Abstract Investigations of the kinetics of the competing oxide growth vs. fluorine-induced corrosion of the oxide layer at the titanium anode/electrolyte interface of an anodization cell have been carried-out under dynamic biasing conditions. Periodical sawtooth voltage ramps with duration of 100 s and variable start values (0, 10, 20 and 30 V) and increasing slopes (0.3, 0.2, 0.1 and 0.0 V/s) were used to grow titania nanotubes, while monitoring the temporal variation of the anodization current. The electrolyte solution was a mixture of glycerol (C3H8O3) and ammonium fluoride (NH4F), 0.5% wt. The evolution of the interface processes during each dynamic-biasing experiment, as reflected in the j(t) characteristics were correlated with the nanotube layer morphology, crystallinity and chemical composition, as derived from SEM, XRD and XPS measurements. Cyclic voltammetry measurements, diffuse reflectance spectroscopy and tests of photocatalytic degradation of methylene blue aqueous solution were carried out to evaluate the photocatalytic activity of the samples. It was found that by gradually increasing the effective anodization voltage above a threshold of 22 V, degradation rates increase by a factor of 7.3. The results may serve both as an additional benchmark for understanding and controlling the chemical reactions at the anode-electrolyte interface, but also to design flexible set-ups for the fabrication of high-quality TNA-based devices for energy and environmental applications.

中文翻译：

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动态阳极氧化下TiO 2 纳米管阵列的生长和表征。光催化活性

摘要 在动态偏置条件下，对阳极氧化电池钛阳极/电解质界面处氧化层的竞争性氧化物生长与氟诱导腐蚀的动力学进行了研究。使用持续时间为 100 秒和可变起始值（0、10、20 和 30 V）和递增斜率（0.3、0.2、0.1 和 0.0 V/s）的周期性锯齿电压斜坡来生长二氧化钛纳米管，同时监测时间变化阳极氧化电流。电解质溶液是甘油 (C3H8O3) 和氟化铵 (NH4F) 的混合物，重量百分比为 0.5%。每个动态偏置实验期间界面过程的演变，如 j(t) 特性所反映的，与纳米管层形态、结晶度和化学成分相关，如从 SEM 得出的，XRD 和 XPS 测量。进行循环伏安法测量、漫反射光谱和亚甲基蓝水溶液光催化降解测试，以评估样品的光催化活性。发现通过将有效阳极氧化电压逐渐增加到 22 V 以上的阈值，降解率增加了 7.3 倍。结果既可以作为理解和控制阳极-电解质界面化学反应的额外基准，也可以为制造用于能源和环境应用的高质量基于 TNA 的设备设计灵活的设置。通过漫反射光谱和亚甲基蓝水溶液的光催化降解试验来评价样品的光催化活性。发现通过将有效阳极氧化电压逐渐增加到 22 V 以上的阈值，降解率增加了 7.3 倍。结果既可以作为理解和控制阳极-电解质界面化学反应的额外基准，也可以为制造用于能源和环境应用的高质量基于 TNA 的设备设计灵活的设置。通过漫反射光谱和亚甲基蓝水溶液的光催化降解试验来评价样品的光催化活性。发现通过将有效阳极氧化电压逐渐增加到 22 V 以上的阈值，降解率增加了 7.3 倍。结果既可以作为理解和控制阳极-电解质界面化学反应的额外基准，也可以为制造用于能源和环境应用的高质量基于 TNA 的设备设计灵活的设置。