scholarly journals Phase Transformations and Photocatalytic Activity of Nanostructured Y2O3/TiO2-Y2TiO5 Ceramic Such as Doped with Carbon Nanotubes

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1943
Author(s):  
Artem L. Kozlovskiy ◽  
Inesh Z. Zhumatayeva ◽  
Dina Mustahieva ◽  
Maxim V. Zdorovets
Keyword(s):  
Phase Transition ◽  
Carbon Nanotubes ◽  
Photocatalytic Activity ◽  
Phase Composition ◽  
Annealing Temperature ◽  
Orthorhombic Phase ◽  
Uv Spectra ◽  
Initial Sample ◽  
X Ray ◽  
Nanostructured Ceramics

This work is devoted to the study of phase transition processes in nanostructured ceramics of the Y2O3/TiO2-Y2TiO5 type doped with carbon nanotubes as a result of thermal annealing, as well as to the assessment of the prospects of the effect of phase composition on photocatalytic activity. By the method of X-ray phase analysis, it was found that an increase in the annealing temperature leads to the formation of the orthorhombic phase Y2TiO5, as well as structural ordering. Based on the obtained UV spectra, the band gap was calculated, which varies from 2.9 eV (initial sample) to 2.1 eV (annealed at a temperature of 1000 °C). During photocatalytic tests, it was established that the synthesized nanostructured ceramics Y2O3/TiO2-Y2TiO5 doped CNTs show a fairly good photocatalytic activity in the range of 60–90% decomposition of methyl orange.

scholarly journals Photocatalytic Activity and Optical Properties of Blue Persistent Phosphors under UV and Solar Irradiation

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
C. R. García ◽  
L. A. Diaz-Torres ◽  
J. Oliva ◽  
M. T. Romero ◽  
P. Salas
Keyword(s):  
Photocatalytic Activity ◽  
Annealing Temperature ◽  
Uv Light ◽  
Solar Irradiation ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Water Cleaning ◽  
Different Temperatures ◽  
The Eu

Blue phosphorescent strontium aluminosilicate powders were prepared by combustion synthesis route and a postannealing treatments at different temperatures. X-ray diffraction analysis showed that phosphors are composed of two main hexagonal phases: SrAl2O4and Sr3Al32O51. The morphology of the phosphors changed from micrograins (1000°C) to a mixture of bars and hexagons (1200°C) and finally to only hexagons (1300°C) as the annealing temperature is increased. Photoluminescence spectra showed a strong blue-green phosphorescent emission centered atλem=455 nm, which is associated with4f65d1→4f6  (8S7/2)transition of the Eu2+. The sample annealed at 1200°C presents the highest luminance value (40 Cd/m2) with CIE coordinates (0.1589, 0.1972). Also, the photocatalytic degradation of methylene blue (MB) under UV light (at 365 nm) was monitored. Samples annealed at 1000°C and 1300°C presented the highest percentage of degradation (32% and 38.5%, resp.) after 360 min. In the case of photocatalytic activity under solar irradiation, the samples annealed at 1000°C, 1150°C, and 1200°C produced total degradation of MB after only 300 min. Hence, the results obtained with solar photocatalysis suggest that our powders could be useful for water cleaning in water treatment plants.

The tetragonal-to-orthorhombic phase transition in RbAlF4: an X-ray scattering study

1990 ◽  
Vol 2 (51) ◽  
pp. 10549-10558 ◽  
Author(s):  
F Brunet ◽  
D F McMorrow ◽  
A Gibaud ◽  
C Patterson
Keyword(s):  
Phase Transition ◽  
Orthorhombic Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

