Spectroscopy analysis of the active component of chromia-alumina dehydrogenation catalysts

Abstract

The active component of chromia-alumina dehydrogenation catalysts has been studied by Raman and photoluminescence spectroscopy. The stress state at the Al₂O₃–Cr₂O₃ interface has been determined by photoluminescence spectroscopy. A model of the spatial distribution of the stresses in Cr₂O₃ crystals of the catalysts was developed on the basis of the Raman spectroscopy data. Two parameters characterizing this distribution have been determined: P_M and α – maximum stress and the rate of the stress drop in Cr₂O₃ crystals, respectively. It was shown that decrease in the stress at the surface of the Cr₂O₃ crystals from 0.9 to 0.5 GPa is accompanied by decreasing of the catalytic activity in the dehydrogenation process – the conversion of n-butane to unsaturated derivatives decreases from 27.4% to 23.0%.