Photocatalytic Activity of Nanocoatings Based on Mixed Oxide V-TiO2 Nanoparticles with Controlled Composition and Size

V-TiO2 photocatalyst with 0 ≤ V ≤ 20 mol% was prepared via the sol–gel method based on mixed oxide titanium–vanadium nanoparticles with size and composition control. The mixed oxide vanadium–titanium oxo-alkoxy nanonoparticles were generated in a chemical micromixing reactor, coated on glass beads via liquid colloid deposition method and underwent to an appropriate thermal treatment forming crystallized nanocoatings. X-ray diffraction, Raman, thermogravimetric and differential thermal analyses confirmed anatase crystalline structure at vanadium content ≤ 10 mol%, with the cell parameters identical to those of pure TiO2. At a higher vanadium content of ~20 mol%, the material segregation began and orthorhombic phase of V2O5 appeared. The crystallization onset temperature of V-TiO2 smoothly changed with an increase in vanadium content. The best photocatalytic performance towards methylene blue decomposition in aqueous solutions under UVA and visible light illuminations was observed in V-TiO2 nanocoatings with, respectively, 2 mol% and 10 mol% vanadium.

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Thermal analyses of bulk amorphous oxides and silicates of zirconium and hafnium

MRS Proceedings ◽

10.1557/proc-745-n1.4 ◽

2002 ◽

Vol 745 ◽

Cited By ~ 4

Author(s):

S. V. Ushakov ◽

C. E. Brown ◽

A. Navrotsky ◽

A. Demkov ◽

C. Wang ◽

...

Keyword(s):

Crystallite Size ◽

Thermal Analyses ◽

Sol Gel ◽

Tetragonal Zirconia ◽

Interface Energy ◽

Silica Content ◽

Scanning Calorimetry ◽

Amorphous Oxides ◽

Hafnium Silicate ◽

Crystallization Onset

ABSTRACTAmorphous pure and Y-doped ZrO2 and HfO2 were prepared by precipitation with ammonia or hydrazine. Amorphous zirconium and hafnium silicates with SiO2 content from 10 to 90 mol % were prepared by sol-gel. Crystallization was studied by differential scanning calorimetry (DSC) at 20 °C/min and crystallite size after crystallization was determined from XRD data. ZrO2 crystallized into the tetragonal phase with ΔH -21 ±2 kJ/mol and HfO2 into the monoclinic phase with ΔH -31 ±2 kJ/mol. Doping with 20 at.% Y decreased crystallite size after crystallization. Crystallization temperatures for pure and Y-doped ZrO2 samples were in the range 420–440 °C. Crystallization temperatures for pure and Y-doped HfO2 samples varied from 470 to 570°C and correlate with surface area. Crystallization onset temperature in silicates increased with silica content from about 650 to 950 °C for ZrO2·SiO2 and from 740 to 1030 °C for HfO2·SiO2. Tetragonal zirconia and hafnia were the only crystalline phases formed below 1100 °C in all zirconium silicates and in hafnium silicates with more than 10 mol% SiO2. Crystallite size after crystallization decreased with increase in silica content. In hafnium silicate, a decrease in HfO2 crystallite size from 5 to 2.5 ±1 nm corresponds to a crystallization enthalpy change from -22 to -15 ±2 kJ/mol. The tetragonal HfO2/amorphous SiO2 interface energy can be calculated from calorimetric data as ∼0.25 J/m2. The critical particle size for the tetragonal to monoclinic transformation of HfO2 in HfO2-SiO2 system is about 6 nm. We predict that tetragonal HfO2 will be stabilized in films thinner than 2 nm.

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Ag-Enhanced Antibacterial Property of MgO Film

Materials Science Forum ◽

10.4028/www.scientific.net/msf.859.90 ◽

2016 ◽

Vol 859 ◽

pp. 90-95 ◽

Cited By ~ 5

Author(s):

Zafer Alajmi ◽

Tao Fu ◽

Yan Tao Zhao ◽

Shui Yun Yang ◽

Jia Mao Sun

Keyword(s):

