Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: IMorphology and Microstructure of As-Synthesized Anodic TiO2 Nanotube Arrays | Cao et al. Nanoscale Res Lett 2011 6 64 http content 6 1 64 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Morphology and Microstructure of As-Synthesized Anodic TiO2 Nanotube Arrays Chunbin Cao1 2 Guoshun Zhang1 Xueping Song2 Zhaoqi Sun2 Abstract The as-grown structure of electrochemically synthesized titania nanotube arrays is investigated by scanning electron microscope SEM in combination with transmission electron microscope TEM as well as X-ray diffraction XRD . The analysis reveals a preferred growth direction of the nanotubes relative to the substrate surface and the well control on the nanotube arrays morphology. The crystal structure of the anatase phase is detected and exists in the tube walls without any thermal treatment which makes it possible to realize the application of as-formed TiO2 nanotubes avoiding the degradation of the nanotube structures when sintering. In addition a new growth layered model of the anodic TiO2 nanotubes is presented to obtain further understanding of the growth mechanism. Introduction Highly ordered and high surface area TiO2 nanotube arrays have attracted much attention for their potential use in several practical applications such as photocataly-tic applications 1 2 sensing 3 4 photoelectrolysis 5 6 polymer-based bulk heterojunction photovoltaics 7 8 dye-sensitized solar cells 9 10 biofluids filtration drug delivery and other biomedical applications 11 12 . It is known that the as-fabricated nanotube arrays commonly have an amorphous crystallographic structure. After annealing at elevated temperatures in atmosphere the nanotube walls transform into anatase phase and a layer underneath the nanotubes converts into rutile 13-17 . TiO2 properties depend on the crystallinity and hence the utility of their applications also varies. For example anatase phase is preferred in charge-separating devices such as dye-sensitized solar cells and in photocatalysis while rutile is used
