Performance Of TiO2 Nanotubes Research Articles

Application of Taguchi Method to Study Morphological Evolution of TiO2 Nanotubes Obtained Via Anodization Process

The growth of titanium dioxide nanotubes (TiO2) via anodization process depends on the controlling parameters such as applied potential, anodization time, and electrolyte composition. In the present work, the Taguchi method was applied to evaluate statistically the influence of the anodization parameters on the morphology of anodized TiO2 films. Mixture of ethylene-glycol and glycerol was used as an electrolyte and the settings of the experimental design were parameterized on the basis of four important anodization factors consisting of chemical pretreatment, amount of fluoride, water content and applied potential. Samples were characterized by XRD and FEG-SEM. Based on 4 variables at 3 different settings, full factorial plan requires 34 = 81 tests. In this work the experiment was designed on the basis of an L9 (34) orthogonal array (4 variables, 3 levels, 9 tests). The optimum conditions were found on the basis of smaller-is-better and larger-is-better analyses. The signal-to-noise ratio was employed to find optimal process parameters levels and to analyze the influence of these parameters on the tubular length, internal and external diameters and formation of nanograss on the film surface. Hence, it is clearly shown that the performance of TiO2 nanotubes can be evaluated by the Taguchi method.

Fabrication and interfacial electron transfer of ultrathin g-C3N4 nanosheet/TNT@CNTs ternary nanostructure heterojunction for high-efficiency visible-light-driven photocatalysis

The purpose of this research is to design and fabricate a novel ternary hybrid nanostructure heterojunction with high-efficiency visible-light-driven photocatalysis. The porous layered TiO2 nanotubular structures (TNTs) with high percentage of photocatalytic reactive facets, which were turned into by commercially available TiO2, were wrapped on the surface of hydroxylation carbon nanotubes (CNTs) through the formation of Ti–O=C and/or Ti–O–C bond between CNTs and TiO2. Then the TNT@CNT nanotubular composites were coated by ultrathin g-C3N4 nanosheets with a thickness of 3–4 nm. The ternary nanocomposites owned strong absorption performance, low charge recombination rates and high-efficiency photocatalytic activities, which were all owe to high surface areas and excellent adsorptivity of the CNTs, photocatalytic performance of TiO2 nanotubes (TNTs) and moderate band gap of g-C3N4 nanosheet. What’s more, the formation of chemical bonds greatly improved visible-light photocatalytic activity with a degradation rate of 98.2 and 97.9% for methylene blue and rhodamine B in 60 min under visible-light irradiation, which showed ~ 10 times enhancement compared to pure TiO2. In addition, the existence of h+ and ·OH and ·O2− radicals played main role in the photocatalytic process. The new material was of great significance to environmental protection and energy criss.

Synthesis of TiO<sub>2</sub> Nanotubes and the Effects of Deionized Water on their Surface Morphology and Microstructure

Nanotubes of TiO2 have been synthesized on titanium metal by DC anodization at 50 V in an EG/NH4F/D.I. H2O electrolyte. The anodization apparatus which uses a platinum cathode is unique and designed to allow only for a single-face anodization. The influence of deionized water (D.I. H2O) on the surface morphology of the nanotubes was investigated using the scanning electron microscope (SEM), while the microstructure before and after calcination was studied using X-ray diffraction technique (XRD). Results show that the surface density and uniformity of the TiO2 nanotube arrays varies with the percentage of D.I. H2O in the electrolyte. The best result was obtained at 6% vol D.I. H2O after calcination. This result is useful since, the surface morphology and microstructure play a vital role in the performance of TiO2 nanotubes in various applications.

