TiO2 nanotubes have been synthesized by sol–gel template method using alumina membrane.
Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, UV absorption
spectrum and X-ray diffraction techniques have been used to investigate the structure, morphology
and optical properties of TiO2 nanotubes. SEM image showed that TiO2 nanotubes obtained were ordered and
uniform. The diameter and length of the nanotubes were decided by the pore size and thickness of alumina
template. Raman and XRD measurements confirmed the crystallinity and anatase phase of the TiO2 nanotubes.
The optical absorption measurement of TiO2 nanotubes exhibits a blue shift with respect to that of the
bulk TiO2 owing to the quantum size effect.
Nanometric TiO2 powders were obtained from low tem-perature calcination of a TiO2 resin prepared using the Pechini’s method. Firing the TiO2 resin at 500 oC/2h a powder with anatase phase was obtained, otherwise firing the TiO2 resin at 700 oC/2h a powder with rutile phase was achieved as measured by X-ray diffraction (XRD). The anatase powder presented average particle size of 60 nm observed by Scanning Electronic Microscopy (SEM-FEG) micrographs and average crystallite size of 13 nm calcu-lated from the XRD, while the rutile powder presented av-erage crystallite size of 34 nm. Nanocrystalline TiO2 films with good homogeneity and optical quality were obtained with 80 nm and 320 nm in thickness by Electron Beam Physical Vapour Deposition (EB-PVD) in vacuum on amorphous quartz substrates submitted at 350oC during the evaporation. The 80 nm-thick film presented average particle size of 140 nm and roughness (Ra) of 1.08 nm and the 320 nm-thick film showed average particle size of 350 nm and roughness (Ra) of 2.14 nm measured by Atomic Force Microscopy (AFM). In these conditions of deposi-tion the films presented only anatase phase observed by XRD and MicroRaman spectroscopy.
Characterization of different dopants in TiO2 Structure by Pulsed Laser Dep...sarmad
Characterization of different dopants in TiO2 Structure by Pulsed Laser Deposition
A thesis submitted By: Khaled Z.Yahya
Supervised by: Prof.Dr. Adawiya J.Haider Prof.Dr. Raad M.S.Al-Haddad
Synthesis Of Nanostructured TiO2 Thin Films By Pulsed Laser Deposition (PLD) ...sarmad
Sarmad Sabih Al-Obaidi
Ali Ahmed Yousif
Abstract
In this work, nanostructured TiO2 thin films were grown by pulsed laser deposition (PLD) technique on glass substrates. TiO2 thin films then were annealed at 400-600 °C in air for a period of 2 hours. Effect of annealing on the structural and morphological were studied. Many growth parameters have been considered to specify the optimum conditions, namely substrate temperature (300 °C), oxygen pressure (10-2 Torr), laser fluence energy density (0.4 J/cm2), using double frequency Q-switching Nd:YAG laser beam (wavelength 532nm), repetition rate (1-6 Hz) and the pulse duration of 10 ns. The results of the X-ray test show that all nanostructures tetragonal are polycrystalline. These results show that grain size increase from 19.5 nm to 29.5 with the increase of annealing temperature. The XRD results also reveal that the deposited thin film, annealed at 400 °C of TiO2 have anatase phase. Thin films annealed at 500 °C and 600 °C have mixed anatase and rutile phases. Full Width at Half Maximum (FWHM) values of the (101) peaks of these films decrease from 0.450° to 0.301° with the increase of annealing temperature. Surface morphology of the thin films have been studied by using atomic force microscopes (AFM). AFM measurements confirmed that the films have good crystalline and homogeneous surface. The Root Mean Square (RMS) value of thin films surface roughness are increased with the increase of annealing temperature.
الخلاصة
على (PLD) النانویة بوساطة تقنیة ترسیب اللیزر النبضي (TiO في ھذا البحث، تم انماء أغشیة اوكسید التیتانیوم ( 2
الرقیقة من 400 الى 600 درجة مئویة في الھواء مدة ساعتین . ودرس تأثیر TiO قواعد زجاجیة. ومن ثم لدنت أغشیة 2
التلدین في الخصائص التركیبیة والطبوغرافیة. عوامل عدیدة لأنماء الأغشیة اخذت بنظر الاعتبار لتحدید الحالة المثلى مثل
0.4 ) باستخدام J/cm 10-2 ) ،كثافة طاقة الفیض اللیزري( 2 Torr) 300 ) ،ضغط الأوكسجین ºC) درجة حرارة القاعدة
532 بمعدل تكراریة - 1 nm التردد المضاعف للیزر النیدیمیوم- یاك الذي یعمل بتقنیة عامل النوعیة عند الطول الموجي
6 ھرتز) وامد نبضة 10 نانوثانیة. تظُھر نتائج فحوصات الأشعة السینیة أن جمیع التراكیب النانویة رباعیة متعددة )
التبلور. وان ھذه النتائج تظھر زیادة في حجم الحبیبات من 19.5 نانومتر الى 29.5 نانومترمع زیادة درجة حرارة التلدین.
