scholarly journals Structural and Optical Properties of Zirconia Nanoparticles by Thermal Treatment Synthesis

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Aysar S. Keiteb ◽  
Elias Saion ◽  
Azmi Zakaria ◽  
Nayereh Soltani
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Thermal Treatment ◽  
Calcination Temperature ◽  
Large Scale ◽  
Homogeneous Solution ◽  
Treatment Method ◽  
Nanocrystalline Powder ◽  
Average Particle ◽  
Zirconia Nanoparticles

Zirconium dioxide nanoparticles with monoclinic blended structure were successfully synthesized by thermal treatment method using zirconium (IV) acetate hydroxide as the metal precursor, polyvinylpyrrolidone as the capping agent, and deionized water as a solvent. The chemicals were mixed and stirred to form a homogeneous solution and hereafter directly underwent calcination to attain the pure nanocrystalline powder, which was confirmed by FTIR, EDX, and XRD analyses. The control over the size and optical properties of nanoparticles was achieved through changing in calcination temperatures from 600 to 900°C. The obtained average particle sizes from XRD spectra and TEM images showed that the particle size increased with increasing calcination temperature. The optical properties which were investigated using a UV-Vis spectrophotometer showed a decrease in the band gap energy with increasing calcination temperature due to the enlargement of the particle size. These results prove that, by eliminating drying process (24 h) in the present thermal treatment method, size-controlled zirconia nanoparticles were conveniently manufactured with a reduction of synthesize time and energy consumption, suitable for large-scale fabrication.

Fabrication and Characterization of Nanospinel ZnCr2O4 Using Thermal Treatement Method

2015 ◽  
Vol 1107 ◽  
pp. 301-307 ◽  
Author(s):  
Salahudeen A. Gene ◽  
Elias B. Saion ◽  
Abdul Halim Shaari ◽  
Mazliana A. Kamarudeen ◽  
Naif Mohammed Al-Hada
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Average Particle Size ◽  
Treatment Method ◽  
Esr Spectra ◽  
Resonance Spectroscopy ◽  
Average Particle ◽  
Face Centered Cubic ◽  
X Ray ◽  
Xrd Patterns

The fabrication of nanospinel zinc chromite (ZnCr2O4) crystals by the means of thermal treatment method from an aqueous solution containing metal nitrates, polyvinyl pyrrolidone (PVP), and deionized water was described in this study. The samples were calcined at various temperatures ranging from 773 to 973 K for the decomposition of the organic compounds and crystallization of the nanocrystals. PVP was used as capping agent to control the agglomeration of the particles. The characterization studies of the fabricated samples were carried out by X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), energy dispersed X-ray spectroscopy (EDX) and electron spin resonance spectroscopy (ESR). The corresponding peaks of Zn, Cr and O were observed in the EDX spectrum of the sample which confirms the formation of ZnCr2O4. The XRD patterns also confirmed the formation of the single faced nanocrystallines of spinel ZnCr2O4 with a face-centered cubic structure. The average particle size of the synthesized crystals was also determined from the XRD patterns using the Scherers formula which shows that the crystallite sizes increases with increase in calcination temperature and was in good agreement with the TEM images which shows cubical ZnCr2O4 nanocrystals with uniform morphology and particle size distributions. The ESR spectra confirmed the existence of unpaired electron in the fabricated samples and the increase in g-factor and decreases in resonant magnetic field (Hr) were observed as the calcination temperature increases.

scholarly journals The Influence of Calcination Temperature on the Formation of Zinc Oxide Nanoparticles by Thermal-Treatment

2013 ◽  
Vol 446-447 ◽  
pp. 181-184 ◽  
Author(s):  
Naif Mohammed Al-Hada ◽  
Elias Saion ◽  
A.H. Shaari ◽  
M.A. Kamarudin ◽  
Salahudeen A. Gene
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Thermal Treatment ◽  
Band Gap ◽  
Calcination Temperature ◽  
Zinc Oxide Nanoparticles ◽  
Treatment Method ◽  
Band Gap Energy ◽  
Oxide Nanoparticles ◽  
Gap Energy

