Article,
Influence of catalyst treatments on the adsorption properties of gamma-Al2O3 supported Pt, Rh and Ru catalysts
Microporous and Mesoporous Materials, 77 (2-3): 245-255 (2005)
Abstract
The influence of different treatments (reduction with hydrogen, oxidation
with air and treatment with inert gas) of alumina supported Pt, Rh
and Ru catalysts on the adsorption of different n-alkanes, cycloalkanes,
aromatics and chlorinated compounds was studied. The effect of these
treatments is twofold: change in the oxidation state of the active
metal, and the presence of adsorbed hydrogen or oxygen, which affects
the adsorption of the organic compounds. The first effect was characterized
by temperature-programmed reduction (TPR) and oxidation (TPO) of
catalyst samples, whereas the strength of the O2 and H2 adsorption
was determined by temperature-programmed desorption (TPD). Inverse
gas chromatography (IGC) was used to characterize the adsorption
of five n-alkanes (C6-C10) in the 200-230 degree signC temperature
range. Moreover, heats of adsorption, entropies of adsorption and
free energy of adsorption, are also reported. Interaction parameters
of polar molecules (benzene, chloroform, trichloroethylene, etc.)
with the stationary phase have also been determined and compared
with those for the n-alkanes. It was observed that catalyst treatment
affects the adsorption capacity, strength and nature of the studied
catalysts.