CHARACTERISATION OF Al DEFECTS IN SmBa2Cu3-XAlXO6+δ SUPERCONDUCTOR

2003 ◽  
Vol 17 (04n06) ◽  
pp. 936-941 ◽  
Author(s):  
M. SCAVINI ◽  
L. MOLLICA ◽  
R. BIANCHI ◽  
G. A. COSTA ◽  
M. FERRETTI ◽  
...  
Keyword(s):  
Phase Transition ◽  
Short Range ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Orthorhombic Phase ◽  
Superconducting Phase ◽  
Al Doping ◽  
X Ray ◽  
Reducing Conditions ◽  
Almost All

We present here a study on the effect of Al doping on the stucture of SmBa 2 Cu 3-X Al X O 6+δ (Sm-123) superconductor. Electron MicroProbe Analysis (EMPA) and X-Ray Powder Diffraction (XRPD) have revealed that the limit of a aluminium solubility x is between 0.5 and 0.6. For further doping BaAl 2 O 4 appears besides the superconducting phase. XRPD analysis on samples annealed in both oxidising and reducing conditions have revealed that the Al doping inhibits the tetragonal to orthorhombic phase transition. Nuclear Magnetic Resonance (NMR) analysis has shown that almost all the Al ions are coordinated tetrahedrally. The comparison between oxygen non-stoichiometry in pure and Al doped SmBa 2 Cu 3-X Al X O 6+δ suggests that the Al ions are ordered in clusters. A model is proposed for short-range order around Al doping ions which allows us to interpret the phase transition inhibition.

scholarly journals X Preparation and Characterization of Carbon-Based Composite Nanofibers for Supercapacitor

2017 ◽  
Vol 17 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Dawei Gao ◽  
Lili Wang ◽  
Chunxia Wang ◽  
Yuping Chang ◽  
Pibo Ma
Keyword(s):  
Carbon Nanotubes ◽  
Phase Composition ◽  
Electron Microscope ◽  
Surface Area ◽  
Composite Nanofibers ◽  
Carbon Composite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Abstract Polyacrylonitrile (PAN)/Co(OAc)2/carbon nanotubes (CNTs) composite nanofibers were fabricated via electrospinning with N,N-dimethylformamide (DMF) as solvent, and by carbonization and activation of the above precursor nanofibers, porous carbon composite nanofibers were successfully obtained. Scanning electron microscope, X-ray diffraction, ASAP 2020, and Solartron 1470 were used to characterize the surface morphology, the phase composition, specific surface area, and electrochemical property of the nanofibers, respectively. The result showed that some of the fibers were broken after sintering, and the surface area and pore volume of the porous C/Cu/CNTs were 771 m2/g and 0.347 cm3/g, respectively. The specific capacitance of the composite nanofibers reached up to 210 F/g at the current density of 1.0 A/g. Its energy density and power density were 3.1 Wh/Kg and 2,337 W/Kg, respectively, at the current of 0.5 and 5 mA.

The Preparation of InxBi1-xVO4 Photocatalyst Particles and their Photocatalytic Activity

2013 ◽  
Vol 726-731 ◽  
pp. 491-494
Author(s):  
En Guo Wang ◽  
Zhen Qin Zhan
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Sintering Temperature ◽  
Orthorhombic Phase ◽  
Indium Content ◽  
Light Irradiation ◽  
Solid Reaction ◽  
X Ray

InxBi1-xVO4 photocatalyst particles were prepared by low temperature solid reaction using nitrate of indium and bismuth and NH4VO4 as the starting materials, and followed by the sintering at various temperatures. The as-prepared samples were investigated by X-ray powder diffraction (XRD), and the photocatalytic activity was carried out by the concentration change of methylene blue in the solution after visible light irradiation. The experiment results show that the orthorhombic phase InVO4 is dominant in the photocatalyst samples prepared at sintering temperature higher than 600°C. In addition, the increase in indium content in the InxBi1-xVO4 particle has greatly improved the photocatalytic activity for decomposition of aqueous methylene blue under visible light irradiation.

