scholarly journals CO CLUSTER FORMATION IN TiO2 DMS AND A METHOD OF ESTIMATION

2017 ◽  
Vol 24 (1&2) ◽  
pp. 199-204
Author(s):  
Le Van Hong ◽  
Nguyen Chi Thuan ◽  
Nguyen Van Dai ◽  
Nguyen Xuan Phuc
Keyword(s):  
Raman Scattering ◽  
Magnetic Moment ◽  
Annealing Temperature ◽  
Anatase Phase ◽  
Cluster Formation ◽  
Sol Gel ◽  
Magnetic Hysteresis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Magnetization

The paper presents experimental observations of the Co cluster formation in TiO2/Co powder samples prepared by the Sol-Gel method. The obtained X-ray diffraction patterns and Raman scattering show that the anatase phase of TiO2 was successfully synthesized at an annealing temperature of 450°C. Comprehensive studies by means of X-ray diffraction, Raman scattering, thermal magnetization in a temperature range of 300–1000 K and magnetic hysteresis at room temperature confirm that a part of Co did not substitute for Ti in TiO2 structure, otherwise it has reasonably formed cluster of Co in samples. Based on the thermal magnetization curves a method to estimate the magnetic moment per one Co ion substituted for Ti in TiO2 structure was proposed. By means of this method the volume of Co substituted for Ti has been estimated for samples annealed at various temperatures around 450°C. The obtained results show that the volume of Co cluster rises when the annealing temperature increases. This obtained result persuasively explains the large divergence in the magnetic moment per one Co ion reported in the most published papers. 

Fourier Electron Density Maps for Nanostructured TiO2 and TiO2-CeO2 Sol-Gel Solid

2009 ◽  
Vol 5 ◽  
pp. 87-94 ◽  
Author(s):  
Félix Galindo-Hernández ◽  
Ricardo Gómez
Keyword(s):  
Crystallite Size ◽  
Electron Density ◽  
Annealing Temperature ◽  
Anatase Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Electronic Density ◽  
X Ray ◽  
Density Maps ◽  
Gel Preparation

Sol-gel TiO2 and TiO2–CeO2 materials were synthesized at pH3 using HNO3 as hydrolysis catalysts. Gels were annealed at 473, 673 and 873 K for 4h. X-ray diffraction Rietveld refinement was used to determine the mean crystallite size, TiO2 stoichiometry (titanium deficiency) and Fourier electronic density maps. It has been found that the fractal surface dimension diminishes on TiO2 a nd TiO2–CeO2 surfaces as the annealing temperature increases. The X-ray diffraction patterns showed nanocrystalline anatase phase in the range of 8.9 to 43.6 nm in depending of the annealing temperature. A dependency between the crystallite size and the titanium deficiency [V+Ti4+] per unit cell was found, as lowest is the crystallite highest is the titanium deficiency. Strong differences on the Fourier electron density map were found on TiO2 and TiO2–CeO2 materials. It was concluded that the sol-gel preparation method favors the formation of nanosized TiO2 with high Ti4+ stoichiometry deficiency.

Photoluminescence of Eu3+-Doped TiO2 Thin Films Prepared by Sol-Gel Method

2010 ◽  
Vol 150-151 ◽  
pp. 707-710
Author(s):  
Dan Hong Wang ◽  
Xiao Ru Zhao ◽  
Hui Nan Sun ◽  
Li Bing Duan ◽  
Chang Le Chen
Keyword(s):  
Thin Films ◽  
Doping Concentration ◽  
Annealing Temperature ◽  
Anatase Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method

The sol-gel method was employed to prepare the Eu3+-doped TiO2 thin films. The influence of doping concentration and annealing temperature on the structures and photoluminescence (PL) properties was investigated. The result of X-ray diffraction revealed that all the films are of anatase phase. It is shown that the PL intensities of the films increased with Eu3+ concentration and reached the maximum at 1.4 mol%, then decreased with the concentration. Observed anatase phase appeared at temperature above 400 °C, and the luminescence intensity increased with the increase of annealing temperature.

