Abstract
Structural investigations of dispersed Pd/SiO2 catalysts were carried out with XRD and SAXS techniques, supported by TPR and CO chemisorption measurements. The stoichiometry of Pd hydride, β-PdHx, was determined by measuring the shift of Pd 111 XRD reflection in the presence of hydrogen. It was confirmed thatx decreases when the metal dispersion increases. This behaviour could be quantified up to about 0.45 of Pd dispersion since the angular position of XRD peaks cannot be determined with the necessary precision at higher dispersions. TPR data, obtained up to dispersions of about 0.6, confirms such behaviour. The β-PdHx stoichiometry versus Pd dispersion relationship substantially agrees with that found with other techniques by Boudart and Hwang.
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W. Palczewska, in:Hydrogen Effects in Catalysis, eds. Z. Paál and P.G. Menon (Dekker, New York, 1988) p. 373.
G. Gubitosa, A. Berton, M. Camia and N. Pernicone, in:Preparation of Catalysts III, eds. G. Poncelet, P. Grange and P.A. Jacobs (Elsevier, Amsterdam, 1983) p. 431.
A.L. Bonivardi and M.A. Baltanas, J. Catal. 138 (1992) 500.
J.H. Sepulveda and N.S. Figoli, Appl. Surf. Sci. 68 (1993) 257.
M. Boudart and H.S. Hwang, J. Catal. 39 (1975) 44.
R.J. Davis, S.M. Landry, J.A. Horsley and M. Boudart, Phys. Rev. B 39 (1989) 10580.
A. Benedetti, G. Cocco, S. Enzo, F. Pinna and L. Schiffini, J. Chim. Phys. 78 (1981) 875.
B. Moraweck, C. Clugnet and A. Renouprez, J. Chim. Phys. 83 (1986) 265.
P. Nandi, R. Pitchai, S.S. Wong, J.B. Cohen, R.L. Burwell Jr. and J.B. Butt, J. Catal. 70 (1981) 298.
P. Nandi, P. Georgopoulos, J.B. Cohen, J.B. Butt and R.L. Burwell Jr., J. Catal. 77 (1982) 421.
G. Fagherazzi, A. Benedetti, A. Martorana, S. Giuliano, D. Duca and G. Deganello, Catal. Lett. 6 (1990) 263.
A. Guinier and G. Fournet, in:Small-Angle Scattering of X-rays (Wiley/Chapman and Hill, New York/London, 1955) p. 165.
J. Pielaszek, Catal. Lett. 1 (1988) 117.
P. Gallezot, in:Catalysis, Science and Technology, Vol. 5, eds. J.A. Anderson and M. Boudart (Springer, Berlin, 1984) ch. 4, p. 242.
S. Enzo, S. Polizzi and A. Benedetti, Z. Krist. 170 (1985) 275.
D.I. Svergun, A.V. Semenyuk and L. A. Feigin, Acta Cryst. A 44 (1988) 244.
C. Dall'Agnol, A. Gervasini, F. Morazzoni, F. Pinna, G. Strukul and L. Zanderighi, J. Catal. 96 (1985) 106.
G. Fagherazzi, A. Benedetti, G. Deganello, D. Duca, A. Martorana and G. Spoto, J. Catal. 150 (1994) 117.
J.R. Anderson,Structure of Metallic Catalysts (Academic Press, London, 1975) p. 296.
P. Adler and C.N.J. Wagner, J. Appl. Phys. 33 (1962) 3451.
C.S. Barret and T.B. Massalski,Structure of Metals, McGraw-Hill Series in Materials Science and Engineering (McGraw-Hill, New York, 1966) p. 372.
A. Benedetti, G. Fagherazzi, F. Pinna, G. Rampazzo, M. Selva and G. Strukul, Catal. Lett. 10 (1991) 215.
G. Lietz, M. Nimz, J. Völter, K. Lázár and L. Guczi, Appl. Catal. 45 (1988) 71.
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Fagherazzi, G., Benedetti, A., Polizzi, S. et al. Structural investigation on the stoichiometry of β-PdHx in Pd/SiO2 catalysts as a function of metal dispersion. Catal Lett 32, 293–303 (1995). https://doi.org/10.1007/BF00813223
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DOI: https://doi.org/10.1007/BF00813223