نتائج الأشعة السینیة اظھرت ایضا ان الغشاء المرسب والملدن في 400 درجة مئویة لثنائي اوكسید
Effect of Annealing on the Structural and Optical Properties of Nanostr...sarmad
Effect of Annealing on the Structural and Optical Properties of Nanostructured TiO2 Films Prepared By PLD. تأثير التلدين على الخواص التركيبية والبصرية لأغشية أوكسيد التيتانيوم (TiO2) ذات التراكيب النانوية المحضرة بتقنية ترسيب الليزر النبضي (PLD)
Transparent and Conducting TiO2 : Nb Thin Films Prepared by Spray Pyrolysis T...arj_online
To date, only sputtering and pulsed laser deposition (PLD) techniques have been employed
successfully to fabricate highly conducting and transparent TiO2:Nb (TNO) films. In this article, we demonstrate
that transparent and conducting
TiO2
: Nb
films can be made by the spray pyrolysis technique. The films were
deposited on Corning 7059 glass substrates at 500
15˚C using an alcoholic precursor solution consisting of
titanium (iv) isopropoxide and
NbCl5
. The influence of increasing
Nb
concentration on the electrical, optical
and structural properties was investigated. The minimum resistivity, 3.36
-3 10
Ω cm, for
Ti1-xNbxO2
film (x
= 0.15) was obtained after 1 hour post deposition annealing in hydrogen atmosphere at 500˚C. The x-ray
diffraction of hydrogen annealed films showed a polycrystalline anatase (004)-oriented phase without any second
phases. The optical band gap for undoped and doped films lay in the range 3.38 – 3.47 eV. Using dispersion
analysis, optical constants were determined from spectro-photometric measurements for films on glass.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Nanometric TiO2 powders were obtained from low tem-perature calcination of a TiO2 resin prepared using the Pechini’s method. Firing the TiO2 resin at 500 oC/2h a powder with anatase phase was obtained, otherwise firing the TiO2 resin at 700 oC/2h a powder with rutile phase was achieved as measured by X-ray diffraction (XRD). The anatase powder presented average particle size of 60 nm observed by Scanning Electronic Microscopy (SEM-FEG) micrographs and average crystallite size of 13 nm calcu-lated from the XRD, while the rutile powder presented av-erage crystallite size of 34 nm. Nanocrystalline TiO2 films with good homogeneity and optical quality were obtained with 80 nm and 320 nm in thickness by Electron Beam Physical Vapour Deposition (EB-PVD) in vacuum on amorphous quartz substrates submitted at 350oC during the evaporation. The 80 nm-thick film presented average particle size of 140 nm and roughness (Ra) of 1.08 nm and the 320 nm-thick film showed average particle size of 350 nm and roughness (Ra) of 2.14 nm measured by Atomic Force Microscopy (AFM). In these conditions of deposi-tion the films presented only anatase phase observed by XRD and MicroRaman spectroscopy.
Characterization of different dopants in TiO2 Structure by Pulsed Laser Dep...sarmad
Characterization of different dopants in TiO2 Structure by Pulsed Laser Deposition
A thesis submitted By: Khaled Z.Yahya
Supervised by: Prof.Dr. Adawiya J.Haider Prof.Dr. Raad M.S.Al-Haddad
Synthesis Of Nanostructured TiO2 Thin Films By Pulsed Laser Deposition (PLD) ...sarmad
Sarmad Sabih Al-Obaidi
Ali Ahmed Yousif
Abstract
In this work, nanostructured TiO2 thin films were grown by pulsed laser deposition (PLD) technique on glass substrates. TiO2 thin films then were annealed at 400-600 °C in air for a period of 2 hours. Effect of annealing on the structural and morphological were studied. Many growth parameters have been considered to specify the optimum conditions, namely substrate temperature (300 °C), oxygen pressure (10-2 Torr), laser fluence energy density (0.4 J/cm2), using double frequency Q-switching Nd:YAG laser beam (wavelength 532nm), repetition rate (1-6 Hz) and the pulse duration of 10 ns. The results of the X-ray test show that all nanostructures tetragonal are polycrystalline. These results show that grain size increase from 19.5 nm to 29.5 with the increase of annealing temperature. The XRD results also reveal that the deposited thin film, annealed at 400 °C of TiO2 have anatase phase. Thin films annealed at 500 °C and 600 °C have mixed anatase and rutile phases. Full Width at Half Maximum (FWHM) values of the (101) peaks of these films decrease from 0.450° to 0.301° with the increase of annealing temperature. Surface morphology of the thin films have been studied by using atomic force microscopes (AFM). AFM measurements confirmed that the films have good crystalline and homogeneous surface. The Root Mean Square (RMS) value of thin films surface roughness are increased with the increase of annealing temperature.
الخلاصة
على (PLD) النانویة بوساطة تقنیة ترسیب اللیزر النبضي (TiO في ھذا البحث، تم انماء أغشیة اوكسید التیتانیوم ( 2
الرقیقة من 400 الى 600 درجة مئویة في الھواء مدة ساعتین . ودرس تأثیر TiO قواعد زجاجیة. ومن ثم لدنت أغشیة 2
التلدین في الخصائص التركیبیة والطبوغرافیة. عوامل عدیدة لأنماء الأغشیة اخذت بنظر الاعتبار لتحدید الحالة المثلى مثل
0.4 ) باستخدام J/cm 10-2 ) ،كثافة طاقة الفیض اللیزري( 2 Torr) 300 ) ،ضغط الأوكسجین ºC) درجة حرارة القاعدة
532 بمعدل تكراریة - 1 nm التردد المضاعف للیزر النیدیمیوم- یاك الذي یعمل بتقنیة عامل النوعیة عند الطول الموجي
6 ھرتز) وامد نبضة 10 نانوثانیة. تظُھر نتائج فحوصات الأشعة السینیة أن جمیع التراكیب النانویة رباعیة متعددة )
التبلور. وان ھذه النتائج تظھر زیادة في حجم الحبیبات من 19.5 نانومتر الى 29.5 نانومترمع زیادة درجة حرارة التلدین.
