scholarly journals Upconversion Properties of Nanocrystalline ZrO2:Yb3+, Er3+Phosphors

2007 ◽  
Vol 2007 ◽  
pp. 1-8 ◽  
Author(s):  
Iko Hyppänen ◽  
Jorma Hölsä ◽  
Jouko Kankare ◽  
Mika Lastusaari ◽  
Laura Pihlgren
Keyword(s):  
Combustion Synthesis ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Ir Laser ◽  
Fluorite Type ◽  
Intense Luminescence ◽  
Crystallite Sizes ◽  
Ft Ir ◽  
Scherrer Formula ◽  
Ft Ir Spectroscopy

Combustion and sol-gel methods were used to prepare the upconverting nanocrystallineZrO2:Yb3+,Er3+phosphors. The crystal structure was studied by X-ray powder diffraction and the crystallite sizes were estimated with the Scherrer formula. Impurities and nanomaterials' thermal degradation were analyzed with FT-IR spectroscopy and thermal analysis, respectively. Upconversion luminescence and luminescence decays were studied with IR-laser excitation at 977 nm. All nanomaterials possessed the cubicZrO2fluorite-type structure except for a small monoclinic impurity obtained with the sol-gel method. The conventionalNO3−andOH−impurities were observed for the combustion synthesis products. TheZrO2:Yb3,Er3+nanomaterials showed red (630–710 nm) and green (510–570 nm) upconversion luminescence due to the4F9/2→4I15/2and(2H11/2,4S3/2)→4I15/2transitions ofEr3+, respectively. The products of the combustion synthesis exhibited the most intense luminescence intensity and showed considerable afterglow. It was concluded that excitation energy is partially trapped in the system and subsequently bleached thermally to the luminescentEr3+center to yield “persistent upconversion”.

Antifelting-Coating for Wool from PPD-[Si(OH)3]2 Agent via a Sol-Gel Process

2011 ◽  
Vol 233-235 ◽  
pp. 151-154 ◽  
Author(s):  
Yi Hu ◽  
Jin Qiang Liu ◽  
Chun Lei Xu
Keyword(s):  
Ir Spectroscopy ◽  
Sol Gel ◽  
Test Method ◽  
Curing Temperature ◽  
Cure Process ◽  
Sol Gel Process ◽  
Ft Ir ◽  
Fiber Microstructure ◽  
Ft Ir Spectroscopy

A sol type anti-felting agent containing PPD-[Si(OH)3]2 synthesized and applied to the wool with pad-dry-cure process. The structure of the prepolymer was characterized by FT-IR spectroscopy and the film transparency and the fiber microstructure were proved though UV-vis analysis and WAXD. The results indicated that the coating could endow a better anti-felting effect with low curing temperature at 120°C and 3 min, the area shrinking rate from13.44% of the original fabric decrease to 2.86% of the treated samples without strength decreased and handle changed stiff seriously, which accord with the IWS Test Method 31 standard.

Development of Permeable Reactive Barrier for Phosphorus Removal

2010 ◽  
Vol 636-637 ◽  
pp. 1365-1370 ◽  
Author(s):  
M. Oliveira ◽  
Ana Vera Machado ◽  
Regina Nogueira
Keyword(s):  
Hybrid Material ◽  
Phosphorus Removal ◽  
Sol Gel ◽  
Permeable Reactive Barriers ◽  
Permeable Reactive Barrier ◽  
Aluminium Isopropoxide ◽  
Reactive Barrier ◽  
Ft Ir ◽  
Flow Through ◽  
Ft Ir Spectroscopy

Permeable reactive barriers were developed for phosphorus removal. The barrier consists in an organic-inorganic hybrid material, which allows water and others species to flow through it, while selectively removes the contaminants. Polyethylene oxide (POE) and aluminium oxide (Al2O3) were used as the organic and the inorganic parts, respectively. The hybrid material was obtained by sol-gel reaction, using aluminium isopropoxide as inorganic percursor in order to attain Al2O3. The hybrid material produced was characterized by FT-IR spectroscopy and thermogravimetry. The previous tests for phosphorus removal have shown the effectiveness capacity of the developed material to remove it.

scholarly journals Synthesis of NiFe2O4 nanofibers by joint sol-gel and electrospinning technique

10.30544/387 ◽  
2018 ◽  
Vol 24 (3) ◽  
pp. 173-180
Author(s):  
Aleksandar Grujić ◽  
Vladan Ćosović ◽  
Jasna Stajić-Trošić ◽  
Aleksandar Ćosović ◽  
Mirko Stijepović ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Sol Gel ◽  
Morphological Characteristics ◽  
Magnetic Behavior ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Web Structure ◽  
Crystallite Sizes ◽  
Ft Ir

In this study, electrospinning combined with sol-gel technique is applied in order to produce magnetic nickel ferrite (Ni-ferrite) nanofibers. The prepared Ni-ferrite gel was mixed with poly(vinylpyrrolidone) (PVP) solution which was used as a spinning aid to enable spinnability of the mixture. Structural and morphological characteristics of the as-spun ferrite gel/PVP composite web structure and calcinated Ni-ferrite nanofibers were analyzed using scanning electron microscopy (SEM). Phase composition analysis was carried out by Fourier-transform infrared (FT-IR) spectroscopy, X-Ray diffraction analysis (XRD) and 57Fe Mössbauer spectroscopy (MS). The obtained results suggest that the pure nanocrystalline NiFe2O4 dense mat to the almost coral-like structure of fibers with diameters ranging from hundreds of nanometers to few micrometers was obtained. The results of MS analysis revealed the existence of a crystallite size distribution within the material as well as the existence of a superparamagnetic fraction with very small crystallite sizes (<13nm). Magnetic behavior of the obtained material at elevated temperatures was also scrutinized using thermomagnetic measurements (TM) up to 800 °C.