Synthesis and characterization of MnO2nanowires

2017 ◽  
Vol 31 (02) ◽  
pp. 1750006 ◽  
Author(s):  
Mohammad Hossein Ghorbani ◽  
Abdol Mahmood Davarpanah
Keyword(s):  
Lithium Batteries ◽  
Manganese Oxides ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Method

Manganese oxides are of more interest to researchers because of their ability as catalysts and lithium batteries. In this research, MnO2nanowires with diameter about 45 nm were synthesized by sol–gel method at room temperature (RT). Effect of increasing the annealing temperature from 400[Formula: see text]C to 600[Formula: see text]C on crystalline structure of nanostructure were studied and average crystallite size was estimated about 22 nm. X-ray Diffraction (XRD) method, Energy-Dispersive X-ray Diffraction (EDXD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) were used to characterize the nanowires of MnO2.

EFFECT OF ANNEALING ON THE PROPERTIES OF VANADIUM PENTOXIDE FILMS PREPARED BY SOL–GEL METHOD

2014 ◽  
Vol 21 (02) ◽  
pp. 1450027 ◽  
Author(s):  
YAQIANG LIU ◽  
XUELIAN DU ◽  
XUEQIN LIU
Keyword(s):  
Vanadium Pentoxide ◽  
Annealing Temperature ◽  
Substrate Surface ◽  
Sol Gel ◽  
Amorphous Structure ◽  
Spectral Transmittance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tauc Plot ◽  
Silicon Substrate Surface

The vanadium pentoxide ( V 2 O 5) films were obtained by using sol–gel procedure and then were annealed at different temperature in air. The effect of different annealing temperatures on the composition, the microstructure, the surface morphology and the optical properties of the films were characterized by methods such as by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and spectral transmittance. The results revealed that the film annealed at 150°C has amorphous structure and dense with a smooth surface and the films annealed at 300°C and 450°C have a polycrystalline V 2 O 5 structure with preferred growth orientation along (001) planes, the c-axis and perpendicular to the silicon substrate surface. From the spectral transmittance we determined the absorption edge using the Tauc plot. The results indicated that optical bandgap of V 2 O 5 thin films decreased with annealing temperature.

Characterization of Titanium Dioxide Nanopowder Synthesized by Sol Gel Grinding Method

2012 ◽  
Vol 626 ◽  
pp. 425-429 ◽  
Author(s):  
N.N. Hafizah ◽  
Mohamed Zahidi Musa ◽  
Mohamad Hafiz Mamat ◽  
M. Rusop
Keyword(s):  
Electron Microscopy ◽  
Anatase Phase ◽  
Sol Gel ◽  
Precursor Concentration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grinding Method ◽  
Fesem Micrographs ◽  
Scanning Electron

In this study, TiO2nanopowder was synthesized via a sol-gel grinding method. The effects of TiO2precursor concentration of TiO2nanopowder were investigated. The TiO2nanopowder obtained were characterized using X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM) for their structural properties. From the calculation of the crystallite size in XRD, the size of the nanoparticles obtained is 49.55 nm at the highest TiO2precursor concentration. In contrast, at the lower concentration of 0.4 molar give the cryatallite size of 12.84 nm. Further, XRD and Raman spectrum results confirmed the TiO2nanopowder obtain composed of only anatase phase. The FESEM micrographs of TiO2nanopowder also were discussed in this paper.

Dielectric Properties of Sol-Gel Derived MgAl2O4 Thin Films

2012 ◽  
Vol 151 ◽  
pp. 314-318
Author(s):  
Ching Fang Tseng ◽  
Cheng Hsing Hsu ◽  
Chun Hung Lai
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Dissipation Factor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Preheating Temperature ◽  
Surface Morphologies

This paper describes microstructure characteristics of MgAl2O4 thin films were deposited by sol-gel method with various preheating temperatures and annealing temperatures. Particular attention will be paid to the effects of a thermal treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction. The surface morphologies of treatment film were examined by scanning electron microscopy and atomic force microscopy. At a preheating temperature of 300oC and an annealing temperature of 700oC, the MgAl2O4 films with 9 μm thickness possess a dielectric constant of 9 at 1 kHz and a dissipation factor of 0.18 at 1 kHz.

