scholarly journals An Accurate Growth Mechanism and Photocatalytic Degradation Rhodamine B of Crystalline Nb2O5 Nanotube Arrays

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1480
Author(s):  
Wei Guo ◽  
Libin Yang ◽  
Jinghao Lu ◽  
Peng Gao ◽  
Wenjing Li ◽  
...  
Keyword(s):  
Growth Mechanism ◽  
Ion Concentration ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Fluoride Ions ◽  
Initial Oxidation ◽  
Increasing Trend ◽  
Key Factor ◽  
Degradation Activity ◽  
Inner Diameter

To effectively improve photocatalytic activity, the morphology and crystallinity of semiconductor photocatalysts must be precisely controlled during the formation process. Self-aligned Nb2O5 nanotube arrays have been successfully fabricated using the electrochemical anodization method. A novel growth mechanism of Nb2O5 nanotubes has been proposed. Starting from the initial oxidation process, the “multi-point” corrosion of fluoride ions is a key factor in the formation of nanotube arrays. The inner diameter and wall thickness of the nanotubes present a gradually increasing trend with increased dissociative fluorine ion concentration and water content in the electrolyte. With dehydroxylation and lattice recombination, the increased crystallinity of Nb2O5 represents a reduction of lattice defects, which effectively facilitates the separation and suppresses the recombination of photo-generated carriers to enhance their catalytic degradation activity.

scholarly journals Electrochemical Anodization and Characterization of Titanium Oxide Nanotubes for Photo Electrochemical Cells

2021 ◽  
Vol 2070 (1) ◽  
pp. 012073
Author(s):  
C U Bhadra ◽  
D Henry Raja ◽  
D Jonas Davidson
Keyword(s):  
Titanium Oxide ◽  
Oxygen Vacancies ◽  
Ammonium Fluoride ◽  
Band Gap Energy ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Photoluminescence Intensity ◽  
Titania Nanotube Arrays ◽  
Titanium Oxide Nanotubes ◽  
Inner Diameter

Abstract Due to its multitude of applications, titanium oxide is one of the most coveted and most sought-after materials. The above experiment demonstrated that TiO2 nanotube arrays might be formed by electrochemical anodization of titanium foil. The 0.25 wt% ammonium fluoride (NH4F) was added to a solution of 99% ethylene glycol. Anodization is carried out at a constant DC voltage of 12V for 1 hour. Then, the annealing process is carried out for 1 hour at 4800C, which is known as an annealing. FE-SEM were utilized to evaluate the surface morphology of the nanotube arrays that were made. At the wavelength of 405 nm, sharply peaked photoluminescence intensity was observed, which corresponded tothe band gap energy (3.2 eV) of the anatase TiO2 phase. Since free excitations appear at 391 and 496 nm, and since oxygen vacancies are developed on the surface of titania nanotube arrays, it is reasonable to conclude that free excitations and oxygen vacancies are the causes of humps at 391 and 496 nm, and that they may also be present at 412 and 450 nm. FESEM results showed uniformly aligned TiO2 nanotube arrays with an inner diameter of 100 nm and a wall thickness of 50 nm

Effect of Fluoride Concentration and Water Content on Morphology of Titania Nanotubes in Ethylene Glycol Solution

2013 ◽  
Vol 829 ◽  
pp. 907-911 ◽  
Author(s):  
Meysam Naghizadeh ◽  
Saber Ghannadi ◽  
Hossein Abdizadeh ◽  
Mohammad Reza Golobostanfard
Keyword(s):  
Ethylene Glycol ◽  
Water Content ◽  
Fluoride Concentration ◽  
Pure Titanium ◽  
Ammonium Fluoride ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Geometrical Parameters ◽  
High Concentration ◽  
Inner Diameter

Titanium dioxide (TiO2) nanotube arrays were prepared at room temperature by electrochemical anodization of a pure titanium foil in electrolyte solutions containing ethylene glycol as a solvent and de-ionized water and ammonium fluoride as additives. Since the morphology and size of TiO2 nanotubes play critical roles in determining their performance, the control of geometrical parameters of the nanotube arrays including length and inner diameter are of great importance. The present research demonstrates the significant effects of fluoride concentration and water content in anodizing electrolyte on formation of nanotubes and their dimensions. Scanning electron microscope investigation shows that nanotube arrays are no longer formed in very low or very high concentration of ammonium fluoride. Also, increase in fluoride concentration causes increase in lengths and inner diameters of the nanotubes. Moreover, it is evident that the maximum nanotube growth rate was achieved in medium amount of water. In addition, it is found that the nanotube inner diameter increases by adding more water to the solution.

