scholarly journals The Synthesis of Nanophosphors YPxV1–xO4 by Spray Pyrolysis and Microwave Methods

2020 ◽  
Vol 22 (4) ◽  
pp. 496-503
Author(s):  
Elena V. Tomina ◽  
Dmitry A. Lastochkin ◽  
Sergey A. Maltsev
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Spray Pyrolysis ◽  
Microwave Radiation ◽  
Sol Gel ◽  
Rare Earth Doping ◽  
High Chemical ◽  
Chemical Homogeneity ◽  
Yttrium Vanadate ◽  
New Variant

Due to rare earth doping, phosphates and vanadates are the leading materials for the synthesis of phosphors due to their thermal stability, low sintering temperature, and chemical stability. Phosphors in the nanoscale state are of particular interest. The simple, fast, and scalable synthesis of nanophosphors with high chemical homogeneity is a priority task. The purpose of this work was to synthesize powders of mixed yttrium vanadate-phosphate crystals of various compositions by coprecipitation under the action of microwave radiation and spray pyrolysis, as well as to compare the characteristics ofthe obtained samples. Samples of YVхP1–хO4 of different compositions were synthesized by coprecipitation under the action of microwave radiation and spray pyrolysis in different modes. In the case of the synthesis of yttrium vanadate-phosphate YVхP1–хO4 by spray pyrolysis followed by annealing, according to the X-ray phase analysis data, single-phase nanopowders were formed. The morphological characteristics of the samples were revealed by the methods of transmission electron microscopy and scanning electron microscopy. Depending on the annealing conditions, the samples were either faceted or spherical particlesless than 100 nm in size. The composition of the YVхP1–хO4 , samples synthesized by the coprecipitation method under the action of microwave radiation strongly depended on the pH of the precursor solution. The minimum content of impurity phases was reached at pH 9.Spray pyrolysis allows the synthesis of yttrium vanadate phosphate YVхP1–хO4 nanopowders of high chemical homogeneity with a particle size of less than 100 nm. The maximum chemical homogeneity of yttrium vanadate-phosphate powders was achieved at pH = 9 during the synthesis of YVхP1–хO4 by coprecipitation under the action of microwave radiation. However, the particle size dispersion was large, within the range of 2–60 μm.       References 1. Wu C., Wang Y., Jie W. Hydrothermal synthesisand luminescent properties of LnPO4:Tb (Ln = La, Gd)phosphors under VUV excitation. Journal of Alloys andCompounds. 2007;436: 383–386. DOI: https://doi.org/10.1016/j.jallcom.2006.07.0562. Huang J., Tang L., Chen N., Du G. Broadeningthe photoluminescence excitation spectral bandwidthof YVO4:Eu3+ nanoparticles via a novel core-shell andhybridization approach. Materials. 2019;12: 3830. DOI:https://doi.org/10.3390/ma122338303. Wu Y., Zhang Z., Suo H., Zhao X., Guo C. 808 nmlight triggered up-conversion optical nano-thermometerYPO4:Nd3+/Yb3+/Er3+ based on FIR technology.Journal of Luminescence. 2019;214: 116478. DOI:https://doi.org/10.1016/j.jlumin.2019.1165784. Xiu Z., Wu Y., Hao X., Li X., Zhang L. Uniformand well-dispersed Y2O3:Eu/YVO4:Eu composite microsphereswith high photoluminescence prepared bychemical corrosion approach. Colloids Surf. A.2012;401(5): 68–73. DOI: https://doi.org/10.1016/j.colsurfa.2012.03.0215. Vats B. G., Gupta S. K., Keskar M., Phatak R.,Mukherjee S., Kannan S. The effect of vanadium substitutionon photoluminescent properties of KSrLa(-PO4)x(VO4)2x:Eu3+ phosphors, a new variant of phosphovanadates.New Journal of Chemistry. 2016;40(2):1799–1806. DOI: https://doi.org/10.1039/c5nj02951a6. Riwotzki K., Haase M. Colloidal YVO4:Eu andYP0.95V0.05O4:Eu nanoparticles: luminescence and energytransfer processes. The Journal of Physical ChemistryB. 