Preparation of Mesoporous Magnetic TiO2/CoFe2O4 Photocatalysts Using Ionic Liquid as Template Agent

2013 ◽  
Vol 345 ◽  
pp. 201-204 ◽  
Author(s):  
Kai Wang ◽  
Lan Bo Di ◽  
Li Juan Zhang ◽  
Gui Fu Dong ◽  
Xiu Ling Zhang
Keyword(s):  
Phase Transition ◽  
Methylene Blue ◽  
Ionic Liquid ◽  
Photocatalytic Activity ◽  
Calcination Temperature ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bet Analysis

A simple sol-gel method using 1-butyl-3-methylimidazoliun tetrafluoroborate ([C4MIM]BF4) ionic liquid as template agent was used to prepared mesoporous magnetic TiO2/CoFe2O4photocatalysts (denoted as IL-TiO2/CoFe2O4). The photocatalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis. The results showed that well crystallized anatase TiO2in IL-TiO2/CoFe2O4photocatalysts could be obtained when the calcination temperature was as low as 200 °C, and the phase transition temperature from anatase to rutile was increased to 800 °C. BET analysis showed that IL-TiO2/CoFe2O4was mesoporous structure. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of methylene blue (MB). The results showed that photocatalytic activity of IL-TiO2/CoFe2O4was 6 times higher than that of TiO2/CoFe2O4when a low calcination temperature of 350 °C was used.

Preparation of Nano-Sized TiO2 Photocatalysts by a Multi-Gelation Method and Their Application to the Degradation of 2-Propanol Diluted in Water

2005 ◽  
Vol 486-487 ◽  
pp. 93-96
Author(s):  
B. Neppolian ◽  
Hiromi Yamashita ◽  
Yusuke Okada ◽  
H. Nishijima ◽  
Masakazu Anpo
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
Photocatalytic Activity ◽  
Phase Composition ◽  
Pore Diameter ◽  
Rutile Phase ◽  
Tio2 Photocatalysts ◽  
Tio2 Particles ◽  
Control Of Parameters ◽  
Ph Swing

TiO2 photocatalysts prepared by a novel multi-gelation method showed good photocatalytic activity for the degradation of 2-propanol diluted in water by the control of parameters such as particle size, surface area, crystallinity, pore-volume, pore-diameter as well as anatase and rutile phase composition by changing the number of pH swings during preparation. In particular, with this method the phase transition from anatase to rutile at higher pH swing times can be controlled and high purity and uniformity of the TiO2 particles which leads to higher photocatalytic activity of the particles can be achieved. From our experimental results, it has been observed that TiO2 catalysts prepared by this unique multi-gelation method, i.e., adopting variations in the pH swing, significantly shows higher photocatalytic activity for the degradation of 2- propanol diluted in water. It can be considered a viable alternative over existing commercial methods for the preparation of photofunctional catalysts.

The monoclinic/orthorhombic phase transition in Ba2Cu(HCOO)6: An optical and x-ray powder diffraction study

2000 ◽  
Vol 72 (1) ◽  
pp. 15-24 ◽  
Author(s):  
G. Polla ◽  
D. Vega ◽  
A. G. Leyva ◽  
P. K. De Perazzo ◽  
H. Lanza ◽  
...  
Keyword(s):  
Phase Transition ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Orthorhombic Phase ◽  
X Ray

scholarly journals Impact of Machining and Phase Composition Change of Titanium Alloyed with Molybdenum

2022 ◽  
Author(s):  
B. Kodess
Keyword(s):  
Phase Composition ◽  
Single Crystal ◽  
High Precision ◽  
Orthorhombic Phase ◽  
Unit Cell Dimension ◽  
Unit Cell ◽  
Cell Dimension ◽  
Composition Change ◽  
X Ray

Abstract. The titanium samples alloyed with molybdenum and aluminum are used to conduct full high-precision X-ray experiments enabling to determine the characteristic of the atomic interrelations - the unit cell dimension, and to establish the phase components of the doped single crystal. An orthorhombic phase is found, the volume of which increases after the deformation impact.

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