Abstract
Support Pt-W catalysts are studied for 3-methylhexane reforming. The increase in tungsten loading and the use of SiO2 support instead of Al2O3 in Pt-W catalysts leads to the decrease in total activity and aromatization selectivity. X-ray Photoelectron Spectroscopy (XPS) has been applied to bimetallic Pt-W/Al2O3 and SiO2 catalysts with different Pt/W ratios to try to explain the catalytic results. Observations lead to the conclusion that tungsten species are strongly anchored on the support in Pt-W/Al2O3 catalysts at low tungsten concentration. In this case, tungsten species are not reducible (oxidation state +VI) and not accessible catalytically; tungsten is hindered by small Pt particles. At large tungsten loadings, beyond the theoretical monolayer capacity of the support, a fraction of tungsten species migrates to the surface and becomes reducible. This fraction of tungsten-reducible species and large platinum particles are accessible on the surface, but another fraction of tungsten species strongly anchored on the support remains not accessible and not reducible. A model is proposed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
P. Tittarelli, A. Iannibello and P.L. Villa, J. Solid. State. Chem. 37 (1981) 95.
R. Thomas, V.H.J. de Beer and J.A. Moulijn, Bull. Soc. Chim. Belg. 90 (1981) 1349.
L. Salvati Jr., L.E. Makovsky, J.M. Stencel, F.R. Brown and D.M. Hercules, J. Phys. Chem. 85 (1981) 3700.
S. Soled, L. Murrel, I. Wachs and G. McVicker, in:Symposium on the Role of Solid State Chem. in Catal; Am. Chem. Soc., Washington, D.C., Meeting, 1983, 1310.
M. Molière, Thesis, Strasbourg, 1978.
P. Biloen and G.T. Pott, J. Catal. 30 (1973) 169.
J.R. Regalbuto, T.H. Fleish and E.E. Wolf, J. Catal. 107 (1987) 114.
G. Leclercq, T. Romero, S. Pietrzyk, J. Grimblot and L. Leclercq, J. Mol. Cat. 25 (1984) 67.
F. Garin, S. Aeiyach, P. Legare and G. Maire, J. Catal. 77 (1982) 323.
J.M. Dartigues, A. Chambellan, S. Corolleur, F.G. Gault, A. Renouprez, B. Moraweck, P. Bosch-Giral and G. Dalmai-Imelik, Nouv. J. Chim. 3 (1979) 591.
J.S. M'Boungou, J.L. Schmitt, G. Maire and F. Garin, Catal. Lett. 10 (1991) Part I, previous paper.
A. Katrib, C. Petit, P. Legare, L. Hilaire and G. Maire, J. Phys. Chem. 92 (1988) 3527.
S. Doniach and M. Sunjic, J. Phys. 3 (1970) 285.
J.H. Scofield, J. Elect. Spect. Rel. Phen. 8 (1976) 129.
K.T. Ng and D.M. Hercules, J. Phys. Chem. 80 (1976) 2094.
R.J. Colton and J.W. Rabalais, Inorg. Chem. 15 (1976) 236.
Handbook of Chem. Phys., Physical Electronics, 67th ed. (1986–1987) F-165.
K.S. Kim, N. Winograd and R.E. Davis, J. Am. Chem. Soc. 93 (1971) 629.
J. Escard, B. Pontvianne and J.P. Contour, J. Elect. Spectr. 6 (1975) 17.
J.C. Fuggle and N. Martensson, J. Elect. Spectr., Rel. Phen. 21 (1980) 275.
J.E. Benson, H.W. Kohn and M. Boudart, J. Catal. 5 (1966) 307.
F.P.J.M. Kerkhof and J.A. Moulijn, J. Phys. Chem. 83 (1979) 1612.
P.J. Angevine, J.C. Vartuli and W.N. Delgass,Proc. 6th Int. Congr. Cat., 1976, 2 (1977) 611.
S.C. Fung, J. Catal. 58 (1979) 454.
S.J. Tauster and S.C. Fung, J. Catal. 55 (1978) 29.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
M'Boungou, J.S., Hilaire, L., Maire, G. et al. Role of tungsten in supported Pt-W reforming catalysts Part II. Influence of the tungsten loading and metal-support interactions effect. Catal Lett 10, 401–411 (1991). https://doi.org/10.1007/BF00769175
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00769175