scholarly journals Single Step Formation of C-TiO2Nanotubes: Influence of Applied Voltage and Their Photocatalytic Activity under Solar Illumination

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Chin Wei Lai ◽  
Srimala Sreekantan
Keyword(s):  
Photocatalytic Activity ◽  
Applied Voltage ◽  
Active Surface ◽  
Ammonium Fluoride ◽  
Single Step ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Surface Areas ◽  
High Uniformity ◽  
Anodization Process

Self-aligned and high-uniformity carbon (C)- titania (TiO2) nanotube arrays were successfully formed via single step anodization of titanium (Ti) foil at 30 V for 1 h in a bath composed of ethylene glycol (EG), ammonium fluoride (NH4F), and hydrogen peroxide (H2O2). It was well established that applied voltage played an important role in controlling field-assisted oxidation and field-assisted dissolution during electrochemical anodization process. Therefore, the influences of applied voltage on the formation of C-TiO2nanotube arrays were discussed. It was found that a minimal applied voltage of 30 V was required to form the self-aligned and high-uniformity C-TiO2nanotube arrays with diameter of ~75 nm and length of ~2 μm. The samples synthesized using different applied voltages were then subjected to heat treatment for the conversion of amorphous phase to crystalline phase. The photocatalytic activity evaluation of C-TiO2samples was made under degradation of organic dye (methyl orange (MO) solution). The results revealed that controlled nanoarchitecture C-TiO2photocatalyst led to a significant enhancement in photocatalytic activity due to the creation of more specific active surface areas for incident photons absorption from the solar illumination.

scholarly journals Low-Cost Synthesis of Cu-Modified Immobilized Nanoporous TiO2 for Photocatalytic Degradation of 1H-Benzotriazole

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Tihana Čižmar ◽  
Ivana Panžić ◽  
Krešimir Salamon ◽  
Ivana Grčić ◽  
Lucija Radetić ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Spin Coating ◽  
Low Cost ◽  
Electrochemical Anodization ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Titanium Foils ◽  
The Given

Cu-modified immobilized nanoporous TiO2 photocatalysts, prepared by electrochemical anodization of titanium foils, were obtained via four different synthesis methods: hydrothermal synthesis, anodization with Cu source, electrodeposition, and spin-coating, using two different copper sources, Cu(NO3)2 and Cu(acac)2. The objective of this research was to investigate how copper modifications can improve the photocatalytic activity of immobilized nanoporous TiO2 under the UV/solar light irradiation. The best photocatalytic performances were obtained for Cu-modifications using spin-coating. Therefore, the effect of irradiated catalyst surface areas on the adsorption of model pollutants, methylene blue (MB) and 1H-benzotriazole (BT), was examined for samples with Cu-modification by the spin-coating technique. The mechanisms responsible for increased degradation of MB and BT at high Cu concentrations (0.25 M and 0.5 M) and decreased degradation at low Cu loadings (0.0625 M and 0.125 M) were explained. 1H-benzotriazole was used to study the photocatalytic activity of the given samples because it is highly toxic and present in most water systems. The characterization of the synthesized Cu-modified photocatalysts in terms of phase composition, crystal structure, and morphology were investigated using X-ray Diffraction, Raman Spectroscopy, Scanning Electron Microscopy, and Energy Dispersive X-ray spectroscopy.

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

scholarly journals Fabrication of Mo+N-Codoped TiO2Nanotube Arrays by Anodization and Sputtering for Visible Light-Induced Photoelectrochemical and Photocatalytic Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Min Zhang ◽  
Dandan Lu ◽  
Guotian Yan ◽  
Juan Wu ◽  
Jianjun Yang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Photocurrent Density ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Step Method ◽  
X Ray ◽  
New States

Mo,N-codoped TiO2nanotube arrays (TNAs) were fabricated by a two-step method consisting of electrochemical anodization and subsequent magnetron sputtering of Mo. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The results showed that the Mo,N-codoped TiO2nanotube arrays exhibited higher visible light absorbance and remarkably enhanced photocurrent density and photocatalytic activity compared with single N-doped TiO2. The highly efficient photoelectrochemical and photocatalytic activity is associated with the codoping effect between Mo and N, which plays a key role in producing new states, narrowing the bandgap, and reducing the recombination thereby effectively improving the visible light absorption and photocatalytic activity of TNAs.

scholarly journals Surface Morphology and Growth of Anodic Titania Nanotubes Films: Photoelectrochemical Water Splitting Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Chin Wei Lai
Keyword(s):  
Oxide Layer ◽  
Water Splitting ◽  
Active Surface ◽  
Ammonium Fluoride ◽  
Photocurrent Density ◽  
Photon Absorption ◽  
Electrochemical Anodization ◽  
Nanoporous Structure ◽  
Active Surface Area ◽  
Surface Morphologies

