【作者】 赵岩；

【导师】 刘贵昌；

【作者基本信息】 大连理工大学 ， 化学工程， 2008， 硕士

【摘要】 电解海水防污技术是防止冷却水系统生物污损最安全、有效的办法。而金属氧化物阳极材料是该技术的关键,其电催化性和电化学稳定性是最终评价阳极性能的两个主要指标。在某些盐度较低,受锰离子污染的特殊海域,目前的阳极却存在着电催化活性和稳定性不足的问题。针对上述问题,本文应用热分解法,通过引入中间层和改变工艺条件考察对阳极性能的影响。采用析氯析氧电位、循环伏安曲线、极化曲线及加速寿命等测试方法考察阳极涂层的电化学性能,并通过扫描电镜（SEM）、电子探针（EPMA）和X射线衍射分析（XRD）等观察涂层表面形貌及进行物相分析,研制出一种适合电解海水,特别是淡海水应用的氧化物阳极。对改善电极稳定性的研究表明:IrCo中间层能提高表层与基体的结合力,不仅显著改善了电极的稳定性而且保持了良好的电催化活性。随中间层层数的增加,阻挡氧渗透的作用增强,延缓电极的失效。强化寿命值达到了RuTiSn电极的44倍。通过SEM、EPMA及交流阻抗测试分析得出两种电极的失效机理不同:Ti/RuTiSn电极的失效是由于活性物质的丧失和不导电的TiO₂膜的生成;Ti/IrCo/RuTiSn电极的失效则是主要是由于基体不导电的TiO₂的生成。通过考察制备工艺条件（溶剂种类、涂液浓度、涂刷次数及热氧化温度等）对催化性能的影响,结果表明异丙醇和正丁醇混合作为溶剂有利于提高电催化活性。随涂液浓度的增加,阳极表面的龟裂纹增加,伏安电量随之增加。涂液浓度为0.4mol/L时,电极呈现了较好的电催化活性。随着涂刷次数的增加,涂层呈现出阳极典型的龟裂纹形貌,涂刷次数不应少于14次。热氧化温度为420℃时涂液的氧化反应已完全,涂层表面形成固溶的金红石型稳定结构,电极电催化活性较好。通过失效阳极的分析知,在电解过程中MnO₂的沉积是导致阳极失效的重要原因。同时考察了电极在普通海水和淡海水中的电流效率,并进行了含锰离子的强化寿命实验。结果表明含中间层的RuTiSn电极在盐度较低时仍具有较高的电流效率,并呈现很好的抗Mn²⁺污染的能力。更多还原

【Abstract】 Electrolytic seawater anti-fouling is the best and most effective technique in preventing cooling water system from marine organisms fouling. The metal oxide anode is crucial element of the technology. The electrocatalytic activity and stability are primary aspects to evaluate the performance of anode. In some sea area, there is lower salinity than the natural sea water, and even is contaminated by Mn²⁺, so there are some defects such as low electrocatalytic activity and short service life in the application of anodes.Based on the above problems, the anodes are prepared by thermal decomposition. The effects of intermediate layer and preparation techics on the performance are discussed. The electrochemical properties of these anodes are studied by chlorine evolution potential and oxygen evolution potential, cyclic voltammetric curves（CV）, accelerated life tests and electrochemical impedance spectroscopy（EIS）. The anode microcosmic morphology, element composition are charactered by scanning electron microscopy（SEM）, electronic probe microanalysis（EPMA） and X-ray diffraction analysis（XRD）. An excellent anode are prepared for Electrolyzing seawater, especially for diluent seawater.The effect of intermediate layer on the electrochemical stability of RuTiSn anode is studied firstly. The results show that not only the stability of anode is improved observably, but also it holds high electrocatalytic activity as a result of intermediate layer between Ti substrate and coating. The intermediate layer can block oxygen diffusing to substrate effectively, so its’ accelerated life is extended greatly, which is 43 times higher than the anode without intermediate layer. The change of anode before and after degradation is detected by SEM, EPMA and EIS. The deactivation mechanisms are different between anodes without and with intermediate layer. The degradation of former is resulted from the coating flaked off and the insulating TiO₂ grown on Ti substrate, While the latter is mainly resulted from the insulating TiO₂ grown on Ti substrate.The effects on electro-catalytic activity of preparation technics are studied. The results show that the mixed solvent of isopropanol and n-butanol is beneficial to improve the electro-catalytic activity. The superficial cracks are increased and become wider and deeper as the solution concentration increased. As the concentration is 0.4mol/L, the anodic electro-catalytic activity is best. The anodic superficial cracks become more and more visible as the coating times increased. And the coating times should not less than 14 times. The anode prepared at the thermal decomposition temperature of 420℃has better electrocatalytic activity. Its crystal structure of electrode is rutile which is the most stable style.The manganese ion deposited on the anode surface in the form of MnO₂ induced the degradation of the anode dominantly. The current efficiency in natural and diluent seawater and the accelerated life test are measured. The results show that the RuTiSn anode with intermediate layer has higher current efficiency in lower salinity solution and superior property of preventing manganese depositing.更多还原