scholarly journals Nitrogen-Doped TiO2Nanotube Arrays with Enhanced Photoelectrochemical Property

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Shipu Li ◽  
Shiwei Lin ◽  
Jianjun Liao ◽  
Nengqian Pan ◽  
Danhong Li ◽  
...  
Keyword(s):  
Reaction Time ◽  
Electrochemical Deposition ◽  
Photoelectron Spectroscopy ◽  
Electrolyte Concentration ◽  
Orthogonal Experiment ◽  
Kinetic Constant ◽  
Electrochemical Anodization ◽  
Visible Range ◽  
Nanotube Arrays ◽  
N Doping

N-doped TiO2nanotube arrays were prepared by electrochemical anodization in glycerol electrolyte, followed by electrochemical deposition in NH4Cl solution. An orthogonal experiment was used to optimize the doping conditions. Electrolyte concentration, reaction voltage, and reaction time were the main factors to influence the N-doping effect which was the determinant of the visible range photoresponse. The optimal N-doping conditions were determined as follows: reaction voltage is 3 V, reaction time is 2 h, and electrolyte concentration is 0.5 M. The maximal photocurrent enhanced ratio was 30% under white-light irradiation. About 58% improvement of photocatalytic efficiency was achieved in the Rhodamine B degradation experiment by N doping. The kinetic constant of the N-doped TNT arrays sample was almost twice higher than that of the undoped sample. Further analysis by X-ray photoelectron spectroscopy supported that electrochemical deposition is a simple and efficient method for N doping into TiO2nanotube arrays.

scholarly journals Photoelectrochemical properties of N-doped self-organized titania nanotube layers with different thicknesses

2006 ◽  
Vol 21 (11) ◽  
pp. 2824-2828 ◽  
Author(s):  
J.M. Macak ◽  
A. Ghicov ◽  
R. Hahn ◽  
H. Tsuchiya ◽  
P. Schmuki
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nitrogen Doping ◽  
Electrochemical Anodization ◽  
Tube Length ◽  
Ammonia Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Organized ◽  
Structure Morphology ◽  
N Doping

The present work reports nitrogen doping of self-organized TiO2 nanotubular layers. Different thicknesses of the nanotubular layer architecture were formed by electrochemical anodization of Ti in different fluoride-containing electrolytes; tube lengths were 500 nm, 2.5 μm, and 6.1 μm. As-formed nanotube layers were annealed to an anatase structure and treated in ammonia environment at 550 °C to achieve nitrogen doping. The crystal structure, morphology, composition and photoresponse of the N-doped were characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and photoelectrochemical measurements. Results clearly show that successful N-doping of the TiO2 nanotubular layers can be achieved upon ammonia treatment. The magnitude of the photoresponse in ultraviolet and visible light is strongly dependent on the thicknesses of the layers. This effect is ascribed to recombination effects along the tube length.

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 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.

Study on Special Morphology Hydroxyapatite Bioactive Coating by Electrochemical Deposition

2013 ◽  
Vol 537 ◽  
pp. 256-260
Author(s):  
Cai Ge Gu ◽  
Qian Gang Fu ◽  
He Jun Li ◽  
Jin Hua Lu ◽  
Lei Lei Zhang
Keyword(s):  
Electrochemical Deposition ◽  
Current Density ◽  
Electrolyte Concentration ◽  
Spherical Particles ◽  
Constant Current ◽  
Constant Current Density ◽  
Depth Direction ◽  
Special Morphology ◽  
Calcium Phosphate Coatings ◽  
Coating Weight

Bioactive calcium phosphate coatings were deposited on carbon/carbon（C/C） composites using electrochemical deposition technique. The effects of electrolyte concentration and constant current density on morphology, structure and composition of the coating were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results show that, the coating weight elevated gradually with the increase of electrolyte concentration, and the morphology of coatings changed from spherical particles to nanolamellar crystals with interlocking structure initially. Then the coating transformed into seaweed-like and nano/micro-sized crystals along the depth direction of the coating. The coatings showed seaweed-like morphology as the deposition current density was less than 20mA. With the less current density, the coating became more homogenous. However, the coating was fiakiness crysal, with needlike crystal stacked upside as the current density reached to 20mA/cm2. The coating weight was improved gradually when the current density increased from 2.5mA/cm2 to 10mA/cm2, then reduced with the increasing current density in the range of 10 to 20mA/cm2.

scholarly journals Ferromagnetic Properties of N-Doped and Undoped TiO2 Rutile Single-Crystal Wafers with Addition of Tungsten Trioxide

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1934 ◽  
Author(s):  
Jing Xu ◽  
Haiying Wang ◽  
Zhongpo Zhou ◽  
Zhaorui Zou
Keyword(s):  
Magnetic Properties ◽  
Single Crystal ◽  
Saturation Magnetization ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Tio2 Surface ◽  
Doped Tio2 ◽  
X Ray ◽  
N Doping ◽  
Tio2 Rutile

In this work, undoped, N-doped, WO3-loaded undoped, and WO3-loaded with N-doped TiO2 rutile single-crystal wafers were fabricated by direct current (DC) magnetron sputtering. N-doping into TiO2 and WO3 loading onto TiO2 surface were used to increase and decrease oxygen vacancies. Various measurements were conducted to analyze the structural and magnetic properties of the samples. X-ray diffraction results showed that the N-doping and WO3 loading did not change the phase of all samples. X-ray photoelectron spectroscopy results revealed that W element loaded onto rutile single-crystal wafers existed in the form of WO3. UV-Vis spectrometer results showed that the absorption edge of WO3-loaded undoped and WO3-loaded with N-doped TiO2 rutile single-crystal wafers had red shift, resulting in a slight decrease in the corresponding band gap. Photoluminescence spectra indicated that oxygen vacancies existed in all samples due to the postannealing atmosphere, and oxygen vacancies density increased with N-doping, while decreasing with WO3 loading onto TiO2 surface. The magnetic properties of the samples were investigated, and the saturation magnetization values were in the order N-doped > WO3-loaded with N-doped > undoped > WO3-loaded undoped rutile single-crystal wafers, which was the same order as the oxygen vacancy densities of these samples. N-doping improved the saturation magnetization values, while WO3-loaded decreased the saturation magnetization values. This paper reveals that the magnetic properties of WO3-loaded with N-doped rutile single-crystal wafers originate from oxygen vacancies.

