Catalytic properties of Ni/ceria-yttria electrode materials for partial oxidation of methane

The catalytic properties of electrode materials Ni/Ce1-xYxO2-d (x = 0.05, 0.10, 0.15 and 0.20) were investigated for partial oxidation of methane (POM). The CeO2-Y2O3 solid solutions were prepared by co-precipitaion method. The Ni-based catalysts supported on the solid solutions were obtained using the impregnation method. Structural, surface and redox characteristics of the prepared catalysts were systematically examined by means of X-ray diffraction (XRD), N2 adsorption-desorption (Brunauer-Emmet-Teller BET method), H2 temperature-programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS) methods. The results indicated that yttria doped in the ceria system, forming a good solid solution, readily induced more defects and oxygen vacancies that favored the improvement of catalytic activity and coking resistance. In the temperature range of 600–850 °C, Ni/Ce0.90Y0.10O1.950 catalyst exhibited the best catalytic activity among the four tested catalysts, with the CH4 conversion, CO selectivity and H2 selectivity of 78.8%, 90.6% and 89.8%, respectively, at 850 °C. And the H2/CO molar ratio in products of Ni/Ce0.90Y0.10O1.950 catalyst was closer to the theoretical value of 2.0. The excellent coking resistant behaviors for all catalysts were clearly manifested by thermal analysis.