Nanostructured gold catalysts supported on CeO2 and SiO2 were prepared by the deposition–precipitation (DP) and the solvated metal atomdispersion (SMAD) techniques. The structural and electronic properties of the catalysts were investigated by X-ray diffraction (XRD), X-rayabsorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). Gold was found as small metal nanoparticles (cluster size 2 nm) inthe SMAD-prepared samples and in ionic state in the DP catalysts. The catalytic activity of the samples was tested in the reaction of lowtemperature CO oxidation. Gold nanosized particles in a pure metallic state exhibited a worse catalytic performance, both on ceria and silica. Thepresence of non-metallic Au species seems to be the main requisite for the achievement of the highest CO conversion at the lowest temperature. Thehigher activity of the Au/CeO2 (DP) sample with respect to the Au/SiO2 (DP) catalyst can be ascribed to a better stabilization of the Au+1 ions,probably as AuO- species, by the cerium oxide.
|Numero di pagine||8|
|Rivista||Applied Catalysis A: General|
|Stato di pubblicazione||Published - 2006|
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