Kinetic analysis of the anodic growth of TiO2 nanotubes: effects of voltage and temperature

2019 ◽  
Vol 7 (45) ◽  
pp. 14098-14108
Author(s):  
Wanggang Zhang ◽  
Yiming Liu ◽  
Fei Guo ◽  
Jiameng Liu ◽  
Fuqian Yang
Keyword(s):  
Ethylene Glycol ◽  
Kinetic Analysis ◽  
Tio2 Nanotubes ◽  
Organic Electrolyte ◽  
Growth Time ◽  
Nanotube Arrays ◽  
Anodization Voltage ◽  
Anodization Process

Two-step anodization process is used to grow TiO2 nanotube arrays in an organic electrolyte consisting of water, NH4F, and ethylene glycol. The growth of TiO2 nanotubes is dependent on temperature, anodization voltage and growth time.

EFFECT OF VOLTAGE ON TIO2 NANOTUBES FORMATION IN ETHYLENE GLYCOL SOLUTION

2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Syahriza Ismail ◽  
Khairil Azwa Khairul ◽  
Nurul Asyikin Ahmad Nor Hisham ◽  
Md Shuhazlly Mamat ◽  
Mohd Asyadi Azam
Keyword(s):  
Heat Treatment ◽  
Ethylene Glycol ◽  
Crystalline Phase ◽  
Tio2 Nanotubes ◽  
Oxygen Vacancies ◽  
Ammonium Fluoride ◽  
Nanotube Arrays ◽  
Anodization Voltage ◽  
Ionic Mobilities ◽  
Glycol Solution

The crystalline phase of the TiO2 nanotubes without further heat treatment were studied. The TiO2 nanotube arrays were produced by anodization of Ti foil at three different voltage; 10, 40, and 60 V in a bath with electrolytes composed of ethylene glycol (EG), ammonium fluoride (NH4F), and hydrogen peroxide (H2O2). The H2O2 is a strong oxidizing agent which was used as oxygen provider to increase the oxidation rate for synthesizing highly ordered and smooth TiO2 nanotubes. Anodization at voltage greater than 10 V leads to the formation of tubular structure where higher anodization voltage (~ 60 V) yield to larger tube diameter (~ 180 nm). Crystallinity of the nanotubes is improved as the voltage was increased. The transformation of amorphous to anatase can be obtained for as anodized TiO2 without any heat treatment. The Raman spectra results show the anodization at 40 V and 60 V gives anatase peak in which confirms the crystalline phase. The stabilization of the crystalline phase is due to the oxygen vacancies and ionic mobilities during the anodization at high voltage. 

Morphology and Electronic Properties of TiO2 Nanotubes Arrays Synthesized by Electrochemical Method

2018 ◽  
Vol 9 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Henia Fraoucene ◽  
Djedjiga Hatem ◽  
Florence Vacandio ◽  
Marcel Pasquinelli
Keyword(s):  
Ethylene Glycol ◽  
Electronic Properties ◽  
Tio2 Nanotubes ◽  
Titanium Foil ◽  
Electrochemical Anodization ◽  
Geometrical Parameters ◽  
Ultrapure Water ◽  
Anodization Voltage ◽  
Anodization Process ◽  
Tio2 Nts

