Nature

Publication date: December 2014
Source:Journal of Catalysis, Volume 320
Author(s): Mira Skaf , Samer Aouad , Sara Hany , Renaud Cousin , Edmond Abi-Aad , Antoine Aboukaïs
Two silver–cerium oxide samples (Ag 10wt.%) were prepared by two different methods: impregnation and deposition–precipitation. The XRD, EPR, XPS, and TPR techniques were used for physicochemical characterization. Catalysts were tested in C3H6, CO, and carbon black oxidation reactions. The impregnated catalyst showed better performance compared to the one prepared by deposition–precipitation in the different reactions. The EPR technique allowed the identification of three different Ag²⁺ sites in the impregnated solid along with the distinction of the Ag²⁺ isotopes (¹⁰⁷Ag²⁺ and ¹⁰⁹Ag²⁺) ions. The impregnated catalyst reduced at lower temperatures compared to the one prepared by deposition–precipitation. The catalytic activity of the impregnated solid was attributed to the presence of Ag²⁺ species that enhance the redox potential of the solid by creating three different redox couples: Ag²⁺/Ag⁺, Ag²⁺/Ag⁰, and Ag⁺/Ag⁰.

Graphical abstract