Anodic Aluminum Oxide Template And One-dimensional Nanostructures Materials

One-dimensional nanostructure materials, due to its unique physical and chemical properties, have a wide application prospect in catalysis, photoelectric devices, medicine, magnetic media etc.Anodic alumina oxide (AAO) template has been used widely as template materials for synthesis of one-dimensional nanostructures, due to which its pores are very uniform in diameter and length, and its pore diameter and shape can be controlled rather easily by varying chemical or electrochemical parameters. In recent years, more attention was paid to the AAO template and the template-based synthesis of one-dimensional nanostructure materials.In this thesis, two-step anodization process was used to fabricate AAO template in 0.3M oxalic acid solution, and various nanostructure materials were prepared via electrochemical deposition method in AAO template. The main works were as follows:(1) AAO templates with various thickness and pore diameter were prepared by varying the anodization voltage and time. The results demonstrated that the pore size, pore spacing and growth rate of AAO increased with the applied voltage. During the anodization process in oxalic acid, the oxidation and dissolution reactions occurred simultaneously and played opposite effect in modifying the growth rate of the AAO template, so the AAO growth rate increased to a maximum, and then began to decline and tend to smooth finally as the anodization time prolonged. According to the experimental results, the growth mechanism of AAO template was discussed. These results would help to control the synthesis of AAO template.(2) The chemical etch was fulfilled by immersing AAO template in 1: 9 (V/V, about 15 wt%) H₃PO₄ solution and 10 wt% NaOH solution respectively. The results demonstrated that the pores of AAO template were widened firstly, and the alumina nanowires were synthesized finally in etching process. The etching reaction was faster in NaOH solution than in H3PO4 solution. The results could be valuable in widening AAO template pores, synthesizing the alumina nanostructures via AAO template and removing the AAO template after assembly of materials.(3) Electrochemical deposition method was adopted to prepare Zn nanowires, Bi nanowires, Ni nanowires, Cu nanowires, ZnS nanowires, CdS nanowires, CuNi alloy nanowire in AAO template. On the above-mentioned basis, Cu/Ni heterojunctionnanowires were fabricated by two-step electrochemical deposition method, and thesubstitution reaction was found in assembling the nanowires to form heterojunction. Theseresults would be valuable for application of nanowires in nano-devices and synthesis ofheterojunction.