物理化学学报 >> 2002, Vol. 18 >> Issue (01): 14-20.doi: 10.3866/PKU.WHXB20020104

研究论文 上一篇    下一篇

Ti基IrO2+Ta2O5阳极在H2SO4溶液中的电解时效行为

胡吉明;孟惠民;张鉴清;曹楚南   

  1. 浙江大学理学院化学系,杭州 310027;北京科技大学材料学院腐蚀与防护中心,北京 100083;中国科学院金属研究所,金属腐蚀与防护国家重点实验室,沈阳 110016
  • 收稿日期:2001-06-29 修回日期:2001-08-27 发布日期:2002-01-15
  • 通讯作者: 曹楚南 E-mail:cncao@sun.zju.edu.cn

Aging Performances of Ti Based IrO2+Ta2O5 Anodes in Sulfuric Acid During Electrolysis

Hu Ji-Ming;Meng Hui-Min;Zhang Jian-Qing;Cao Chu-Nan   

  1. Department of Chemistry,Zhejiang University,Hangzhou 310027;Corrosion and Protection Center,University of Science and Technology Beijing,Beijing 100083;State Key Laboratory For Corrosion and Protection,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016
  • Received:2001-06-29 Revised:2001-08-27 Published:2002-01-15
  • Contact: Cao Chu-Nan E-mail:cncao@sun.zju.edu.cn

摘要: 研究了450 ℃制备所得Ti/70%IrO230%Ta2O5(摩尔分数)高寿命阳极在H2SO4溶液电解过程中电极的物理、化学及电化学性能的时效行为.结果发现,整个电解过程可分为“活化”、“稳定”及“失效”三个阶段.在“活化”及“稳定”区内主要发生电极表面活性氧化物的溶解,涂层中IrO2金红石相的(110)、(101)晶面择优取向随电解时间延长而减弱,而(002)晶面择优增强.但是在“失效区”内,各晶面的择优程度却不随电解时间的变化而变化,这表明在“失效区”内氧化物的损失机制发生了变化.电化学阻抗谱测试表明,电极的析氧电化学反应电阻随电解时间的延长发生缓慢而连续的上升,而整个电极的物理阻抗在“失效区”内却发生突升现象.X射线衍射分析(XRD)表明,随电解时间的延长TiO2金红石相的衍射强度增大,达“失效区”时衍射强度发生突升.根据实验现象特别是“失效区”内阳极的时效行为提出高寿命Ti基氧化物涂层阳极的失效机制.

关键词: 失效机理, 钛阳极, 二氧化铱, 五氧化二钽

Abstract: Physicochemical and electrochemical performances of long service life Ti/70%IrO230%Ta2O5 (mole fraction) anodes prepared at 450 ℃ have been investigated over the whole electrolysis time in H2SO4 solution .The results showed that the whole electrolysis process of this anode could be divided into three stages consisting of ‘active',‘stable' and ‘deactive' ones.In the first two stages,the dissolution of coated oxides was dominated (with preferential loss of IrO2 component).It was found that,in these two stages,the preferential orientations of (110) and (101) planes in IrO2 rutile decreased with the electrolysis time,and that of (002) plane increased,while the preferential orientations remained to be stabilized in the ‘deactive' region.This indicated that the loss mechanism of the catalyst coatings was changed.Electrochemical impedance spectroscopy (EIS) measurements showed a slight increase in oxygen evolution reaction resistance of the oxide catalysts while a sharp rise in totally physical impedance of the whole anode in the ‘deactive' region.Xray diffraction analysis (XRD) showed that the intensity of TiO2 rutile reflections increased with the electrolysis time,with a sharp increasing in ‘deactive' region.According to the experimental results the degradation mechanism for long service life Ti based coating anodes has been proposed.

Key words: Degradation mechanism, Titanium anodes, IrO2, Ta2O5