Abstract:

As an excellent semiconductor material, the TiO₂ is widely used in the areas of photocatalysis, solar cells, and biomedical devices. Various technologies have been established to prepare TiO₂ nanotube array. These technologies mainly include numerous hydrothermal methods, template method, sol-gel method, and anodic oxidation method. Among them, the anodic oxidation method attracts much attention because of its highly ordered, uniform distribution and variable structure control. At present, the modified preparation of TiO₂ nanotube array is still studied by researchers. However, basic study on the kinetic mechanism of the growth process of nanotube array is rare. Herein, we proposed the diffusion-reaction coupled strengthening mechanism based on the electrosynthesis of titanium dioxide nanotube array. Furthermore, the evolution of TiO₂ nanotube array with electrolysis time was investigated, and the nonlinear dynamic mechanism of TiO₂ nanotube array structure growth process was discussed in combination with SEM and electrochemical impedance analysis. It was found that the formation of TiO₂ nanotube array was a self-organization behavior in the diffusion-reaction coupling process of oligomer hydroxyl titanium intermediates. Moreover, the reaction kinetics mechanism was established by analyzing the electrochemical growth mechanism, and its linear stability was analyzed. Besides, the parameter threshold space formed by the ordered structure in TiO₂ nanotube array and the accompanying electrochemical oscillation were explained, and its evolution process was also discussed. After optimization, TiO₂ nanotube array with ordered structure was prepared. It revealed the internal mechanism of diffusion-reaction coupling in the electrosynthesis of TiO₂ nanotube array. In addition, the nonlinear dynamic mechanism proposed in this paper exists widely in the electrodissolution process of various metals, which has a significant influence on the structure formation of products and the power consumption of reaction process. This also provides a theoretical basis for strengthening the batch electrosynthesis process of new nanomaterials.

Key words: titanium dioxide nanotube array, nanostructure, nonlinear kinetics, chemical reaction, electrochemical oscillation, linear stability analysis

摘要：

研究针对TiO₂纳米管材料批量电合成过程的结构有序性耗失问题，考察了TiO₂纳米管阵列生长过程中的非线性动力学机制，及其随电解时间等的演变机制。结合扫描电镜（SEM）及电化学分析表明，TiO₂纳米管阵列形成是低聚羟基钛中间体扩散-反应耦合过程中的自组织行为。研究建立了电合成体系的反应-扩散动力学方程组，并对其进行了线性稳定性分析，阐释了TiO₂纳米管阵列有序结构形成，乃至出现周期性电化学振荡的参数阈值空间，在此基础上提出了TiO₂纳米管阵列电合成过程的扩散-反应耦合强化机制。研究提出的非线性动力学机制广泛存在于各种金属的电溶过程中，并对产物结构及过程电耗有深刻影响。这也为新型纳米材料的批量电合成过程强化提供了理论依据。

关键词: TiO₂纳米管阵列, 纳米结构, 非线性动力学, 化学反应, 电化学振荡, 线性稳定性分析