Silver Nanoparticles ◽

Photoelectron Spectroscopy ◽

Antibacterial Property ◽

Thermal Analyses ◽

Sol Gel ◽

Inhibition Zone ◽

X Ray Diffraction ◽

X Ray ◽

Antibacterial Surface ◽

Modification Of Titanium

MgO and silver-containing MgO (AgMgO, 3.3, 9.1 at% Ag) films were sol-gel coated on titanium to improve its antibacterial property. Thermal analyses of MgAc2·4H2O powder revealed that MgO was crystallized at 400 °C. X-ray diffraction analysis showed that MgO was converted to Mg(OH)2 or Mg5(CO3)4(OH)2·4H2O during the ageing in air. Silver nanoparticles at the surface of AgMgO films were identified by scanning electron microscopy and x-ray photoelectron spectroscopy. The MgO film was about 1.5 um thick. The potentiodynamic polarization test in the Ca-free Hank’s balanced salt solution showed that the coated titanium samples had better corrosion resistance than the polished one. The dissolution of silver nanoparticles resulted in a current peak in the polarization plots. In the antibacterial test against E. Coli, the inhibition zone width was 0.3, 1.6, 2.0 mm for the films with 0, 3.3, 9.1 at% Ag, respectively. The bactericidal mechanisms of the MgO and AgMgO films were discussed. The present work would provide a facile method for antibacterial surface modification of titanium based osteo-implants.

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EFFECT OF ANNEALING TEMPERATURE ON STRUCTURAL AND OPTICAL PARAMETERS OF SOL–GEL ROUTED MOLYBDENUM OXIDE THIN FILM

Surface Review and Letters ◽

10.1142/s0218625x15500547 ◽

2015 ◽

Vol 22 (04) ◽

pp. 1550054 ◽

Cited By ~ 6

Author(s):

P. ADAL ARASU ◽

R. VICTOR WILLIAMS

Keyword(s):

Refractive Index ◽

Annealing Temperature ◽

Sol Gel ◽

Orthorhombic Phase ◽

Oxide Thin Film ◽

Optical Parameters ◽

X Ray Diffraction ◽

Absorption Region ◽

Lower Annealing Temperature ◽

Transparent Region

The influence of annealing temperature on structural and optical properties of sol–gel routed spin-coated molybdenum tri oxide ( MoO 3) thin films are studied. The higher annealing temperatures improve the crystalline nature of the film. The X-ray diffraction (XRD) study reveals the formation of α-orthorhombic phase at higher annealing temperature and amorphous nature at lower annealing temperature. The optical bandgap of molybdenum tri oxide ( MoO 3) film is found to be 3.3–3.8 eV, and the refractive index of the film is found to be 2.2–2.9. The dispersion curve of the refractive index shows that an abnormal dispersion in the absorption region and normal dispersion in the transparent region are observed. The optical polarizability, optical conductivity, dielectric constant, volume and surface energy loss parameters are evaluated.

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Sol-Gel Processing of Glasses and Glass-Ceramics for Microelectronic Packaging

MRS Proceedings ◽

10.1557/proc-249-59 ◽

1991 ◽

Vol 249 ◽

Author(s):

M.A. Sriram ◽

P.N. Kumta

Keyword(s):

Dielectric Constant ◽

Thermal Analyses ◽

Sol Gel ◽

Glass Ceramics ◽

Signal Propagation ◽

Ceramic Materials ◽

X Ray Diffraction ◽

Low Dielectric ◽

Heat Treated ◽

Gel Processing

In recent years considerable progress has been made in electronic packaging substrate technology. The future need of miniaturization of devices to increase the signal processing speeds calls for an increase in the device density requiring the substrates to be designed for better thermal, mechanical and electrical efficiency.Fast signal propagation with minimum delay requires the substrate to possess very low dielectric constant. Several glasses and glass-ceramic materials have been identified over the years which show good promise as candidate substrate materials. Among these borophosphate and borophosphosilicate glass-ceramics have been recently identified to have the lowest dielectric constant (3.8). Sol-gel processing has been used to synthesize borosilicate, borophosphosilicate and borophosphate glasses and glass-ceramics using inexpensive boron oxide and phosphorus pentoxide precursors. Preliminary results of the processing of these gels and the effect of volatility of boron alkoxide and its modification on the gel structure are described. X-ray diffraction, Differential thermal analyses and FTIR have been used to characterize the as-prepared and heat treated gels.

