Ni/CeO sub(2)-ZrO sub(2) catalysts for the dry reforming of methane

Nickel catalysts supported on binary CeO sub(2)-ZrO sub(2) carriers (28-100% CeO sub(2) molar content) were prepared and evaluated regarding their catalytic performance for the CO sub(2) reforming of CH sub(4) (Dry Reforming of Methane, DRM). The textural and structural properties of catalysts and supports were studied in their calcined, reduced and used state by N sub(2) adsorption-desorption, XRD, UV-vis DRS, TPR, SEM-EDS and TPH. Zirconium improves the textural properties of the CeO sub(2)-ZrO sub(2) supports and the corresponding catalysts and enhances their textural stability under thermal reductive treatment. XRD analysis shows the formation of Ce sub()xr sub(1-)x sub(2) solid solution for all Ce/(Ce + Zr) ratios. Considerable alterations in the electronic environment of the cations and increased lattice defects in the binary solid solutions were detected by UV-vis DR spectroscopy. A significant increase in the reducibility of both supports and catalysts is observed in the presence of Zr. Compared to the zirconia-free sample, the Ni/CeO sub(2)-ZrO sub(2) catalysts exhibited much higher activity for the title reaction, accredited to the increase of the surface concentration of the active sites. However, the amount of carbonaceous deposits is not straightforward related to the activity but depends on the Ce/Zr ratio. Among the zirconium containing catalysts, the zirconium-rich one exhibited the higher activity and the stronger resistance to the formation of carbonaceous deposits.