Papers by Keyword: TiO₂ Nanotube

Abstract: In the paper, the array ordering of the TiO₂ nanotubes obtained by method of the anodic oxidation in different modes in the fluorine-containing aqueous-non-aqueous electrolytes containing glycerin as well as the surface-active reagents is considered. It was shown that such characteristics as the two-dimensional Fourier-spectrum, autocorrelation function and its spectrum allow us to identify the ordering nature and to obtain the preliminary quantitative estimates of SEM order.

Abstract: Orderly TiO₂ nanotube arrays (TNTs) with high surface area became a prospective catalyst support. TNTs were obtained by anodizing Ti plate, and then the Ni-Cu-B/TNTs electrodes were prepared by cyclic voltammetry electrodeposition (CVE) method. SEM, EDS and electrochemical testing were used to investigate the microstructure and catalytic performance Ni-Cu-B/TNTs electrodes for methanol electro-oxidation. Effects of electrodeposition time, CVE scanning rate and times on the methanol electrooxidation were studied. The results show the shape of Ni-Cu-B particles on surface change from fusiform-like to spherical with an increasing of deposition temperature. The peak current density initially increased and then decreased with increasing electrodeposition time, rate and number of CVE scanning. The Ni-Cu-B/ TNTs electrode prepared by 30 cyclic times in 30°C at-0.8~0.2V and the scan rate of 20mV s^-1 appear the best electrocatalytic activity for methanol oxidation. After cycled 1300 times for methanol oxidation, the peak current density decreased by 12%, indicating excellent long term stability of Ni-Cu-B/TNTs electrode.

Abstract: The osseointegration of titanium (Ti) implants highly depends on their surface properties, including roughness, wettability and composition. Ti surfaces with micron-scale roughness have demonstrated more rapid bone apposition compared with polished ones. Besides, Ti implants with nanostructured surface also exhibit better cell adhesion and proliferation behavior. However, the optimal surface for bone regeneration is still unknown, partly due to the difficulty in fabricating surfaces with highly reproducible micron-and nanotopography. In this study, Ti implants with two hierarchies of roughness were fabricated by powder metallurgy, followed by anodization treatment to obtain self-assembled TiO₂ nanotubes on the micro-roughened surface. X-ray diffraction (XRD), scanning electron microscopy (SEM), 3D Laser Scanning Microscope (3D LSM), and fluorescence microscope were used to investigate the properties of the samples. Ra of the powder metallurgy surface was about 5 μm, while, nanotubes of around 100 nm in diameter were observed after the anodization process. Compared with the reference samples, i.e., the ones with either smooth or single-level-structure surfaces, the ones with micro-to-nanoscaled hierarchical topography exhibited lower contact angle, higher protein adsorption and significantly improved mesenchymal stem cells (MSCs) early adhesion.

Abstract: Due to its excellent physical properties and inert chemical reaction activity of C₆₀, it is possible to synthesize solution-processing polymer containing C₆₀ utilizing the inclusive characteristics of polymer chain segment, and then to prepare organic/inorganic nanocomposites with enhanced some key properties. In order to harvest the visible light of TiO₂ effectively the surface modification of TiO₂ nanotube with polymer containing C₆₀ was carried out in this study. A series of characterizations were performed by SEM (scanning electron microscopy), TEM (transmission electron microscopy), Fourier-Transform Infrared (FTIR) spectra, UV-Vis (Ultra-violet visible spectroscopy), XRD patterns analysis. The results showed that the UV-Vis of resulting nanocomposite was almost covered the whole region of visible light. The photoconductivity response to visible light with low-power were studied based on interdigital electrodes of Au on flexible PET (polyethylene terephthalate) film substrate with casting method. The results indicated that the photoresponses of two kinds of polymer containing C₆₀ to weak visible light emerged photo-switching behavior, its recoverability was also rapidly, and the photoresponse of TiO₂ nanotube modified with two kinds of polymer containing C₆₀ to weak visible light also changed greatly. This illustrated that the organic-inorganic nanocomposites showed good activities to weak visible light. Photocatalytic efficiency was examined by selecting typical organic pollutants, some good results were obtained. It may develop organic-inorganic nanocomposites with external stimuli response, photocatalyst, et al.

