The effect of different types of additives on the catalytic activity of Au/Al2O3 in propene total oxidation: transition metal oxides and ceria

The total oxidation of C3H6 was investigated over Au/Al2O3, and multicomponent Au/MOx/Al2O3 (M: Ce, Mn, Co, Fe) catalysts prepared by deposition-precipitation with urea. The catalysts have been characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), total surface area (BET), and diffuse reflectance ultraviolet-visible spectroscopy DR/UV-Vis. Based on this characterization, it was concluded that gold is present as Au-0. The most active catalyst is Au/CeOx/Al2O3. Ceria and the transition metal oxides act as cocatalysts. It can supply oxygen via a Mars and van Krevelen mechanism. (C) 2004 Elsevier Inc. All rights reserved.