499.
G. Ramis, G. Busca, V. Lorenzelli and P. Forzatti, Appl. Catal. 64 (1990) 243.
A.A. Tsyganenko, D.V. Posdnyakov and V.N. Filimonov, J. Mol. Struct. 29 (1975) 299.
G.T. Went and A.T. Bell, Catal. Lett. 11 (1991) 111.
K. Nakamoto,Infrared and Roman Spectra of Inorganic and Coordination Compounds, 4th Ed. (Wiley, New York, 1977) p. 167.
K. Morishige, F. Kanno, S. Ogawara and S. Sasaki, J. Phys. Chem. 89 (1985) 4404.
B. Boddenberg and R. Niepmann, Mol. Phys. 79 (1993) 405.
K. Tanabe,Solid Acid and Bases (Academic Press, New York, 1970).
G.D. Parfitt, J. Ramsbotham and C.H. Rochester, Trans. Faraday Soc. 67 (1971) 841.
G.T. Went, L.-J. Leu and A.T. Bell, J. Catal. 134 (1992) 479.
J.D. Hill, I.G. Worsley and L.G. Hepler, Chem. Rev. 71 (1971) 127.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Pittman, R.M., Bell, A.T. Raman investigations of NH3 adsorption on TiO2, Nb2O5, and Nb2O5/TiO2 . Catal Lett 24, 1–13 (1994). https://doi.org/10.1007/BF00807369
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00807369