Preparation Of Pt/WO3 Powders and Thin Coatings on Carbon Black and Metal Supports by The Complex Sol-Gel Process (CSGP)

1997 ◽  
Vol 496 ◽  
Author(s):  
A. Deptula ◽  
W. Lada ◽  
T. Olczak ◽  
B. Sartowska ◽  
A. Ciancia ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Thermal Treatment ◽  
Carbon Black ◽  
Sol Gel ◽  
Molar Ratio ◽  
Thin Coatings ◽  
Ascorbic Acid Solution ◽  
Sol Gel Process ◽  
Immersion Technique ◽  
Metal Supports

ABSTRACTIn this work the CSGP was applied for preparation of Pt-WOx and its coatings on carbon black, silver and titan substrates. Saturated tungsten sol (0.15M) was prepared by dissolving (NH4)4W5O17 2.5 H2O in ascorbic acid solution. To this solution H2PtCl6 was added to obtain the molar ratio Pt:W=l. After evaporation and heating at 700°C for 2h homogeneous yellow-green powders were obtained. Another part of this solution was diluted with ethanol and after ultrasonic mixing used for preparation of coatings on Ag and Ti substrates by the immersion technique. Gel layers were dried at 200°C for 20h and then calcined at 700°C for 2h. The resulting white colored layers (thickness 10–65μm) were very adherent. Ascorbate aqueous tungsten-platinum sol diluted to 0.03 or 0.06 M ΣMe was used for preparation of Pt-W (10 and 20 %) catalyst by impregnation of carbon black Vulcan XC-72, followed by thermal treatment in air, argon and hydrogen atmospheres.

scholarly journals Interlayer-free Glucose Carbonised Template Silica Membranes for Brine Water Desalination

2019 ◽  
Vol 280 ◽  
pp. 03010 ◽  
Author(s):  
Dwi Rasy Mujiyanti ◽  
Muthia Elma ◽  
Mufidah Amalia
Keyword(s):  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Water Desalination ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Nacl Solution ◽  
Silica Membranes ◽  
Salt Ions ◽  
Sol Gel Process ◽  
Free Glucose

Interlayer-free glucose carbonized template silica membranesbased on tetraethyl orthosilicate (TEOS) and glucose were successfullyprepared using an acid-base catalysed sol-gel method for artificial brinewater desalination (7.5% wt NaCl solution %) at temperatures range from25, 40 and 60 °C. These membranes calcined at 250 and 400 °C. Themembranes were fabricated through sol-gel process by using TEOS(tetraethyl orthosilicate); ethanol; nitric acid; ammonia; aquadest andglucose as a template. By molar ratio is 1: 38: 0.0007: 0.0003: 5 and0.25%; 0.5%, 1% w/v glucose as template. The results show the highestwater fluxes of 1.8, 2.2 and 4.8 kg m−2 h−1 for 25, 40 and 60 °Cdesalination process with excellent salt rejections of 99.5, 99.5 and 99.7%, respectively. It was found that the higher the NaCl solution temperature asfeed solution as well as glucose concentration (0.25% to 1% wt) astemplate attached in the silica matrixes, the higher water fluxes eventhough the salt rejection remain the same. This study demonstrates that theorganosilica membranes offered the carbonized silica mesostructuremembranes with excellent separation of water from the hydrated salt ions, particularly for processing brine salt solutions.

scholarly journals Preparation of Transparent and Antireflective Silica Thin Coatings on Plastic Substrates by Sol-Gel Process

Proceedings ◽  
2020 ◽  
Vol 57 (1) ◽  
pp. 6
Author(s):  
Raluca Manea ◽  
Violeta Purcar ◽  
Valentin Rădițoiu ◽  
Alina Rădițoiu ◽  
Monica Florentina Raduly ◽  
...  
Keyword(s):  
Sol Gel ◽  
Thin Coatings ◽  
Plastic Substrates ◽  
Sol Gel Process ◽  
Self Cleaning

Due to their range of applications, from anti-icing to self-cleaning, low-adhesion, antibacterial. [...]