Background: A nano-tubular structure of Titanium dioxide (TiO2) was obtained using an electrochemical process based on the anodization of titanium foil in an organic electrolyte prepared with ethylene glycol (HOCH2CH2OH) containing Ammonium fluorides (NH4F) and ultrapure water under different anodization voltage. The morphological characteristics showed the formation of TiO2 nanotubes with different geometrical parameters. The electronic properties of the TiO2 NTs films were measured by the Mott-Schottky (MS) plots, indicating a positive slope for all graphs implying the n-type semiconductor nature of the TiO2 nanotubes (TiO2 NTs). The donor density (Nd) and the flat band potential (Efb) increases slightly with increase the anodization voltage. Methods: Prior the anodization, the titanium (Ti) foils were cut into square shape (2.25 cm2) with a selected work area of 0.6 cm2. The samples were subjected to a final polishing using a rotating felt pad (01 &µm) impregnated with alumina until a metallic mirror surface was obtained. The Ti foils were degreased by sonication in acetone, methanol and 2-Propanol for 10 minutes respectively, rinsed with ultrapure water and dried in a stream of compressed air. To form a TiO2 NTs, electrochemical anodization process was carried out at room temperature in Ethylene Glycol (EG) solution containing 0.3 wt% Ammonium fluorides (NH4F) and 2wt % ultrapure water for three (03) hours at different anodization voltage (20, 40 and 60V). A two-electrode cell was used for all the anodization measurements, with a platinum plate as the counter electrode, separated from the working electrode (titanium foil) by 1.5 cm. Immediately after anodization, the samples were soaked in ultrapure water to remove residual electrolyte for 10 minutes and then dried in an oven at 50 °C for 10 minutes. Results: TiO2 NTs grown from anodization of Ti foil in fluoride EG solution for 3h by varying the anodization voltage. The micrographic analysis shows a strong influence of the anodizing voltage on the morphology and geometrical parameters of the TiO2 NTs. Non homogenous NTs morphology was observed at 20 V with the presence of corrugations along the walls of the tubes. A perfect and regular nanotublar structure with smooth’s walls tubes was obtained at an anodization voltage of 60V. Moreover, the increase of anodization voltage leads to an increase in both the diameter and the length of tubes. In fact, the inner diameter and the length of the tubes (Di and L) values increase with increasing potential, being around (39 nm and 2 &µm) respectively at 20 V and (106 nm and 16,1 &µm) at 60 V. The measured electronic properties of TiO2 NTs indicating the n type semiconducting nature. It is remarkable that the donor density Nd increases toward higher values by increasing the anodizing voltage until 40V. However, for an anodization at 60V, the Nd has a small decrease value (7, 03 * 1019 cm-3) indicating a diminution of defects present in the material. Also, by increasing the anodizing voltage, Efb takes increasingly more positive values. In fact, the Efb values are – 0.12, 0.05 and 0.15 V for films prepared at 20, 40 and 60 V respectively. Therefore, this behavior can be attributed to a displacement of the Fermi level toward the conduction band edge which leads to a larger band bending at the interface. Conclusion: By varying the anodization voltage, titanium dioxide nanotubes (TiO2 NTs) were grown using electrochemical anodization of titanium foil in fluoride ethylene glycol solution for 3 hours. The morphology of the TiO2 NTs obtained was considerably affected; the anodizing potential determines the migration of ions in electrolyte during anodization process and simultaneously the tube diameter. An average small a nanotube diameter around 39 nm was obtained for 20V corresponding to 106 nm average diameter for TiO2 NTs structure synthesized at 60V. Furthermore, the semiconductor properties of the TiO2 NTs films have also been modified with increased values while increasing the anodization voltage. This behavior was attributed that the TiO2 NTs structure is more disordered, having much more defects provide abundant local donor energy levels which increases conductivity and decrease the probability of recombination of electrons and holes in these films, that can be integrated as active layer in the solar cells, in particular the Gratzel cells.

The Fabrication of Highly Ordered TiO2 Nanotube Arrays and their Application in Dye-Sensitized Solar Cells

2011 ◽  
Vol 217-218 ◽  
pp. 1553-1558 ◽  
Author(s):  
Hong Mei Xu ◽  
Yong Liu ◽  
Hai Wang ◽  
Wen Xia Zhao ◽  
Hong Huang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Tio2 Nanotubes ◽  
Dye Sensitized Solar Cells ◽  
Tube Length ◽  
Nanotube Arrays ◽  
Anodization Voltage ◽  
Dye Sensitized ◽  
Anodization Time ◽  
Inner Diameter ◽  
Sensitized Solar Cells

Highly ordered closely packed TiO2 nanotubes were successfully fabricated by anodization of Ti foils in ethylene glycol-based electrolytes. For an identified electrolyte, the dependence manner of the nanotube dimension to the anodization parameters, including anodization voltage and time were systematically investigated. The inner diameter depends linearly on the anodization voltage but is time independent. The morphology of the tube is relative to the anodization voltage. The tube length is closely relative to the anodization time. Keeping the anodization voltage, the length will increase with the time rising to an extent and then maintain a relatively steady value. Longer nanotubes will be obtained when the anodization voltage is higher for a determined time. TiO2 nanotube-based dye-sensitized solar cells (DSSCs) were fabricated. The results showed that the conversion efficiency was related to the tube dimension. The optimum efficiency of 4.25% is obtained.

