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Pd-Ho/γAl2O3 catalysts exhibit higher activity for styrene hydrogenation than Pd/γAl2O3 ones. The addition of holmium to Pd catalysts changes the place of the palladium impregnation front depending on the state of the supported palladium. As a consequence of the interaction between holmium and Pd/γAl2O3 support, oxidized forms as holmium aluminate were formed. These forms are catalytically inactive but represent adsorption centers for styrene. On holmium containing catalysts, hydrogenation takes place between the styrene adsorbed on basic centers and the hydrogen spilled over from palladium particles.

The embedding of a enantioselective homogeneous catalyst — the chiral manganese(III) cationic complex of salen type (Jacobsen complex I) — into the pores of mesoporous substituted silicates is investigated. The host/guest interaction is studied by different methods: TG-DTA, UV-VIS, and FTIR. The results are consistent with a location of the large Mn complex inside the mesopores. Catalytic tests in olefin epoxidation prove the fully maintenance of the catalytic activity and stereoselectivity of the complex after embedding. This promising result indicates that MCM-like materials might have perspectives as supports for the heterogenization of homogeneous catalysts.

The surface of alumina supported catalysts containing 10 wt.% metal (Fe and/or Ni) has been spectroscopically investigated by CO adsorption. The stretching vibration range characteristic for CO bonded to metallic species shows very large absorptions, indicating a high surface heterogeneity. A certain Fe∶Ni stoichiometry seems to impose the reduction extent and the catalytic properties.

CO conversion to hydrocarbons at various reaction temperatures and atmospheric pressure has been investigated on alumina-supported Fe, Ni and Fe−Ni catalysts. Maxima of activity and selectivity were obtained in hydrocarbon formation as a function of Fe content in the samples, which corresponds to a certain stoichiometry of metallic components.

Pd-Ln/γ-Al 2 O 3 (Ln-Sm, Gd, Dy, Ho, Tm) catalysts containing 0.1%Pd- 1%Ln, 0.3%Pd -1% Ln and respectively, 0.5% Pd -1% Ln (percentage in wt.%) were investigated. Introduction of Ln leads to an increase of the vinylbenzenes conversion comparatively with monometallic Pd/γ-Al 2 O 3 catalysts. The turnover frequency (TOF) calculus of the latter catalysts suggests that there are no difference among these. In the case of bicomponent Pd-Ln/γ-Al 2 O 3 catalysts, if one considers that the reaction occurs only on the palladium particles, then introduction of Ln seems to increase the TOF and vinylbenzenes hydrogenation seems to be, controlled by the mass transfer processes as indicated by the Koros-Nowak criterion. However, by taking Ln into consideration when calculate the TOF, it results that bicomponent catalysts behave like those monocomponent and the slope of the Koros-Novak dependence is included in a range typical for kinetically controlled reactions. This behavior could be associated to direct participation of Ln to reaction using hydrogen spilled over from the palladium particles.

The behavior of some supported Ni catalysts for methane synthesis from CO and steam in correlation with the specific metal-support interactions is discussed.

The species resulting in CO, CO+H2 or CO+D2O adsorption on supported Ni catalysts were followed by IR spectroscopy and their role in methane synthesis mechanism is discussed.

IR spectra of adsorbed CO species after prolonged contact with the catalyst surface show that surface carbon is formed and it participates in methane synthesis.