Effect of Catalyst Type on Structural, Morphological, and Optical Properties of SiO2 Thin Film Applied by Sol-Gel Method

2013 ◽  
Vol 829 ◽  
pp. 446-450
Author(s):  
Najme Lari ◽  
Shahrokh Ahangarani ◽  
Ali Shanaghi
Keyword(s):  
Sol Gel ◽  
Silica Coating ◽  
Molar Ratio ◽  
Antireflective Coatings ◽  
Adhesive Properties ◽  
Gel Method ◽  
Sol Gel Method ◽  
Catalyst Type ◽  
Solar Thermal Collectors ◽  
Infrared Spectrophotometer

The application of antireflective coatings to the glass covers of solar thermal collectors, allows increasing the efficiency of the whole system. Among the methods for applying nanostructure coatings, sol-gel method was selected in this study. Via this method, an antireflective silica coating deposited on glass and the solar transmittance was investigated. The precursor solutions were made by mixing tetraethylorthosilicate (TEOS), ethanol, water and alkali (NH3) or acid (HNO3) catalyst in the molar ratio of 1:3.5:0.35:0.005. In addition, the role of two types of catalysts was examined. UV-visible spectroscopy, Fourier-transformed infrared spectrophotometer, Scanning electron and Optical microscopy were used for the characterization of silica thin films. Results showed that nanoporous silica layers cause to considerable reduction of these light reflections compared with uncoated glasses. It was found that the amount of reduction as well as the adhesive properties is depending on the type of catalyst. Results revealed that not only solar transmittance of acidic-catalyzed coatings is higher than of alkali-catalyzed coatings, but also acidic-catalyzed coatings possess adhesive-resistance higher than alkali-catalyzed coatings. However, at high pH condition, the condensation rate is very fast, and the growth tends to form spherically expanding clusters cause to increasing porosity. The dense and strong binding acidic-catalyzed films have a good antireflective property; because of that, the nanoporousity appears on the surface.

scholarly journals Silica coating of indium phosphide nanoparticles by a sol–gel method and their photobleaching properties

2019 ◽  
Vol 1 (12) ◽  
Author(s):  
Masaya Kambayashi ◽  
Noriko Yamauchi ◽  
Kouichi Nakashima ◽  
Masaki Hasegawa ◽  
Yuki Hirayama ◽  
...  
Keyword(s):  
Indium Phosphide ◽  
Sol Gel ◽  
Silica Coating ◽  
Gel Method ◽  
Sol Gel Method

Iron-Zircon Pigments Prepared by Non-Hydrolytic Sol-Gel Method at Low Temperature

2011 ◽  
Vol 412 ◽  
pp. 223-226 ◽  
Author(s):  
Wei Hui Jiang ◽  
Yan Hui Yang ◽  
Qing Xia Zhu ◽  
Jian Min Liu
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Ferric Chloride ◽  
Lithium Fluoride ◽  
Sol Gel ◽  
Zircon Crystal ◽  
Molar Ratio ◽  
Gel Method ◽  
Sol Gel Method ◽  
Anhydrous Ferric Chloride

ron-zircon pigment has been synthesized by non-hydrolytic sol-gel method using zirconium chloride and tetraethoxysilane as precursors, anhydrous ferric chloride as colorant, lithium fluoride as mineralizer and anhydrous ethanol as solvent. Iron-zircon pigment has been characterized by means of DTA-TG, XRD, Colorimeter and TEM. The results show that only a small fraction of iron is incorporated in the zircon crystal structure while the remaining iron cations are trapped within the zircon matrix. The iron-zircon with the red value (a*) of 20.64 can be synthesized at 700°C with the optimum Fe/Zr molar ratio of 0.2.

Iron and Iron-oxide on Silica Nanocomposites Prepared by the Sol-gel Method

2002 ◽  
Vol 17 (3) ◽  
pp. 590-596 ◽  
Author(s):  
G. Ennas ◽  
M. F. Casula ◽  
G. Piccaluga ◽  
S. Solinas ◽  
M. P. Morales ◽  
...  
Keyword(s):  
Sol Gel ◽  
Silica Matrix ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Gel Method ◽  
Sol Gel Method ◽  
Silica Nanocomposites ◽  
Transmission Electron ◽  
Nanometric Particles

