scholarly journals Structural Analysis of Nanoceria Powder Precipitated in Different pH

2016 ◽  
Vol 3 (02) ◽  
pp. 158
Author(s):  
Iis Nurhasanah ◽  
Nurul Wahyu Puspaningrum ◽  
Ida Nursati
Keyword(s):  
Crystallite Size ◽  
Single Phase ◽  
Inorganic Material ◽  
Mixed Solvent ◽  
Fluorite Structure ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sem Image ◽  
Sunscreen Product

<span>Nanoceria has been proposed as inorganic material for sunscreen product because of its <span>excellent UV absorpsition ability. Fine particle nanoceria and non-aglomeration determines <span>comport and covering capability on human skin. Particle size and aglomeration could be <span>controlled by parameters and medium synthesis. In the present work, nanoceria powders were <span>synthesized using precipitation method in different pH of 7 and 10. Precipitation was caried<br /><span>out in water/isopropanol mixed solvent. Cerium nitrate and amonium hydroxide was used as <span>source of cerium and precipitation agent, respectively. Crystal structure of nanoceria was <span>examined using x-ray diffraction (XRD). Scanning electron microscope (SEM) was used to <span>observe morphology of nanoceria. Diffraction pattern analysis shows that the precipitates <span>were single phase of nanoceria with cubic fluorite structure and lattice contants of 0.5429 nm<br /><span>and 0.5419 nm. Crystallite size and lattice strain were obtained from Williamson-Hall method. <span>Precipitation in pH of 7 resulted in smaller crystallite size which correlated to the larger lattice <span>strain and lattice constant. SEM image shows spherical morphology with less agglomeration <span>occuring for nanoceria precipitated in pH 10.</span></span></span></span></span></span></span></span></span></span></span></span></span><br /></span>

scholarly journals STRUCTURE CHARACTERIZATION OF CALCIUM DEFICIENT ELEMENT-SUBSTITUTED HYDROXYAPATITE WITH CONSTANT DOPANT RATIO OF DIFFERENT ELEMENTS

2020 ◽  
Vol 51 (5) ◽  
pp. 1420-1427
Author(s):  
Al-Sabbagh & et al.
Keyword(s):  
Single Phase ◽  
Atomic Radius ◽  
Calcium Hydroxyapatite ◽  
Structure Characterization ◽  
Precipitation Method ◽  
Vibration Modes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Groups

The element-substituted calcium Deficient hydroxyapatite samples were synthesized using liquid-phase precipitation method. Different element ions (Mg+2, Zn+2, and Cu+2) were added at constant ratio (5% wt.). The phase composition of the element-substituted calcium hydroxyapatite samples was investigated by using X-ray diffraction. A comparison with known characteristics of the synthetic ion-substituted forms of hydroxyapatite was conducted. It was determined, that the investigated materials are single-phase solid solutions of the element-substituted hydroxyapatite. By the methods of IR spectroscopy and Raman scattering (RS) it was discovered the dependence of incorporation of the carbonate anion that occupies a positions of phosphorus-oxygen groups in the hydroxyapatite structure as a result of embedding element ions (Zn+2, Cu+2, Mg+2) in the crystal lattice. Besides, It was determined, that the ratio of the intensities for the C03 group mode to the P04 groups mode depended on the nature of the element atom, which replace the calcium in the lattice of HAP, and reduced by substituting the calcium atoms by the atoms of Zn, Cu, and Mg from 0.15 to 0.06. Modeling of the vibration modes of Raman spectroscopy showed that incorporation of carbon atoms to the hydroxyapatite structure correlate with the Zn, Cu and Mg atomic radius, charge, and activity   

scholarly journals Microstructures, Magnetic Properties and Microwave Absorption Characteristics of Ti2+ -Mn4+Substituted Barium Hexaferrite

2016 ◽  
Vol 14 (1) ◽  
pp. 15 ◽  
Author(s):  
Maykel Manawan ◽  
Azwar Manaf ◽  
Bambang Soegijono ◽  
Asep Yudi Hercuadi
Keyword(s):  
Crystallite Size ◽  
Microwave Absorption ◽  
Single Phase ◽  
Barium Hexaferrite ◽  
Grain Morphology ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Xrd Patterns ◽  
Substituted Barium Hexaferrite