2001;105(51): 12709–12713. DOI: https://doi.org/10.1021/jp01137357. Wu C.-C., Chen K.-B., Lee C.-S., Chen T.-M.,Cheng B.-M. Synthesis and VUV photoluminescencecharacterization of (Y,Gd)(V,P)O4:Eu3+ as a potentialred-emitting PDP phosphor. Chem. Mater. 2007;19(13):3278–3285. DOI: https://doi.org/10.1021/cm061042a8. Shimomura Y., Kurushima T., Olivia R., Kijima N.Synthesis of Y(P,V)O4:Eu3+ red phosphor by spray pyrolysiswithout postheating. The Japan Society of Applied.2005;44(3): 1356–1360. DOI: https://doi.org/10.1143/JJAP.44.13569. Lai H, Chen B., Xu W., Xie Y., Wang X., Di W. Fineparticles (Y,Gd)PxV1−xO4:Eu3+ phosphor for PDP preparedby coprecipitation reaction. Materials Letters.2006; 60 (11): 1341-1343. DOI: https://doi.org/10.1016/j.matlet.2005.11.05110. Singh V., Takami S., Aoki N., Hojo D., Arita T.,Adschiri T. Hydrothermal synthesis of luminescentGdVO4:Eu nanoparticles with dispersibility in organicsolvents. Journal of Nanoparticle Research. 2014;16(5):2378. DOI: https://doi.org/10.1007/s11051-014-2378-211. Song W.-S., Kim Y.-S., Yang H. Hydrothermalsynthesis of self-emitting Y(V,P)O4 nanophosphors forfabrication of transparent blue-emitting display device.Journal of Luminescence. 2012;132(5): 1278–1284.DOI: https://doi.org/10.1016/j.jlumin.2012.01.01512. Yu M., Lin J., Fu J., Han Y. Sol–gel fabrication,patterning and photoluminescent properties ofLaPO4:Ce3+, Tb3+ nanocrystalline thin films. ChemicalPhysics Letters. 2003;5(1-2): 178–183. DOI: https://doi.org/10.1016/S0009-2614(03)00239-213. Raoufi D., Raoufi T. The effect of heat treatmenton the physical properties of sol–gel derived ZnO thinfilms. Applied Surface Science. 2009;255(11): 5812–5817. DOI: https://doi.org/10.1016/j.ap-susc.2009.01.01014. Shao J., Yan J., Li X., Li S., Hu T. Novel fluorescentlabel based on YVO4:Bi3+, Eu3+ for latent fingerprintdetection. Dyes and Pigments. 2019;160: 555–562.DOI: https://doi.org/10.1016/j.dyepig.2018.08.03315. Dolinskaya Yu. A., Kolesnikov I. E., KurochkinA. V., Man’shina A. A., Mikhailov M. D., SemenchaA. V. Sol-Gel synthesis and luminescent propertiesof YVO4: Eu nanoparticles. Glass Physics and Chemistry.2013;39(3): 308–310. DOI: https://doi.org/10.1134/s108765961303006116. Tomina E. V., Sladkopevtsev B. V., Knurova M. V.,Latyshev A.N., Mittova I. Y., Mittova V. O. Microwavesynthesis and luminescence properties of YVO4:Eu3+.Inorganic Materials. 2016;52(5): 495–498. DOI: https://doi.org/10.7868/S0002337X1605017117. Tomina E. V., Mittova I. J., Burtseva N. A.,Sladkopevtsev B. V. Method for synthesis of yttrium orthovanadate-based phosphor: patent for invention No2548089. The patent holder FGBOU VPO “Voronezhstate University” No 2013133382/05; declared12.11.2013; published. 20.05.2015.18. Tomina E. V., Kurkin N. A., & Mal’tsev S. A.Microwave synthesis of yttrium orthoferrite dopedwith nickel. Kondensirovannye sredy i mezhfaznyegranitsy = Condensed Matter and Interphases.2019;21(2): 306–312. DOI:https://doi.org/10.17308/kcmf.2019.21/768 (In Russ., abstract in Eng.)19. Huang J., Gao R., Lu Z., Qian D., Li W., Huang B.,He X. Sol–gel preparation and photoluminescenceenhancement of Li+ and Eu3+ co-doped YPO4 nanophosphors.Optical Materials. 2010;32(9): 857–861.DOI: https://doi.org/10.1016/j.optmat.2009.12.01120. Brandon D., Kaplan W. D. MicrostructuralCharacterization of Materials. John Wiley & Sons Ltd;1999. 409 p. DOI: https://doi.org/10.1002/9780470727133

scholarly journals Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Synthesis Method ◽  
Double Perovskite ◽  
Synthesis Methods ◽  
X Ray ◽  
Sol Gel Synthesis

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.