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.

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.

scholarly journals Amorphous Ni x Co y P-supported TiO2 nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

2019 ◽  
Vol 10 ◽  
pp. 62-70 ◽  
Author(s):  
Yong Li ◽  
Peng Yang ◽  
Bin Wang ◽  
Zhongqing Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Nanotube Arrays ◽  
Active Surface Area ◽  
X Ray ◽  
Transmission Electron

Bimetallic phosphides have been attracting increasing attention due to their synergistic effect for improving the hydrogen evolution reaction as compared to monometallic phosphides. In this work, NiCoP modified hybrid electrodes were fabricated by a one-step electrodeposition process with TiO2 nanotube arrays (TNAs) as a carrier. X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy and scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy were used to characterize the physiochemical properties of the samples. The electrochemical performance was investigated by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. We show that after incorporating Co into Ni–P, the resulting Ni x Co y P/TNAs present enhanced electrocatalytic activity due to the improved electron transfer and increased electrochemically active surface area (ECSA). In 0.5 mol L−1 H2SO4 electrolyte, the Ni x Co y P/TNAs (x = 3.84, y = 0.78) demonstrated an ECSA value of 52.1 mF cm−2, which is 3.8 times that of Ni–P/TNAs (13.7 mF cm−2). In a two-electrode system with a Pt sheet as the anode, the Ni x Co y P/TNAs presented a bath voltage of 1.92 V at 100 mA cm−2, which is an improvment of 79% over that of 1.07 V at 10 mA cm−2.

scholarly journals Photocatalytic activity of graphene oxide–TiO 2 thin films sensitized by natural dyes extracted from Bactris guineensis

2019 ◽  
Vol 6 (3) ◽  
pp. 181824 ◽  
Author(s):  
William Vallejo ◽  
Angie Rueda ◽  
Carlos Díaz-Uribe ◽  
Carlos Grande ◽  
Patricia Quintana
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Photocatalytic Degradation ◽  
Photoelectron Spectroscopy ◽  
Chemical Characterization ◽  
Sem Analysis ◽  
Visible Range ◽  
X Ray ◽  
Natural Sensitizer

This study synthesized and characterized composites of graphene oxide and TiO 2 (GO–TiO 2 ). GO–TiO 2 thin films were deposited using the doctor blade technique. Subsequently, the thin films were sensitized with a natural dye extracted from a Colombian source ( Bactris guineensis ). Thermogravimetric analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance measurements were used for physico-chemical characterization. All the samples were polycrystalline in nature, and the diffraction signals corresponded to the TiO 2 anatase crystalline phase. Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) verified the synthesis of composite thin films, and the SEM analysis confirmed the TiO 2 films morphological modification after the process of GO incorporation and sensitization. XPS results suggested a possibility of appearance of titanium (III) through the formation of oxygen vacancies (O v ). Furthermore, the optical results indicated that the presence of the natural sensitizer and GO improved the optical properties of TiO 2 in the visible range. Finally, the photocatalytic degradation of methylene blue was studied under visible irradiation in aqueous solution, and pseudo-first-order model was used to obtain kinetic information about photocatalytic degradation. These results indicated that the presence of GO has an important synergistic effect in conjunction with the natural sensitizer, reaching a photocatalytic yield of 33%.

scholarly journals Formation of TiO2 Nanotubular Layers on Ti-6Al-4V Based Dental Implants for Inhibiting Biofilm Growth

2020 ◽  
Vol 32 (7) ◽  
pp. 1543-1548
Author(s):  
SLAMET ◽  
BOY M. BACHTIAR ◽  
PRASWASTI P.D.K. WULAN ◽  
BILLY APRIANTO ◽  
MUHAMMAD IBADURROHMAN
Keyword(s):  
Dental Implants ◽  
Calcination Temperature ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Biofilm Inhibition ◽  
Biofilm Growth ◽  
Promising Alternative

Modification of Ti-6Al-4V through electrochemical anodization method has been investigated on the purpose of generating TiO2 nanotube arrays (TiNTAs) on the surface of Ti-6Al-4V films. The as-anodized samples were calcined in an atmospheric furnace at various temperatures, in the range of 500-800 ºC. The evaluation of biofilm inhibition was performed by an in vitro method with Streptococcus mutans as a bacterium model. FE-SEM imaging confirmed the successful formation of TiO2 nanotube arrays while XRD results implied a phase transformation from anatase to rutile when the calcination temperature was around 600-650 ºC with average crystallite size of 18 nm. Calcination temperature is one of determining factors in the adjustment of crystallinity and morphology of TiO2, which in turn affects its capability to suppress biofilm formation. This study revealed that the best sample for biofilm inhibition was calcined at 600 ºC with a crystallite phase of mostly anatase. This sample managed to improve antibacterial activity of up to five times as compared to the unmodified Ti-6Al-4V. The output of this study is expected to give some insight on a promising alternative for preventing the formation of harmful biofilm on dental implants.

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