The effect of Ti2+-Mn4+substitution on microwave absorption has been studied for BaFe12-2xTixMnxO19 ferrite, where x varies from 0.2, 0.4, 0.6 and 0.8.Ti2+-Mn4+ ions were obtained from TiO and MnO2 precursors which were mechanically alloyed together with BaCO3 and Fe2O3 precursors. X-ray diffraction (XRD) patterns for sintered samples confirmed that the materials are consisted with single phase BHF structure. Unit cell volume and crystallite size was found increase with increasing x. Crystallite size for all samples below 70 nm, but the grain morphology shown that the grains is in range of 200 - 400 nm, which concluded that each grain are polycrystalline. The saturation magnetization is increases up to x = 0.4 and decrease for higher x values, while the coercivity remains decreases monotonically. These results were interpreted in terms of the site preferential occupation of Ti2+ and Mn4+ at low level substitution.These substitution revealed of enhanced reflection loss (RL) up to 25 dB forx=0.6.It suggested that the synthesized can be employed as effective microwave absorbers in various devices.

The Effect of Calcination Time on Crystallite Size of LiMn1.8Ni0.2O4 Cathode Materials

2020 ◽  
Vol 307 ◽  
pp. 136-140
Author(s):  
Michelle Matius ◽  
Norlida Kamarulzaman ◽  
Mohd Sufri Mastuli ◽  
Nor Syamilah Syamimi Mohd Abdillih ◽  
Kelimah Elong
Keyword(s):  
Crystallite Size ◽  
Cathode Materials ◽  
Single Phase ◽  
Small Mass ◽  
Li Ion Batteries ◽  
X Ray Diffraction ◽  
Calcination Time ◽  
X Ray ◽  
Li Ion ◽  
Materials Used

Spinel LiMn2O4 is one of the promising cathode materials used in commercial Li-ion batteries. In this study, Ni was partially substituted in order to give the material LiMn1.8Ni0.2O4, which was successfully synthesized using a self-propagating combustion (SPC) method. Results from Simultaneous Thermogravimetric Analysis (STA) show the small mass loss about 4.6%. The precursor then was calcined at temperature of 800 °C for 24 h, 48 h and 72 h. X-Ray Diffraction (XRD) confirms that the final products are pure and single phase with no impurities present. The morphology and crystallite size of pure samples are examined using Field Emission Scanning Electron Microscope (FESEM). The result shows that all the materials consist of crystalline particles with smooth surface and polyhedral shaped materials.

Optical Properties of Zn-Doped CeO2 Nanoparticles as a Function of Zn Content

2014 ◽  
Vol 896 ◽  
pp. 108-111 ◽  
Author(s):  
Iis Nurhasanah ◽  
Heri Sutanto ◽  
Ririn Futikhaningtyas
Keyword(s):  
Visible Region ◽  
Ultra Violet ◽  
Fluorite Structure ◽  
Zinc Nitrate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Zn Content ◽  
Uv Absorbers

CeO2 and Zn-doped CeO2 nanoparticles were synthesized by simple precipitation method in water/isopropanol mixed solvent from cerium nitrate and zinc nitrate with various mole ratios. The precipitates were then calcined at 300°C for 4 hours and characterized by X-ray diffraction (XRD) and uv-vis spectroscopy. Characterization by x-ray diffraction shows that high crystallinity of cubic fluorite structure of CeO2 with crystallite size in the range 6 12 nm depending on Zn content. CeO2 nanoparticles exhibits tranparent in the visible region and strong absorbance in the ultra-violet region. It was also found that significant effect of Zn content on transmittance and optical band gap. In addition, Zn substitution into Ce suppressing photocatalytic activity of pure CeO2 nanoparticle under sunlight irradiation. These results suggest that Zn-doped CeO2 nanoparticle is more prommising for safer optical UV-absorbers.

scholarly journals Structural Analysis using X-Ray Diffraction and FTIR Spectroscopic Studies on Mn2+ Substituted CaWO4 Materials Synthesized by Coprecipitation Method

2019 ◽  
Vol 32 (1) ◽  
pp. 49-52
Author(s):  
M. Jaganadha Rao ◽  
K.S.R. Murthy ◽  
Ch. Ravi Shankar Kumar ◽  
Anjali Jha ◽  
G.S.V.R.K. Choudary ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Point Group ◽  
Size Composition ◽  
Spectroscopic Studies ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Patterns ◽  
Co Precipitation ◽  
Synthesis Of Materials