Synthesis of Highly Ordered Nanotubular Oxide Layers on Ti-6Al-4V Alloys by Anodization Technique

2011 ◽  
Vol 219-220 ◽  
pp. 1541-1544
Author(s):  
Shi Kai Liu ◽  
Hong Sen Zuo ◽  
Hai Bin Yang ◽  
Wen Jun Zou ◽  
Zheng Xin Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Applied Voltage ◽  
Electrochemical Anodization ◽  
Tube Length ◽  
Nanotube Arrays ◽  
Anodization Time ◽  
Tc4 Alloy ◽  
Inner Diameter ◽  
Scanning Electron

Highly ordered nanotube arrays were fabricated via electrochemical anodization of Ti-6Al-4V (TC4) alloy foils in aqueous fluorine containing electrolytes. The formation of ordered nanotubular films was affected by the applied anodization potential and the anodization time. The optimal applied voltage and anodization time were 20V and 1h, respectively, as-prepared anodic nanotubular films were in highly ordered with the average inner diameter of about 120nm, the wall thickness of 17nm and the tube length about 300nm. The tubular nanostructures were examined by field emission scanning electron microscopy. The possible nanotube formation mechanism was also discussed.

scholarly journals Synthesis of TiO2 nanotubes by electrochemical anodization method for photocatalytic application

2013 ◽  
Vol 16 (2) ◽  
pp. 5-12
Author(s):  
Tien Thuy Thai ◽  
Quyen Van Le ◽  
Tuyen Van Au ◽  
Nhi Hai Ha ◽  
Hung Huu Khanh Nguyen ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Tio2 Nanotubes ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Photo Degradation ◽  
Self Organized ◽  
Photocatalytic Application ◽  
Inner Diameter

Self–organized TiO2 nanotube arrays were synthesized by anodization of Ti foil in ethylene glycol electrolyte containing water and NH4F. The photocatalytic activities of fabricated samples were evaluated by the degradation of methylene blue under UV A irradiation. Various factors such as electrolyte composition, voltage, anodization time, annealing time were also investigated in order to find out the conditions for synthesis of TiO2 nanotube arrays which show the highest photocatalytic activity. The as–synthesized TiO2 nanotubes were highly ordered, with the inner diameter of 6–130nm and the length of 2–3μm. The nanotubes presented a good adhesion with the Ti foil. The photocatalytic efficiency of the best sample (2x2cm area) reached 69% in the photo-degradation of 100ml of 5.10–6M methylene blue after 3 hours under UV A irradiation.

scholarly journals Vertically Aligned Binder-Free TiO2 Nanotube Arrays Doped with Fe, S and Fe-S for Li-ion Batteries

2021 ◽  
Author(s):  
Suriyakumar Dasarathan ◽  
Mukarram Ali ◽  
Tai-Jong Jung ◽  
Junghwan Sung ◽  
Yoon-Cheol Ha ◽  
...  
Keyword(s):  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Kinetic Properties ◽  
Outer Diameter ◽  
Impregnation Method ◽  
Binder Free ◽  
Vertically Aligned ◽  
Inner Diameter ◽  
Current Densities ◽  
Discharge Capacities

Vertically aligned Fe, S, and Fe-S doped anatase TiO2 nanotube arrays are prepared by electrochemical anodization process using an organic electrolyte in which lactic acid is added as an additive. In the electrolyte, nanotube layers of greater length (12 μm) and high order with inner diameter of approx. 90 nm and outer diameter of approx. 170 nm are achieved. Doping of Fe, S, and Fe-S via simple wet impregnation method substituted Ti and O sites with Fe and S, which leads to enhance the rate performance at high discharge current densities. Discharge capacities of TiO2 tubes increased from 82 mAh g-1 (bare) to 165 mAh g-1 for Fe-S doped TiO2 at high current densities of 0.3 mAcm-2 after 100 cycles with exceptional capacity retention of 85% after 100 cycles. Owing to the enhancement of thermodynamic and kinetic properties by doping of Fe-S, Li-diffusion increas2ed resulting in remarkable discharge capacities of 143 mAh g-1 and 89 mAh g-1 at a current density of 7.4 mA cm-2 and 19 mA cm-2, respectively.

scholarly journals Highly Ordered TiO2 Nanotube Arrays with Engineered Electrochemical Energy Storage Performances

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 510
Author(s):  
Wangzhu Cao ◽  
Kunfeng Chen ◽  
Dongfeng Xue
Keyword(s):  
Tio2 Nanotubes ◽  
Lithium Ion ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Free Standing ◽  
Structured Materials ◽  
Self Organized ◽  
Binder Free

Nanoscale engineering of regular structured materials is immensely demanded in various scientific areas. In this work, vertically oriented TiO2 nanotube arrays were grown by self-organizing electrochemical anodization. The effects of different fluoride ion concentrations (0.2 and 0.5 wt% NH4F) and different anodization times (2, 5, 10 and 20 h) on the morphology of nanotubes were systematically studied in an organic electrolyte (glycol). The growth mechanisms of amorphous and anatase TiO2 nanotubes were also studied. Under optimized conditions, we obtained TiO2 nanotubes with tube diameters of 70–160 nm and tube lengths of 6.5–45 μm. Serving as free-standing and binder-free electrodes, the kinetic, capacity, and stability performances of TiO2 nanotubes were tested as lithium-ion battery anodes. This work provides a facile strategy for constructing self-organized materials with optimized functionalities for applications.

