Sol-Gel Synthesis and Characterization of Ultrafine ZrSiO4 Powder

2014 ◽  
Vol 906 ◽  
pp. 66-71
Author(s):  
Zhen Quan Li ◽  
Qiang Zhen ◽  
Ya Li Wang
Keyword(s):  
Wavelength Range ◽  
High Purity ◽  
Raw Materials ◽  
Formation Rate ◽  
Sol Gel ◽  
Molar Ratio ◽  
Sem And Tem ◽  
Homogeneous Product ◽  
Sol Gel Synthesis ◽  
Calcined Temperature

High purity ZrSiO4 powder were synthesized using Si (C2H5O)4 and ZrOCl2·8H2O as raw materials by the sol-gel method, LiCl was added as mineralizer to promote crystallization of zircon. The influences of molar ratio of Zr:Si, calcined time and calcined temperature on the synthesis of ZrSiO4 powder were investigated. XRD, SEM and TEM were used to characterize the powders. It was found that when the molar ratio of Zr:Si was 1:1.2, the calcined temperature was 1600°C and the calcined time was 4h, the high purity ZrSiO4 ultrafine powder was obtained. The ZrSiO4 formation began at 1300°C and when the gel was calcined at 1600°Cfor 4 h, the formation rate of ZrSiO4 was up to 95%. SEM and TEM studies reveal a homogeneous product with particle sizes on the order of 0.1-1μm. The IR emissivity of ultrafine ZrSiO4 is 0.892 at the whole wavelength range, and that is up to 0.951 at the wavelength range of 8-14 μm.

Photocatalytic Degradation of Active Brilliant Red on TiO2/SiO2 Composite Catalysts

2012 ◽  
Vol 488-489 ◽  
pp. 221-225 ◽  
Author(s):  
Chun Hua Cao
Keyword(s):  
Photocatalytic Activity ◽  
Raw Materials ◽  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Molar Ratio ◽  
Tetrabutyl Titanate ◽  
Initial Concentration ◽  
Composite Catalysts ◽  
Composite Photocatalysts ◽  
Calcined Temperature

TiO2/SiO2composite catalysts were prepared using two-step sol-gel method, with tetrabutyl titanate and tetraethyl orthosilicate as the main raw materials, and its photocatalytic properties for degradation of active brilliant red X-3B solution were researched throuth Ti:Si molar ratio, calcined temperature, initial concentration and photocatalyst dosage. The results indicate that the TiO2/SiO2composite catalysts prepared with Ti:Si molar ratio of 6, calcination at 500°C have the best photocatalytic activity, and the photocatalytic activity of the composite materials is higher than that of pure TiO2under the same conditions; moreover, it was found that degradation rate of active brilliant red X-3B solution increased with its lower initial concentration, and the optimum dosage of composite photocatalysts is 1.6g/L when the initial concentration of active brilliant red X-3B solution is 25mg/L.

Sol-gel synthesis and characterization of Ag nanoparticles in ZrO2 thin films

2009 ◽  
Vol 24 (8) ◽  
pp. 2541-2546 ◽  
Author(s):  
Eisuke Yokoyama ◽  
Hironobu Sakata ◽  
Moriaki Wakaki
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Composite Films ◽  
Dip Coating ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Silver Surface ◽  
Molar Ratios ◽  
Sol Gel Synthesis

ZrO2 thin films containing silver nanoparticles were prepared using the sol-gel method with Ag to Zr molar ratios [Ag]/[Zr] = 0.11, 0.25, 0.43, 0.67, 1.00, 1.50, and 2.33. After dip coating on glass substrate, coated films were annealed at 200 and 300 °C in air. X-ray diffraction peaks corresponding to crystalline Ag were observed, but a specific peak corresponding to ZrO2 was not observed. At the molar ratio [Ag]/[Zr] = 0.25, the particle size of Ag distributed broadly centered at 17 nm for an annealing temperature of 200 °C and at 25 nm for 300 °C. The films annealed in air at 200 °C showed an absorption band centered at 450 nm because of the silver surface plasmon resonance, whereas films heated at 300 °C in air caused a red shift of the absorption to 500 nm. The absorption peak was analyzed using the effective dielectric function of Ag-ZrO2 composite films modeled with the Maxwell-Garnett expression.

scholarly journals Improving anti-infrared radiation and heat insulation by potassium hexatitanate whisker-doped Al 2 O 3 –SiO 2 composite xerogel

2018 ◽  
Vol 5 (12) ◽  
pp. 180787
Author(s):  
Liang Furong ◽  
Liu Weijun ◽  
Han Xiuxiu ◽  
Zhang Boru ◽  
Zhang Shuhua
Keyword(s):  
Thermal Conductivity ◽  
Infrared Radiation ◽  
Near Infrared ◽  
Raw Materials ◽  
Sol Gel ◽  
Spectral Characteristics ◽  
Molar Ratio ◽  
Thermal Insulating ◽  
Infrared Spectral ◽  
Potassium Hexatitanate

