non-crystalline copper oxide highly dispersed on mesoporous alumina: synthesis, characterization and catalytic activity in glycerol conversion to acetol

Polymeric precursor method and wet impregnation route were applied to synthesize copper and aluminium-based catalysts in order to obtain a material with interesting properties in catalytic reactions. The changes in the structural, morphological and textural properties due to the choice of preparation method were characterized by different techniques, such as XRD, N2 physisorption isotherms and SEM. The XRD results of the solids present the formation of γ-Al2O3 or CuO and β-Al(OH)3, depending on the preparation method. The average crystallite diameters of the alumina were estimated by the Scherrer's formula with a particle size of 5.2 nm. N2 physisorption isotherms analysis shows that the alumina is a mesoporous material with a high specific surface area. An excessive increase in surface area was observed after Cu2+ insertion by wet impregnation from β-Al(OH)3 support, which is explained by the redissolution and recrystallization of bayerite to γ-Al2O3 during the impregnation of Cu2+ and recalcination process, respectively. The SEM images confirmed this phenomenon. Catalytic tests explain that the combination of the two methods improves the activity, selectivity and the stability in the conversion of glycerol to acetol. The results indicate that the way of catalyst preparation affects its structural, textural and morphological properties and consequently the catalytic performance