scholarly journals Preparation and Characterization of Nanosized Substituted Perovskite Compounds with Orthorhombic Structure

2021 ◽  
Vol 22 (4) ◽  
pp. 664-686
Author(s):  
M.B. Khanvilkar ◽  
A.K. Nikumbh ◽  
R.A. Pawar ◽  
N.J. Karale ◽  
D.V. Nighot ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Hall Effect ◽  
Inductively Coupled Plasma ◽  
Average Particle Size ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
Orthorhombic Structure ◽  
Magnetic Studies ◽  
Ionic Radii ◽  
X Ray

In this work, five substituted perovskite such as (Gd0.9Sr0.1) Mn0.8Co0.2O3, Tb0.8Sr0.2FeO3, Gd0.6Sr0.4RuO3, SrCe0.95Y0.05O3, and Mn0.6Co0.4SnO3 were synthesized by tartrate and hydroxide precursor method. The resulting samples were characterized by inductively coupled plasma spectroscopy, energy dispersive X-ray analysis, infrared spectroscopy, thermal analysis, X-ray powder diffraction, transmission electron microscope (TEM), selected field of electron diffraction (SAED), d.c. electrical conductivity, Hall effect, dielectric measurements, and low-temperature magnetization measurements. The X-ray diffraction pattern for all compounds was indicated the formation of single-phase perovskite with orthorhombic structure except Tb0.8Sr0.2FeO3 and Mn0.6Co0.4SnO3 perovskite. These compounds showed a cubic and rhombohedral structure, respectively. The lattice parameter and the unit cell volume slightly decreased as ionic radii decrease in agreement with the lanthanide contraction. The average size of cation ˂ RA ˃, mismatch factor (σ2), and tolerance factor (t) gives the combined effects of disorder and inhomogeneity in these compounds. The average particle size determined from TEM was in the range of 22 to 77 nm for all compounds. The temperature dependence of electrical conductivity for all compounds showed a definite break in 500 K to 610 K. except the Gd0.6Sr0.4RuO3 compound, which corresponds to semiconducting behavior. While the Gd0.6Sr0.4RuO3 sample shows a metallic-like semiconductor. The thermoelectric power and Hall effect measurements for all compounds were n-type semiconductivity except the SrCe0.95Y0.05O3 compound. It showed p-type semiconductivity. The frequency dependence of the dielectric constant and dielectric loss in these substituted perovskites were discussed using the Maxwell-Wagner model. Magnetic studies showed that the thermo-magnetic irreversibility for all compounds.

Preparation, characterization and dechlorination property of nano Pd-Ni/γ-Al2O3 bimetallic catalyst

2019 ◽  
Vol 12 (06) ◽  
pp. 1951003 ◽  
Author(s):  
Yu Zhang ◽  
Yiyang Wang ◽  
Yalong Liao ◽  
Muyuan Guo ◽  
Gongchu Shi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Bimetallic Catalyst ◽  
Average Particle Size ◽  
Nitrogen Adsorption ◽  
Precipitation Method ◽  
Emission Spectrometry ◽  
Average Particle ◽  
Plasma Atomic Emission Spectrometry ◽  
X Ray

Nano Pd-Ni/[Formula: see text]-Al2O3 bimetallic catalyst was prepared by chemical precipitation method enhanced with ultrasonic wave. The influence of dosage of dispersant, ultrasonic intensity and mass ratio of Pd to Ni on the dechlorination property of the catalyst obtained was investigated in detail. The appearance morphology, composition and structure of the catalysts prepared were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption, while the specific surface area was determined using the Brunauer–Emmett–Teller (BET) isotherm and the chemical composition of active gradients was tested with inductively coupled plasma-atomic emission spectrometry (ICP-AES). Results indicate that the nano Pd-Ni/[Formula: see text]-Al2O3 bimetallic catalyst prepared has uniform distribution of active ingredients with an average particle size of 4.91[Formula: see text]nm, and the chlorine content of shellac dechlorinated with the catalyst obtained is 0.34[Formula: see text]wt.% which is lower than that reported in the literature, meaning the perfect dechlorination property of the catalyst.

scholarly journals Dielectric properties of BNT-xBT prepared by hydrothermal process

2017 ◽  
Vol 07 (03) ◽  
pp. 1750019 ◽  
Author(s):  
Natheer B. Mahmood ◽  
Emad K. Al-Shakarchi
Keyword(s):  
Strong Dependence ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Industrial Applications ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Depolarization Temperature ◽  
X Ray ◽  
Ceramic Disc

The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications, especially in energy harvesting from crystal vibrations. In order to enhance the performance of BNT ceramic, the solid solution was chosen by substitution with Ba[Formula: see text] at Morphtropic Phase Boundary (MPB). The BNT-[Formula: see text]BT powders with [Formula: see text], 0.07, 0.06 and 0 were prepared by the hydrothermal method with average particle size (65–150[Formula: see text]nm) at (90[Formula: see text]C/72[Formula: see text]h). The ceramic disc was sintered at (1150[Formula: see text]C/4[Formula: see text]h) and showed excellent relative density of about 96%. The results of X-ray diffraction (XRD) confirmed the MPB for [Formula: see text] and 0.07, while the BNT had a rhombohedral structure and BT had a tetragonal structure. The dielectric measurements showed that BNT, BNT-7BT, BNT-6BT behave as the relaxator ferroelectric and showed a strong dependence on frequency, especially in the MPB region while BT behaves as a normal ferroelectric. Both the Curie temperature and depolarization temperature decrease at the MPB region and showed strong dependency on frequency.