Study of Au-CeO2 Nano-particles using analytical Transmission Electron Microscopy

2007 ◽  
Vol 1 (1) ◽  
Author(s):  
P. Gu ◽  
G. Yang ◽  
R.F. Klie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Rare Earth ◽  
Lattice Parameter ◽  
Nano Particles ◽  
Rare Earth Doping ◽  
Analytical Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Shift Reaction

Cerium oxide doped with various rare earth metals is often used as a support for nano-sized gold particles, and demonstrates to be a promising catalyst for the water gas shift reaction at low temperatures. Many factors are hypothesized to affect the activity of this heterogeneous catalyst, including its loading with gold, the rare-earth dopant, the support and Au particle size, and leaching of the sample. In this study, we examined several Au/CeO2-based catalyst samples, including 2.4% Au/(Ce,Gd)O2, 1.8% Au/(Ce,La)O2 leached, 0.5% Au/(Ce,Gd)O2 leached, and 0.75% Au/CeO2 utilizing analytical transmission electron microscopy. The effects of Au and rare-earth doping on the ceria lattice parameter were investigated, and it was determined that there are no significant variations in the particle's structure or lattice-spacing. Furthermore, the particle sizes of each of the four samples were investigated concluding that although the 1.8% Au/(Ce,La)O2 leached sample has a slightly larger particle size, and the 2.4% Au/(Ce,Gd)O2 sample has a slightly smaller particle size, the differentiation is not adequate to be accountable for the radical distinction in catalytic activity.

scholarly journals CHARACTERIZATION OF THE SOL-GEL PROCESS IN THE SYSTEM YxBax+nCu2x+nOδ (x = 1, n=1, x=2, n=3, x=3, n=2)

2017 ◽  
pp. 31-34
Author(s):  
A. Pilipenko ◽  
I. Fesych ◽  
S. Nedilko ◽  
A. Dzyazko
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Solid Phase ◽  
Sol Gel ◽  
Complex Oxide ◽  
Present Calculation ◽  
Calculation Algorithm ◽  
Oxide Systems ◽  
Chemical Homogeneity ◽  
Lower Temperature

With the help of sol-gel technology was obtained superconducting compound number YxBax+nCu2x+nOδ (x=1, n=1; x=2, n=3; x=3, n=2) with submicron size particles. As a gel maker in these systems was used citric acid monohydrate. An extensive scheme fusion technology was shown. The process described synthesis using thermal, infrared spectroscopic analysis and scanning electron microscopy. There are some aggregations of microparticles mostly for the phases that are synthesized at higher temperatures. Due to Thermal Analysis of modes were optimized heat treatment samples. According to IR spectroscopy were controlled processes of decomposition of the charge and the formation of the superconducting phase. It was grounded the choice of analysis methods for the starting compounds and the present calculation algorithm for this synthesis. Studies have shown that even at the beginning of the synthesis batch contained no impurity compound allowing argued that the sol-gel synthesis is a promising method that provides high homogeneity of the material the early stages of the synthesis and enables lower temperature and a subsequent heat treatment. The results of electron microscopy showed that due to the relatively low temperature of synthesis occurs the formation of submicron sized particles, while solid-phase techniques facilitate rapid crystal growth due to the formation of liquid phases at high temperature. The principles and ideas described in this paper can be adapted to more complex oxide systems. Thus, in this paper describes how you can achieve chemical homogeneity at the molecular level in multicomponent systems YxBax+nCu2x+nOδ (x=1, n=1; x=2, n=3; x=3, n=2) using sol-gel technology.

