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

Abstract

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.