La1－xSrxNi1－yCoyO3双功能氧电极的电化学性能

采用溶胶-凝胶法制备了一系列La1－xSrxNi1－yCoyO3（x=0、0.1、0.2、0.5； y=0～1.0）型的钙钛矿催化剂，并以活性碳为载体制备双功能氧电极.对催化剂进行了XRD结构分析以及XPS表面分析.采用三电极体系测试了氧电极的稳态极化曲线和电化学交流阻抗谱并对其阴极极化和阳极极化谱图进行了分析.实验表明，对于LaNiO3化合物，B位掺杂可显著提高催化剂表面的B离子浓度, 从而提高电催化性能；而A位掺杂由于导致有序化氧空位的增多和电导的降低而造成活性下降.电极氧还原反应的极化主要由电荷转移反应和能斯特扩散过程造成.

Electrochemical Properties of La1-xSrxNi1-yCoyO3 Bifunctional Oxygen Electrodes

A series of novel La1-x SrxN1-yCoyO3( x = 0, 0. 1, 0. 2, 0. 5; y = 0 - 1. 0)perovskite oxides were prepared by sol-gel method and characterized by XRD and XPS. The activity of bifunctional oxygen electrodes made by the perovskite-type catalyst dispersed on active carbon were investigated using electrochemical impedance spectroscopy(EIS). The impedance spectra of both cathodic and anodic polarization were analyzed. The results show that the properties of electrodes are improved by doping Co3+ ions on B site because the concentration of B site ions on the catalysts surface are increased. But by doping Sr2 + ions on A site could impair the effect because the ordering level of oxygen vacancy and the electrode resistance are increased. The polarization resistance is mainly caused by the slow Nernstian diffusion and charge transfer reaction and not by concentration of adsorption of oxygen species and oxygen vacancy. So it is concluded that by increasing the concentration of B site ions on perovskite oxide surface and improving the thickness of electrolyte film the performance of oxygen electrodes could by improved.