Gold catalysts supported on cerium-gallium mixed oxide for the carbon monoxide oxidation and water gas shift reaction

Abstract

The synthesis, characterization and catalytic properties of gold supported on ceria, gallia and a cerium-gallium mixed oxide were investigated. The nanostructural characterization of the cerium-gallium support (nominal atomic composition Ce80Ga20) showed that gallium(III) cations are homogenously distributed into the ceria matrix by substituting cerium(IV) cations of the fluorite-type structure of ceria. Au was added to the supports by the deposition-precipitation method using urea. High Au dispersions were achieved for all the fresh materials (D > 60%). The CO oxidation and the water gas shift (WGS) reaction were tested on the whole set of catalysts. All the supported-gold catalysts showed high activity for the CO oxidation reaction. However, those containing gallium in their formulation deactivated due to gold particle sinterization. Au(2%)/CeO2 was the most active material for the WGS reaction, and the Au(2%)/Ce80Ga20 was as active as a Au(3%)/Ce68Zr32 catalyst for CO oxidation, and even more active than the reference catalyst of the World Gold Council, Au(2%)/TiO2.