scholarly journals VOC and CO Removals by Perovskite Type Nanocatalysts Supported on Commercial Substrates

2021 ◽  
Vol 8 ◽  
pp. 24-35
Author(s):  
Shahriar Hosseinpour ◽  
Mahsa Bahramgour ◽  
Seyyed Reza Hosseini ◽  
Yılmaz Yildirim ◽  
Aligholi Niaei
Keyword(s):  
Flow Reactor ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Dip Coating ◽  
Perovskite Catalyst ◽  
Weight Percentage ◽  
Synthesis Technique ◽  
Activity Test ◽  
Variable Weight ◽  
Sol Gel Synthesis

In this research, it was tried to choose a kind of perovskite catalyst with optimized formulation La0.8Sr0.2Co0.66Fe0.34O3 to remove air pollutants. This perovskite catalyst stabilized on the various supports such as alumina and ZSM-5 with the sol-gel synthesis technique and ceramic monolith by dip-coating method. Four different catalysts by variable weight percentage including PE-Al 10%, PE-Al 20%, PE-Al 30%, and PE-Al 40% were prepared by sol-gel synthesis technique. In this work, the XRD technique was used to confirm the formation of perovskite catalysts’ crystalline phases on the supports. As a result, XRD patterns revealed the formation of the perovskite phase onto the alumina and zeolite supports. Activity tests of these four catalysts were examined in the catalytic oxidation of Toluene and CO using an experimental setup consisting of a tubular flow reactor at the temperature 280-400°C and 100-400°C for the toluene and CO removal systems, respectively. According to the results of the catalysts’ activity test, the alumina supported with 40% w/w perovskite catalyst showed the best performance, and its activity was similar to the activity of the bulk catalyst (over 95% conversion of toluene at about 290°C). For the coated catalysts on a ceramic monolith, the complete removal of carbon monoxide at 50°C was lower than the powdered form. Results from the activity test in a toluene removal system that show coating of the bulk and supported catalysts on ceramic monolith; have an essential impact on the activity test of these catalysts. 

scholarly journals Aqueous Sol-Gel Synthesis of Different Iron Ferrites: From 3D to 2D

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Substrate Surface ◽  
Sol Gel ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
Dip Coating ◽  
Yttrium Iron ◽  
Iron Garnet ◽  
Dip Coating Technique ◽  
Sol Gel Synthesis

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.

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.

A Molecular Route to Dip-coated Transition Metal Nitride Thin Films.

2004 ◽  
Vol 848 ◽  
Author(s):  
Andrew W. Jackson ◽  
Andrew L. Hector
Keyword(s):  
Thin Films ◽  
Transition Metal ◽  
Spin Coating ◽  
Sol Gel ◽  
Particle Growth ◽  
Dip Coating ◽  
Stable Emulsion ◽  
Transition Metal Nitride ◽  
Sol Gel Synthesis ◽  
Gel Processing

ABSTRACTThere is an increasing interest in sol-gel synthesis of nitrides. The ability to deposit films of these materials by dip- or spin-coating will increase the range of applications in which they are viable and is an important step toward general sol-gel processing of nitride materials.With transition metals, the ammono based analogue of the well established alkoxy route to gels is inherently difficult to control. Due to the basicity of the system, the overwhelming tendency is of the starting materials to favour particle growth which results in a precipitate rather than a stable emulsion, unless both environment and synthetic pathway are carefully controlled. Hence reports to date of sol-gel routes to nitrides describe production of powders. We report work on a sol-gel route to titanium nitride with the ammonolysis of titanium amides controlled by temperature and chemical moderators, resulting in stable emulsions useful for dip-coating.

scholarly journals Sol–Gel Synthesis and Characterization of Coatings of Mg-Al Layered Double Hydroxides

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3738 ◽  
Author(s):  
A. Smalenskaite ◽  
M. M. Kaba ◽  
I. Grigoraviciute-Puroniene ◽  
L. Mikoliunaite ◽  
A. Zarkov ◽  
...  
Keyword(s):  
Thin Films ◽  
Layered Double Hydroxides ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Dip Coating ◽  
Dipping Process ◽  
Synthetic Approaches ◽  
Sol Gel Synthesis ◽  
Double Hydroxides ◽  
Steel Substrates

In this study, new synthetic approaches for the preparation of thin films of Mg-Al layered double hydroxides (LDHs) have been developed. The LDHs were fabricated by reconstruction of mixed-metal oxides (MMOs) in deionized water. The MMOs were obtained by calcination of the precursor gels. Thin films of sol–gel-derived Mg-Al LDHs were deposited on silicon and stainless-steel substrates using the dip-coating technique by a single dipping process, and the deposited film was dried before the new layer was added. Each layer in the preparation of the Mg-Al LDH multilayers was separately annealed at 70 °C or 300 °C in air. Fabricated Mg-Al LDH coatings were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and atomic force microscopy (AFM). It was discovered that the diffraction lines of Mg3Al LDH thin films are sharper and more intensive in the sample obtained on the silicon substrate, confirming a higher crystallinity of synthesized Mg3Al LDH. However, in both cases the single-phase crystalline Mg-Al LDHs have formed. To enhance the sol–gel processing, the viscosity of the precursor gel was increased by adding polyvinyl alcohol (PVA) solution. The LDH coatings could be used to protect different substrates from corrosion, as catalyst supports, and as drug-delivery systems in medicine.

