Heterogeneous nanocatalysts containing
metal nanoparticles (Me
= Ir, Rh, and Ru) deposited on mesoporous saponite (magnesium aluminosilicate)
were prepared from metal chlorides by the incipient wetness impregnation
method and tested in the ring-opening reaction at high pressures using
decalin as a substrate. The elemental composition of the catalysts
and the carrier, the surface area, pore size and pore volume, the
charge state, the size of metal nanoparticles, and the acidity were
characterized by the following methods: scanning electron microscopy
with energy-dispersive X-ray analysis, nitrogen adsorption–desorption
analysis, Fourier-transform infrared spectroscopy, diffuse-reflectance
Fourier-transform infrared spectroscopy, transmission electron microscopy,
CO chemisorption, X-ray photoelectron spectroscopy, and X-ray diffraction
analysis. It was shown that the structure of the carrier and the mesopore
system were preserved after metal deposition. Metal particles have
an extremely small size and high dispersion. The carrier has a small
number of Brønsted acid
sites (BAS), which decreases when the metal is supported. The highest
BAS/LAS (Lewis acid sites) ratio is determined for the Rh/saponite
catalyst. It was found that the activity, selectivity, and product
composition were mostly affected by the metal nature. The Ir/saponite
catalyst provides a selectivity of about 90% for the ring-opening
products, both full and partial ring opening, at the total decalin
conversion of about 80%. Over the Rh/saponite catalyst, up to 30%
of the bicyclic products of the skeletal isomerization of decalin
are formed along with the ring-opening products (mainly partial).
The formation of a large number of C1–C9 hydrocracking products is observed over the Ru/saponite catalyst,
besides the ring-opening products. Changes in the activity and selectivity
of the catalysts with the variation of the main reaction parameters
(T, P, WHSV, H2/C10 M ratio, and decalin partial
pressure) were also determined.