Physico-chemical and catalytic studies on the calcination products of BaCrO 4-CrO 3 mixture

Abstract

The phase composition, electrical behaviour, and the catalytic activity towards H 2O 2 decomposition were studied for the products of the solid state reaction of BaCrO 4-CrO 3 mixture (1:1 molar ratio) in the temperature range 300–1000 °C. Experimental evidence from acid-soluble chromate estimation and X-ray analysis revealed that the presence of the low melting point component CrO 3 enhances the chromite spinel formation. On the basis of these experimental data together with those obtained from electrical conductivity measurements, a mechanism of chromite formation was suggested. The decisive role of surface Cr 6+ ions in the catalytic decomposition reaction of H 2O 2 indicated the existence of these surface active centers in different energy states depending on the calcination temperature. This was also verified from the electrical conductivity measurements.