SELF-ORDERING ELECTROCHEMICAL SYNTHESIS OF TiO2 NANOTUBE ARRAYS: CONTROLLING THE NANOTUBE GEOMETRY AND THE GROWTH RATE

2011 ◽  
Vol 10 (01n02) ◽  
pp. 55-58 ◽  
Author(s):  
KRISHNA KANT ◽  
DUSAN LOSIC
Keyword(s):  
Growth Rate ◽  
Ethylene Glycol ◽  
Electrochemical Synthesis ◽  
The Self ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Anodization Voltage ◽  
Nanotube Array ◽  
Anodization Time ◽  
Nanotube Growth

We report the fabrication of highly ordered TiO 2 nanotube arrays employing electrochemical anodization of titanium using an organic electrolyte comprised of water, NH 4 F , and ethylene glycol. To achieve the self-ordering regime of TiO 2 nanotube growth and reliable fabrication optimal potential window between 80 and 100 V was determined. We show that anodization voltage can be used not only to control nanotube diameters (70–180 nm) but also to have impact on nanotube growth rate. The anodization voltage and anodization time were used to adjust the length of TiO 2 nanotube (thickness of nanotube layer). TiO 2 nanotube array films and self-supporting layers with thickness from < 5 μm to > 250 μm were routinely fabricated.

scholarly journals Investigation the effect of anodization voltage on the geometrical properties and photocatalytic activity of TiO2 nanotube arrays for degradation of p-nitrophenol

2019 ◽  
Author(s):  
Kamyar Khoshsirat Janekbari ◽  
Neda Gilani ◽  
azadeh ebrahimian pirbazari
Keyword(s):  
Photocatalytic Degradation ◽  
Tio2 Nanotubes ◽  
Cumulative Effect ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Polluted Water ◽  
Nanotube Arrays ◽  
Order Kinetic ◽  
Anodization Voltage ◽  
Geometrical Properties

p-nitrophenol (PNP) is a nitroaromatic compound that poses a potential environmental hazard because of its acute toxicity, high carcinogenicity, low biodegradability and cumulative effect. Titanium dioxide (TiO2) nanotubes have shown great potential as ideal and powerful photocatalysts in purification of polluted water due to their high photo oxidation, anti-fogging, nontoxicity, good chemical stability and low cost. Therefore, TiO2 nanotube arrays were fabricated by two-step anodization process at 30,40 and 50V; and were used in photocatalytic degradation of organic pollution p-nitrophenol. In order to have the crystal structure, nanotubes were annealed at 450 °C for 2 hours. Characterizing of TiO2 nanotubes were evaluated by FESEM, XRD and Spectrophotometry analyses. Effect of anodization voltage on nanotube’s length and diameter were investigated. The result showed that as anodization voltage increases from 30V to 50V, nanotube’s length, diameter and wall thickness increase linearly from 1.4 μm to 4.8 μm, 45 nm to 100nm and 15nm to 25 nm, respectively. Increasing in anodization voltage lead to enhancement in porosity (0.4-0.5) and roughness factor (109-194) of TiO2 nanotubes, respectively. By investigating kinetic of degradation of p-nitrophenol, it was observed that mechanism of photocatalytic degradation for all samples are followed first order kinetic. The results indicate that amongst all synthesized samples, 50 V sample with 38%, shows the most efficiency in degradation of p-nitrophenol under UV irradiation.

TiO2 Nanowires/Nanobelts Originating from Anodically Grown Nanotube Arrays

2012 ◽  
Vol 463-464 ◽  
pp. 802-807 ◽  
Author(s):  
Hai Jun Tao ◽  
Jie Tao ◽  
Tao Wang ◽  
Zuo Guo Bao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ethylene Glycol ◽  
Field Emission ◽  
Special Structure ◽  
Nanotube Arrays ◽  
Anodization Voltage ◽  
Anodization Time ◽  
Chemical Etch ◽  
Scanning Electron

TiO2nanotube arrays have aroused great interest because of their enormous application in areas such as gas sensor, catalysts, biological materials, and solar cells. In this report, TiO2nanowires/nanobelts originating from TiO2 nanotube arrays are fabricated by simple anodization of Ti foils in ethylene glycol (EG) containing 0.25wt% NH4F. From the field emission scanning electron microscopy (FE-SEM) it is observed that the morphology of the special structure is influenced by anodization voltage, water content and anodization time. In these factors, small amount of water plays a very important role in making the special nanostructure. Moreover, a possible mechanism that showed a relationship between the formation of the special structure and electric field directed chemical etch is proposed.

