Preparation and investigation of co-doped VO2 powders

2019 ◽  
Vol 12 (02) ◽  
pp. 1950015 ◽  
Author(s):  
Lingna Liu ◽  
Yi Hou ◽  
Xiuzhao Yin ◽  
Fang Zhang ◽  
Zifei Peng
Keyword(s):  
Phase Transition ◽  
Vanadium Dioxide ◽  
Room Temperature ◽  
Hydrothermal Reaction ◽  
Raw Materials ◽  
Sodium Molybdate ◽  
Tungstic Acid ◽  
Ft Ir ◽  
Preliminary Study ◽  
Co Doped

In this paper, tungsten-and molybdenum-doped vanadium dioxide (VO[Formula: see text] powders were prepared by hydrothermal reaction using vanadium pentoxide (V2O[Formula: see text], H2O2, white tungstic acid (WPTA) and sodium molybdate (Na2MoO[Formula: see text] as raw materials. The microstructure and composition of VO2 powders were characterized by means of XRD, XPS, DSC and FT-IR. We made a preliminary study on the thermal-induced phase transition properties of powders. The experimental results show that the co-doped samples are monoclinic rutile. Tungsten and molybdenum atoms exist in the lattice at the positive six valence. When the W and M W were 3% and 2%, respectively, the transition temperature of co-doped samples were close to room temperature can reach 25.5∘C.

Preliminary Study of WO3 Nanostructures Produced via Facile Hydrothermal Synthesis Process for CO2 Sensing

2013 ◽  
Vol 431 ◽  
pp. 37-41 ◽  
Author(s):  
Amirul Abd Rashid ◽  
Nor Hayati Saad ◽  
Chia Sheng Daniel Bien ◽  
Wai Yee Lee ◽  
M.A.S.M. Haniff
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Hydrothermal Reaction ◽  
Hydrothermal Process ◽  
Single Step ◽  
Synthesis Process ◽  
Sensor Element ◽  
Response Measurement ◽  
Sensor Fabrication ◽  
Preliminary Study

Tungsten trioxide (WO3) nanostructure with aspect ratio of 20 (length/diameter) have been successfully synthesized by single step hydrothermal reaction at moderate temperature of 180 °C. The crystal structure and morphology evolution are characterized by SEM and Raman while the carbon dioxide (CO2) sensing capability was tested by simple sensor fabrication .It was observed that the nanorods were initially coalesce in bundles before breaking up loosely towards the end of the hydrothermal process. A response measurement reveals that the sensor was able to detect CO2 at room temperature with the sensitivity around 13ohm/100 ppm. The detection performance of such nanostructure provides a positive indication that it can be a competitive sensor element candidate not only for CO2 applications in particular but can be expanded to other gas sensing application such as O2, C2H4 and NO2.

Characteristic Investigations of Stoichiometric LiNbO3 Single Crystal Fiber Co-Doped with Tb and Mn

2004 ◽  
Vol 449-452 ◽  
pp. 985-988
Author(s):  
S.M. Lee ◽  
J.W. Shur ◽  
T.I. Shin ◽  
W.S. Yang ◽  
G.Y. Kim ◽  
...  
Keyword(s):  
Absorption Band ◽  
Single Crystal ◽  
Optical Microscopy ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Crystal Fiber ◽  
Ft Ir ◽  
Homogeneous Distributions ◽  
Co Doped

[MnO2(1.0mol%) : Tb4O7(0.5mo%)] doped stoichiometric LiNbO3 (Mn:Tb:SLN) single crystals of 0.5~1.0 mm in diameter and 30~35 mm in length were grown by micro pulling down(µ-PD) method. We investigated the photoluminescence (PL) properties of Mn:Tb:SLN single crystal. The OH- absorption band of the single crystals observed infrared the absorption spectra by using an FT-IR spectrophotometer at room temperature. Homogeneous distributions of Mn and Tb concentration were confirmed by the EPMA and observed defects by optical microscopy.

Minimum Particle Diameter of the Vanadium/Iron Co-Doped Nano TiO2 Transparent Hydrosol at Room Temperature

2014 ◽  
Vol 989-994 ◽  
pp. 611-614
Author(s):  
Ling Li ◽  
Wen Ming Zhang ◽  
Hua Yan Zhang ◽  
Zi Hao Xu ◽  
Sen Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Raw Materials ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Ferric Nitrate ◽  
Average Particle ◽  
Hydrolysis Method ◽  
Vanadium Iron ◽  
Co Doped

Vanadium/iron co-doped nanoTiO2 transparent hydrosol with an average particle size of 3.8 nm was synthesized by a novel complexation-controlled hydrolysis method at room temperature and atmospheric pressure by using TiCl4, ferric nitrate, ammonium metavanadate, etc. as raw materials. The composition, phase structure, particle size, absorbance spectrum, and photocatalytic performance of samples were characterized by XRD, EDS, nanolaser particle size analyzer, and UV-Vis spectrophotometer. The photocatalytic properties of V/Fe doped TiO2 were studied through degrading acid 3R dye, and the results show that when the content of V/Fe was 0.5%, the degradation rate reached more than 96% under irridation for 60 min.