Taking potassium hexatitanate whisker (PTW) modified by silane coupling agent KH550, aluminium nitrate inorganic salt and tetraethyl orthosilicate and deionized water, respectively, as infrared sunscreen, aluminium source and raw materials forming the network structure of a composite xerogel, a series of structurally intact PTW-doped Al 2 O 3 –SiO 2 composite xerogel thermal-insulating materials were prepared by the sol–gel method and dried under atmospheric pressure. The infrared spectral characteristics, infrared radiation transmittance, microstructures, morphology and thermal conductivity of different composite materials prepared have been determined by a Fourier transform infrared spectrometer, UV–visible–near-infrared spectrophotometer, X-ray diffractometer, scanning electron microscope and thermal conductivity tester. The results exhibit that when the Al to Si molar ratio is 1 : 9, the composite material with 5 wt% modified PTW shows the best infrared radiation blocking performance and the lowest thermal conductivity (0.0604 W m −1 K −1 ).

Synthesis Method and its Influence Factors of Hydrotalcite-Like Compounds

2013 ◽  
Vol 690-693 ◽  
pp. 351-354 ◽  
Author(s):  
Hong Dan Xue ◽  
Fu Li Wang ◽  
Guo Li Li ◽  
Pu Liu ◽  
Yong Qing Bai ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Reduction Method ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Synthesis Method ◽  
Influence Factors ◽  
Synthetic Methods ◽  
Molar Ratio ◽  
Temperature Reaction

Hydrotalcite-like compounds are a class of anionic lays or layed double hydroxiods (LDHs) which consists of alkalescence, anion-exchanges and memory effect. The synthetic methods of LDHs include coprecipitation, hydrothermal synthesis, mirowave radiation, ion exchange, sol-gel method, roasting reduction method, instant synthesis, etc.The molar ratio of raw materials, pH value,reaction temperature,reaction time and so on have a greater impact on the purity and crystallinity of the LDHs.

Effect of the Sol-Gel Synthesis Parameters on the Incorporation of an Anti-inflammatory Drug in a Ceramic Material

2007 ◽  
Vol 1007 ◽  
Author(s):  
Aracely Hernandez ◽  
Patricia Esquivel-Ferriño ◽  
Idalia Gomez ◽  
Lucia Cantu
Keyword(s):  
Ceramic Material ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Molar Ratio ◽  
Inflammatory Drug ◽  
Synthesis Conditions ◽  
Synthesis Parameters ◽  
Anti Inflammatory ◽  
Drug Incorporation ◽  
Sol Gel Synthesis

ABSTRACTIn the present work, sol-gel method was used to incorporate in a ceramic material a non steroidal anti-inflammatory drug (piroxicam) as model drug. The incorporation of the drug in the SiO2 network was carried out at different sol-gel synthesis parameters, such as pH (3 and 5) and the alkoxide/water ratio (1:6 and 1:8). The biomaterial obtained was analyzed by thermal analysis TGA-DTA, infrared spectroscopy (FTIR), Scanning Electronic Microscopy (SEM) and X-ray diffraction (XRD); specific surface area and porosity were analyzed from nitrogen adsorption isotherm. Better drug incorporation into the material was achieved at the synthesis conditions of pH 5 and 1:6 alkoxide/water molar ratio.

Effect of Sintering Time on the Phase Composition in PFN Ceramics Prepared by Sol-Gel Process

2009 ◽  
Vol 409 ◽  
pp. 317-321 ◽  
Author(s):  
Helena Bruncková ◽  
Ľubomír Medvecký ◽  
Ján Mihalik
Keyword(s):  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Molar Ratio ◽  
Sintering Time ◽  
Sol Gel Process ◽  
Sol Gel Synthesis ◽  
Spherical Grains ◽  
Bimodal Grain Size ◽  
Iron Niobate

Lead iron niobate Pb(Fe0.5Nb0.5)O3 (PFN) ceramics were prepared using sol-gel synthesis by mixing acetates Pb and Fe with Nb-ethylene glycol-tartarate (Pechini) complex at 80°C, calcination of gels at 600°C and sintering at 1150°C for various times. The metastable pyrochlore phase Pb3Nb4O13 in stoichiometric precursor was partially decomposed to perovskite phase Pb(Fe0.5Nb0.5)O3 in ceramics sintered at temperature of 1150°C for 2, 4 and 6 hours. Excess of Pb in molar ratio (Pb:Fe:Nb = 1.2:0.5:0.5) caused the increase of the content of the perovskite phase (~50 vol.%) in nonstoichiometric PFN ceramics sintered at 1150°C for 6 hours while the decrease in perovskite phase content was found in stoichiometric PFN ceramics (~16 vol.%). In microstructures of PFN ceramics sintered at 1150°C for different times, the bimodal grain size distribution was observed with small spherical grains of perovskite phase and larger octahedral grains of pyrochlore phase. EDX analysis confirm that complex types of pyrochlore phases that differ in iron content were present in ceramics.