Zinc oxide nanoparticles were synthesized by the thermal-treatment method. Polyvinyl pyrrolidone was used as capping agent and Zinc nitrate was used as a precursor. The samples were calcined at 500 and 550°C for removal of the organic compounds. The structural characteristics of the calcined samples were examined by X-ray diffraction and transmission electron microscopy. The results show that the average particle size increases with increase in calcination temperature. The optical properties were characterized at room temperature using a UV–Vis spectrophotometer in the wavelength range between 200–800 nm and the band gap energy was calculated from reflectance spectra using kubalka munk function and the results indicated that the band gap energy decreased from 3.23 eV at 500 oC to 3.21 eV at 600 °C due to an increase of particle size. This simple thermal-treatment method has advantages of the pure nanoparticles formation as no additional chemicals were required, a lack of by-product effluents, and environmentally friendly process.

scholarly journals Influence of Calcination Temperature on Crystal Growth and Optical Characteristics of Eu3+ Doped ZnO/Zn2SiO4 Composites Fabricated via Simple Thermal Treatment Method

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 115
Author(s):  
Suhail Huzaifa Jaafar ◽  
Mohd Hafiz Mohd Zaid ◽  
Khamirul Amin Matori ◽  
Sidek Hj. Ab Aziz ◽  
Halimah Mohamed Kamari ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Band Gap ◽  
Calcination Temperature ◽  
Emission Intensity ◽  
Emission Spectra ◽  
Treatment Method ◽  
Absorption Bands ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Zno Crystal

This research paper proposes the usage of a simple thermal treatment method to synthesis the pure and Eu3+ doped ZnO/Zn2SiO4 based composites which undergo calcination process at different temperatures. The effect of calcination temperatures on the structural, morphological, and optical properties of ZnO/Zn2SiO4 based composites have been studied. The XRD analysis shows the existence of two major phases which are ZnO and Zn2SiO4 crystals and supported by the finding in the FT-IR. The FESEM micrograph further confirms the existence of both ZnO and Zn2SiO4 crystal phases, with progress in the calcination temperature around 700–800 °C which affects the existence of the necking-like shape particle. Absorption humps discovered through UV-Vis spectroscopy revealed that at the higher calcination temperature effects for higher absorption intensity while absorption bands can be seen at below 400 nm with dropping of absorption bands at 370–375 nm. Two types of band gap can be seen from the energy band gap analysis which occurs from ZnO crystal and Zn2SiO4 crystal progress. It is also discovered that for Eu3+ doped ZnO/Zn2SiO4 composites, the Zn2SiO4 crystal (5.11–4.71 eV) has a higher band gap compared to the ZnO crystal (3.271–4.07 eV). While, for the photoluminescence study, excited at 400 nm, the emission spectra of Eu3+ doped ZnO/Zn2SiO4 revealed higher emission intensity compared to pure ZnO/Zn2SiO4 with higher calcination temperature exhibit higher emission intensity at 615 nm with 700 °C being the optimum temperature. The emission spectra also show that the calcination temperature contributed to enhancing the emission intensity.

scholarly journals Surface and Catalytic Properties of NiO and Co3O4 Solids Doped with Cobalt and Nickel Ions

2002 ◽  
Vol 20 (5) ◽  
pp. 467-484
Author(s):  
G.A. El-Shobaky ◽  
A.M. Turky ◽  
A.M. Ghozza
Keyword(s):  
Particle Size ◽  
Thermal Treatment ◽  
Surface Area ◽  
Catalytic Properties ◽  
Excess Oxygen ◽  
Average Particle ◽  
Surface Excess ◽  
Nickel Ions ◽  
Nickel Species ◽  
Cobalt And Nickel