Structural Phase Transition of Tungsten-Doped Vanadium Dioxide Nanopowders Prepared by Thermolysis

2008 ◽  
Vol 8 (3) ◽  
pp. 1417-1421 ◽  
Author(s):  
Zifei Peng ◽  
Wei Jiang ◽  
Heng Liu
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Transition Temperature ◽  
Vanadium Dioxide ◽  
Structural Phase ◽  
Hysteresis Loops ◽  
Tungstic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron

Tungsten-doped vanadium dioxide (VO2) nanopowders were prepared by thermolysis of (NH4)5[(VO)6(CO3)4(OH)9] · 10H2O at low temperature, with active white powdery tungstic acid used as a substitutional dopant. The composition and microstructure of the powders were examined by X-ray diffraction, transmission electron microscope, and differential scanning calorimetry. The change in electrical resistance due to the S–M transition was measured from 0 to 150 °C by the four-probe method. Hysteresis loops and differential scanning calorimetry analysis of the samples indicated that the phase-transition temperature of VO2 nanopowders was 67.15 °C. For tungstendoped VO2 nanopowders, the temperature was reduced to 26.46 °C. After sintering the nanopowders, Tc rose from 26.46 °C to 34.85 °C with the sizes increasing to the bulk. A significant direct correlation between particle size and Tc was confirmed. The results indicated that white powdery tungstic acid is exceptionally effective as a dopant for reducing transition temperature.

Preparation of Strontium Ferrite Powders by Mechanochemical Process

2011 ◽  
Vol 110-116 ◽  
pp. 1736-1740 ◽  
Author(s):  
Ju Hua Luo
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Single Phase ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Starting Mixture ◽  
Ft Ir ◽  
Mechanochemical Treatments ◽  
Firing Method

Sr-ferrite powders were preparated by mechanochemical treatments using SrCO3 and Fe2O3 as raw materials. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM) were employed to evaluated the morphologies, structures and magnetic properties of samples. The results indicated that the starting mixture became amorphous stage after ball-milled for 30h, and single phase SrFe12O19 could be obtained after annealed at 900°C for 2h. And the saturation magnetization was 58.2Am2/kg, and coercivity was 281.2 kA/m at room temperature. In comparison with the traditional firing method , the mechanochemical method benefited achieving the higher coercivity, which indicated that the samples had a better magnetic properties.

Characterization of Chitin Extracted from Waste Sources via XRD, FTIR, and TGA Techniques

2012 ◽  
Vol 488-489 ◽  
pp. 1404-1408 ◽  
Author(s):  
Suraida Basosidik ◽  
Piyapong Pankaew ◽  
Ekachai Hoonnivathana ◽  
Pichet Limsuwan ◽  
Kittisakchai Naemchanthara
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Raw Materials ◽  
Crab Shell ◽  
Shrimp Shell ◽  
Naoh Solution ◽  
Ft Ir

This work presents the chitin preparation from waste sources, the chitin powders were successfully extracted from shrimp shell, crab shell and squid pen. To prepare chitin powders, all raw materials were washed and grounded using agate mortar, which the particle size of powder is 212–250 μm. Then, the powdered materials were immersed into solution of chloroform and methanol (with 2:1 ratio) at room temperature for removing fat. The deprotienation and decarbonation, the samples were immersed in 50 wt% of NaOH solution for 24 h and in 4 wt% of HCl for 1 h, respectively. The XRD, FT-IR and TGA techniques were used to indicate the different characteristic between α-chitin and β-chitin prepare.

Study on Defect Complexes in High-K Sr and Zr Co-Doped BaTiO3 Ceramics

2013 ◽  
Vol 750-752 ◽  
pp. 501-505
Author(s):  
Da Yong Lu ◽  
Xiu Yun Sun
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Diffuse Phase Transition ◽  
Room Temperature ◽  
Raman Band ◽  
Phase Transition Behavior ◽  
Defect Complexes ◽  
High K ◽  
Diffuse Phase ◽  
Co Doped

In order to investigate the evidence for the formation of Sr2+-Zr4+ defect complexes in high-k Sr and Zr co-doped BaTiO3 ceramics, BaTiO3, (Ba0.85Sr0.15)TiO3, Ba (Ti0.8Zr0.2)O3, and (Ba0.85Sr0.15)(Ti0.8Zr0.2)O3 (BS15TZ20) ceramics were prepared using a mixed oxide method. The Y5V-type BS15TZ20 shows a high-k diffuse phase transition behavior (ε ́m = 8000) and its Curie peak occurs near room temperature. The evolution in crystal structure and in dielectric property for the four samples gives four evidences for the formation of Sr2+-Zr4+ defect complexes in BS15TZ20. The splitting of the 720 cm-1 Raman band does not relate to Sr2+-Zr4+ defect complexes, but to a multiphonon (A1 (TO2) + A1 (TO3)).

The Synthesis and Characterization of Zinc Borate Zn2B6O11·7H2O

2013 ◽  
Vol 652-654 ◽  
pp. 795-798
Author(s):  
Xin Liu ◽  
Shao Ju Bian ◽  
Dan Dan Gao ◽  
Qing Fen Meng ◽  
Ming Wei ◽  
...  
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Zinc Borate ◽  
Synthesis And Characterization ◽  
Ft Ir

Zinc borate Zn2B6O11•7H2O was prepared at room temperature using Na2B4O7•10H2O, ZnSO4•7H2O and H3BO3 as raw materials. The synthesized product was characterized by XRD, SEM, TG-DSC and FT-IR. SEM results showed that the synthesized zinc borate had uniform morphology with a length up to a few microns. The experiment result indicates that additional H3BO3 in starting materials was beneficial to the uniform morphology of Zn2B6O11•7H2O.

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