Redox property of Ce1-xZrxO2 and its effect on CO2 reforming of CH4

The structure and redox properties of Ce1-xZrxO2 (0 <= x <= 1) were characterized by X-ray diffraction (XRD) and H-2 temperature-programmed reduction (H-2-TPR). The catalytic performance of the Ce1-xZrxO2 catalysts for CO2 reforming of CH4 was investigated at 700 similar to 850 degrees C. The results of XRD and TPR showed that the samples existed as a cubic Ce-Zr-O solid solution and their reducibility increased with increasing Zr content when x <= 0.25; while a tetragonal ZrO2 phase mixed with a cubic Ce-Zr-O solid solution was detected for samples with x > 0.25 and the overall reducibility of the mixed phases decreased with increasing Zr content. Thus, the sample with x = 0.25, Ce0.75Zr0.25O2, showed the highest reducibility. The catalytic performance of the Ce1-x ZrxO2, catalysts was closely related to their reducibility. The Ce0.75Zr0.25O2 catalyst with the highest reducibility also showed the highest catalytic activity and stability for the reforming of CH4 with CO2.