Characterization of Bismuth Titanate Powders

2007 ◽  
Vol 26-28 ◽  
pp. 247-250 ◽  
Author(s):  
Pusit Pookmanee ◽  
Sukon Phanichphant
Keyword(s):  
Single Phase ◽  
Bismuth Titanate ◽  
Sol Gel ◽  
Average Particle Size ◽  
Titanium Isopropoxide ◽  
Average Particle ◽  
Orthorhombic Structure ◽  
Acetic Acid Medium ◽  
X Ray

Bismuth titanate was prepared from the sol-gel method. Bismuth nitrate and titanium isopropoxide were used as the starting precursors with the mole ratio of Bi:Ti as 4:3. Solutions were mixed in acetic acid medium and heat at 80 oC for 2h. Sols were obtained after adjusting the final of pH of solution to 2. Gels were formed after drying at 100 oC for 24h. The milled powders were calcined at 500-800 oC for 2h. The phase formation was investigated by X-ray diffractometry (XRD). Single phase with orthorhombic structure of bismuth titanate was obtained after calcination at 700 oC for 2h. The morphology and chemical composition were studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The average particle size was 0.50- 1.5 μm with the irregular shape. The elemental composition of bismuth, titanium and oxygen showed the characteristic X-ray energy values.

scholarly journals X-RD, TEM, Magnetic Studies on NixZn1-xFe2O4 (Where x= 0.2, 0.4, 0.5, 0.6 and 0.8) Nano Scale Particles by Chemical Co-Precipitation Method

2015 ◽  
Vol 60 ◽  
pp. 20-24
Author(s):  
B. Suryanarayana ◽  
V. Raghavendra ◽  
K. Chandra Mouli
Keyword(s):  
Average Particle Size ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Zinc Nanoparticles ◽  
X Ray ◽  
Xrd Patterns ◽  
Co Precipitation

Nickel zinc nanoparticles NixZn1-xFe2O4 (where x= 0.2, 0.4, 0.5, 0.6 and 0.8) by Chemical Co-Precipitation method. The samples were characterised by X-ray diffraction (XRD), TEM, VSM .The powders of XRD patterns confirm a single spinel crystalline phase with cubic structure formation with no indication of any other secondary or unidentified phase. The lattice parameter changed from 8.336 Å to 8.382 Å. The average particle size ranged 20 to 80 nm was observed by TEM.

Fabrication of Bi0.5Na0.5ZrO3 Powder by Mixed Oxide Method

2011 ◽  
Vol 695 ◽  
pp. 49-52 ◽  
Author(s):  
Panupong Jaiban ◽  
Ampika Rachakom ◽  
Suwapitcha Buntham ◽  
Sukanda Jiansirisomboon ◽  
Anucha Watcharapasorn
Keyword(s):  
Mixed Oxide ◽  
Dwell Time ◽  
Single Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bismuth Sodium ◽  
Powder Phase

Lead-free bismuth sodium zirconate powder with formula Na0.5Bi0.5ZrO3 was prepared by conventional mixed oxide method. Bismuth sodium zirconate (BNZ) powder with 10wt%Na2CO3 was calcined at 800 °C for 2 h dwell time. Investigation of the effects of re-calcination and dwell time on phase formation of powders was also carried out. The results revealed that re-calcination significantly affected the formation of single-phase BNZ powder. Phase characteristics were checked by X-ray diffraction (XRD). Powder Cell software was employed to simulate crystal structure of BNZ powder. It was found that BNZ powder most likely possessed an orthorhombic structure. SEM result showed its average particle size was 0.47 mm and composition measured EDX correlated with theoretical composition of BNZ.

scholarly journals Chemical Synthesis of Crystalline, Pure or Mn-doped ZnGa2O4 Powders at 90 °C

2002 ◽  
Vol 17 (6) ◽  
pp. 1425-1433 ◽  
Author(s):  
A. Cuneyt Tas ◽  
Peter J. Majewski ◽  
Fritz Aldinger
Keyword(s):  
Inductively Coupled Plasma ◽  
Average Particle Size ◽  
Atomic Emission ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Air Atmosphere ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Mn Doped