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Effect of fuel content on formation of zinc aluminate nano and micro-particles synthesised by high rate sol–gel autoignition of glycine-nitrates

Chemical Papers ◽

10.1515/chempap-2015-0205 ◽

2016 ◽

Vol 70 (3) ◽

Cited By ~ 1

Author(s):

Shiva Salem

Keyword(s):

Thermal Analyses ◽

Sol Gel ◽

High Rate ◽

Zinc Aluminate ◽

X Ray Diffraction ◽

Micro Particles ◽

Transmission Electron ◽

Xrd Patterns ◽

Average Size ◽

20 Nm

AbstractThe autoignition technique using glycine as fuel and related nitrate salts as an oxidiser is able to produce zinc aluminate spinel. The precursors were synthesised with lean and rich fuel at pH of 7.0 and the materials so obtained were calcined at various temperatures ranging from 600-1200°C. The autoignition process of precursors was studied by the simultaneous thermo-gravimetric and differential thermal analyses to determine the ignition mechanism. The calcined powders were characterised by X-ray diffraction, Brunauer-Emmett-Teller technique and transmission electron microscopy. The product contains nano-sized particles with an average size of approximately 20 nm. The XRD patterns showed the formation of ZnO in the powder obtained by the fuel-rich precursor and calcined at 600°C which disappears at 800°C due to solid-state reaction and proper crystallisation after heat treatment. The results presented here can be useful in manufacturing nano and micro-sized ZnAl

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Effect of Sr on the properties of Ce-Zr-La mixed oxides

Journal of the Serbian Chemical Society ◽

10.2298/jsc0603285r ◽

2006 ◽

Vol 71 (3) ◽

pp. 285-291 ◽

Cited By ~ 1

Author(s):

Richuan Rao ◽

LI Lianyong ◽

LI Fengyi

Keyword(s):

Mixed Oxide ◽

Storage Capacity ◽

Mixed Oxides ◽

Sol Gel ◽

Oxygen Storage Capacity ◽

Oxygen Storage ◽

X Ray Diffraction ◽

Pulse Technique ◽

X Ray ◽

Good Thermal Stability

Ce-Zr-La-Sr mixed oxides, with different Sr contents, were prepared by the sol-gel method. In a flow-system microreactor, the reduction properties and the oxygen storage capacity (OSC) of the Ce-Zr-La-Sr mixed oxides were investigated by a temperature programmed reduction (TPR) and a pulse technique. It was shown that the properties of the Ce-Zr-La mixed oxides depend on the Sr content and that the optimum Sr content in the Ce-Zr-La-Sr mixed oxide is 3 mol%. The Ce-Zr-La-Sr mixed oxides doped with 3 mol% Sr (Ce0.52Zr0.4La0.05Sr0.03O1.945) has the largest specific surface area and better reduction properties and oxygen storage capacity in comparison to the other investigated samples. The XRD results of the Ce-Zr-La-Sr mixed oxides showed that their X-ray diffraction patterns are well in agreement with that of fluorite-type CeO2 with Sr ions incorporated into the Ce-Zr-La mixed oxide structures. With increasing calcination temperature, the intensity of the X-ray diffraction peaks increased, but no new peaks were observed. All of these indicate that the synthesized samples had good thermal stability.

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Hydrophilic Properties Study of Mn-TiO2 Thin Films Deposited by Dipping Technique

Iraqi Journal of Physics (IJP) ◽

10.30723/ijp.v19i49.646 ◽

2021 ◽

Vol 19 (49) ◽

pp. 62-74

Author(s):

Sura Y Khalaf ◽

Falah H. Ali

Keyword(s):

Thin Films ◽

Sol Gel ◽

Pure Tio2 ◽

Ultraviolet Rays ◽

X Ray Diffraction ◽

Tio2 Thin Films ◽

Visible Absorption ◽

Attractive Option ◽

Gel Technique ◽

Uv Visible

in this paper, the current work was devoted to the manufacture of TiO2 nanoparticles doped with manganese, synthesis by the sol-gel technique using a dip-conting device, for their hydrophilic properties and photocatalytic activity, and the products were characterized by X-ray diffraction, scanning electron microscopy, and Uv-Visible absorption, and the results XRD showed an phase Anatase , and the results of the SEM Explained the shape of the morphology of the samples after the doping process compared with pure TiO2, and the results of a shift in light absorption from ultraviolet rays to visible light were evident. The results showed that the thin films have a high wettability under visible rays proven to have excellent optical stimulation in the visual area, making the application of a thin film as a self-cleaning material an attractive option.

