钴掺杂Sr_4Fe_6O_(13)混合导体氧化物结构及透氧测定

用湿化学法合成了Ｓｒ４ＣｏｘＦｅ６－ｘＯ１３±δ系列混合导体氧化物，对其相结构与透氧性能进行了研究．钴离子的引入导致材料中钙钛矿型杂相的出现，Ｘ＝２．０时材料中还产生了ＣｏＯ杂相，ｘ＝２．６时材料呈现钙钛矿型结构．Ｓｒ４Ｆｅ４Ｃｏ２Ｏ１３±δ的相结构还与焙烧温度及环境气氛中的氧浓度密切相关．随着氧浓度的降低，材料从纯相Ｓｒ４Ｆｅ６Ｏ１３结构（纯氧气气氛下）转变为Ｓｒ４Ｆｅ６Ｏ１３结构、钙钛矿型结构和ＣｏＯ共存（空气气氛下），直至转变为针镍矿结构、 Ｓｒ４Ｆｅ６Ｏ１３结构和 ＣｏＯ共存． Ｓｒ４Ｆｅ６Ｃｏ１３±δ导体膜在ａｉｒ／Ｈｅ氧浓差梯度下的透氧量为 １．５×１０８ｍｏｌ／ｃｍ２·ｓ（８５０℃），在６５０～８５０℃范围内透氧活化能为７０ｋＪ／ｍｏｌ．

Crystal Structure and Oxygen Permeation Study of Cobalt Doped Sr_4Fe_6O_(13) Mixed-Conducting Oxides

Mixed-conducting Sr4CoxFe6-xO13±δoxides were synthesized by pyrolysis of cellulose-citric-metal salt compound.Their crystal structures were investigated,and oxygen permeability of Sr4Co2Fe4O13±δ was also studied by a GC method.The introduction of cobalt in Sr4Fe6O13 led to the occurrence of perovskite phase in the Sr4Fe6O13 bulk even at low doping content of cobalt (x=0.5),some minor CoO phase was also observed when x=2.0,and the material mainly demonstrated perovskite structure when x=2.6.The phase structure of Sr4CoxFe6-xO13±δwas found to be closely related with the calcined temperature and the oxygen concentration in the ambient atmosphere during calcination or retreatment at high temperature.The air-synthesized sample had the intergrowth phase SrFe6-xCOXO13±δ and the perovskite phase Sr(Fe,Co)O3-δ coexisted along with CoO impurity.The N2-annealed sample coexisted of Sr4Fe6O13 phase,brownmillerite phase and minor CoO impuirty.When Sr4Co2Fe4O13±δwas treated in pure oxygen environ-ment,the sample changed to single phase (Sr4Fe6O13 type phase).The oxygen permeability of Sr4Co2Fe4O13±δ membrane had a value close to 1.5×10-8mol/cm2.s at 1123K.From 923K to 1223K,the activation energy for oxygen transportation was about 70kJ/mol.