The effects of doping NiO and Co3O4 solids with cobalt and nickel species on their surface and catalytic properties were investigated. The amounts of dopant, in the form of the corresponding nitrate, were varied between 0.5–6.0 mol% cobalt ions and 2.0–6.0 mol% nickel ions. Pure and variously doped solids were subjected to thermal treatment at 300–700°C. The techniques employed were XRD, nitrogen adsorption at −196°C, decomposition of H2O2 at 30–50°C and estimation of the amount of surface excess oxygen on the variously prepared solids as determined by the hydrazine method. The results obtained revealed that the pure and variously doped NiO samples precalcined at 300°C consisted of a finely divided NiO phase having an average particle size of ca. 40 Å. Pure and variously doped Co3O4 specimens preheated at 500°C and 700°C were composed of a Co3O4 phase with a much bigger particle size (230 Å and 350 Å, respectively, for the solids precalcined at 500°C and 700°C). Doping of NiO followed by thermal treatment at 300°C and 500°C resulted in a measurable decrease in its BET surface area (19–23%), while doping of Co3O4 with nickel species followed by heating at 500°C and 700°C brought about a significant increase in its specific surface area (56–60%). Doping each of the NiO and Co3O4 solids with cobalt and nickel species greatly increased the amount of surface excess oxygen and effected a considerable increase in their catalytic activities. This increase was, however, much more pronounced in the case of NiO which attained a value of ca. 100-fold. Doping of NiO with cobalt species followed by thermal treatment at 300°C and 500°C decreased the activation energy (DE) of the catalyzed reaction to an extent proportional to the amount of dopant added. On the other hand, doping of Co3O4 with nickel species followed by thermal treatment at 500°C and 700°C did not change the value of DE. These results suggest that doping of Co3O4 with nickel species did not modify the mechanism of the catalyzed reaction but increased the concentration of catalytically active sites without changing their energetic nature.

scholarly journals An Overview on Nanocrystalline ZnFe2O4, MnFe2O4, and CoFe2O4 Synthesized by a Thermal Treatment Method

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Mahmoud Goodarz Naseri ◽  
Elias B. Saion ◽  
Ahmad Kamali
Keyword(s):  
Thermal Treatment ◽  
Treatment Method ◽  
Vinyl Pyrrolidone ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ft Ir ◽  
Poly Vinyl Pyrrolidone ◽  
Co Nanoparticles ◽  
Oxide Bands

This study reports the simple synthesis of MFe2O4 (where M=Zn, Mn, and Co) nanoparticles by a thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly(vinyl pyrrolidone) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average particle sizes were obtained by TEM images, which were in good agreement with the XRD results. Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands for all the calcined samples. Magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed that the calcined samples exhibited superparamagnetic and ferromagnetic behaviors.

Synthesis, Structural and Optical Properties of Cerium Oxide Nanoparticles Prepared by Thermal Treatment Method

2017 ◽  
Vol 268 ◽  
pp. 132-137 ◽  
Author(s):  
Anwar Ali Baqer ◽  
Khamirul Amin Matori ◽  
Naif Mohammed Al-Hada ◽  
Abdul Halim Shaari ◽  
Elias Saion ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Calcination Temperature ◽  
Treatment Method ◽  
Fluorite Structure ◽  
Band Gap Energy ◽  
Treatment Technique ◽  
Structural And Optical Properties ◽  
Gap Energy ◽  
Calcination Temperatures ◽  
Fesem Micrographs

A sample thermal treatment technique was utilised to synthesis cerium dioxide (CeO2) nanoparticles, using cerium (111) nitrate as a precursor, Polyvinylpyrrolidone as a capping agent, and deionized water as a solvent. The product underwent calcination treatment of 500, 550, 600, and 650 1C to crystallize the nanoparticles and to remove organic compounds. It was verified by XRD that by varying the calcination temperature, the cubic fluorite structure of CeO2 nanoparticles with pure products was achieved. Furthermore, the crystal sizes of the CeO2 nanoparticles were assessed to be 4 nm for the lowest calcination temperature and 23 nm for the highest calcination temperature. The FESEM micrographs of the CeO2 nanoparticles revealed a structure of CeO2 nanospherical that exhibited a tendency to amalgamate at higher calcination temperatures. The optical characteristics that were evaluated with the help of a UV-Vis spectrophotometer indicated a decrease in the band gap energy with an increase in calcination temperature as a result of the increase in the crystal sizes.