Study on Preparation and Hydrophobicity of MTES Derived Silica Sol and Gel

2012 ◽  
Vol 535-537 ◽  
pp. 2563-2566 ◽  
Author(s):  
Yu Ma ◽  
Hye Ryeon Lee ◽  
Toshinori Tsuru
Keyword(s):  
Reaction Rate ◽  
Sol Gel ◽  
Phase Segregation ◽  
Silica Sol ◽  
Molar Ratio ◽  
Modified Silica ◽  
Sol Gel Process ◽  
One Step ◽  
Inorganic Precursors

The synthesis of hydrophobic sol by one-step sol-gel process ammonia catalyzed was investigated. The water molar ratio and catalyst molar ratio were discussed to prevent phase segregation during the hydrolysis and co-condensation of the organic and inorganic precursors. The reactant system with water molar ratio 70 could make the reaction rate of MTES slightly less than that of TEOS, so that the hydrolysis - condensation – gelling reaction with MTES and TEOS as co-precursors could be synchronously. With the increase of the MTES/TEOS molar ratio, the reaction rate of the silica sol preparation decreased, the hydrophobicity of the sol and gel increased as the molar ratio MTES/TEOS change from 0.5~4. But the hydrophobicity of the methyl-modified silica sol and gel prepared with pure MTES in the sol-gel process were slightly lower than that of the methyl-modified silica sol and gel prepared with MTES and TEOS as co-precursors.

Preparation of Titanium Oxide and Metal Titanates as Powders, Thin Films, and Microspheres by Novel Inorganic Sol-Gel Process

2005 ◽  
Vol 900 ◽  
Author(s):  
A. Deptuła ◽  
Kenneth C Goretta ◽  
Tadeusz Olczak ◽  
Wieslawa Lada ◽  
Andrzej G. Chmielewski ◽  
...  
Keyword(s):  
Thin Films ◽  
Ascorbic Acid ◽  
Nitric Acid ◽  
Titanium Oxide ◽  
Sol Gel ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Metal Hydroxides ◽  
X Ray ◽  
Sol Gel Process

ABSTRACTTitanium oxide and titanates based on Ba, Sr and Ca were prepared from commercial solutions of TiCl4 and HNO3. The main preparation steps for the sols consisted of elimination of chloride anions by distillation with nitric acid and addition of metal hydroxides for the titanates. Resulting sols were gelled and used to (1) prepare irregularly shaped powders by evaporation; (2) produce by a dipping technique thin films on glass, Ag, or Ti substrates; and (3) produce spherical powders (diameters <100 μm) by solvent extraction. Results of thermal and X-ray-diffraction analyses indicated that the temperatures required to form the various compounds were lower than those necessary to form the compounds by conventional solid-state reactions and comparable to those required with use of organometallic based sol-gel methods. Temperatures of formation could be further reduced by addition of ascorbic acid to the sols.

Preparation of Nano-TiO2 Using a Sol-Gel Process Mediated in Reverse Microemulsion Combined with a Solvent Thermal Technique

2011 ◽  
Vol 287-290 ◽  
pp. 1731-1734 ◽  
Author(s):  
Han Sheng Li ◽  
Hang Xu ◽  
Shi Ying Wang ◽  
Ya Lin Pan ◽  
Qin Wu ◽  
...  
Keyword(s):  
Sol Gel ◽  
Average Particle Size ◽  
High Photocatalytic Activity ◽  
Reverse Microemulsion ◽  
Molar Ratio ◽  
Average Particle ◽  
Anatase Structure ◽  
Sol Gel Process ◽  
Triton X ◽  
Thermal Technique

Anatase nano-titania (nano-TiO2) was prepared by using a sol-gel process mediated in reverse microemulsion combined with a solvent thermal technique. The results show that the anatase structure appears in the calcination temperature range of 400-510°C, while the transformation of anatase into rutile takes place above 510°C. The average particle size (dP) of the nano-TiO2 increases with the rise of water/Triton X-100 molar ratio (ω) but decreases with the rise of acetyl acetone/n-TBT molar ratio (p) and n-hexanol/Triton X-100 molar ratio (m). The obtained TiO2 particles with a small size have high photocatalytic activity.

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.