Present day technology requires synthesis of materials with low energy consumption, free mercury pollution and its reliability. A novel material with control of crystallite size, composition and simple for white light relies in synthesis of materials. The present focus of article attributes series of manganese doped Ca1-xMnxWO4 luminescent materials with co-precipitation method. Reported studies attempts with change in structure of calcium tungstate (CaWO4) are observed with dopants like Eu3+, Eu2+, Tb3+, etc. However the effect of Mn2+ on structural properties of CaWO4 are quite interesting. The synthesized samples were characterized with X-ray diffraction for lattice parameters, crystallite size and FTIR studies for bonding mechanism of O-W-O stretching and W-O-W bridge bond. Rietveld profile refinement of XRD patterns using MAUD program Ca1-xMnxWO4 revealed the Scheelite type structure with C4h point group and I41/a space group. Characterization studies reveal that doping of Mn2+ doping upto 0.1 in place of Ca2+ will not change the phase of Scheelite structure.

Structure and Ionic Conductivity of Ln2Zr2O7-Type Rare Earth Zirconates

2007 ◽  
Vol 336-338 ◽  
pp. 420-423 ◽  
Author(s):  
Rui Zhang ◽  
Qiang Xu ◽  
Wei Pan ◽  
Chun Lei Wan ◽  
Long Hao Qi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Solid State ◽  
Ionic Conductivity ◽  
Single Phase ◽  
Complex Impedance ◽  
Pyrochlore Structure ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
X Ray

Three rare earth zirconates (Sm2Zr2O7, Gd2Zr2O7 and Er2Zr2O7) were prepared by solid state reaction. The crystal structure and ionic conductivity of these zirconates were characterized by X-ray diffraction (XRD) and complex impedance spectroscopy. The results show that Sm2Zr2O7 exhibits single-phase pyrochlore structure and Er2Zr2O7 exhibits single-phase fluorite structure, while Gd2Zr2O7 has pyrochlore and fluorite structure. Among three zirconates, the ionic conductivity of Sm2Zr2O7 is highest, while that of Er2Zr2O7 is lowest.

scholarly journals Novel Nano-Fe2O3-Co3O4 Modified Dolomite and Its Use as Highly Efficient Catalyst in the Ozonation of Ammonium Solution

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Manh B. Nguyen ◽  
Giang H. Le ◽  
Trang T. T. Pham ◽  
Giang T. T. Pham ◽  
Trang T. T. Quan ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Catalytic Ozonation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Kcal Mole ◽  
Efficient Catalyst ◽  
X Ray ◽  
Sem Image ◽  
Temperature Programmed ◽  
Adsorption Desorption

Catalytic ozonation is a new method used for removal of NH4OH solution. Therefore, high catalytic performance (activity and selectivity) should be achieved. In this work, we report the synthesis and catalytic performance of Fe2O3-Co3O4 modified dolomite in the catalytic ozonation of NH4OH solution. Dolomite was successfully activated and modified with Fe2O3 and Co3O4. Firstly, dolomite was activated by heating at 800°C for 3 h and followed by KOH treatment. Activated dolomite was modified with Fe2O3 by the atomic implantation method using FeCl3 as Fe source. Fe2O3 modified dolomite was further modified with Co3O4 by precipitation method. The obtained catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N2 adsorption–desorption (BET), and temperature-programmed reduction (H2-TPR). From SEM image, it was revealed that nano-Fe2O3 and Co3O4 particles with the size of 80–120 nm. Catalytic performance of activated dolomite, Fe2O3 modified dolomite, and Fe2O3-Co3O4 modified dolomite in catalytic ozonation of NH4+ solution was investigated and evaluated. Among 3 tested catalysts, Fe2O3-Co3O4 modified dolomite has the highest NH4+ conversion (96%) and N2 selectivity (77.82%). Selectivity toward N2 over the catalyst was explained on the basis of bond strength M-O in oxides through the standard enthalpy ΔH°f of oxide. Catalyst with lower ΔH°f value has higher N2 selectivity and the order is the following: Co3O4 (ΔH°f of 60 kcal (mole O)) > Fe2O3 (ΔH°f of 70 kcal (mole O)) > MgO (ΔH°f of 170 kcal (mole O)). Moreover, high reduction ability of Fe2O3-Co3O4 modified dolomite could improve the N2 selectivity by the reduction of NO3- to N2 gas.