Coupling TiO2 nanotubes photoelectrode with Pd nano-particles and reduced graphene oxide for enhanced photocatalytic decomposition of diclofenac and mechanism insights

In order to improve the separation efficiency of photogenerated charge carriers and photocatalytic (PC) performance of TiO2 nanotubes (TiO2 NTs) photoelectrode, Pd nanoparticles and reduced graphene oxide co-modified TiO2 NTs (Pd-RGO/TiO2 NTs) photoelectrode was fabricated through two-step electrodeposition in this study. Subsequently, physicochemical properties of the resulting samples were investigated through SEM, XRD, XPS and Raman techniques. Additionally, the generation of (OH)-O-center dot was detected by fluorescence spectra using terephthalic acid as the probing molecule. Furthermore, the photoelectrochemical properties of Pd-RGO/TiO2 NTs photoelectrode were studied through UV-vis DRS, photocurrent density and electrochemical impedance spectroscopy. As a result, Pd-RGO/TiO2 NTs photoelectrode exhibited a significantly enhanced photocurrent density of 0.111 mA cm(-2) and charge carrier concentration of 1.43 x 10(19) cm(-3), as well as efficient PC performance of 58.4% for the degradation of diclofenac aqueous solution. Moreover, the enhanced-PC mechanism was proposed. The efficient visible PC performance of Pd-RGO/TiO2 NTs photoelectrode could mainly be attributed to the co-modification of Pd and RGO species, which could not only improve the light harvesting property, but also the effective separation of photogenerated charge carriers. Furthermore, the enhanced PC mechanism for degradation of diclofenac was proposed and confirmed. This study provides an effective strategy to fabricate TiO2 NTs-based photoelectrode which could be applied in the fields of organic pollutants elimination and wastewater treatment. (C) 2015 Elsevier B.V. All rights reserved.

The Effect of Cu Concentration on TiO2 Nanotubes for Low Concentration of Pb(II) Removal

Lead (Pb) has been recognized to be acutely toxic to human beings and studies have shown that young children, infants and pregnant women are particularly at risk to unsafe Pb (II) level. Generally, high level of Pb(II) can be removed by using alginate beads. However, at low level, it is not possible to be removed by alginate. For that reason, low concentration (10 ppm) of Pb(II) removal by photocatalytic activity is explored in this work. Cu loaded TiO₂ nanotube was prepared by wet impregnation with different Cu concentration. The initial concentration of Cu involved were 0.01 M, 0.06 M and 0.1 M. For heavy metal removal, the initial concentration of Pb(II) solution used was 10 ppm. The remnant concentration of Pb(II) solution after irradiated under ultraviolet(UV) light was determined by using Atomic Absorption Spectroscopy (AAS). It was observed that the optimal condition of Cu loaded nanotube was at 0.01 M and it exhibited highest removal of Pb(II) with 50%. However, at high Cu concentration(> 0.06 M), it declined the performance of TiO₂ nanotubes for Pb(II) removal. The removal of Pb(II) obtained at 0.06 M and 0.01M was only 23.3% and 17.1%.

On the Performance of TiO2 Nanotubes and Its Derivatives as Anode Materials for Li-Ion Microbatteries

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Electrochemical performance of anodized TiO2Nanotubes for rechargeable Lithium Batteries

ABSTRACTThe electrochemical storage performance of anatase TiO2nanotubes (NT) is compared to the performance of TiO2nanotubes covered by sulfur. Charge/discharge curves and cycling performance of TiO2NT with and without sulfur deposition with respect to lithium anodes are demonstrated in electrochemical test cells. At 0.5C cycle rate the TiO2NT exhibited a first cycle specific charge/discharge capacity of 180/155 mAh/g, whereas the TiO2NT deposited with sulfur showed a remarkably higher performance at 0.5C cycle rate with first cycle charge/ discharge specific capacities of 258/260 mAh/g and a coulombic efficiency of 98%.

Role of TiO2 Nanotube on Improvement of Performance of Hybrid Photovoltaic Devices

The performance of TiO2 nanotubes in bulk heterojunction of poly (2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylenevinylene) (MEH-PPV)/TiO2 nanotubes is investigated. The transport properties are studied by using the time-of-fight technique (TOF). The carrier mobilities of both holes and electrons are not improved for the MEH-PPV:TiO2 composites compared with the pristine MEH-PPV. However, photoluminescence under the influence of the electric field indicates that the dissociation of excitons in the MEH-PPV:TiO2 composites, which is facilitated by photoinduced charge transfer, only requires a smaller electric field.