Critical Influence of Nanofaceting on the Preparation and Performance of Supported Gold Catalysts
Résumé
A partial transformation of the (100) surfaces of ceria nanocubes into a set of nanometer-heighted, (111)-ounded, peaks was achieved by an oxidation treatment at 600 degrees C. This particular type of surface nanostructuration allows the preparation of CeO2 nanoparticles in which (111) nanofacets contribute significantly to their surface crystallography. This transformation of the surface structure plays a key influence on the behavior of ceria as a support of gold catalysts. Thus, the appearance of well-developed (111)-nanofacets leads to a much higher efficiency in the usage of this noble metal in the synthesis of catalysts when prepared by the deposition precipitation method. Moreover, gold catalysts supported on the surface-reconstructed oxide present an intrinsic (per gold surface atom) CO oxidation activity much higher than that of catalysts prepared on the nontreated oxide.