【作者】 管东升；

【导师】 方海涛；

【作者基本信息】 哈尔滨工业大学 ， 材料物理与化学， 2008， 硕士

【摘要】 近年来,TiO₂纳米管阵列的制备与应用得到了广泛的研究。阳极氧化法制备TiO₂纳米管阵列具有工艺简单、成本低廉、易于放大等优点,引起人们的极大关注。为了获得TiO₂纳米管阵列的最佳性能,一方面需要有效地控制纳米管管径、管长、管壁厚度、管壁形貌、表面形貌质量等;另一方面就是对TiO₂纳米管阵列进行掺杂改性。本文采用阳极氧化法分别在水溶液和丙三醇溶液中制备了掺杂与未掺杂的TiO₂纳米管阵列,并研究了纳米管的形貌可控性、掺杂元素对纳米管形貌和热稳定性的影响,以及掺杂元素对TiO₂晶粒生长和相变的影响。首先,研究了氧化电压和水分含量对TiO₂纳米管管径、管长、表面形貌的影响。发现采用高的氧化电压可以制备出大管径的TiO₂纳米管,并且纳米管的管径随着氧化电压的升高而线性地增大。当丙三醇溶液中的水分含量从零开始升高时,TiO₂纳米管的管径随之增大,但是管长先减小后增大,表面形貌质量先上升后下降。此外,讨论了节状管壁的产生机理,认为水分是产生节状纳米管的必备条件。其次,通过氧化钛锆合金的方法制备出锆掺杂的TiO₂纳米管,发现锆掺杂可以增加TiO₂纳米管的长度。在480°C至680°C的高温热处理过程中,锆元素能够阻碍锐钛矿相TiO₂晶粒的生长以及向金红石相的转变,并且ATNTA中锆含量越多,阻碍作用越明显。同时,锆掺杂还可以明显提高纳米管阵列形貌的热稳定性。此外,ATNTA的锆掺杂量可以通过改变基体的成分而很方便地得到调整。最后,通过氧化钛铬合金的方法制备出铬掺杂的TiO₂纳米管,发现铬掺杂改变了TiO₂纳米管阵列的形貌。管壁较厚的TiO₂纳米管排列松散,管间距较大。在480°C至580°C的高温热处理过程中,基体发生了由β相向α相的转变,但没有破坏纳米管阵列的结构。铬掺杂促进了锐钛矿相TiO₂晶粒向金红石结构的转变。在热处理的过程中,氧化膜中一直没有出现锐钛矿型的TiO₂,而是在非晶的氧化膜中直接产生了金红石型的TiO₂晶粒。更多还原

【Abstract】 The preparation and application of TiO₂ nanotube array is widely investigated in recent years. Anodic oxidation adopted to prepare TiO₂ nanotube array has attracted intensive attention due to its simplicity, low cost and easy industrialization. The preparation of TiO₂ nanotube array by anodic oxidation is reviewed in this paper. Two approaches are applied to optimize the properties of TiO₂ nanotube array: one is the efficient control of pore size, tube length, wall thickness, wall appearance and the quality of surface morphology; the other is the introduction of effective modification methods.In this investigation, undoped and doped TiO₂ nanotube arrays were prepared in both aqueous solution and glycerol electrolytes. The control of tube morphology and the effects of dopants on tube morphology, phase transition and thermal stability are also studied.First, the effect of anodization voltage and water addition on pore size, tube length and surface morphology was studied. High anodization voltage results in TiO₂ nanotube of large pore size. Furthermore, the outer diameter is found to be linear increase with the voltage. Wide TiO₂ nanotubes can also be produced in glycerol solutions with high water content. These tubes shorten first and then prolong a little as more water addition is contained in glycerol electrolytes. For surface morphology, it becomes better first and worse later as the water content increases. Also, the detailed growth mechanism of ridges on outer tube walls is proposed with the presence of water.Additionally, Zr-doped TiO₂ nanotube array was produced by anodizing Ti-Zr alloy in fluoride containing solutions. The dopants cause a sharp increase, as far as three times, in the length of TiO₂ nanotubes. The Zr⁴⁺ ions replace a portion of Ti⁴⁺ ions in the crystal matrixs and successfully retard the growth of anatase TiO₂ grains and their phase transition to rutile structure when the nanotube array was annealed at elevated temperatures from 480°C to 680°C. Besides, the nanotube array can keep stable at high temperatures due to Zr-doping. Futhermore, the Zr content in TiO₂ nanotubes array can be conveniently adjusted by varying the composition of Ti-Zr alloys. Finally, Cr-doped TiO₂ nanotube array was produced by anodizing Ti-Cr alloys in fluoride containing solutions. The morphology of TiO₂ nanotube array on Ti-Cr alloys is quite different form that on Ti and Ti-Zr alloys, notably the large distance among tubes. Phase transition fromβ-type toα-type of substrate takes place when the samples were annealed at elevated temperatures from 480°C to 580°C. This event has few negative effects on the structural stability of nanotube array. In addition, the phase transition from anatase TiO₂ to rutile TiO₂ is found to be accelerated with Cr-doping during the heat treatment. Rutile TiO₂ has emerged in heated amorphous oxide films on Ti-Cr alloys, while anatase TiO₂ has not been found.更多还原