Synthesis of Powders Nanometer Al2O3 Method by Sol-Gel

2012 ◽  
Vol 727-728 ◽  
pp. 9-13
Author(s):  
Suzana Arleno S. Santos ◽  
Eduardo Sousa Lima ◽  
Luis Henrique Leme Louro ◽  
Célio Albano da Costa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Thermogravimetric Analysis ◽  
Calcination Temperature ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Size ◽  
Scanning Electron

This study aimed to produce nanometric powders of alumina by sol-gel route. Six samples were produced by varying the amount of water for dilution of aluminum nitrate and the calcination temperature. The final products were evaluated by thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and particle size. It could be noticed that, beyond the time of gelation and calcination temperature, the addition of water also influenced the average size of the clusters.

EVALUATION OF HYDROXYAPATITE-FORSTERITE-BIOACTIVE GLASS COMPOSITE NANOPOWDER PREPARED VIA SOL-GEL METHOD

2012 ◽  
Vol 05 ◽  
pp. 510-518
Author(s):  
MARYAM MAZROOEI SEBDANI ◽  
MOHAMMADHOSSEIN FATHI
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Bioactive Glass ◽  
Sintering Temperature ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Bioactive Ceramics ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Sol Gel Process

In spite of attractive bioactivity of bioactive ceramics i.e. hydroxyapatite and bioactive glasses, their poor mechanical properties have restricted their clinical applications. To overcome these limitations, an alternative approach suggested is preparation a composite including these bioactive ceramics with others. It is expected that a ceramic reinforcement with reduced grain size below 100 nm promotes theirs. The aim of this work was fabrication and characterization of hydroxyapatite-forsterite-bioglass composite nanopowder. Novel hydroxyapatite-forsterite-bioglass composite nanopowder was synthesized by incorporation of the forsterite and bioactive glass in hydroxyapatite matrix via a sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infrared (FTIR) spectroscopy techniques were utilized in order to evaluate the phase composition, agglomerates size distribution, morphology and particle size and functional groups of synthesized. The effects of sintering temperature and time were also investigated. Results showed that the appropriate temperature for calcination was 600°C and the particle size of composite nanopowder was about 60-70nm. The decomposition of hydroxyapatite was increased with the increase of the sintering temperature and sintering time. Obtained results indicate that prepared composite nanopowder could be a good candidate for medical applications.

scholarly journals Process for Producing Nano-Alpha-Alumina Powder

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Fatemeh Mirjalili ◽  
Luqman Chuah Abdullah ◽  
Hasmaliza Mohamad ◽  
A. Fakhru'l-Razi ◽  
A. B. Dayang Radiah ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Sol Gel ◽  
Alumina Nanoparticles ◽  
Alumina Powder ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Stirring Time ◽  
Particle Size And Shape

This paper is trying to explore the effect of stirring time on the synthesis of nano-α-Alumina particles. In this study, alumina nanoparticles were synthesized through alkoxide route using sol-gel method, where aqueous solutions of aluminum isopropoxide and 0.5 M aluminum nitrate nanohydrate were used for preparing alumina sol. Sodium dodecylbenzen sulfonate (SDBS) was used as the surfactant stabilizing agent. The prepared solution was stirred at different times (24, 36, 48, and 60 hours) at 60°C. The Samples were, then, characterized by X-ray diffraction, thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Transmission Electron Microscopy(TEM) . The introduction of different stirring times affected the particle size and shape and the degree of aggregation. By increasing the stirring time, (starting from 24 to 48 hours) the particle size decreased, but agglomeration became hard for 60 hours of stirring time. The finest particle size (20–30 nm) was obtained at 48-hour stirring time.

scholarly journals LiMnPO4 Olivine as a Cathode for Lithium Batteries

2011 ◽  
Vol 5 (1) ◽  
pp. 222-227 ◽  
Author(s):  
Zhumabay Bakenov ◽  
Izumi Taniguchi
Keyword(s):  
Spray Pyrolysis ◽  
Lithium Batteries ◽  
Low Cost ◽  
Sol Gel ◽  
Environmental Safety ◽  
Polyol Synthesis ◽  
Narrow Particle Size Distribution ◽  
Operating Voltage ◽  
Chemical Homogeneity ◽  
Metal Phosphates

The olivine structured mixed lithium-transition metal phosphates LiMPO4 (M = Fe, Mn, Co) have attracted tremendous attention of many research teams worldwide as a promising cathode materials for lithium batteries. Among them, lithium manganese phosphate LiMnPO4 is the most promising considering its high theoretical capacity and operating voltage, low cost and environmental safety. Various techniques were applied to prepare this perspective cathode for lithium batteries. The solution based synthetic routes such as spray pyrolysis, precipitation, sol-gel, hydrothermal and polyol synthesis allow preparing nanostructured powders of LiMnPO4 with enhanced electrochemical properties, which is mostly attributed to the higher chemical homogeneity and narrow particle size distribution of the material. Up-to-date, the LiMnPO4/C composites prepared by the spray pyrolysis route have the best electrochemical performance among the reported in the literature.

