Characteristics of Cr2O3–CuO/MgF2 catalysts and a comparison with Cr2O3/MgF2 and CuO/MgF2 systems
Abstract
A characterization of binary preparations containing Cr2O3 and CuO supported on magnesium fluoride has been carried out. The IR study enabled characterization of complexes formed on the surface of the samples, namely, the [CrO6], [CrO4] structures and Cu2+ ions in the neighbourhood of oxygen or fluorine-containing ligands. Some of these species were also detected by EPR spectroscopy. The results proved that electron transfer from Cr3+ to Cu2+ takes place. Cr2O3–CuO/MgF2 preparations were also tested in model catalytic reactions such as: propan-2-ol decomposition, the dehydrogenation of cyclohexane, cumene cracking and hydrogenation of nitrobenzene. A distinct increase in the activity of the binary preparations over those of the Cr2O3/MgF2 and CuO/MgF2 systems was observed. In every case the rise in activity was attributed to the Cr–Cu interaction.