scholarly journals Vertically Aligned Binder-Free TiO2 Nanotube Arrays Doped with Fe, S and Fe-S for Li-ion Batteries

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2924
Author(s):  
Suriyakumar Dasarathan ◽  
Mukarram Ali ◽  
Tai-Jong Jung ◽  
Junghwan Sung ◽  
Yoon-Cheol Ha ◽  
...  
Keyword(s):  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Kinetic Properties ◽  
Outer Diameter ◽  
Impregnation Method ◽  
Binder Free ◽  
Vertically Aligned ◽  
Discharge Capacities

Vertically aligned Fe, S, and Fe-S doped anatase TiO2 nanotube arrays are prepared by an electrochemical anodization process using an organic electrolyte in which lactic acid is added as an additive. In the electrolyte, highly ordered TiO2 nanotube layers with greater thickness of 12 μm, inner diameter of approx. 90 nm and outer diameter of approx. 170 nm are successfully obtained. Doping of Fe, S, and Fe-S via simple wet impregnation method substituted Ti and O sites with Fe and S, which leads to enhance the rate performance at high discharge C-rates. Discharge capacities of TiO2 tubes increased from 0.13 mAh cm−2(bare) to 0.28 mAh cm−2 for Fe-S doped TiO2 at 0.5 C after 100 cycles with exceptional capacity retention of 85 % after 100 cycles. Owing to the enhancement of thermodynamic and kinetic properties by doping of Fe-S, Li-diffusion increased resulting in remarkable discharge capacities of 0.27 mAh cm−2 and 0.16 mAh cm−2 at 10 C, and 30 C, respectively.

Growth Mechanism of TiO2 Nanotube Arrays by Etching Treatment and Their Photoelectric Property

2019 ◽  
Vol 40 (4) ◽  
pp. 459-467
Author(s):  
孙 琼 SUN Qiong ◽  
游 迪 YOU Di ◽  
臧 韬 ZANG Tao ◽  
吴松浩 WU Song-hao ◽  
洪 永 HONG Yong ◽  
...  
Keyword(s):  
Growth Mechanism ◽  
Photoelectric Property ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Nanotube Arrays

Enhancing visible light photocatalytic performance with N-doped TiO2 nanotube arrays assisted by H2O2

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940025 ◽  
Author(s):  
Chao Xiong ◽  
Shengsen Zhang ◽  
Yu Zhao ◽  
Min Zheng ◽  
Dongdong Hou ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Performance ◽  
Organic Pollutant ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Pollutant Degradation ◽  
Organic Pollutant Degradation ◽  
Acid Orange Ii ◽  
Photocatalytic Material ◽  
Visible Light Photocatalytic

N-doped TiO2 nanotube arrays were prepared by an electrochemical anodization method and subsequent ammonia annealing. Microstructures, morphology, optical properties and photocatalytic properties of the N-doped TiO2 nanotube arrays were measured and analyzed. In the degradation of Acid Orange II(AO-II), the photocatalytic degradation efficiency of the N-doped TiO2 nanotube arrays assisted by H2O2 are 12 times, 2 times and 5 times higher than TiO2 nanotube arrays, TiO2 nanotube arrays assisted by H2O2 and H2O2, respectively. Experimental results show that the N-doped TiO2 nanotube arrays is a promising photocatalytic material for organic pollutant degradation under visible light, especially under the assistance of H2O2.

Si-corrole-based fluoride fluorometric turn-on sensor

2020 ◽  
Vol 24 (05n07) ◽  
pp. 929-937
Author(s):  
Ewa Jaworska ◽  
Fabrizio Caroleo ◽  
Corrado Di Natale ◽  
Krzysztof Maksymiuk ◽  
Roberto Paolesse ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Linear Dependence ◽  
Porous Membrane ◽  
Ion Concentration ◽  
Fluoride Ion ◽  
Fluoride Ions ◽  
Acidic Solutions ◽  
Turn On ◽  
New Type ◽  
Receptor Layer

We present here a new type of fluoride ion optode, constituted by a highly lipophilic PVDF porous membrane modified with a liquid receptor layer containing the emission-active Si corrole F[Formula: see text] selective ionophore. For the optimized composition of the receptor layer, in acidic solutions an increase of Si-corrole emission was observed by increasing fluoride ion concentration, a behavior different from most porphyrinoid-based optical sensors. An observed linear dependence of the Si corrole emission intensity (read at 635 nm) was within the range 10[Formula: see text] to 10[Formula: see text] M of fluoride ions.

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