Influence of Anodization Parameters on the Growth Rate and Morphology of the TiO2 Nanotube Arrays

2011 ◽  
Vol 694 ◽  
pp. 8-11 ◽  
Author(s):  
Yan Wang ◽  
Yu Cheng Wu ◽  
Yong Qiang Qin ◽  
Jie Wu Cui ◽  
Hong Mei Zheng
Keyword(s):  
Growth Rate ◽  
Titanium Dioxide ◽  
Tio2 Nanotubes ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Anodization Voltage ◽  
Structured Materials ◽  
The Past ◽  
Series Of Experiments

Titanium dioxide (TiO2) nanotubes (TN) are an ideal nano-structured materials due to its promising applications in various scientific areas. Highly ordered TN arrays (TNAs) fabricated by electrochemical anodization proved to one of the exciting achievements during the past decades. In this paper, we did a series of experiments to investigate the influence of anodization parameters on the growth rate and morphology of the TNAs. And the results suggested that the anodization voltage, as well as the concentration of the anodization electrolyte, had a significant impact on the morphology of the TNAs. In-depth discussion for the TNAs was also presented.

Nucleation of octahedral titanate crystals using waste anodic electrolyte from the anodization of TiO2 nanotubes

CrystEngComm ◽  
2017 ◽  
Vol 19 (43) ◽  
pp. 6406-6411 ◽  
Author(s):  
Kar Chun Lee ◽  
Srimala Sreekantan ◽  
Zainal Arifin Ahmad ◽  
Khairul Arifah Saharudin ◽  
Mustaffa Ali Azhar Taib
Keyword(s):  
Ethylene Glycol ◽  
Tio2 Nanotubes ◽  
Nanotube Arrays ◽  
Chemical Recycling

Anodization conducted in ethylene glycol with H2O2 produces nanotube arrays. Octahedral crystals were extracted from the electrolyte waste for chemical recycling.

Fabrication of TiO2 Nanotube Arrays in Ethylene Glycol Electrolyte by the Electrochemical Anodization Method

2013 ◽  
Vol 302 ◽  
pp. 31-34 ◽  
Author(s):  
Rui Liu ◽  
Liang Sheng Qiang ◽  
Wein Duo Yang ◽  
Hsin Yi Liu
Keyword(s):  
Electron Microscopy ◽  
Ethylene Glycol ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Anodization Voltage ◽  
Good Uniformity ◽  
Anodization Method ◽  
Scanning Electron

Highly-ordered TiO2 nanotube arrays were successfully fabricated by electrochemical anodization of titanium. The morphology of TiO2 nanotube arrays, the length and pore size were represented by field emission scanning electron microscopy (FE-SEM). The parameters of various anodization including F- concentration, reaction temperature and anodization voltage were investigated in detail. The results show that as-prepared TiO2 nanotube arrays possess good uniformity and well-aligned morphology in mixture of ethylene glycol and 0.3 wt% NH4F electrolyte at 40 V for 25 °C. The growth rates of TiO2 nanotube arrays can show activation energy.

Anodic synthesis of TiO2 nanotubes by step-up voltages

2021 ◽  
pp. 002199832110237
Author(s):  
V Sivaprakash ◽  
R Narayanan
Keyword(s):  
Corrosion Resistance ◽  
Tio2 Nanotubes ◽  
Biomedical Applications ◽  
Phase Changes ◽  
Electrochemical Anodization ◽  
Corrosion Resistant ◽  
Anodization Process ◽  
Anodic Synthesis ◽  
Input Potential

Fabrication of TiO2 nanotubes (NTs) has extensive application properties due to their high corrosion resistant and compatibility with biomedical applications, the synthesis of TiO2 nanotubes over titanium has drawn interest in various fields. The synthesis of TiO2 NTs using novel in-situ step-up voltage conditions in the electrochemical anodization process is recorded in this work. For manufacturing the NTs at 1 hour of anodization, the input potential of 30, 40 and 50 V was selected. With increasing step-up voltage during the anodization process, an improvement in the NTs was observed, favoring corrosion resistance properties. The surface of NTs enhances the structure of the ribs, raising the potential for feedback over time. XRD was used to analyze phase changes, and HR-SEM analyzed surface topography. Impedance tests found that longer NTs improved the corrosion resistance.

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