摘要
利用固相反应法制备出固态质子导体SrCe0 .95Yb0 .0 5O3 -α,并使用X射线衍射分析法及低频阻抗测量法对其电子结构和导电特性进行了研究 .X射线分析结果表明 ,该物质为钙钛矿晶体结构 ,具有p型电子空穴和氧离子空穴 .在低温下主要为电子导电 ,且电子导电率随温度的升高而增大 .在含氢气环境中 ,当温度高于 5 5 0K时 ,SrCe0 .95Yb0 .0 5O3 -α具有明显的质子导电性 ,随着温度的升高 ,质子导电性增强 .当温度高于 80 0K时 ,质子是导体中的主要载流子 ,质子电导率可达 4 .5mS/cm .
The ytterbium doped perovskite-type strontium cerate(SrCe 0.95Yb 0.05O 3-α)has been prepared by solid-state reactions and it's structural and electrical characterization has been characterized using X-ray diffraction and AC impedance spectroscopy. X-ray power diffraction analysis shows that SrCe 0.95Yb 0.05O 3-α has a single phase of orthorhombic perovskite-type structure, and the results suggested that Yb 3+ substituted the position of Ce 4+ and forming oxygen vacancy. The electrical conductivity studies of SrCe 0.95Yb 0.05O 3-α have been made as a function of temperature. At temperature lower than 500 K, the ytterbium doped perovskite-type strontium cerate exhibits p-type conduction and the electric conduction is increased with increasing of temperature. However, at elevated temperatures and in hydrogen-containing atmospheres, it exhibits protonic conduction. At 800 K, the total conductivity is dominated by protonic conductivity, reaching a maximum value of 4.5 mS/cm. The proton migration mechanism could be proposed as 'free' migration mechanism model, in which the proton moves by jumping between stationary host oxygen ions. Membranes based on dense SrCe 0.95Yb 0.05O 3-α thin films can be expect to applied in fuel cells, chemical hydrogen pumps and hydrogen sensors.