Effects of Calcination Time on Structure and Morphology of Porous TiO2-Al2O3 Material

2012 ◽  
Vol 496 ◽  
pp. 161-164 ◽  
Author(s):  
Wen Jie Zhang ◽  
Jin Lei Chen
Keyword(s):  
Sol Gel ◽  
Anatase Tio2 ◽  
Tetrabutyl Titanate ◽  
Calcination Temperatures ◽  
Crystallite Sizes ◽  
Diffraction Peaks ◽  
Scherrer Formula ◽  
Xrd Patterns ◽  
Tio2 Phase ◽  
Amorphous Al2o3

Porous TiO2-Al2O3 composites were prepared through sol-gel method after calcination at 500 oC for different time. PEG1000 was used as a template and tetrabutyl titanate and aluminum isopropoxide were used as the precursors. The materials prepared under different calcination temperatures were all composed of anatase TiO2 and amorphous Al2O3. All the samples presented anatase TiO2 crystalline structure. There was no rutile TiO2 phase appearing in the patterns. Meanwhile, there were no noticeable diffraction peaks of any of crystalline phases of Al2O3. Calculated from Scherrer formula on (101) plane of the XRD patterns, crystallite sizes of anatase TiO2 were 10.06 nm, 10.55 nm, and 11.13 nm, respectively. The surfaces of the materials were very rough with long grooves on the surface. The materials were composed of large amorphous like matrix, along with some small particles laying on the surface.

scholarly journals Synthesis and characterization of magnetic recyclable Fe-substituted zinc aluminate photocatalysts with enhanced sunlight-driven degradation of industrial dyes

2020 ◽  
Author(s):  
Thanit Tangcharoen ◽  
Jiraroj T-Thienprasert ◽  
Chanapa Kongmark
Keyword(s):  
Organic Dyes ◽  
Magnetic Measurements ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Bandgap Energy ◽  
Magnetic Photocatalyst ◽  
Auto Combustion ◽  
Crystallite Sizes ◽  
Phase Spinel ◽  
Ft Ir

Abstract Using the sol-gel auto combustion approach with diethanolamine (DEA) as fuel, a sequence of iron-substituted zinc aluminates, ZnFexAl2−xO4 powders, including variable Fe3+ ion concentrations (0 ≤ x ≤ 2) were effectively created. XRD, FT-IR, SEM, EDS, BET, UV-DRS, and VSM were employed to examine the structures, chemical bonds, morphologies, composition, surface area, and optical properties as well as the magnetic behavior of the collected samples. A single-phase spinel structure was gained for the calcined aluminate powders with different interplanar spacing and crystallite sizes, as revealed by the classification results. The bandgap energy (Eg) of adapted aluminates was in the range of 2.08–3.14 eV, identified as being much lower compared to the pure sample (5.60 eV). Thus, Fe3+-substituted ZnAl2O4 samples could be successfully photoexcited using both ultraviolet and visible light, as suggested by the results. Examination of how the four main pollutant types decay when irradiated by sunlight was carried out to assess the samples and establish photocatalytic activity. These contaminants included phenol rhodamine B (RhB), heteropolyaromatic methylene blue (MB), azoic methyl orange (MO) and methyl red (MR). The performance of photocatalytic degradation reached 98% after 150 minutes for all optimal samples of organic dyes. Besides, each of the altered photocatalysts could be recycled and displayed high stability. The S-shaped curve of ferrimagnetism can result from in those samples as found by the magnetic measurements, though pure ZnAl2O4 displays diamagnetic characteristics. The adapted samples show intense improvement in the remanent magnetization (Mr) when compared to pure ZnAl2O4, signifying that magnetic photocatalyst recovery by applying an external magnetic field is easy. Thus, these results offer a convincing sign that ZnAl2O4 powders replaced by Fe3+ could provide the ability to aid in the ecologically-friendly collection of solar energy.

scholarly journals Structural, Morphological and Impedance Spectroscopic Analyses of Nano Li(Li0.05Ni0.4Co0.3Mn0.25)O2 Cathode Material Prepared by Sol-Gel Method

2014 ◽  
Vol 17 (3) ◽  
pp. 153-158
Author(s):  
A. Nichelson ◽  
S. Thanikaikarasan ◽  
Pratap Kollu ◽  
P. J. Sebastian ◽  
T. Mahalingam ◽  
...  
Keyword(s):  
Cathode Material ◽  
Sol Gel ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Diffusion Path ◽  
X Ray Diffraction ◽  
Electrical Studies ◽  
Ft Ir ◽  
Gel Technique ◽  
Ft Ir Spectroscopy

