Pd/(Ce x Zr (1-x) O 2)/MCM-41 catalysts containing variable loadings of Ce and Zr with fixed molar ratio Ce/Zr=1/2 are prepared by impregnation. Synthesized MCM-41, Pd(acac) 2 , Ce(NO 3) 3 .6H 2 O and Zr(acac) 4 are used as chemicals. The effect of Ce and Zr contents on the textural, structural and catalytic properties of the prepared catalyst is studied. N 2physisorption, H 2-chimisorption, XRD, TEM-EDX and TPR are the main techniques used to characterize these catalysts. The obtained results show that Ce and Zr addition impacts differently the surface area, porosity and particle sizes of the Pd/(Ce x Zr (1-x) O 2)/MCM-41 catalysts, depending on the variable amount of Ce and Zr. A huge enhancement in the methane combustion activity is obtained.

Aerogel Pd/(Ce 0.33 Zr 0.66 O 2 )SiO 2 catalysts (CeZry) were prepared with variable Ce and Zr loadings (molar ratio Ce/Zr = 1/2) by combining sol-gel and impregnation methods. First, N 2 -physisorption was used to investigate the texture evolution. Then, H 2 -chimisorption and TEM were performed to study the effect on particle dispersion. After, TPR was used to determine the catalyst reducibility. Furthermore, XPS characterization was done to identify the palladium oxidation state and to evaluate the Pd-support interaction. Finally, the prepared catalysts were tested in methane combustion to assess their catalytic activity. The obtained results showed that, when the Zr and Ce loadings are varied between 0% and 8% and between 0% and 6% respectively, the BET surface area was increased from 615 to 744 m 2 /g, the porosity diameter from 45.7 to 83.6 Å, the Pd particle diameter from 5.2 to 7.0 nm, the CeO 2 and ZrO 2 particle size from 0 to 68 nm, the reduction temperature shift reached 16˚C, the Pd binding energy shift attained 0.6 eV, but an optimum amounts of Zr (4 wt.%) and Ce (3 wt.%) are needed to maximize the PdO reducibility and to enhance the catalytic activity. In effect, 100% conversion of methane was reached at around 415˚C on the CeZr4 catalyst.