海水电解用金属氧化物阳极的失活机理

The Deactivation Mechanism of Metal Oxide Anode Used in Seawater Electrolysis

摘要:

海水电解制氯用钛基金属氧化物阳极的等效电路可用LR5（QdlRct）（QfRf）来描述，上反映了阳极涂层复杂的微观结构，（QdlRct）对应电极／溶液体系的电化学特征，（QfRf）反映了涂层内表面／钛基体之间的物理阻抗。在阳极失效前后，Qdl和Rct没有发生突变，而Qf和Rf发生了突变，EIS谱图上发生明显的变化。SEM和EPMA分析表明，失活后表面还有一定的活性组分存在。阳极失活的主要原因是在钛基体和涂层之间形成了不导电的TiO2层，而阳极活性组分的电化学溶解和涂层的机械脱落不是阳极失活的主要原因，但对生成不导电TiO2有促进作用。

Abstract:

The equivalent circuit model of the metal oxide anodes used in seawater electrolysis can be described by LRs (QdlRct) (QfRf). The L shows the complex microstructure of the electrode. The (QdlRct) describes the electrochemical behavior of the electrode/solution. The (QfRf) the physical impedance of the Ti-support/active oxide coating. Qdl and Rct do not change sharply in de-active region, but Qf and Rf change abruptly in this region. There are still some active components existing in the surface of the anode. The main reason for the deactivation of the anode is the formation of TiO2 between Ti base and the active coating. The dissolution of the active components and the mechanical lose are not the main reasons for the deactivation of the anodes, but they accelerate the formation of TiO2.