نتائج الأشعة السینیة اظھرت ایضا ان الغشاء المرسب والملدن في 400 درجة مئویة لثنائي اوكسید
Effect of Annealing on the Structural and Optical Properties of Nanostr...sarmad
Effect of Annealing on the Structural and Optical Properties of Nanostructured TiO2 Films Prepared By PLD. تأثير التلدين على الخواص التركيبية والبصرية لأغشية أوكسيد التيتانيوم (TiO2) ذات التراكيب النانوية المحضرة بتقنية ترسيب الليزر النبضي (PLD)
Transparent and Conducting TiO2 : Nb Thin Films Prepared by Spray Pyrolysis T...arj_online
To date, only sputtering and pulsed laser deposition (PLD) techniques have been employed
successfully to fabricate highly conducting and transparent TiO2:Nb (TNO) films. In this article, we demonstrate
that transparent and conducting
TiO2
: Nb
films can be made by the spray pyrolysis technique. The films were
deposited on Corning 7059 glass substrates at 500
15˚C using an alcoholic precursor solution consisting of
titanium (iv) isopropoxide and
NbCl5
. The influence of increasing
Nb
concentration on the electrical, optical
and structural properties was investigated. The minimum resistivity, 3.36
-3 10
Ω cm, for
Ti1-xNbxO2
film (x
= 0.15) was obtained after 1 hour post deposition annealing in hydrogen atmosphere at 500˚C. The x-ray
diffraction of hydrogen annealed films showed a polycrystalline anatase (004)-oriented phase without any second
phases. The optical band gap for undoped and doped films lay in the range 3.38 – 3.47 eV. Using dispersion
analysis, optical constants were determined from spectro-photometric measurements for films on glass.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Study of Annealing Effect on the Some Physical Properties of Nanostructured T...sarmad
Ali A.Yousif ● , Sarmad S. Al-Obaidi ●●
Abstract
Nanostructured Titanium Dioxide (TiO2) thin films were prepared by pulsed
laser deposition (PLD) on the glass substrates. The effects of different annealing
temperature (400, 500 and 600 °C) towards the some physical properties such as
structural, morphological and optical have been studied. From X-ray diffraction
result, the crystallinity of TiO2 thin films improved at higher annealing
temperature. It also could be observed that the rutile phase start to exist at
annealing temperatures of 500 °C and 600 °C. The Full Width at Half
Maximum (FWHM) of the (101) peaks of these films decreases from 0.450° to
0.301° with increasing of annealing temperature. AFM measurements confirmed
that the films grown by this technique have good crystalline and homogeneous
surface. The Root Mean Square (RMS) value of thin films surface roughness
increased with increasing of the annealing temperature. From UV-VIS
spectrophotometer measurements, the optical transmission results shows that the transmission over than ~65% in the near-infrared region which decrease with the increasing of annealing temperatures. The allowed indirect optical band gap of the films was estimated to be in the range from 3.49 to 3.1 eV. The allowed direct band gap was found to decrease from 3.74 eV to 3.55 eV with the increase of annealing temperature. The refractive index of the films was found from 2.27 -2.98 at 550nm. The extinction coefficient, real and imaginary parts of the dielectric constant increase with annealing temperature.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Structural, Dielectric and Optical properties of Sputtered TiO2 nano-filmsIOSR Journals
Thin films of TiO2 were deposited on quartz and p-Si (100) substrates held at room temperature by sputtering of titanium target at various sputter powers in the range 80 - 200 W. The as-deposited films were annealed in air for an hour at 1023 K. The annealed films were characterized by using Fourier transform infra red spectroscopy, X-ray diffraction, Surface morphology, dielectric and optical properties. The deposition rate of the films increased from 1.26 to 6.66 nm/min. with increase of sputter power from 80 to 200 W. TiO2 films formed at sputter power of 80 W and annealed at 1023 K were polycrystalline in nature with anatase phase crystallite size of 40 nm, dielectric constant of 10, optical band gap of 3.65 eV and refractive index 2.35.
Microstructural and Magnetic Properties of Cobalt Ferrite Nanoparticles Synth...ijtsrd
Cobalt ferrite (CoFe2O4), an inverse spinal ferrite has high permeability, good saturation 1magnetization and no preferred direction of magnetization, high Curie temperature, and high electromagnetic performance. In the present work 0.2M cobalt nitrate 0.3M ferric nitrate and 0.4 M citric acid is used to synthesis cobalt ferrite nanoparticle by sol-gel technique. As the magnetic property depends on the grain size of the synthesized nanoparticle, metal nitrate to citric acid ratio is varied from 0.8, 0.6 and 0.4 and the structural, functional morphological and magnetic characteristics are analyzed. The structural analysis shows the decrease in the average crystallite from 37 to 27nm when CAMN ratio decreases from 0.8 to 0.4. The strain is directly proportional to dislocation density and it reflects the growth of the average grain size, and in the present study, it reflects the same. The calculated lattice parameter is found to be close to 8.373 Ã… and the volume of the cell is found to be 5.63x10-28 m is close to the standard value for the cobalt ferrite nanoparticles. From the EDS spectrum, the presence of Co, Fe, and O in the synthesized nanoparticles are noted. Functional groups analysis by FTIR shows the presence of organic sources. Surface morphology by Scanning electron microscope shows the distribution of spherical sized nanoparticles agglomerated in different sizes and the grain size calculated by image J software are close to the calculated value by Scherrer formula from XRD. Chitra | T Raguram | K S Rajni"Microstructural and Magnetic Properties of Cobalt Ferrite Nanoparticles Synthesized by Sol-Gel Technique" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd15871.pdf http://www.ijtsrd.com/physics/other/15871/microstructural-and-magnetic-properties-of-cobalt-ferrite-nanoparticles-synthesized-by-sol-gel-technique/chitra
Dielectric behaviour of Ni+2 substituted Cu Co Nanocrystalline Spinel Ferrite...inventionjournals
Herein, the dielectric properties such as permittivity (real part ε’ and imaginary part ε”) and dielectric loss tangent (tan δ) are reported for the series [Nix Cu(constant) Co0.8-x Fe2O4] where constant=0.2 with x=0.2, 0.4 and 0.6 of ferrites, prepared by Sol-Gel auto-combustion technique by using high purity metal nitrate and citric acid as a catalyst. The variation in the real part (ε’) of dielectric constant , imaginary part ( ε”) of dielectric constant and dielectric loss tangent (tan δ) are studied at room temperature in the frequency range of 100 Hz to 5 MHz. Structural characterization of the annealed samples was done with the help of X-ray diffraction method. The particle size and single phase formation of NiCuCoFe2O4 ferrite was confirmed by Xray diffraction analysis and TEM. The particle size of prepared sample was confirmed by Scherer’s formula. The effect on Particle size (t) and lattice constant (Å) is observed due to substitution of Ni2+ in Cu Co. The digital LCR meter is used to obtain the magnetic properties of prepared pallets. The variations in the structural and dielectric properties of the prepared ferrite material are discussed
Synthesis and characterization of zno thin films deposited by chemical bath t...eSAT Journals
Abstract ZnO thin films have been deposited on silica glass substrate using the chemical bath deposition technique. The precursors used were zinc chloride and aqueous ammonia. The solution was stirred continuously with the help of a magnetic stirrer at a bath temperature of 70 oC and a deposition time of 70 minutes. The elemental composition and the surface morphology were studied using energy dispersive and scanning electron microscopy. The band gap was 2.72, 2.66, 2.60 eV for as-deposited, annealed at 200 oC and 300 oC respectively. There was a red shift in the band gap energy as the annealing temperature was increased. This might be due to an improvement in the crystallinity of the ZnO thin films. Index Terms: Zinc oxide, chemical bath, band gap, annealing
Maiyalagan,Template synthesis and characterization of well aligned nitrogen c...kutty79
The synthesis of well-aligned nitrogen containing carbon nanotubes by pyrolysis of polyvinyl pyrrolidone (PVP) on alumina membrane
template is described. The nanotubes were characterized by elemental analysis, electron microscopic analyses, Raman, IR and X-ray photoelectron
(XPS) spectroscopic techniques. SEM, transmission electron microscopy (TEM) and AFM images reveal the hollow structures and
vertically aligned features of the nanotubes. Raman spectrum shows the characteristic bands at 1290 cm−1 (D-band) and 1590 cm−1 (G-band).