SiO2ZrO2 Thin Films as Low Temperature NO2 and O3 Sensors

2015 ◽  
Vol 1088 ◽  
pp. 81-85 ◽  
Author(s):  
T.N. Myasoedova ◽  
Victor V. Petrov ◽  
Nina K. Plugotarenko ◽  
Dmitriy V. Sergeenko ◽  
Galina Yalovega ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Operating Temperatures ◽  
Scanning Electron

Thin SiO2ZrO2films were prepared, up to 0.2 μm thick, by means of the sol–gel technology and characterized by a Scanning electron microscopy and X-ray diffraction. It is shown the presence of monoclinic, cubic and tetragonal phases of ZrO2in the SiO2matrix. The crystallites sizes depend on the annealing temperature of the film and amount to 35 and 56 nm for the films annealed at 773 and 973 K, respectively. The films resistance is rather sensitive to the presence of NO2and O3impurity in air at lower operating temperatures in the range of 30-60°C.

scholarly journals Reducing the ordering temperature of FePt nanoparticles by Cu additive and alternate reduction method

2017 ◽  
Vol 07 (06) ◽  
pp. 1750039
Author(s):  
Fang Wang ◽  
Xiaojun Bai
Keyword(s):  
Annealing Temperature ◽  
Reduction Method ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Metal Salts ◽  
Fept Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Cu Additive

(FePt)[Formula: see text]Cu[Formula: see text] nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium. Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature. Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature. It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.

A comparative study of doped and un-doped sol-gel TiO2 and P25 TiO2 (photo)electrodes

2007 ◽  
Vol 55 (12) ◽  
pp. 153-160 ◽  
Author(s):  
Y. Pooarporn ◽  
A. Worayingyong ◽  
M. Wörner ◽  
P. Songsiriritthigul ◽  
A.M. Braun
Keyword(s):  
Indium Tin Oxide ◽  
Electrochemical Impedance ◽  
Anatase Phase ◽  
Sol Gel ◽  
Oxide Glass ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Titanium Dioxide Films ◽  
Indium Tin Oxide Glass

Doped and undoped titanium dioxide films have been deposited on indium tin oxide glass using the sol-gel technique. The percentage of rutile in the prepared TiO2, calcined at 823 K and determined by X-ray diffraction, was 23% compared to 24% of rutile in P25-TiO2. Cerium doped TiO2 showed mainly the anatase phase, as characterised by both X-ray diffraction and Raman spectroscopy. The electrochemical and photoelectrochemical properties of the films were studied by cyclic voltammetry and electrochemical impedance spectroscopy. The (photo)electrochemical characteristics of the different films are reported and discussed.

scholarly journals Antibacterial Activity of Ag-Doped TiO2 and Ag-Doped ZnO Nanoparticles

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Gebretinsae Yeabyo Nigussie ◽  
Gebrekidan Mebrahtu Tesfamariam ◽  
Berhanu Menasbo Tegegne ◽  
Yemane Araya Weldemichel ◽  
Tesfakiros Woldu Gebreab ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Zno Nanoparticles ◽  
Pathogenic Bacteria ◽  
Anatase Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
Sem Images ◽  
X Ray ◽  
Doped Zno

We report in this paper antibacterial activity of Ag-doped TiO2 and Ag-doped ZnO nanoparticles (NPs) under visible light irradiation synthesized by using a sol-gel method. Structural, morphological, and basic optical properties of these samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectrum, and UV-Vis reflectance. Room temperature X-ray diffraction analysis revealed that Ag-doped TiO2 has both rutile and anatase phases, but TiO2 NPs only have the anatase phase. In both ZnO and Ag-doped ZnO NPs, the hexagonal wurtzite structure was observed. The morphologies of TiO2 and ZnO were influenced by doping with Ag, as shown from the SEM images. EDX confirms that the samples are composed of Zn, Ti, Ag, and O elements. UV-Vis reflectance results show decreased band gap energy of Ag-doped TiO2 and Ag-doped ZnO NPs in comparison to that of TiO2 and ZnO. Pathogenic bacteria, such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, were used to assess the antibacterial activity of the synthesized materials. The reduction in the viability of all the three bacteria to zero using Ag-doped ZnO occurred at 60 μg/mL of culture, while Ag-doped TiO2 showed zero viability at 80 μg/mL. Doping of Ag on ZnO and TiO2 plays a vital role in the increased antibacterial activity performance.

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