Crystalline, pure or Mn-doped ZnGa2O4 powders have been prepared in situ in urea (with or without enzyme urease)-containing Zn and Ga nitrate (and Mn nitrate) solutions by simply holding those for 24–48 h, at 90 °C, in screw-capped glass bottles in a constant-temperature laboratory oven. Single-phase pure or Mn-doped zinc gallate powders synthesized with the spinel crystal structure had an average particle size around 15 to 18 nm. Powders were characterized by x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectroscopy, inductively-coupled plasma atomic emission spectroscopy, simultaneous thermogravimetry and differential thermal analysis, Fourier-transformed infrared spectroscopy, and carbon and nitrogen analyses. Calcination behavior of the as-filtered powders was later studied in an air atmosphere over the temperature range of 90 to 1200 °C.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

Influence of Excess Bi2O3 and Na2Co3 on Crystal Structure and Microstructure of Bismuth Sodium Titanate Ceramics

2011 ◽  
Vol 474-476 ◽  
pp. 1711-1714 ◽  
Author(s):  
Panadda Sittiketkron ◽  
Arrak Klinbumrung ◽  
Theerachai Bongkarn
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Perovskite Phase ◽  
Average Particle Size ◽  
Sodium Titanate ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
Average Grain Size

This study investigated the influence of excess Bi2O3 and Na2CO3 on the crystal structure, microstructure and dielectric properties of (Bi0.5Na0.5)TiO3 (BNT) ceramics. The BNT ceramics were synthesized using the solid-state reaction method with various excess Bi2O3 and Na2CO3 levels (0, 1, 2, 3 and 4 mol%). The X-ray characterization revealed that all samples had a rhombohedral structure. A pure perovskite phase was obtained in all samples. The lattice parameter a tended to increase with increased excess Bi2O3 and Na2CO3 content in the calcined powders and sintered ceramics. The average particle size increased while, the average grain size tended to decreased with increased of excess Bi2O3 and Na2CO3 content. The depolarization temperature (Td) and the Curie temperature (Tc) were slightly decreased with the increase of excess Bi2O3 and Na2CO3 content. The dielectric properties were related to the density.

Fabrication of monoclinic BiVO4 photocatalyst film and its photocatalytic activity for organic pollutant removal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saranyoo Chaiwichian ◽  
Buagun Samran
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Average Particle Size ◽  
Pollutant Removal ◽  
Light Irradiation ◽  
Average Particle ◽  
Film Sample ◽  
Acid Orange 7 ◽  
Acid Orange ◽  
X Ray

Abstract Monoclinic BiVO4 photocatalyst films decorated on glass substrates were successfully fabricated via a dip-coating technique with different annealing temperatures of 400 °C, 450 °C, 500°C, and 550 °C. All of the physical and chemical properties of as-prepared BiVO4 photocatalyst film samples were investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectra techniques. The results revealed that the as-prepared BiVO4 photocatalyst film samples retained a monoclinic phase with an average particle size of about 50 – 100 nm. Moreover, the BiVO4 photocatalyst film samples showed a strong photoabsorption edge in the range of visible light with the band gap energy of 2.46 eV. The photocatalytic activities of all the film samples were tested by the degradation of model acid orange 7 under visible light irradiation. The BiVO4 photocatalyst film sample annealed at a temperature of 500 °C showed the highest photoactivity efficiency compared with other film samples, reaching up to 51%within 180 min. In addition, the stability and reusability of BiVO4 photocatalyst film sample made with an annealing temperature of 500 °C did not show loss of photodegradation efficiency of acid orange 7 after ten recycles. A likely mechanism of the photocatalytic process was established by trapping experiments, indicating that the hydroxyl radical scavenger species can be considered to play a key role for acid orange 7 degradation under visible light irradiation.

Nanocrystalline α-Fe2O3: A Superparamagnetic Material for w-LED Application and Waste Water Treatment

2021 ◽  
Author(s):  
Mahesh Gaidhane ◽  
Deepak Taikar ◽  
Pravin Gaidhane ◽  
Kalpana Nagde
Keyword(s):  
Photocatalytic Activity ◽  
Waste Water Treatment ◽  
Sol Gel ◽  
Average Particle Size ◽  
Emission Spectra ◽  
Broad Emission Band ◽  
Average Particle ◽  
X Ray ◽  
Prepared Material ◽  
Cie Chromaticity

Abstract Nanocrystalline α-Fe2O3 is synthesized by sol-gel technique. The prepared nanomaterial was characterized by X-ray diffraction (XRD), SEM, TEM, Fourier Transform Infrared (FTIR) spectroscopy, Vibrating Sample Magnetometry (VSM) and photoluminescence (PL) techniques. X-ray powder diffraction analysis confirmed the formation of α-Fe2O3. Electron microscopy showed spherical morphologies with an average particle size of 30-40 nm. The magnetic property of the prepared material was studied by VSM at room temperature. VSM study shows superparamagnetic nature of the synthesized nanoparticles. Photoluminescence (PL) emission spectra show intense broad emission band centered at 570 nm with 393 nm excitation indicating its usefulness for w-LED application. The CIE-chromaticity color coordinates of prepared material were calculated. The photocatalytic activity of the α-Fe2O3 nanoparticles was analyzed and the nanopowder exhibited good photocatalytic activity for the removal AO7 from its aqueous solution.

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