镨掺杂对无钴钙钛矿型氧化物BaFeO3-δ电导率和透氧性能的影响

Among the perovskite-type oxides with symmetrical structure applied in oxygen permeable membranes,cubic phase structure is the most favorable for oxygen permeation.In order to stabilize the cubic perovskite structure of BaFeO_3-δ material at room temperature,iron was partially substituted by praseodymium.BaFe_1-yPr_yO_3-δ powders were synthesized by a solid state reaction method,and sintered samples were prepared from the synthesized BaFe_1-yPr_yO_3-δ powders.X-ray diffraction results reveal that the BaFe_1-yPr_yO_3-δ samples remain cubic structure at praseodymium substitution amount of y=0.05,0.075,0.1.Scanning electron microscope observation indicates that the sintered samples contain only a small amount of enclosed pores and the grain size of BaFe_1-yPr_yO_3-δ increase monotonically with the increase of the praseodymium doping amount,praseodymium doping promotes the grain size growth.Tests of electrical conductivity and oxygen permeation flux show that praseodymium doping improves the conduction properties of BaFe_1-yPr_yO_3-δ and BaFe_0.9Pr_0.1O_3-δ composition has an electrical conductivity of 6.5 S/cm and an oxygen permeation of 1.112 mL/(cm²·min) at 900 ℃,respectively.High temperature XRD investigation shows that the crystal structure of BaFe_0.975Pr_0.025O_3-δ membrane completely transform to cubic phase at 700 ℃.The present test results have shown that partially substitution of Fe by praseodymium in BaFeO₃ can stabilize the cubic structure and improve the properties.  

氧化还原可逆Nb2TiO7复合阴极电解池高温水蒸气电解研究

系统地研究Nb₂TiO₇与Nb_1.33Ti_0.67O₄材料相互转变的氧化还原循环可逆性能，同时研究Nb2TiO7和Nb_1.33Ti_0.67O₄样品随温度和氧分压变化的电导率，并与复合电极对称电池和电解池的电化学性能相关联. 在830 oC下，对Nb_1.33Ti_0.67O₄复合电极电解池进行水蒸气的电解研究测试. 电流电压曲线和电解池短期性能测试表明在低电压下主要为电极的还原和活化过程；而在高电压下主要为水蒸气的电解. 当3%H₂O/Ar/4%H_{2气体通入阴极时电解池水蒸气电解的法拉第效率为98.9%；而当通入气体转换为3%H2O/Ar时效率为89%.}