In the present work, layered lithium rich Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode materials were synthesized and its structural and electrical studies were analyzed. Layered Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was prepared by sol-gel technique using citric acid as chelating agent. The prepared sample was characterized by X-ray diffraction, SEM-EDS studies. The crystallite size of the Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was about 57 nm in which the diffusion path of lithium ion is effectively possible. The complexation behavior of prepared cathode material was analyzed by FT-IR spectroscopy. The electrical properties of the prepared Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was studied by impedance and dielectric spectral analyzes. The maximum ionic conductivity of LiLi0.05Ni0.4Co0.3Mn0.25)O2 was found to be in the order of 10-3.4 S/cm. The dielectric analysis of cathode material confirms the non-Debye type behavior.

Alginate/Gelatin Sponges Composited with ZnO Sponge Effective Extensibility and Compressibility as a Wound Dressing for the Care of Fracture Surgery

2021 ◽  
Vol 11 (10) ◽  
pp. 1873-1880
Author(s):  
Yumei Wang ◽  
Huichao Fu ◽  
Ying Lin
Keyword(s):  
Wound Healing ◽  
Human Fibroblasts ◽  
Sol Gel ◽  
Antibacterial Properties ◽  
Surface Characteristics ◽  
Future Application ◽  
Ft Ir ◽  
Cell Construction ◽  
Ft Ir Spectroscopy

We designed and synthesized highly porous alginate and gelatin hydrogels with zinc oxide nanoparticles (AGZNPs) as dressings using sol–gel methods. The presence of functional groups and the surface characteristics of the as-synthesised dressings were analyzed via Fourier transforminfrared (FT-IR) spectroscopy, while their morphology was studied via scanning electron microscopy (SEM). Additionally, the mechanical, inflammatory, and antibacterial properties and biocompatibility of the AGZNPs were evaluated to determine the efficiency of these bandages for wound healing applications. The AGZNPs demonstrated enhanced inflammatory and antibacterial properties. The biocompatibility of the nanocomposites was investigated in noncancerous NIH3T3 human fibroblasts. Furthermore, in-vivo examinations showed that the composition of the synthesized AGZNPs enhanced wound healing and promoted rapid cell construction and growth. Therefore, the AGZNP strategy promotes the future application of these nanoformulation hydrogels for wound bandaging in fracture surgeries.

Mechanochemical Processes in the System “Titanium - Heptane” during Ball Milling

2020 ◽  
Vol 989 ◽  
pp. 532-536
Author(s):  
Olga M. Kanunnikova ◽  
V.V. Aksenova ◽  
G.A. Dorofeev
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Phases ◽  
Crystallite Sizes ◽  
Ft Ir ◽  
Titanium Powders ◽  
Ft Ir Spectroscopy

The transformations of the solid and liquid phases at high energy planetary ball milling of heptane together with titanium powder were investigated. The sequence of structural heptane transformations using UV-and FT-IR spectroscopy was investigated. Phase constitutions of ball milled titanium powders were studied by X-ray diffraction. It is shown that mechanically induced destruction of heptane occurs by the mechanism of catalytic cracking. The main solid products of the mechanosynthesis were hexagonal (HCP) and cubic (FCC) titanium carbohydrides. Evolution of lattice parameters, crystallite sizes, and micro-stresses of the solid phases during ball milling as a function of the ball milling time have been discussed.

Characterization and Thermal Properties of Sol-Gel Processed PMMA/SiO2 Hybrid Materials

2008 ◽  
Vol 55-57 ◽  
pp. 749-752
Author(s):  
A. Buasri ◽  
K. Liangraksa ◽  
T. Sirisom ◽  
N. Tangkachalakul
Keyword(s):  
Hybrid Materials ◽  
Hybrid Material ◽  
Sol Gel ◽  
Inorganic Materials ◽  
Pure Pmma ◽  
Interesting Phenomenon ◽  
Near Surface ◽  
Sem Image ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Hybrid organic-inorganic materials were fabricated using sol-gel technique using poly(methyl methacrylate) and methacrylic acid 3-(trimethoxysilyl)propyl ester (MAMSE) with 90/10, 80/20 and 70/30 (%w/w) ratios with tetrahydrofuran (THF) solvent. The thin films were then characterized using FTIR spectra, SEM, DSC and TGA thermograms. From the preliminary characterization, the hybrid material was found to have nano and ultra scale tight pore ranges. FT-IR spectroscopy uncovered all the signature peaks characteristic of silicate structures in the near-surface regions. Fingerprints of Si-O-Si groups in cyclic and linear molecular substructures are present. The SEM image clearly shows that hybrid materials have homogenous and smooth surface. DSC analysis of the material shows interesting phenomenon regarding glass transition temperature (Tg). The hybrid material was found to have higher Tg than pure PMMA. From TGA analysis, the hybrid materials were observed to have higher thermal stability than pure PMMA.

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