IR spectral bands indicated the characteristic C–N bonds in carbon nanotubes. This confirms the presence of nitrogen atoms in the carbon
framework. The XPS and elemental analyses further indicate significant amount of nitrogen in the nanotubes. IR, elemental and XPS analyses
clearly provide evidence for the presence of nitrogen in carbon nanotubes.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...Mahendra Kumar Trivedi
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
Improvement Structural and Optical Properties of ZnO/ PVA Nanocompositesiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Oral toxic exposure of titanium dioxide nanoparticles on serum biochemical ch...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Titanium dioxide (TiO2) nanoparticles (NPs) are widely used in commercial food additives and cosmetics worldwide. Uptake of these nanoparticulate into humans by different routes and may exhibit potential side effects, lags behind the rapid development of nanotechnology. Thus, the present study designed to evaluate the toxic effect of mixed rutile and anatase TiO2 NPs on serum biochemical changes in rats.
Materials and Methods:
In this study, adult male Wistar rats were randomly allotted into the experimental and control groups (n=6), which were orally administered with 50 and 100 mg/kg body weight of TiO2 NPs. Toxic effects were assessed by the changes of serum biochemical parameters such as glucose, total protein, albumin, globulin, cholesterol, triglyceride, high density lipoprotein, alanine transaminase, aspartate transaminase, alkaline phosphatase, total bilirubin, blood urea nitrogen, uric acid and creatinine. All the serum biochemical markers were experimented in rats, after 14-days of post exposure.
Results:
Changes of the serum specific parameters indicated that liver and kidney were significantly affected in both experimental groups. The changes between the levels of total protein, glucose, aspartate transaminase, alanine transaminase and alkaline phosphatase indicate that TiO2 NPs induces liver damage. Significant increase in the blood urea nitrogen and uric acid indicates the renal damage in the TiO2 NPs treated rats.
Conclusion:
The data shows that the oral administration of TiO2 NPs (<100nm) may lead to hepatic and renal toxicity in experimental rats.
Study of Annealing Effect on the Some Physical Properties of Nanostructured T...sarmad
Ali A.Yousif ● , Sarmad S. Al-Obaidi ●●
Abstract
Nanostructured Titanium Dioxide (TiO2) thin films were prepared by pulsed
laser deposition (PLD) on the glass substrates. The effects of different annealing
temperature (400, 500 and 600 °C) towards the some physical properties such as
structural, morphological and optical have been studied. From X-ray diffraction
result, the crystallinity of TiO2 thin films improved at higher annealing
temperature. It also could be observed that the rutile phase start to exist at
annealing temperatures of 500 °C and 600 °C. The Full Width at Half
Maximum (FWHM) of the (101) peaks of these films decreases from 0.450° to
0.301° with increasing of annealing temperature. AFM measurements confirmed
that the films grown by this technique have good crystalline and homogeneous
surface. The Root Mean Square (RMS) value of thin films surface roughness
increased with increasing of the annealing temperature. From UV-VIS
spectrophotometer measurements, the optical transmission results shows that the transmission over than ~65% in the near-infrared region which decrease with the increasing of annealing temperatures. The allowed indirect optical band gap of the films was estimated to be in the range from 3.49 to 3.1 eV. The allowed direct band gap was found to decrease from 3.74 eV to 3.55 eV with the increase of annealing temperature. The refractive index of the films was found from 2.27 -2.98 at 550nm. The extinction coefficient, real and imaginary parts of the dielectric constant increase with annealing temperature.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Structural, Dielectric and Optical properties of Sputtered TiO2 nano-filmsIOSR Journals
Thin films of TiO2 were deposited on quartz and p-Si (100) substrates held at room temperature by sputtering of titanium target at various sputter powers in the range 80 - 200 W. The as-deposited films were annealed in air for an hour at 1023 K. The annealed films were characterized by using Fourier transform infra red spectroscopy, X-ray diffraction, Surface morphology, dielectric and optical properties. The deposition rate of the films increased from 1.26 to 6.66 nm/min. with increase of sputter power from 80 to 200 W. TiO2 films formed at sputter power of 80 W and annealed at 1023 K were polycrystalline in nature with anatase phase crystallite size of 40 nm, dielectric constant of 10, optical band gap of 3.65 eV and refractive index 2.35.
