Numerous studies were aimed at the state and structure of
platinum in the Pt/?-Al 2 O 3 systems. Both metallic Pt 0 and oxide
PtO x species were detected by high-resolution transmission elec-
tron microscopy (HRTEM) and X-ray photoelectron spectroscopy
(XPS) [7,8]. X-ray absorption fine structure (XAFS) analysis revealed
that three types of the Pt/?-Al 2 O 3 catalysts with metal, oxide and
metal-oxide platinum species were formed depending on a prepa-
ration procedure [6,9]. Belyi et al. used chemical adsorption for
∗
Corresponding author at: Boreskov Institute of Catalysis, pr. Lavrentieva 5,
630090
Novosibirsk, Russia. Tel.: +7 383 3269597; fax: +7 383 3308056.
E-mail
address: verapakh@catalysis.ru (V.P. Pakharukova).
quantitative determination of
the metallic and ionic platinum
species in the Pt/?-Al 2 O 3 catalysts [10,11]. It was found that Pt
ions, unlike Pt 0 atoms, formed strong ?-donor bonds with water
[10]. Strong interaction with the support was suggested to cause a
high thermostability of the ionic platinum species