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Co/TiO2 nanoparticles: preparation, characterization and its application for photocatalytic degradation of methylene blue

10.31224/osf.io/m6d2j ◽

2018 ◽

Author(s):

azadeh ebrahimian pirbazari ◽

Pejman Monazzam ◽

Behnam Fakhari Kisomi

Keyword(s):

Methylene Blue ◽

Photocatalytic Activity ◽

Tio2 Nanoparticles ◽

Anatase Phase ◽

Sol Gel ◽

Pure Tio2 ◽

Cobalt Doping ◽

X Ray Diffraction ◽

X Ray ◽

Ft Ir

In this work, TiO2 nanoparticles containing diﬀerent amounts of cobalt were synthesized by sol-gel method using titanium (IV) isopropoxide and cobalt chloride as titanium and cobalt precursors, respectively. X-ray diﬀraction (XRD) results showed prepared samples include 100% anatase phase. The presence of cobalt in TiO2 nanoparticle network was established by XRD, scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM-EDX), Fourier transform infrared (FT-IR) and N2 physisorption techniques. The increase of cobalt doping enhanced redshif in the diﬀuse reﬂectance spectra. The photocatalytic activity of the prepared samples was tested for degradation of methylene blue (MB) as a model of dye. Although the photocatalytic activity of pure TiO2 was found to be higher than that of Co/TiO2 samples under UV irradiation, the presence of 0.24% cobalt dopant in TiO2 nanoparticles resulted in a photocatalyst with the highest activity under visible light

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Preparation and characterization of magnetite-based silica nanocomposite

Acta periodica technologica ◽

10.2298/apt0435121p ◽

2004 ◽

pp. 121-129 ◽

Cited By ~ 1

Author(s):

Mihaela Popovici ◽

Cecilia Savii ◽

Daniel Niznanský ◽

Jan Subrt ◽

Eva Vecernikova ◽

...

Keyword(s):

Thermal Analyses ◽

Sol Gel ◽

Nitrogen Atmosphere ◽

Thermal Treatments ◽

Vibrating Sample Magnetometry ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Magnetite Phase

Sol-gel method and successive thermal treatments in vacuum and nitrogen atmosphere were employed to synthesize magnetite nanoparticles isolate them with the aid of amorphous silica. Thermogravimetric and differential thermal analyses coupled with mass spectrometry, X-ray diffraction, transmission electron microscopy, M?ssbauer spectroscopy and vibrating sample magnetometry measurements were performed on the obtained nanocomposites. The effect of atmosphere on the formation of magnetite phase was remarkable.

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Tridoped TiO2 Composite Films for Improved Photocatalytic Activities

Coatings ◽

10.3390/coatings9020127 ◽

2019 ◽

Vol 9 (2) ◽

pp. 127 ◽

Cited By ~ 4

Author(s):

Li-Zhu Zhao ◽

Ke Han ◽

Fang Li ◽

Ming-Ming Yao

Keyword(s):

Sol Gel ◽

Composite Films ◽

Pure Tio2 ◽

Methyl Green ◽

X Ray Diffraction ◽

Electron Hole ◽

Glass Substrates ◽

Photocatalytic Activities ◽

Particle Aggregates ◽

Crystal Type

The Fe/B/F tridoped TiO2-ZnO composite films attached to glass substrates were prepared via a simple sol–gel method. We appraised all samples’ photocatalytic activities by the degradation of methyl green and formaldehyde solutions. The samples were characterized by photoluminescence (PL) spectra, UV-Vis diffraction reflectance absorption spectra (DRS), X-ray diffraction (XRD), differential thermal analysis-thermogravimetry (DTA-TG), field emission scanning electron microscopy (FE-SEM) equipped with energy-dispersive spectroscopy (EDS), and Brunner–Emmet–Teller (BET) measurements. According to the results of DRS and PL spectroscopy, the multi-modification could not only enhance visible light absorption intensity, but also decrease the recombination rate of photo-generated electron-hole pairs. XRD results revealed that the sample was mainly in anatase crystal type. FE-SEM results shown that the sample had fewer particle aggregates and almost no cracks. The specific surface area of the Fe/B/F tridoped TiO2-ZnO was 104.9 m2·g−1, while that of the pure TiO2 was 84.0 m2·g−1. Compared to pure TiO2 and TiO2-ZnO, the Fe/B/F tridoped TiO2-ZnO composite film had the highest photocatalytic activity due to their synergies.

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