Microstructural and Magnetic Properties of Cobalt Ferrite Nanoparticles Synth...ijtsrd
Cobalt ferrite (CoFe2O4), an inverse spinal ferrite has high permeability, good saturation 1magnetization and no preferred direction of magnetization, high Curie temperature, and high electromagnetic performance. In the present work 0.2M cobalt nitrate 0.3M ferric nitrate and 0.4 M citric acid is used to synthesis cobalt ferrite nanoparticle by sol-gel technique. As the magnetic property depends on the grain size of the synthesized nanoparticle, metal nitrate to citric acid ratio is varied from 0.8, 0.6 and 0.4 and the structural, functional morphological and magnetic characteristics are analyzed. The structural analysis shows the decrease in the average crystallite from 37 to 27nm when CAMN ratio decreases from 0.8 to 0.4. The strain is directly proportional to dislocation density and it reflects the growth of the average grain size, and in the present study, it reflects the same. The calculated lattice parameter is found to be close to 8.373 Ã… and the volume of the cell is found to be 5.63x10-28 m is close to the standard value for the cobalt ferrite nanoparticles. From the EDS spectrum, the presence of Co, Fe, and O in the synthesized nanoparticles are noted. Functional groups analysis by FTIR shows the presence of organic sources. Surface morphology by Scanning electron microscope shows the distribution of spherical sized nanoparticles agglomerated in different sizes and the grain size calculated by image J software are close to the calculated value by Scherrer formula from XRD. Chitra | T Raguram | K S Rajni"Microstructural and Magnetic Properties of Cobalt Ferrite Nanoparticles Synthesized by Sol-Gel Technique" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd15871.pdf http://www.ijtsrd.com/physics/other/15871/microstructural-and-magnetic-properties-of-cobalt-ferrite-nanoparticles-synthesized-by-sol-gel-technique/chitra
Dielectric behaviour of Ni+2 substituted Cu Co Nanocrystalline Spinel Ferrite...inventionjournals
Herein, the dielectric properties such as permittivity (real part ε’ and imaginary part ε”) and dielectric loss tangent (tan δ) are reported for the series [Nix Cu(constant) Co0.8-x Fe2O4] where constant=0.2 with x=0.2, 0.4 and 0.6 of ferrites, prepared by Sol-Gel auto-combustion technique by using high purity metal nitrate and citric acid as a catalyst. The variation in the real part (ε’) of dielectric constant , imaginary part ( ε”) of dielectric constant and dielectric loss tangent (tan δ) are studied at room temperature in the frequency range of 100 Hz to 5 MHz. Structural characterization of the annealed samples was done with the help of X-ray diffraction method. The particle size and single phase formation of NiCuCoFe2O4 ferrite was confirmed by Xray diffraction analysis and TEM. The particle size of prepared sample was confirmed by Scherer’s formula. The effect on Particle size (t) and lattice constant (Å) is observed due to substitution of Ni2+ in Cu Co. The digital LCR meter is used to obtain the magnetic properties of prepared pallets. The variations in the structural and dielectric properties of the prepared ferrite material are discussed
Synthesis and characterization of zno thin films deposited by chemical bath t...eSAT Journals
Abstract ZnO thin films have been deposited on silica glass substrate using the chemical bath deposition technique. The precursors used were zinc chloride and aqueous ammonia. The solution was stirred continuously with the help of a magnetic stirrer at a bath temperature of 70 oC and a deposition time of 70 minutes. The elemental composition and the surface morphology were studied using energy dispersive and scanning electron microscopy. The band gap was 2.72, 2.66, 2.60 eV for as-deposited, annealed at 200 oC and 300 oC respectively. There was a red shift in the band gap energy as the annealing temperature was increased. This might be due to an improvement in the crystallinity of the ZnO thin films. Index Terms: Zinc oxide, chemical bath, band gap, annealing
Maiyalagan,Template synthesis and characterization of well aligned nitrogen c...kutty79
The synthesis of well-aligned nitrogen containing carbon nanotubes by pyrolysis of polyvinyl pyrrolidone (PVP) on alumina membrane
template is described. The nanotubes were characterized by elemental analysis, electron microscopic analyses, Raman, IR and X-ray photoelectron
(XPS) spectroscopic techniques. SEM, transmission electron microscopy (TEM) and AFM images reveal the hollow structures and
vertically aligned features of the nanotubes. Raman spectrum shows the characteristic bands at 1290 cm−1 (D-band) and 1590 cm−1 (G-band).
IR spectral bands indicated the characteristic C–N bonds in carbon nanotubes. This confirms the presence of nitrogen atoms in the carbon
framework. The XPS and elemental analyses further indicate significant amount of nitrogen in the nanotubes. IR, elemental and XPS analyses
clearly provide evidence for the presence of nitrogen in carbon nanotubes.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...Mahendra Kumar Trivedi
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
Improvement Structural and Optical Properties of ZnO/ PVA Nanocompositesiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Oral toxic exposure of titanium dioxide nanoparticles on serum biochemical ch...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Titanium dioxide (TiO2) nanoparticles (NPs) are widely used in commercial food additives and cosmetics worldwide. Uptake of these nanoparticulate into humans by different routes and may exhibit potential side effects, lags behind the rapid development of nanotechnology. Thus, the present study designed to evaluate the toxic effect of mixed rutile and anatase TiO2 NPs on serum biochemical changes in rats.
Materials and Methods:
In this study, adult male Wistar rats were randomly allotted into the experimental and control groups (n=6), which were orally administered with 50 and 100 mg/kg body weight of TiO2 NPs. Toxic effects were assessed by the changes of serum biochemical parameters such as glucose, total protein, albumin, globulin, cholesterol, triglyceride, high density lipoprotein, alanine transaminase, aspartate transaminase, alkaline phosphatase, total bilirubin, blood urea nitrogen, uric acid and creatinine. All the serum biochemical markers were experimented in rats, after 14-days of post exposure.
Results:
Changes of the serum specific parameters indicated that liver and kidney were significantly affected in both experimental groups. The changes between the levels of total protein, glucose, aspartate transaminase, alanine transaminase and alkaline phosphatase indicate that TiO2 NPs induces liver damage. Significant increase in the blood urea nitrogen and uric acid indicates the renal damage in the TiO2 NPs treated rats.
Conclusion:
The data shows that the oral administration of TiO2 NPs (<100nm) may lead to hepatic and renal toxicity in experimental rats.
Preparation of Mixed Phase (Anatase/Rutile) TiO2 Nanopowder by Simple Sol Gel...IJLT EMAS
TiO2 nanopowder having both anatase and rutile
phases was prepared by a simple procedure using sol-gel method.
Titanium isopropoxide was used as a titania source and mixed
with methanol and TiO2 nanopowder was obtained after
annealing at 6000C for 1 hour in air. The specimens made from
this powder were characterized by X-ray diffraction (XRD),
Thermogravimetric analyzer (TGA) and Transmission electron
microscopy (TEM). XRD studies revealed the presence of both
anatase and rutile phases with an average crystallite size of 35 ±
5 nm. No significant weight loss up to 7000 C was observed by
TGA curve which indicates that TiO2 nanopowder is thermally
stable. TEM revealed the presence of a number of crystalline
grains in a structured matrix and selected electron diffraction
pattern showed different arrangement of diffracted rings which
confirms a phase evolution of crystalline grains of TiO2
(anatase/rutile) due to thermal annealing. Mixed phase
(anatase/rutile) TiO2 nanopowder has been reported [1], [2] to
exhibit improved photocatalytic and gas sensing properties. It is
proposed to study the gas sensing behavior of these specimens
during our research investigations on TiO2 nanopowder.
