Conversion of bioethanol over oxide catalysts

Abstract

The conversion of bioethanol over supported oxide catalysts (CuO, ZnO, Cr2O3,CeO2) was studied, among which the most active in the production of hydrogenis 3% CuO / γ-Al2O3. Modification of 3% CuO / γ-Al2O3 catalyst with Cr2O3, ZnOand CeO2 promotes the growth of hydrogen yield. The highest concentrationof hydrogen at 300° C and a space velocity of 1 h-1 on CuO-ZnO / γ-Al2O3 was48% by volume. The acidity of catalysts for adsorption-desorption of pyridine byinfrared spectroscopy (ITI Matson FTIR) was determined. When the content ofCuO in the catalyst is increased from 1 to 3%, the amount of Lewis acidic centers(LAS) increases from 58 to 82 µmol/ gcat. Modification with chromium oxide ofthe copper catalyst increases the number of LAS from 82 to 156 µmol/ gcat byadsorption of pyridine at 150° C and from 79 to 120 µmol/ gcat with pyridineadsorption at 250° C. It has been established that an increase in the number ofLewis acid sites has a positive effect on the yield of hydrogen in the conversion ofbioethanol. According to electron microscopy, the modification of catalysts leadsto an increase in the dispersity of the catalyst and to a uniform distribution ofparticles on the surface of the catalyst, which also contributes to its greater activityin the production of hydrogen.