Abstract: A highly ordered nanotube TiO₂ was successfully prepared from sputtered Ti metal film using anodization process. Ethylene glycol and ammonium fluoride was introduced as the electrolyte solution. The applied of anodizing voltage was systematically controlled between 20 - 60 volts along fabrication process, respectively. The physical characteristic of the fabricated TiO₂ nanotube including anodizing rate, tube diameter and tube width was investigated through the characterization system as field emission scanning electron microscope (FE-SEM). According to cross-section FE-SEM photograph, the anodizing rate and tube width significantly increases when the anodizing voltage was future increased due to higher the electric field. Moreover, the tube diameter directly depends with the anodizing voltage also. The anodizing voltage provides a significant role on the feature of TiO₂ nanotube. Finally, the fabricated nanotube TiO₂ is potentially promising for Photo-activated application and Nanostructure template.

Abstract: TiO₂ nanotubes were successfully synthesized by anodization method of Ti foils. The electrolyte was composed of ethylene glycol (EG), ammonium fluoride (0.3%wt NH₄F) and de-ionized water (2% vol H₂O). A constant DC power supply of 50 V was used during anodization with anodizing times of 1 hour, 2 hours, 4 hours and 6 hours. The samples were annealed at 450 °C for 2 hours. The TiO₂ nanotubes were studied by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Structural analysis revealed the presence of pure Ti, and the crystalline anatase phase due to transformation of amorphous TiO₂ after annealing. The morphology of TiO₂ nanotube sizes showed an increase in tube diameter with anodizing time from approximately 50 nm to 200 nm. However, the efficiency of dye-sensitized solar cells increased with anodizing times up to a maximum of 5.74 % for anodizing time of 4 hours.

Abstract: Highly ordered TiO₂ nanotube array hasbeen widely used as the dye-sensitized solar cells’ (DSSCs) light anode material forits abilities of inhibiting electronic recombination at the interface and improving the beam transmission of the carrier. The morphology and structure of the nanotube would influence the efficiency of the cell. In thisstudy, TiO₂ nanotubes (caliber ranging from 50 to 150nm, length ranging from 0.9 to 4μm) were prepared by a two-step anodization method and the morphology of nanotubes was regulated bythe parameters such as oxidation voltage and oxidation time. The absorbing capacities of nanotubes were measured by the dye adsorption test and the corresponding photoelectric conversion efficienciesweremeasured too. The results indicated that the conversion efficiency was related to the specific surface area and length of the nanotube. The length of nanotube would increase with theoxidation time within acertain limit.Then thedissolution on the top of TNT would reduce nanotubes’ length and lead to the decrease of the specific area, eventuallyimpairedthe photoelectric conversion.

Abstract: TiO₂ nanotubes (TNTs) was prepared by hydrothermal method using commercial P25 power as a precursor in alkali solution and was characterized by TEM, XRD and BET. The photocatalytic activity of TNTs was evaluated by degradation of methylene blue (MB). The as-prepared TNTs hydrothermal treated at 150 °C displayed higher photodegradation activity. These results provide further insight into the effect of hydrothermal temperature, and TNTs are expected to be promising for applications in photocatalysis.

Abstract: The self-organized oxide nanotube/pore layers were prepared by anodization on ternary Ti-6Al-4V alloys. The morphologies and structures of layers under different heat treatment tempreture were characterized by means of SEM, XRD, XPS and Raman spectroscopy and DRS. The effects of alloying element under different heat treatment tempreture on the structure, composition and opsorption property of the film catalysts were investigated along with their inherent relationships. The results show that two kinds of Ti-Al-V-O nanostructure grown inthe α and β phase region formed on the surface of the alloy. V doped-TiO₂ can inhibit the formation of anatase. The films show the microcrystalline structure of anatase and rutile and a small amount of V₂O₅ on the surface of film annealed at 400 oC. Moreover, the large surface and the synergy effect of V-doped TiO₂ and V₂O₅ make sample show the highest photocatalytic activity for the photocatalytic hydrogen evolution.

Abstract: As for the low yield and high consumption of electrolyte in conventional anodization for TiO₂ nanotubes, several schemes were proposed to optimize the unit yield. The anode surface area per unit volume of electrolyte and the homogeneity of the electric field are found to affect the unit yield of well-structured TiO₂ nanotube besides voltage, F^- and water content, reaction time and temperature, etc. Experimental results show that the unit yield over the cylindric electrodes quadruples in comparison with conventional anodization, which is attributed to higher anode surface area and homogeneous electric field. And SEM image indicates that well-structured TiO₂ nanotube arrays are fabricated. Thus it can be concluded that the unit yield could be increased by the method proposed in this paper and that our work provides a reference for the bulk preparation of TiO₂ nanotube and the energy-saving and emission-reduction in the process.