Synthesis and charecterization studies of nano ti o2 prepared via sol gel methodeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Photo-electrocatalytic activity of TiO2 nanotubes prepared with two-step anod...Iranian Chemical Society
To improve the photo-catalytic degradation of salicylic acid, we reported the fabrication of ordered TiO2 nanotube arrays by a simple and effective two-step anodization method and then these TiO2 nanotubes treated in a methanol solution under UV light irradiation. The TiO2 nanotubes prepared in the two-step anodization process showed better photo-catalytic activity than TiO2 nanotubes prepared in one-step anodization process. Also, compared with TiO2 nanotubes without the UV pretreatment, the TiO2 nanotubes pretreated in a methanol solution under UV light irradiation exhibited significant enhancements in both photocurrent and activity. The treated TiO2 nanotubes exhibited a 5-fold enhancement in photocurrent and a 2.5-fold increase in the photo-catalytic degradation of salicylic acid. Also the effect of addition of persulfate and periodate on the photo-catalytic degradation of salicylic acid were investigated. The results showed that the degradation efficiency of salicylic acid increased with increasing persulfate and periodate concentrations. These treated TiO2 nanotubes are promising candidates for practical photochemical reactors.
Maiyalagan,Electro oxidation of methanol on ti o2 nanotube supported platinum...kutty79
TiO2 nanotubes have been synthesized using anodic alumina membrane as template. Highly dispersed
platinum nanoparticles have been supported on the TiO2 nanotube. The supported system
has been characterized by electron microscopy and electrochemical analysis. SEM image shows
that the nanotubes are well aligned and the TEM image shows that the Pt particles are uniformly
distributed over the TiO2 nanotube support. A homogeneous structure in the composite nanomaterials
is indicated by XRD analysis. The electrocatalytic activity ofthe platinum catalyst supported on
TiO2 nanotubes for methanol oxidation is found to be better than that of the standard commercial
E-TEK catalyst.
Photoelectrochemical characterization of titania photoanodes fabricated using...Arkansas State University
Design and fabrication of new electrodes for photo-electrolysis using a material that is photo-active, stable, corrosion resistant, and cost effective.
Synthesis, characterization and electrocatalytic activity of silver nanorods ...kutty79
This paper describes a simple method of synthesizing silver nanorods using the polyol process, where propylene glycol serves both as a reducing
agent and as a solvent in the presence of a capping reagent such as polyvinylpyrrolidone (PVP). The diameter and length of silver nanorods could be
controlled by changing the AgNO3/PVP ratio. The end-to-end assembly of the silver nanorods was found. The silver nanorods were characterized by
using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and absorption spectroscopy. The catalytic activity of a
glassy carbon electrode with Ag nanorods exhibits extraordinary electrocatalytic activities towards the electro-reduction of benzyl chloride.
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward exploiting alternative energy resources such as solar energy. Here, we report the successful low-cost and easily accessible synthesis of hybrid semiconductor@TiO2 nanotube photocatalysts. In order to realize its maximum potential in harvesting photons in the visible-light range, TiO2 nanotubes have been loaded with earth-abundant, low-band-gap fibrous red and black phosphorus (P). Scanning electron microscopy– and scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV–vis measurements have been performed, substantiating the deposition of fibrous red and black P on top and inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular morphology of titania and a vapor-transport technique are utilized to form heterojunctions of P and TiO2. Compared to pristine anatase 3.2 eV TiO2 nanotubes, the creation of heterojunctions in the hybrid material resulted in 1.5–2.1 eV photoelectrocatalysts. An enhanced photoelectrochemical water-splitting performance under visible light compared with the individual components resulted for the P@TiO2 hybrids. This feature is due to synergistically improved charge separation in the heterojunction and more effective visible-light absorption. The electronic band structure and charge-carrier dynamics are investigated in detail using ultraviolet photoelectron spectroscopy and Kelvin probe force microscopy to elucidate the charge-separation mechanism. A Fermi-level alignment in P@TiO2 heterojunctions leads to a more reductive flat-band potential and a deeper valence band compared to pristine P and thus facilitates a better water-splitting performance. Our results demonstrate effective conversion efficiencies for the nanostructured hybrids, which may enable future applications in optoelectronic applications such as photodetectors, photovoltaics, photoelectrochemical catalysts, and sensors.
Vapor growth of binary and ternary phosphorus-based semiconductors into TiO2 ...Pawan Kumar
We report successful synthesis of low band gap inorganic polyphosphide and TiO2 heterostructures with the aid of short-way transport reactions. Binary and ternary polyphosphides (NaP7, SnIP, and (CuI)3P12) were successfully reacted and deposited into electrochemically fabricated TiO2 nanotubes. Employing vapor phase reaction deposition, the cavities of 100 μm long TiO2 nanotubes were infiltrated; approximately 50% of the nanotube arrays were estimated to be infiltrated in the case of NaP7. Intensive characterization of the hybrid materials with techniques including SEM, FIB, HR-TEM, Raman spectroscopy, XRD, and XPS proved the successful vapor phase deposition and synthesis of the substances on and inside the nanotubes. The polyphosphide@TiO2 hybrids exhibited superior water splitting performance compared to pristine materials and were found to be more active at higher wavelengths. SnIP@TiO2 emerged to be the most active among the polyphosphide@TiO2 materials. The improved photocatalytic performance might be due to Fermi level re-alignment and a lower charge transfer resistance which facilitated better charge separation from inorganic phosphides to TiO2.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...albertdivis
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
Maiyalagan,Performance of carbon nanofiber supported pd ni catalysts for elec...kutty79
Carbon nanofibers (CNF) supported Pd–Ni nanoparticles have been prepared by chemical reduction
with NaBH4 as a reducing agent. The Pd–Ni/CNF catalysts were characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical
voltammetry analysis. TEM showed that the Pd–Ni particles were quite uniformly distributed on the
surface of the carbon nanofiber with an average particle size of 4.0 nm. The electro-catalytic activity of
the Pd–Ni/CNF for oxidation of ethanol was examined by cyclic voltammetry (CV). The onset potential
was 200mV lower and the peak current density four times higher for ethanol oxidation for Pd–Ni/CNF
compared to that for Pd/C. The effect of an increase in temperature from 20 to 60 ◦C had a great effect on
increasing the ethanol oxidation activity
Polyamidoamine (PAMAM) dendrimers has
been anchored on functionalized carbon nanofibers (CNF)
and supported Pt–Ru nanoparticles have been prepared with
NaBH4 as a reducing agent. The samples were characterized
by X-ray diffraction, scanning electron microscopy,
and transmission electron microscopy (TEM) analysis. It
was shown that Pt–Ru particles with small average size
(2.6 nm) were uniformly dispersed on PAMAM/CNF
composite support and displayed the characteristic diffraction
peaks of Pt face-centered cubic structure. The electrocatalytic
activities of the prepared-composites (20% Pt–Ru/PAMAMCNF)
were examined by using cyclic voltammetry for
oxidation of methanol. The electrocatalytic activity of the
CNF-based composite (20% Pt–Ru/PAMAM-CNF) electrode
for methanol oxidation showed better performance than that
of commercially available Johnson Mathey 20% Pt–Ru/C
catalyst. The results imply that CNF-based PAMAM composite
electrodes are excellent potential candidates for
application in direct methanol fuel cells.
