酸刻蚀处理对IrO2-Ta2O5/Ti阳极寿命的影响

Effect of Acid Etching on Lifetime of IrO2-Ta2O5/Ti Anodes

摘要:

通过改变腐蚀方法，研究了使用H₂C₂O₄和H₂SO₄进行钛基体表面刻蚀对金属氧化物钛阳极电化学性能和表面形貌的影响。采用扫描电子显微镜、X射线衍射仪和光电子能谱等测试方法对样品进行了结构分析。然后利用电化学工作站测试了样品的电催化活性，利用加速寿命测试研究了样品的电化学稳定性。结果表明，通过H₂C₂O₄和H₂SO₄分步腐蚀可以获得更加均匀致密的表面形貌和更好的催化稳定性。在此基础上，进一步研究了预处理对钛阳极寿命的影响原因。IrO₂-Ta₂O₅/Ti阳极的催化活性和稳定性与酸刻蚀处理的先后顺序及表面结构密切相关，并建立了预处理方法与阳极性能之间的关系。分步腐蚀使钛表面具有合适的粗糙度，因而提升了涂层附着力。在热分解过程中，经分步腐蚀形成的氢化钛在不改变表面形貌的情况下转变为金红石结构的氧化钛，有利于电子输运，从而增强涂层附着力并延长加速寿命。

Abstract:

The effect of surface etching by H₂C₂O₄ and H₂SO₄ on Ti substrates on the electrochemical properties and surface morphologies of titanium oxide anode was investigated through different etching methods. The scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy were used to analyze the specimen structure. The electrocatalytic activity and the electrochemical stability of the specimens were also evaluated by the electrochemical workstation and accelerated lifetime tests, respectively. Results show that the dual acid etching can achieve denser and more homogeneous surface with better catalytic stability. In addition, the influence mechanism of pretreatment on the lifetime of Ti anodes was discussed. The catalytic activity and stability of IrO₂-Ta₂O₅/Ti anodes are strongly dependent on the sequence of acid etching and the surface structure of anodes, and thereby the relationship between the pretreatment methods and the anode performance is established. The dual acid etching can achieve a Ti surface with moderate roughness, therefore improving the coating adhesion. The titanium hydride formed through the dual acid-treatment is transformed into the rutile with barely changed surface morphology, which is conducive to the electrons transport. Therefore, the coating adhesion is enhanced and the accelerated lifetime is prolonged.