γ–Fe2O3/SiO2 and Fe/SiO2 nanocomposites, with a Fe/Si molar ratio of 0.25, were prepared by the sol-gel method starting from ethanolic solutions of tetraethoxysilane and iron (III) nitrate. After gelation the xerogels were oxidated or reduced. Samples were investigated by transmission electron microscopy, x-ray diffraction, differential scanning calorimetry, and thermogravimetry. Magnetic properties of the samples were investigated at room temperature (RT) and at 77 K. Nanometric particles supported in the silica matrix were obtained in all cases. Bigger particles (10 nm) were obtained in the case of Fe/SiO2 nanocomposites with respect to the γ–Fe2O3/SiO2 samples (5–8 nm). A slight effect of sol dilution on particle size was observed only in the case of γ–Fe2O3/SiO2 nanocomposites. A superparamagnetic behavior was shown at RT only by γ–Fe2O3/SiO2 nanocomposites. Iron-based composites exhibited coercivity values higher than 700 Oe at RT.

N-Doped Cu11O2 (VO4)6 Photocatalyst Prepared by Sol-Gel Method

2011 ◽  
Vol 393-395 ◽  
pp. 1287-1290
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Qi Xing
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Photodegradation Rate ◽  
Triclinic Phase ◽  
Synthesized Materials

The N-doped Cu11O2 (VO4)6 photocatalyst was prepared using the sol-gel method. Techniques of X-ray diffraction (XRD), scanning electron microscope (SEM) have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of Methy lorange(MO) under the UV-light, the as-prepared N-doped Cu11O2 (VO4)6 exhibits higher activity than the pure Cu11O2 (VO4)6 without doped N. It found that the N-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, N/Cu molar ratio of 12%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 94.42% or so in 60min under 20W ultraviolet lamp.

Synthesis and Characterization of Fluorine-Doped Tin Oxide Nanocrystals Prepared by Sol-Gel Method

2014 ◽  
Vol 977 ◽  
pp. 59-62 ◽  
Author(s):  
Jun Qing Tian ◽  
Hai Ying Shi ◽  
Wei Zheng
Keyword(s):  
Tin Dioxide ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Hall Effect Sensor ◽  
Precursor Material ◽  
20 Nm

Fluorine-doped tin dioxide (FTO) nanocrystals were prepared with sol–gel method using SnCl4·5H2O and NH4F as precursor material. The FTO was characterized with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis and Thermal Grativity (DTA-TG) and Infrared Radiation (IR) respectively. The electrical property was measured with Hall Effect Sensor. The result of XRD and SEM shows that FTO nanocrystal size is about 20 nm and the dimension of the grain is about 300 nm. IR spectrum analysis proves fluorine doping. The crystal phase transformation was discussed with DTA-TG curve. When the sintering temperature is 450°C, the sintering time is 60 min, and the molar ratio of F to Sn is 2:10, the sheet resistance of FTO film is 107Ω/□.

Preparation of nanostructure silica antireflective coatings by using sol–gel method

Optik ◽  
2015 ◽  
Vol 126 (24) ◽  
pp. 5363-5367 ◽  
Author(s):  
Najme Lari ◽  
Shahrokh Ahangarani ◽  
Ali Shanaghi
Keyword(s):  
Sol Gel ◽  
Antireflective Coatings ◽  
Gel Method ◽  
Sol Gel Method

scholarly journals SOL-GEL DERIVED Co AND Ni BASED CATALYSTS: APPLICATION FOR STEAM REFORMING OF ETHANOL

2010 ◽  
Vol 8 (1) ◽  
pp. 47-53
Author(s):  
Haryo Satriya Oktaviano ◽  
Wega Trisunaryanti
Keyword(s):  
Steam Reforming ◽  
Catalyst Activity ◽  
Sol Gel ◽  
Lewis Acid Site ◽  
Morphological Properties ◽  
Molar Ratio ◽  
Gel Method ◽  
Sol Gel Method ◽  
Steam Reforming Of Ethanol ◽  
Ethanol Steam

Cobalt and nickel based catalysts for ethanol steam reforming have been prepared. Preparation of Na-Ni-Mo/C, Na-Co-Mo/C, K-Ni-Mo/C and K-Co-Mo/C have been carried out using sol-gel method by applying citric acid as complexion agent and source for support formation. Prepared catalyst via sol gel showed tailored morphological properties signed by tailored pore size distribution. The acidity of catalyst showed that all catalysts contain only Lewis acid site. The catalyst activity test was conducted by using semi flow method with molar ratio of ethanol : water = 0.33 at 400 oC   Keywords: sol-gel method, steam reforming, ethanol

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