Morphology and Phase Composition of Sol-Gel Derived Aluminum Borate Nanowhiskers

2015 ◽  
Vol 659 ◽  
pp. 121-126 ◽  
Author(s):  
Pat Sooksaen
Keyword(s):  
Fourier Transform ◽  
Phase Composition ◽  
Sol Gel ◽  
Molar Ratio ◽  
Aluminum Borate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature ◽  
Sol Gel Synthesis ◽  
Scanning Electron

Aluminium borate nanowhiskers with varying aspect ratio were synthesized via sol–gel synthesis. The morphology of aluminum borate (Al4B2O9 and Al18B4O33) nanowhiskers could be controlled by varying the aluminum to boron (Al:B) molar ratio in the sol–gel derived precursors. Sintering temperatures (850 and 1100°C) and sintering times (4 and 32 hours) also affected the phase composition and size of the nanowhiskers. Citric acid was also added in the sol–gel derived precursors as a surface stabilizer for obtaining uniform finely dispersed nanostructures. Fine nanowhiskers were obtained by the calcination at 850°C, whereas higher temperature of 1100°C led to thicker and longer nanowhiskers and became rod-like crystals. The morphology and phase composition were investigated by field emission scanning electron microscope and X-ray diffraction. Chemical bond vibrations in the synthesized nanowhiskers were investigated by Fourier-transform infrared spectroscopy.

scholarly journals Synthesis of Silica Nanostructures and Optimization of their Size and Morphology by Use of Changing in Synthesis Conditions

2012 ◽  
Vol 9 (2) ◽  
pp. 659-668 ◽  
Author(s):  
A. Elsagh
Keyword(s):  
Drug Delivery Systems ◽  
Sol Gel ◽  
Molar Ratio ◽  
Synthesis Conditions ◽  
Acid Type ◽  
Silica Nanostructures ◽  
Size And Morphology ◽  
Sol Gel Synthesis ◽  
Optimized Conditions ◽  
Cracking Products

The aim of the present research was optimization of practical conditions of the sol-gel synthesis. In so doing, silica particles were synthesized using sol-gel method and their size and morphology were investigated by use of SEM and TEM images. The effect of changing molar ratio of reactive including acids and silica pre-matter on the particles' morphology and size was studied. Also, acid type and silica pre-matter used in reaction was examined and the result product of the reaction were investigated in the presence of several acids and two types of silica pre-matter. The reaction time was studied as a very important factor in products' digestion phase which plays a significant role in determining particles’ size and rate of cracking products. Finally, in optimized conditions 50-80 nm diameter nanostructures were synthesized. These products can be used as drug delivery systems.

scholarly journals Sol-Gel Synthesis, Magnetic and Optical Properties of Co2+:Nd3+::2:1 molar ratio doped in SiO2

2015 ◽  
Vol 11 (3) ◽  
pp. 3367-3374
Author(s):  
Bidhu Bhusan Das ◽  
Ruppa Govinda Rao
Keyword(s):  
Magnetic Moments ◽  
Sol Gel ◽  
Broad Band ◽  
Molar Ratio ◽  
Amorphous Sio2 ◽  
Asymmetric Mode ◽  
Distorted Octahedral ◽  
Bending Mode ◽  
Sio2 Phase ◽  
Sol Gel Synthesis

Synthesis of Co2+:Nd3+::2:1 molar ratio doped SiO2 with Co2+ ions concentrations viz. 0.0004, 0.001,  0.002, 0.003, 0.004 moles in S1-S5, respectively are performed by sol-gel method. Observed values of the densities and the concentrations of the Co2+ ions in S1-S5 are found to be 2.26, 2.29, 2.37, 3.44, 2.49 g/cm3, and ~ 1020 ions/g, respectively. Powder XRD results show the formation of amorphous SiO2 phase in the samples. DTA-TGA/DTG traces in the range 27-700 ˚C show no characteristic event in the samples. The IR peak in the range 412-418 cm-1 is ascribed to the asymmetric mode of the octahedral [NdO6/2]3- units. The peak around 440 cm-1 in S1-S5 is due to the ν2-symmetric bending mode of the tetrahedral [SiO4/2]4- units. The weak IR peak ~ 670 cm-1 is due to the ν1-mode of the tetrahedral [CoO4/2]4- units. The calculated values of the magnetic susceptibility from the observed magnetic moments data at 300 K are found to be ~10-6  emu/gG in S1-S5 which show the weak paramagnetic nature of the materials.  The EMR lineshapes recorded at 6, 50, 77, and 300 K are very broad, isotropic and smeared out with only two detectable characteristic peaks. The giso-value ~ 2.3 is due to the doped Co2+(3d7) ions in tetrahedral coordinations, while the giso-value ~ 2.01 is due to the doped Nd3+(4f3) ions in distorted octahedral coordinations. The lineshapes only at 6 K are distinct, while at higher temperatures  these peaks are severely smeared out. The optical absorption broad band at ~750 nm (13262 cm-1) is assigned to 4I9/2 ® 4F7/2 + 4S3/2 transitions in optically active Nd3+(4f3) ions, and the  peak ~ 520 nm (19230 cm-1) is attributed to 4A2g ® 4T1g(P) transitions in Co2+ (S=3/2, 3d7) ions in tetrahedral coordinations.

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