Preparation and characterization of Ce/Zr mixed oxides and their use as catalysts for the direct oxidation of dry CH4

In this work, preparation of compositionally homogeneous Ce/Zr oxides by a gel-combustion process and their characterization are reported. A detailed crystallographic study performed by synchrotron radiation X-ray diffraction has been carried out, in order to analyze the correlation between crystal structure and catalytic properties. The oxides presented specific area values, porous size distribution and carbon content values desirable for solid catalysts. Likewise, increasing the content of ZrO2 facilitates the reducibility of both surface and bulk sites in the solid. The oxides have been active in the combustion of methane. Their performances were stable during a typical work period of 8 h, with no evidence of formation of carbonaceous deposits. The experiments were carried out confirm the promising features of these oxides as anodic materials in solid oxide fuel cells.