摘要
The catalytic properties of electrode materials Ni/Ce1-xYxO2-δ （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 system- atically 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 ℃, 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 ℃. 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.
The catalytic properties of electrode materials Ni/Ce1-xYxO2-δ （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 system- atically 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 ℃, 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 ℃. 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.
基金
supported by the National Basic Research Program of China (973 Program) (No. 2005CB221404)
