In order to develop novel cathode materials with high performance for intermediate temperature SOFC（IT-SOFC）,Ca and Mn doped rare earth oxides La1-xCaxFe0.9Mn0.1O3-δ（x=0.1,0.3 and 0.5,denoted as LCFM9191,LCFM7391 ...In order to develop novel cathode materials with high performance for intermediate temperature SOFC（IT-SOFC）,Ca and Mn doped rare earth oxides La1-xCaxFe0.9Mn0.1O3-δ（x=0.1,0.3 and 0.5,denoted as LCFM9191,LCFM7391 and LCFM5591） were synthesized by solid state reaction（SSR） method.The formation process,phase structure and microstructure of the synthesized samples were characterized using thermogravimetry/differential scanning calorimetry（TG/DSC）,X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The thermal expansion coefficients（TEC） of the samples were analyzed at 100-900 oC by thermal dilatometry.The electrical conductivities of the samples were measured with direct current（DC） four-terminal method from 300 to 850 oC.The results indicated that the samples（x=0.1 and 0.3） exhibited a single phase with orthorhombic and cubic perovskite structure,respectively after being sintered at 1200 oC for 3 h.The electrical conductivity of the samples increased with temperature up to a maximum value,and then decreased.The small polaron hopping was regarded as the conducting mechanism for synthesized samples at T≤600 oC.The negative temperature dependence occurring at higher temperature was due to the creation of oxygen vacancies for charge balance.LCFM7391 had higher mixed conductivity（100 S/cm） at intermediate temperature and could meet the demand of cathode material for IT-SOFC.In addition,the average TECs of LCFM9191 and LCFM7391 were 11.9×10-6 and 13.1×10-6 K-1,respectively,which had good thermal match to the common electrolytes.展开更多
Mixed-conducting oxygen permeable membranes represent a class of novel ceramic membranes, which exhibit mixed oxygen ionic and electronic conductivities. At high temperatures, oxygen can permeate through the membrane ...Mixed-conducting oxygen permeable membranes represent a class of novel ceramic membranes, which exhibit mixed oxygen ionic and electronic conductivities. At high temperatures, oxygen can permeate through the membrane from the high to low oxygen pressure side under an oxygen concentration gradient. Theoretically, the permselectivity of oxygen is 100%. Recently, anovel mixed-conducting membrane-Ba0.5Sr0.5Coo.8Feo.2O3-δ has been developed, which showsextremely high oxygen permeability and promising stability. Furthermore, the reactor made with such membranes was successfully applied to the partial oxidation of methane to syngas reaction using air as the oxygen source, which realized the coupling of the separation of oxygen from air and the partial oxidation of membrane reaction in one process. At 850℃, methane conversion 】 88%, CO selectivity 】97% and oxygen permeation rate of about 7.8 mL/(cm2 ·min) were obtained.展开更多
A dense Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane tube was prepared by the extruding method. Furthermore, a membrane reactor with this tubular membrane was successfully applied to partial oxidation of methane (POM) reaction,...A dense Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane tube was prepared by the extruding method. Furthermore, a membrane reactor with this tubular membrane was successfully applied to partial oxidation of methane (POM) reaction, in which the separation of oxygen from air and the partial oxidation of methane are integrated in one process. At 875°C, 94% of methane conversion, 98% of CO selectivity, 95% of H2 selectivity, and as high as 8.8 mL/(min·cm2) of oxygen flux were obtained. In POM reaction condition, the membrane tube shows a very good stability.展开更多
Hydrogen amplification from simulated hot coke oven gas （HCOG） was investigated in a BaCo0.7Fe0.2Nb0.1O3-δ （BCFNO） membrane reactor combined with a Ru-Ni/Mg（Al）O catalyst by the partial oxidation of hydrocarbon...Hydrogen amplification from simulated hot coke oven gas （HCOG） was investigated in a BaCo0.7Fe0.2Nb0.1O3-δ （BCFNO） membrane reactor combined with a Ru-Ni/Mg（Al）O catalyst by the partial oxidation of hydrocarbon compounds under atmospheric pressure. Under optimized reaction conditions, the dense oxygen permeable membrane had an oxygen permeation flux around 13.3 ml/（cm^2·min）. By reforming of the toluene and methane, the amount of H2 in the reaction effluent gas was about 2 times more than that of original H2 in simulated HCOG. The Rn-Ni/Mg（Al）O catalyst used in the membrane reactor possessed good catalytic activity and resistance to coking. After the activity test, a small amount of whisker carbon was observed on the used catalyst, and most of them could be removed in the hydrogen-rich atmosphere, implying that the carbon deposition formed on the catalyst might be a reversible process.展开更多
