Res. Chem. Intermed.
, Vol. 34, Nos 5–7, pp. 565–576 (2008)
Koninklijke Brill NV, Leiden, 2008.
Also available online - www.brill.nl/rci
Dispersion and states of platinum ions in BEA-zeolite
pores: effect of the framework basicity
, J.-M. KRAFFT
Dipartimento di Chimica IFM & NIS Center of Excellence, Università degli Studi di Torino,
via P. Giuria 7, 10125 Torino, Italy
Laboratoire de Réactivité de Surface, UMR 7609 du CNRS, Université Pierre et Marie Curie,
4 place Jussieu, casier 178, 75252 Paris cedex 05, France
Received 22 December 2006; accepted 30 January 2007
Abstract—Pt/Cs-BEA materials prepared by a classical ion-exchange procedure using two Cs-BEA
supports with different Cs loadings, and a reference acidic Pt/H-BEA, have been studied to investigate
the effect of the framework basicity (evaluated by FT-IR of adsorbed CO
) on the state of platinum
species after the initial steps (introduction of Pt complex by ion-exchange and subsequent calcination)
of the preparation procedure. DR-UV data revealed that the framework basicity affects the structure of
complexes introduced as countercations in the zeolite by ion exchange. FT-IR spectra
of adsorbed CO indicated that zeolite basicity rules the fate of platinum species in the subsequent
calcination. Hence, in Pt/H-BEA essentially well dispersed Pt
(4 δ 1) are present, while PtO
particles progressively prevail as the basic character of the zeolite increases.
Keywords: BEA zeolite; basicity; platinum; DR-UV spectroscopy; FT-IR spectroscopy.
Zeolite-based materials represent interesting systems as heterogeneous catalysts
because of their well-deﬁned microporous structure characterized by the presence of
regular distribution of channels or cages, that can be exploited to prepare composite
systems by introducing in their pores one or more host phases, possibly interacting
each other, as in the case of zeolites functionalized with basic and metal phases .
Present address: Dipartimento di Scienze e Tecnologia Avanzate and Nano-SiSTeMI Interdiscipli-
nary Centre, Università del Piemonte Orientale “A. Avogadro”, via Bellini 25/G, 15100 Alessandria,
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