New Nanosilver/Ceria Catalyst for Atmospheric Pollution Treatment

Mesoporous CeO 2 was synthesized by the nanocasting pathway using the mesoporous SBA-15 silica as structure template and cerium nitrate as the CeO 2 precursor via a solid–liquid route. Ag / CeO 2 catalysts were prepared by three different methods: wetness impregnation (WI), deposition–precipitation with urea (DPU) and impregnation–reduction with citrate (IRC), with a loading of silver of 4 wt.%. They were characterized by elemental analysis, H 2 -TPR, X-ray powder diffraction (XRD), Brunauer, Emmett and Teller (BET) surface area, diffuse reflectance and ultraviolet visible spectroscopy (DR/UV-Vis). Ag / CeO 2 catalysts retain the physical properties of mesoporous ceria and its hexagonal order. Catalytic oxidation of propylene and catalytic reduction of NO with propylene as a reducing agent were investigated on Ag /mesoporous ceria catalysts. The silver/mesoporous ceria system toward the deep oxidation of propylene and the catalytic reduction of NO depends on the catalyst preparation method. Ag / CeO 2 (IRC) can be ascribed to higher surface lattice oxygen mobility over this catalyst and also to the strong interaction between silver and mesoporous ceria.