Fabrication of hollow silica nanosphere and its application for thermal insulation coating

2018 ◽  
Vol 33 (2) ◽  
pp. 198-213 ◽  
Author(s):  
Pei Hu ◽  
Dan Ai ◽  
Xiang Jiang ◽  
Xinya Zhang
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Thermal Insulation ◽  
Shell Thickness ◽  
Sol Gel ◽  
Inorganic Filler ◽  
Hollow Silica ◽  
Insulation Coating ◽  
Hollow Silica Nanospheres ◽  
Silica Nanosphere

Hollow silica nanospheres (HSNs) were synthesized via sol–gel method followed by calcination, using positively charged polystyrene (PS) as a hard template, and the tetraethoxysilane as precursor. The inner diameter and shell thickness of the HSNs can be expediently controlled by adjusting the particle size of PS and the amount of ammonia, respectively. The average inner diameters of HSNs increased from 153 nm to 255 nm along with the increasing PS particle size from 150 nm to 300 nm. The shell thickness of HSNs decreased from 20 nm to 12 nm with the increasing amount of ammonia from 1.5 mL to 3.0 mL. The structure of HSNs was verified by Fourier-transform infrared, thermogravimetric, scanning electron microscopy, and transmission electron microscopy characterization. The prepared thermal insulation coating comprised of HSNs shows good temperature retention and thermo-insulating properties, which indicate that the as-prepared HSNs are potentially used as an inorganic filler for thermal insulation coating.

Ultradispersed Powdery Y2O3-Bi2O3-ZnO Composition with High Chemical Homogeneity for Fine-Grained Ceramics

2014 ◽  
Vol 87 ◽  
pp. 36-41
Author(s):  
Elena A. Trusova ◽  
Kirill V. Vokhmintcev ◽  
Aleksey N. Kirichenko
Keyword(s):  
Sol Gel ◽  
Particle Sizes ◽  
High Chemical ◽  
Chemical Homogeneity ◽  
Fine Grained ◽  
Gel Technique ◽  
Average Size ◽  
20 Nm ◽  
New Generation ◽  
Xrd And Tem

The technologically acceptable modified sol-gel technique was developed for obtaining the ultradispersed powdery composition Y2O3-Bi2O3-ZnO, which is promising new generation material for photocatalysts and solar cells. The solution for preparing a sintering composition with a high chemical homogeneity was proposed to provide using ultradispersed powders consisting of ZnO nanoparticles (40-70 nm), decorating with Bi2O3 and Y2O3 particles with average size of 4-20 nm. All synthesized powders were characterized by XRD and TEM methods. It was found that ZnO surface differently affects the dispersity of Bi2O3 and Y2O3 in the composites. TEM microphotographs show that the Bi2O3 particles uniformly distributed over ZnO surface. The Bi2O3 particle size on ZnO surface was 5-11 nm, which is significantly less than in the single powder of Bi2O3 (110-130 nm). However, in the case of Y2O3 similar effect was not observed, and average size of its crystallites was 5-12 nm, which agrees well with particle sizes in single powder.

Analytical Electron Microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

1989 ◽  
Vol 47 ◽  
pp. 272-273
Author(s):  
Sooho Kim ◽  
M. J. D’Aniello
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Noble Metal ◽  
Catalyst Deactivation ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Metal Particles ◽  
Automotive Exhaust ◽  
Exhaust Catalysts ◽  
Analytical Electron

Automotive catalysts generally lose-agtivity during vehicle operation due to several well-known deactivation mechanisms. To gain a more fundamental understanding of catalyst deactivation, the microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing Analytical Electron Microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study.The general microstructure of the supports and the noble metal particles of the two catalysts looks similar; the noble metal particles were generally found to be spherical and often faceted. However, the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases.

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