Frequency dependence and fuel effect on optical properties of nano TiO2-based structures

2016 ◽  
Vol 30 (18) ◽  
pp. 1650247 ◽  
Author(s):  
Mahdi Ghasemifard ◽  
Misagh Ghamari ◽  
Meysam Iziy
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Combustion Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Transmission Electron ◽  
Auto Combustion ◽  
Xrd Patterns

TiO2-(Ti[Formula: see text]Si[Formula: see text]O2 nanopowders (TS-NPs) with average particle size around 90 nm were successfully synthesized by controlled auto-combustion method by using citric acid/nitric acid (AC:NA) and urea/metal cation (U:MC). The structure of powders was studied based on their X-ray diffraction (XRD) patterns. The XRD of TS-NPs shows that rutile and anatase are the main phases of TS-NPs for AC:NA and U:MC, respectively. Particle size and histogram of nanopowders were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Optical properties of TS-NPs were calculated by Fourier transform infrared spectroscopy (FTIR) and Kramers–Kroning (KK) relation. Plasma frequencies of TS-NPs obtained from energy loss functions depend on fuels as a result of changes in crystal structure, particle size distribution, and morphology.

scholarly journals Structural and Optical Properties of Silicon Carbide Powders Synthesized from Organosilane Using High-Temperature High-Pressure Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3111
Author(s):  
Evgeny A. Ekimov ◽  
Vladimir S. Krivobok ◽  
Mikhail V. Kondrin ◽  
Dmitry A. Litvinov ◽  
Ludmila N. Grigoreva ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Synthesis Temperature ◽  
Narrow Particle Size Distribution ◽  
High Tech ◽  
Average Particle ◽  
Coupled Modes ◽  
Dominant Type ◽  
High Structure

The development of new strategies for the mass synthesis of SiC nanocrystals with high structure perfection and narrow particle size distribution remains in demand for high-tech applications. In this work, the size-controllable synthesis of the SiC 3C polytype, free of sp2 carbon, with high structure quality nanocrystals, was realized for the first time by the pyrolysis of organosilane C12H36Si6 at 8 GPa and temperatures up to 2000 °C. It is shown that the average particle size can be monotonically changed from ~2 nm to ~500 nm by increasing the synthesis temperature from 800 °C to 1400 °C. At higher temperatures, further enlargement of the crystals is impeded, which is consistent with the recrystallization mechanism driven by a decrease in the surface energy of the particles. The optical properties investigated by IR transmission spectroscopy, Raman scattering, and low-temperature photoluminescence provided information about the concentration and distribution of carriers in nanoparticles, as well as the dominant type of internal point defects. It is shown that changing the growth modes in combination with heat treatment enables control over not only the average crystal size, but also the LO phonon—plasmon coupled modes in the crystals, which is of interest for applications related to IR photonics.

scholarly journals The Promotion/Inhibition of the Seepage Transport of Copper Ions by Suspension-Colloidal Particles with Wide Size Gradation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qingke Nie ◽  
Huawei Li ◽  
Haipeng Yang ◽  
Tengfei Ni ◽  
Sichen Jiang
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Large Scale ◽  
Colloidal Particles ◽  
Copper Ions ◽  
Small Scale ◽  
Average Particle ◽  
Promoting Effect ◽  
Transport Distance ◽  
Retarding Effect

Sand column tests were conducted to investigate the seepage transport of silicon powders (SPs) with two wide particle size ranges (30-2000 nm and 2-70 μm), including the cotransport of SPs and copper ions. The results show that the graded large-scale SP has an obvious inhibiting influence on the transport of copper ions. In contrast, in the presence of the graded small-scale SP, the concentration of copper ions in the effluent tends to increase; i.e., there appears to be a promoting effect. However, after a long transport distance, the presence of SPs, regardless of particle size, has an overall retarding effect on heavy metal pollutants (e.g., copper ions). The promoting effect of the increase in seepage velocity on the concentration of copper ions in the effluent is greater with the graded large-scale SPs than with the graded small-scale SPs. In terms of the microstructural characteristics by metallographic microscopy, the average particle size of the deposited graded small-scale SPs is almost constant at different transport distances, while that of the deposited graded large-scale SPs tend to decrease significantly with increasing transport distance; i.e., notable bed filtration is exhibited in the latter case. This physical mechanism also determines the sequence and rate of the retarding effect of SPs on heavy metal ions under seepage flow.

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