Maiyalagan, Synthesis and electro catalytic activity of methanol oxidation on...kutty79
Template synthesis of various nitrogen containing carbon nanotubes using different nitrogen containing polymers and the variation of nitrogen
content in carbon nanotube (CNT) on the behaviour of supported Pt electrodes in the anodic oxidation of methanol in direct methanol fuel cells was
investigated. Characterizations of the as-prepared catalysts are investigated by electron microscopy and electrochemical analysis. The catalyst with
N-containing CNT as a support exhibits a higher catalytic activity than that carbon supported platinum electrode and CNT supported electrodes.
The N-containing CNT supported electrodes with 10.5% nitrogen content show a higher catalytic activity compared to other N-CNT supported
electrodes. This could be due to the existence of additional active sites on the surface of the N-containing CNT supported electrodes, which favours
better dispersion of Pt particles. Also, the strong metal-support interaction plays a major role in enhancing the catalytic activity for methanol
oxidation.
Maiyalagan,Electrochemical oxidation of methanol on pt v2 o5–c composite cata...kutty79
Platinum nanoparticles have been supported on V2O5–C composite through the reduction of chloroplatinic
acid with formaldehyde. The catalyst was characterized by X-ray diffraction and transmission electron
microscopy. Catalytic activity and stability for the oxidation of methanol were studied by using
cyclic voltammetry and chronoamperometry. Pt/V2O5–C composite anode catalyst on glassy carbon electrode
show higher electro-catalytic activity for the oxidation of methanol. High electro-catalytic activities
and good stabilities could be attributed to the synergistic effect between Pt and V2O5, avoiding the electrodes
being poisoned.
Maiyalagan, Components of pem fuel cells an overviewkutty79
Fuel cells, as devices for direct conversion of the chemical energy of a fuel into
electricity by electrochemical reactions, are among the key enabling technologies for the transition
to a hydrogen-based economy. Among the various types of fuel cells, polymer electrolyte
membrane fuel cells (PEMFCs) are considered to be at the forefront for commercialization for
portable and transportation applications because of their high energy conversion efficiency and low
pollutant emission. Cost and durability of PEMFCs are the two major challenges that need to be
addressed to facilitate their commercialization. The properties of the membrane electrode assembly
(MEA) have a direct impact on both cost and durability of a PEMFC.
An overview is presented on the key components of the PEMFC MEA. The success of the MEA
and thereby PEMFC technology is believed to depend largely on two key materials: the membrane
and the electro-catalyst. These two key materials are directly linked to the major challenges faced in
PEMFC, namely, the performance, and cost. Concerted efforts are conducted globally for the past
couple of decades to address these challenges. This chapter aims to provide the reader an overview
of the major research findings to date on the key components of a PEMFC MEA.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
2. 706 T Maiyalagan, B Viswanathan and U V Varadaraju
2. Experimental 2.3 Characterization methods
2.1 Materials The scanning electron micrographs were obtained after
the removal of alumina template using a JEOL JSM-840
All the chemicals used were of analytical grade. Titanium model, working at 15 keV. For transmission electron micro-
isopropoxide (Aldrich), 2-propanol (Merck) and Degussa scopic studies, the nanotubes dispersed in ethanol were
P-25 titanium dioxide (Germany) were used as received placed on the copper grid and the images were obtained
(BET surface area, 50 m2/g and anatase : rutile ratio, 80 : 20). using Phillips 420 model, operating at 120 keV. The UV-
Anodisc alumina membranes with a pore size of 200 nm vis absorption spectra were obtained on a Cary 5E spec-
and thickness of 60 µm were purchased from Whatman trophotometer. The X-ray diffraction patterns were obtai-
(catalog no. 6809-6022; Maidstone, UK). ned on a Philips PW 1820 diffractometer with CuKα
(1⋅54178 Å) radiation. Micro-Raman scattering experi-
2.2 Synthesis of TiO2 nanotubes ments were performed on a Bruker FRA106 FT-Raman at
room temperature in a quasi-backscattering geometry
Titanium isopropoxide (5 ml) was added to 25 ml of 2- with parallel polarization incident light. The excitation
propanol (mole ratio [Ti4+]/[2-propanol] = 1 : 20). The source used was an Argon ion laser operating at 514⋅5 nm
solution was stirred for 3 h at room temperature (298 K). with an output power of 20 mW.
The alumina template membrane was dipped into this
solution for 2 min. After removal from the solution, vacuum
was applied to the bottom of the membrane until the entire 3. Results and discussion
volume of the solution was pulled through the membrane.
The membrane was then air-dried for 60 min at 303 K The scanning electron microscopic (SEM) image of the
and then placed in a furnace (in air) with a temperature TiO2 nanotubes obtained after dissolving the 200 nm alu-
ramp of 2°C min –1 to 873 K for 2 h. The temperature was mina template membranes is shown in figure 1a. It can be
then decreased at a ramp rate of 2°C min –1 to room tem- seen that an ordered array of nanotubes with uniform
perature (303 K). The ordered TiO2 nanotube arrays were diameter and length is formed. The individual TiO2 nano-
obtained by dissolving the alumina template in 3 M aqueous tubes were characterized by TEM after dissolving the
NaOH for several minutes. TiO2 nanotubes thus formed alumina membrane template. The open end and the hollow
were then washed several times with distilled water to nature of the TiO2 nanotubes have also been confirmed
remove the dissolved anodic alumina membrane and re- by transmission electron microscopic (TEM) image as
maining NaOH solution. shown in figure 1b. The TEM image shows that the single
Figure 1. SEM image (a) and TEM image (b) of TiO2 nanotubes obtained by sol–gel method calcined
at 650°C for 2 h.