scholarly journals Entropy-Stabilized Oxides owning Fluorite Structure obtained by Hydrothermal Treatment

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 558 ◽  
Author(s):  
Luca Spiridigliozzi ◽  
Claudio Ferone ◽  
Raffaele Cioffi ◽  
Grazia Accardo ◽  
Domenico Frattini ◽  
...  
Keyword(s):  
Single Phase ◽  
Configurational Entropy ◽  
Ceramic Materials ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
State Transformation ◽  
Solid State Transformation ◽  
X Ray ◽  
Phase Stabilization ◽  
Single Phase State

Entropy-Stabilized Oxides (ESO) is a modern class of multicomponent advanced ceramic materials with attractive functional properties. Through a five-component oxide formulation, the configurational entropy is used to drive the phase stabilization over a reversible solid-state transformation from a multiphase to a single-phase state. In this paper, a new transition metal/rare earth entropy-stabilized oxide, with composition Ce0.2Zr0.2Y0.2Gd0.2La0.2O2−δ, was found after several investigations on alternative candidate systems. X-Ray Diffraction (XRD) analyses of calcined powders pointed out different behavior as a function of the composition and a single-phase fluorite structure was obtained after a specific thermal treatment at 1500 °C. Powders presented the absence of agglomeration, so that the sintered specimen exhibited sufficient densification with a small porosity, uniformly distributed in the sample.

Influence of Temperature on the Order-Disorder Transition in Gd2Zr2O7

2016 ◽  
Vol 697 ◽  
pp. 386-389 ◽  
Author(s):  
Jing Lin Shi ◽  
Zhi Xue Qu ◽  
Qun Wang
Keyword(s):  
Fluorite Structure ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Inconsistent Result ◽  
Disorder Transition ◽  
X Ray ◽  
Influence Of Temperature On ◽  
Diffraction Patterns ◽  
Co Precipitation ◽  
Increasing Temperature

Chemical co-precipitation method was used to prepare Gd2Zr2O7 powders. The powders were then heated in air at 1500°C, 1510°C, 1525°C, 1530°C, 1550°C, 1575°C, 1600°C for 5 h, and 1575°C, 1600°C for 10 h, respectively. The samples after heat treatment were characterized by X-ray diffraction and Raman spectroscopy. X-ray diffraction patterns reveal that order-disorder transition of Gd2Zr2O7 occurs between 1550°C and 1575°C. Prior to the transition, the relative intensity of peaks corresponding to the super-lattice of pyrochlores increases with the increasing temperature. On the other hand, Raman spectra give an inconsistent result from the X-ray diffraction data. No appreciable difference can be observed for all the samples though with peaks broadening as temperature increases. The spectra of the samples indicated as fluorite structure in X-ray diffraction patterns appear with six resolvable peaks which is quite different from the spectrum of ideal fluorite structure.

scholarly journals Resistivity Enhancement of Sr-Hexaferrite Using Rare Earth Dopant to Minimize Energy Losses

2018 ◽  
Vol 778 ◽  
pp. 195-199 ◽  
Author(s):  
Nahall Niazi ◽  
Omer Farooq ◽  
Fatima Tuz Zahra ◽  
Muhammad Anis-ur-Rehman
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Strontium Hexaferrite ◽  
Energy Losses ◽  
X Ray Diffraction ◽  
High Frequencies ◽  
X Ray ◽  
Co Precipitation

Strontium hexaferrite is a material of choice due its various magnetic applications. Energy losses are a prominent issue in these magnetic materials. To lower these energy losses, we need to improve the resistivity by reducing eddy current losses. In this work nanoparticles of Gadolinium (Gd) doped Sr-hexaferrite (SrFe12-xGdxO19 x =0 .0, 0.1) have been synthesized by co-precipitation method. Structural analysis was done by using X-ray diffraction technique (XRD). It was found that the formation of single phase i.e. hexagonal structure has been achieved when the samples were sintered at 920°C for 20 minutes. AC electrical properties such as conductivity (𝜎ac), dielectric constant (ε′), dielectric loss (tanδ) and impedance (Z); real (Z') and imaginary (Z") parts have been studied as a function of frequency at room temperature. Aim of the work was to enhance the resistivity and was successfully achieved. Gd doped sample is proposed as an energy efficient material to be used in devices working at high frequencies.

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