基金Project supported by the National Natural Science Foundation of China (10704054)
文摘In order to develop novel cathode materials with high performance for intermediate temperature SOFC（IT-SOFC）,Ca and Mn doped rare earth oxides La1-xCaxFe0.9Mn0.1O3-δ（x=0.1,0.3 and 0.5,denoted as LCFM9191,LCFM7391 and LCFM5591） were synthesized by solid state reaction（SSR） method.The formation process,phase structure and microstructure of the synthesized samples were characterized using thermogravimetry/differential scanning calorimetry（TG/DSC）,X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The thermal expansion coefficients（TEC） of the samples were analyzed at 100-900 oC by thermal dilatometry.The electrical conductivities of the samples were measured with direct current（DC） four-terminal method from 300 to 850 oC.The results indicated that the samples（x=0.1 and 0.3） exhibited a single phase with orthorhombic and cubic perovskite structure,respectively after being sintered at 1200 oC for 3 h.The electrical conductivity of the samples increased with temperature up to a maximum value,and then decreased.The small polaron hopping was regarded as the conducting mechanism for synthesized samples at T≤600 oC.The negative temperature dependence occurring at higher temperature was due to the creation of oxygen vacancies for charge balance.LCFM7391 had higher mixed conductivity（100 S/cm） at intermediate temperature and could meet the demand of cathode material for IT-SOFC.In addition,the average TECs of LCFM9191 and LCFM7391 were 11.9×10-6 and 13.1×10-6 K-1,respectively,which had good thermal match to the common electrolytes.
文摘Mixed-conducting oxygen permeable membranes represent a class of novel ceramic membranes, which exhibit mixed oxygen ionic and electronic conductivities. At high temperatures, oxygen can permeate through the membrane from the high to low oxygen pressure side under an oxygen concentration gradient. Theoretically, the permselectivity of oxygen is 100%. Recently, anovel mixed-conducting membrane-Ba0.5Sr0.5Coo.8Feo.2O3-δ has been developed, which showsextremely high oxygen permeability and promising stability. Furthermore, the reactor made with such membranes was successfully applied to the partial oxidation of methane to syngas reaction using air as the oxygen source, which realized the coupling of the separation of oxygen from air and the partial oxidation of membrane reaction in one process. At 850℃, methane conversion 】 88%, CO selectivity 】97% and oxygen permeation rate of about 7.8 mL/(cm2 ·min) were obtained.
基金This work was supported by the National High Technology Research and Development Program (Grant No. 715-006-0122)the "973" Project of the Ministry of Science and Technology, China (Grant No. G1999022401).
文摘A dense Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane tube was prepared by the extruding method. Furthermore, a membrane reactor with this tubular membrane was successfully applied to partial oxidation of methane (POM) reaction, in which the separation of oxygen from air and the partial oxidation of methane are integrated in one process. At 875°C, 94% of methane conversion, 98% of CO selectivity, 95% of H2 selectivity, and as high as 8.8 mL/(min·cm2) of oxygen flux were obtained. In POM reaction condition, the membrane tube shows a very good stability.
基金supported by the National High Technology Research and Development Program of China (Grant No. 2006AA11A189)Science and Technology Commission of Shanghai Municipality (Grant Nos. 0952NM01400 and 07DZ12036)
文摘Hydrogen amplification from simulated hot coke oven gas （HCOG） was investigated in a BaCo0.7Fe0.2Nb0.1O3-δ （BCFNO） membrane reactor combined with a Ru-Ni/Mg（Al）O catalyst by the partial oxidation of hydrocarbon compounds under atmospheric pressure. Under optimized reaction conditions, the dense oxygen permeable membrane had an oxygen permeation flux around 13.3 ml/（cm^2·min）. By reforming of the toluene and methane, the amount of H2 in the reaction effluent gas was about 2 times more than that of original H2 in simulated HCOG. The Rn-Ni/Mg（Al）O catalyst used in the membrane reactor possessed good catalytic activity and resistance to coking. After the activity test, a small amount of whisker carbon was observed on the used catalyst, and most of them could be removed in the hydrogen-rich atmosphere, implying that the carbon deposition formed on the catalyst might be a reversible process.
