IrO_2-SiO_2涂层钛阳极的失效行为研究

为探讨氧化物涂层阳极的失效原因,采用热分解法在不同焙烧温度下制备了60%IrO2-40%SiO2/Ti氧化物阳极,利用扫描电子显微镜(SEM)、能谱分析(EDX)和循环伏安测试(CV)分析了阳极在硫酸溶液的强化电解过程前后表面形貌、涂层组成和电化学性能的变化。结果表明,IrO2-SiO2涂层钛阳极失效的主要原因是钛基体和涂层之间形成了不导电的TiO2层。在强化电解过程中,低焙烧温度制备的阳极活性组分的电化学溶解和涂层的机械脱落促进TiO2层的生长。高焙烧温度制备的阳极中已生成一定量的TiO2,在电解时加速电极的失效。600℃焙烧温度下制备的电极的强化寿命最高。

A Study on Deactivation Behavior of IrO2 -SiO2 Coated Titanium Anodes

The deactivation behavior of 60% IRO2-40% SiO2 coated titanium anodes prepared at different calcination temperature was studied during an accelerated life test （ALT） at 2 A.cm-2 in 1 mol·L^-1 H2SO, solution using cyclic vohammetry （CV）, scanning electron microscopy （SEM） and energy-disper- sive X-ray analysis （EDX）. The changes of electrochemical characteristics before and after ALT were monitored. The surface morphology and composition of the oxide anode were analyzed. The main reason for the deactivation of anode is the formation of TiO2 layer between Ti base and the active coating. During an ALT, the dissolution of the active components and the mechanical loss of the low temperature calcinat- ed anodes promote the formation of TiO2. However, some TiO2 have been generated during preparation of anodes at high calcination temperature, which accelerates the deactivation of the anodes. The IrO2-SiO2 coated titanium anodes prepared at 600~C have the longest accelerated lifetime.