Palladium-Silica Organic-Inorganic Membrane Materials via a Sol-Gel Process: Preparation and Properties Calcined under H2 Atmosphere

2017 ◽  
Vol 727 ◽  
pp. 889-894
Author(s):  
Jing Yang ◽  
Lin Yu Li ◽  
Hai Yun Hou ◽  
Zhi Tong
Keyword(s):  
Particle Size ◽  
Sol Gel ◽  
Total Pore Volume ◽  
Energy Dispersive Spectrum ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Inorganic Membrane ◽  
X Ray Diffraction ◽  
Membrane Materials ◽  
Sol Gel Process

Pd-doped SiO2 organic-inorganic membrane materials were prepared via a sol-gel process. The sol stability is characterized by sol particle size and zeta potential analysis. And the properties of the Pd-doped SiO2 organic-inorganic membrane materials are investigated by X-ray diffraction (XRD), fourier transform infrared (FTIR), energy dispersive spectrum (EDS) analysis and N2 absorption-adsorption measurement. The results showed that the sol particle size distributions are relatively narrow. With the increase of Pd content, the sol particle sizes slightly increase and the zeta potentials decreases until the palladium/tetraethylorthosilicate molar ratio closes to the isoelectric point. After calcined at 350 °C under H2 atmosphere, the added PdCl2 is reduced to metallic Pd0 completely, and the hydrophobic Si−CH3 groups exist in the SiO2 network. The Pd atoms have a lower concentration on the surface and more Pd atoms embedded in the SiO2 matrix. The Pd-doped SiO2 membrane materials calcined at 350 °C with a palladium/tetraethylorthosilicate molar ratio of 0.15 exhibit large BET surface area (up to 683.36 m2/g) and total pore volume (up to 0.386 cm3/g), as well as a mean pore diameter of about 2.26 nm.

Improvement in Mechanical Property of SiO2 Films Prepared by Sol-Gel

2013 ◽  
Vol 744 ◽  
pp. 269-272 ◽  
Author(s):  
Pei Tao Guo
Keyword(s):  
Mechanical Property ◽  
Thermal Treatment ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Sol Gel ◽  
Dimethyl Formamide ◽  
Good Mechanical Property ◽  
Chemical Additives ◽  
Sol Gel Process ◽  
Silica Sols

Silica films prepared by the base catalyzed sol–gel process show poor mechanical property. In this study, silica anti-reflective films with good mechanical property have been prepared by the catalyzed sol–gel process with dimethyl formamide added as drying control chemical additives. The silica sol was first dip deposited onto substrate to form films on both sides of the substrate and then subjected to thermal treatment. After thermal treatment, the film was achieved due to the formation of porous structure in the resultant film as a result of decomposing tetraethylorthosilicate and dimethyl formamide. Nano-indenter measurement shows that the Young’s modulus and hardness of base catalyzed films are 10-20GPa and 0.25-0.55GPa, respectively. But the films added with dimethyl formamide are much better than those films derived from base-catalyzed silica sols, the Young’s modulus and hardness are 32-39GPa and 1.22-1.47GPa, respectively. The good mechanical properties make such films potential in both military and civil applications.

Optical properties of ZnO nanoparticles synthesized by varying the sodium hydroxide to zinc acetate molar ratios using a Sol-Gel process

Open Physics ◽  
2011 ◽  
Vol 9 (5) ◽  
Author(s):  
Francis Dejene ◽  
Abdub Ali ◽  
Hendrik Swart ◽  
Reinhardt Botha ◽  
Kittesa Roro ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Sol Gel ◽  
Visible Region ◽  
Blue Emission ◽  
Molar Ratio ◽  
Broad Emission Band ◽  
Photoluminescence Intensity ◽  
Molar Ratios ◽  
Quantum Confinement Effects ◽  
Sol Gel Process

AbstractMaterial property dependence on the OH−/Zn2+ molar ratio of the precursor was investigated by varying the amount of NaOH during synthesis of ZnO. It was necessary to control the water content and temperature of the mixture to ensure the reproducibility. It was observed that the structural properties, particle size, photoluminescence intensity and wavelength of maximum intensity were influenced by the molar ratio of the precursor. The XRD spectra for ZnO nanoparticles show the entire peaks corresponding to the various planes of wurtzite ZnO, indicating a single phase. UV measurements show the absorption that comes from the ZnO nanoparticles in visible region. The absorption edge of these ZnO nanoparticles are shifted to higher energies and the determined band gap energies are blue shifted as the OH−/Zn2 molar ration increases, due to the quantum confinement effects. The photoluminescence characterization of the ZnO nanostructures exhibited a broad emission band centred at green (600 nm) region for all molar ratios except for OH−/Zn2+ = 1.7 where a second blue emission around 468 nm was also observed. The photoluminescence properties of ZnO nanoparticles were largely determined by the size and surface properties of the nanoparticles.

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