Design and development of one-dimensional nanoarchitecture titania (TiO) assemblies have gained significant scientific interest, which have become the most studied material as they exhibit promising functional properties. In the present study, anodic TiO2films with different surface morphologies can be synthesized in an organic electrolyte of ethylene glycol (EG) by controlling an optimum content of ammonium fluoride (NH4F) using electrochemical anodization technique. Based on the results obtained, well-aligned and bundle-free TiO2nanotube arrays with diameter of 100 nm and length of 8 µm were successfully synthesized in EG electrolyte containing ≈5 wt% of NH4F for 1 h at 60 V. However, formation of nanoporous structure and compact oxide layer would be favored if the content of NH4F was less than 5 wt%. In the photoelectrochemical (PEC) water splitting studies, well-aligned TiO2nanotubular structure exhibited higher photocurrent density of ≈1 mA/cm2with photoconversion efficiency of ≈2% as compared to the nanoporous and compact oxide layer due to the higher active surface area for the photon absorption to generate more photo-induced electrons during photoexcitation stage.

Preparation and Microstructure of Titania (TiO2) Nanotube Arrays by Anodization Method

2013 ◽  
Vol 802 ◽  
pp. 104-108 ◽  
Author(s):  
Buagun Samran ◽  
Pacharee Krongkitsiri ◽  
Saichol Pimmongkol ◽  
Sopon Budngam ◽  
Udom Tipparach
Keyword(s):  
Ammonium Fluoride ◽  
Deionized Water ◽  
Nanotube Arrays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Dc Power ◽  
Atomic Force ◽  
Anodization Process ◽  
Anodization Method

TiO2 nanotube arrays were successfully synthesized by the anodization method of Ti foils in electrolyte containing the mixtures of ethylene glycol (EG), ammonium fluoride (0.3 wt % NH4F) and deionized water (2 Vol % H2O). A constant dc power supply at 50 V was used anodization process with different anodizing times. The resultant samples were annealed at 450 °C for 2 h. TiO2 nanotube arrays were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The prepared TiO2 NTs has diameter in 50-200 nm. The minimum of diameter TiO2 nanotube arrays was approximately 50 nm for 1 h of anodization process.

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.

Hydrothermal Treatment of TiO2 Nanotube Arrays with AgNO3 Solutions and their Photocatalytic Properties

2011 ◽  
Vol 181-182 ◽  
pp. 702-706
Author(s):  
Yu Cheng Wu ◽  
Yan Wang ◽  
Jie Wu Cui ◽  
Guang Qing Xu ◽  
Xin Yi Zhang
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Hydrothermal Treatment ◽  
Treatment Process ◽  
Photocatalytic Properties ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Special Shape ◽  
Sunlight Irradiation ◽  
Agno3 Solution

In this paper, highly-ordered TiO2 nanotube arrays (TNAs) were firstly fabricated by electrochemical anodization. Secondly, the as-prepared TNAs were used as precursors for hydrothermal treatment and large percentage of nanoparticles with special shape were achieved. Their photocatalytic activity was evaluated based upon the removal of methylene blue (MB) dye in the aqueous solution. In order to enhance the photocatalytic properties, we added a certain amount of AgNO3 solution (0.1M) in the hydrothermal treatment process and the experiment demonstrated that the addition of AgNO3 solution displayed an excellent improvement for the photocatalytic activity. Under sunlight irradiation, the methylene blue pollutant of 1×10−5M was almostly completely degraded by Ag -TiO2 nanoparticles within 300 min.

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.

Preparation of Well-Ordered TiO2 Nanotube Arrays by Electrochemical Anodization of Titanium Foil in Neutral Electrolytes

2011 ◽  
Vol 233-235 ◽  
pp. 2047-2050
Author(s):  
Chao Wang ◽  
Da Chen ◽  
Shu Liu ◽  
Xia Ni Huang ◽  
Yue Xiang Huang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Solar Energy ◽  
Band Gap ◽  
High Performance ◽  
Diffuse Reflectance ◽  
Anatase Phase ◽  
Titanium Foil ◽  
Electrochemical Anodization ◽  
Nanotube Arrays

To obtain high performance TiO2nanotube arrays (TNAs)-based material is interesting because of its wide applications in photocatalysis field such as solar energy conversion, photocatalysis and sensors. In the present work, the well-ordered TNAs were prepared by electrochemical anodization of titanium foil in the SO42−/F−based electrolyte under 20 V for 2 h during which the Ti foil and Pt wire were used as anode and cathode, respectively. The FESEM results showed that the as-obtained TNAs were well-aligned on Ti substrate with ~ 1.5 μm in length and ~ 100 nm pore in diameter. The XRD results indicated that the as-formed TNAs was in the form of amorphous and could be transformed into crystalline anatase phase under the heat treatment at 450 °C. Meanwhile, the UV-vis diffuse reflectance spectra demonstrated that the band-gap of the obtained TNAs was narrower than the commercial TiO2nanoparticles, indicating a better photocatalytic activity of the as-prepared TNAs over the commercial TiO2nanoparticles.

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