3. Fabrication and characterization of uniform TiO2 nanotube arrays 707
TiO2 nanotube is straight and dense. The outer diameter the valence band (VB) to the conduction band (CB). An
of the nanotube is ca. 200 nm, retaining the size and near absorbance below 370 nm was observed for the TiO2
cylindrical shape of the pores of the aluminium oxide nanotubes, which is ascribed to bulk anatase TiO2 . Here
membrane. This indicates that the diameter of the nano- the blue shift of absorption maximum with higher band
tube synthesized is controlled by the pore size of aluminium energy of TiO2 nanotubes compared with that of the bulk
oxide membrane. This result is in agreement with other Degussa TiO2 can be attributed to the quantum-size effect
reports on the sol–gel based template method (Lee et al (Takagahara and Takeda 1992).
2004). The powder XRD was used to investigate the phase of
Figure 2 shows the UV-vis absorption spectrum of the TiO2 nanotubes. The X-ray pattern of the TiO2 nanotube
anatase TiO2 nanotube compared with that of the Degussa arrays is shown in figure 3(b). The diffraction peaks of
TiO2 . The spectral lines for both TiO2 nanotubes and De- (101), (004), (200), (105) and (211) correspond to the
gussa TiO2 exhibit only one characteristic absorption anatase TiO2 phase. The peak positions and their relative
band, which is assigned to the intrinsic transition from intensities are consistent with the standard powder diffrac-
tion pattern of anatase-TiO2 and there is no preferred ori-
entation. Figure 3 shows that the crystal phase of TiO2
nanotubes is polycrystalline anatase structure whereas the
Degussa P-25 contains a mixture of anatase and rutile
phases. Further, no peaks for the amorphous alumina
membrane were observed in the TiO 2 nanotubes.
The Raman spectra of fabricated anatase TiO2 nano-
tubes and Degussa TiO2 are shown in figure 4. The result
of XRD analysis is supported by the Raman spectra of
TiO2 nanotubes as shown in figure 4(b). The vibration
mode symmetries of the anatase are indicated. Raman
peaks at 156⋅9, 206, 408⋅48, 529⋅54, 649⋅54 and 801 cm–1
were assigned to E g, E g, B 1g, A 1g, E g and B 1g, respectively.
The positions and intensities of the six Raman active
modes correspond well with the anatase phase of TiO2
(Bersani and Lottici 1998; Lei et al 2001). A weak overtone
scattering (B 1g) at 801 cm –1 was observed in this study.
Overtone can be found in both bulk Degussa TiO2 and
nanotube, but the intensity of overtone is very less in bulk
Degussa TiO2 . This is due to the large intensity ratio of
Figure 2. UV-vis absorption spectrum of (a) Degussa TiO2
and (b) anatase TiO2 nanotube.
Figure 3. X-ray diffraction patterns of (a) Degussa TiO2 as a Figure 4. Raman spectrum of (a) Degussa TiO2 and (b) fabri-
reference and (b) TiO2 nanotubes obtained by sol–gel method cated anatase-TiO2 nanotube (The vibration mode symmetries
calcined at 650°C for 2 h anatase phase. of the anatase are indicated).
4. 708 T Maiyalagan, B Viswanathan and U V Varadaraju
fundamental peak to overtone one makes it difficult to be Gratzel M 2001 Nature 414 338
observed. While for nanotube, the decreasing ratio makes Gong D, Grimes C A, Varghese O K, Hu W, Singh R S, Chen Z
it easy to be observed. No significant broadening and and Dickey E C 2001 J. Mater. Res. 16 3331
shift of Raman spectra were found when one compared Hagfeldt A and Gratzel M 1995 Chem. Rev. 95 49
Homyara H et al 2001 Thin Solid Films 386 173
the obtained anatase-TiO2 nanotube with that of the bulk
Huang S Y, Kavan L, Gratzel M and Exnar I 1995 J. Electro-
Degussa TiO2 . chem. Soc. 142 142
Kasuga T, Hiramatsu M, Hoson A, Sekino T and Niihara K
4. Conclusions 1998 Langmuir 14 3160
Kavan L, Attia A, Lenzmann F, Elder S H and Gratzel M 2000
J. Electrochem. Soc. 147 2897
In summary, highly ordered TiO2 nanotubes and nano-
Lakshmi B B, Patrissi C J and Martin C R 1997 Chem. Mater. 9
fibrils have been synthesized by sol–gel chemical method 2544
within the pores of anodic alumina template membrane. Lee S, Jeon C and Park Y 2004 Chem. Mater. 16 4292
The results of SEM and TEM show that the synthesized Lei Y, Zhang L D and Fan J C 2001 Chem. Phys. Lett. 338
nanotubes have a uniform length, diameter and form a 231
highly ordered array and the XRD measurements confirm Livraghi S, Votta A, Paganini M C and Giamello E 2005 Chem.
the presence of polycrystalline anatase phase in the TiO2 Commun. 4 498
nanotubes. This method can be employed for obtaining Macak J M, Tsuchiya H and Schmuki P 2005 Angew. Chem.
large surface area TiO2 for use in photocatalysis and as Int. Ed. 44 2100
electrodes in solar cells. Maiyalagan T and Viswanathan B 2005 Mater. Chem. Phys. 93
291
Martin C R 1996 Chem. Mater. 8 1739
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1165
We thank the Council of Scientific and Industrial Research Poulios I, Kositzi M and Kouras A 1998 J. Photochem. Photo-
(CSIR), India, for a senior research fellowship to one of biol. A: Chem. 115 175
the authors (TM). Quan X, Yang S, Ruan X and Zhao H 2005 Environ. Sci. Tech-
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Sander M S, Cote M J, Gu W, Kile B M and Tripp C P 2004
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