X-ray diffraction analysis for thin films of PbTiO3-La2/3TiO3 prepared by the sol-gel method

1994 ◽  
Vol 9 (8) ◽  
pp. 2133-2137 ◽  
Author(s):  
Hideki Yoshioka
Keyword(s):  
Thin Films ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Diffraction Method ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coating Methods ◽  
Diffraction Patterns ◽  
System 1

Thin films in the system (1 - x) PbTiO3−xLa2/3TiO3 were prepared by the sol-gel and dip-coating methods. Phases deposited in the films and the lattice parameters as a function of the composition were investigated by the x-ray diffraction method. The solid solutions with a perovskite structure were formed as a single phase with x up to 0.9. For the composition of x = 1.0, metastable La-Ti-O perovskite phase with a small amount of the impurity phase, La2Ti2O7, was obtained. Simulation of x-ray diffraction patterns based on the defect structure model shows that the structure of the La-Ti-O perovskite phase includes randomly distributed cation vacancies at the A-site, namely (La2/3□1/3)TiO3.

Structure and Dielectric Properties of Zn Doped PST Thin Films Prepared by Sol-Gel Method

2007 ◽  
Vol 336-338 ◽  
pp. 283-286 ◽  
Author(s):  
Zan Zheng ◽  
Xiao Ting Li ◽  
Gao Rong Han ◽  
Wen Jian Weng ◽  
Pi Yi Du
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Phase Structure ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Dip Coating ◽  
In Doping ◽  
Ito Glass ◽  
Coating Method ◽  
Dip Coating Method

(PbySr1-y)ZnxTi1-xO3-x thin films were prepared on ITO/glass substrate by sol–gel process using dip-coating method. The phase structure, morphology, and dielectric properties of thin films were investigated by XRD, SEM and impedance analyzer, respectively. The perovskite phase structure was exhibited in the Zn-doped PST thin films. The formation ability of the thin films of the perovskite phase and its grain size decreased with the increase in doping Zn. The dielectric constant of the thin film was influenced by oxygen vacancies which could be controlled by Zn doping.

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.

Sol–gel synthesis of calcium hydroxyapatite thin films on quartz substrate using dip-coating and spin-coating techniques

2014 ◽  
Vol 71 (3) ◽  
pp. 437-446 ◽  
Author(s):  
Milda Malakauskaite-Petruleviciene ◽  
Zivile Stankeviciute ◽  
Aldona Beganskiene ◽  
Aivaras Kareiva
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Quartz Substrate ◽  
Sol Gel ◽  
Calcium Hydroxyapatite ◽  
Dip Coating ◽  
Sol Gel Synthesis

Sol-gel synthesis and characterization of CuO–based nanosystems

2002 ◽  
Vol 737 ◽  
Author(s):  
Lidia Armelao ◽  
Davide Barreca ◽  
Manuel Bertapelle ◽  
Gregorio Bottaro ◽  
Cinzia Sada ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Copper Acetate ◽  
Dip Coating ◽  
Silica Matrix ◽  
Synthesis And Characterization ◽  
Host Matrix ◽  
X Ray ◽  
Sol Gel Synthesis

ABSTRACTThis paper is focused on the sol-gel synthesis and characterization of CuO-based nanosystems both in the form of supported films and as guest nanoclusters embedded in a silica matrix. In both cases copper acetate (Cu(CH3COO)2 · H2O) was used as Cu source and, for the CuO :SiO2 nanocomposite systems, tetraethoxysilane (Si(OC2H5)4, TEOS) was adopted as silica precursor. Films were obtained by a dip-coating procedure and subsequently treated in air between 100 and 900°C. The system evolution on thermal annealing was studied by X-ray photoelectron spectroscopy (XPS), Glancing-Incidence X-ray diffraction (GIXRD) and optical absorption. Irrespective of the processing conditions, the formation of tenorite (CuO) crystallites with nanometric dimension was observed. In the nanocomposite samples, copper was homogeneously distributed in the host matrix and stable CuO nanoclusters (φ ≈ 15 nm) were obtained.

Sol–gel synthesis of mesoporous CaFe2O4 photocathodes with hierarchical pore morphology

2019 ◽  
Vol 3 (5) ◽  
pp. 1150-1153 ◽  
Author(s):  
Kristin Kirchberg ◽  
Roland Marschall
Keyword(s):  
Sol Gel ◽  
Dip Coating ◽  
Pore Morphology ◽  
Medium Temperature ◽  
Hierarchical Pore ◽  
Sol Gel Synthesis ◽  
First Time

Hierarchical mesoporous p-CaFe2O4 photocathodes are for the first time prepared by sol–gel dip-coating and calcination at only medium temperature (700 °C).

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