Catalytic behaviour of Ce-doped Ni systems supported on stabilized zirconia under dry reforming conditions

Ni supported on bare and modified ZrO₂ samples were synthesized using the incipient wet impregnation method. The t-ZrO₂ phase was stabilized by incorporation of La₂ O₃ into ZrO₂. Moreover, the influence of CeO₂-doping on the physico-chemical and catalytic properties under CO₂ reforming conditions was probed. The characterization data of the investigated catalysts were obtained by using XRD, CO₂ /H₂-TPD, BET, TPR, TPO, TGA, XPS and TEM characterization techniques. In the pristine Ni/Zr catalyst, the t-ZrO₂ phase transformed into the monoclinic phase. However, upon support modification by La₂ O₃, significant effects on the physicochemical properties were observed due to the monoclinic-to-tetragonal ZrO₂ phase transformation also affecting the catalytic activity. As a result, superior activity on the La₂ O₃ modified Ni/Zr catalyst was achieved, while no relevant change in the surface properties and activity of the catalysts was detected after doping by CeO₂. The peculiar behavior of the Ni/La-ZrO₂ sample was related to higher dispersion of the active phase, with a more pronounced stabilization of the t-ZrO₂ phase.