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Crystal Structure Characterization of Thin Layer Zinc Oxide
摘要： In this research the characterization of the crystal structure of a thin layer of ZnO (zinc oxide) were synthesized by sol - gel method and spin coating deposited on a glass substrate. The samples were divided into three sol concentrations of 0.1, 0.3, 0.5 Molar and two deposition temperature is 350 °C, and 550 °C. UV-Vis. spectrophotometer results showed that in the spectrum of visible light (wavelength range 300-800 nm) has a transmittance value of which increases with increasing concentration and temperature deposition of zinc oxide, otherwise the value of the absorption and the band gap energy decreases with temperature. The transmittances value of the highest and lowest absorption was 93.5% and 0.03 is at a concentration of 0.1 M and zinc oxide deposition temperature of 550 °C, with a value of band gap energy of 2.98 eV. The XRD results showed that the zinc oxide crystal orientation in the field of 013 with a crystal grain size 14.4472 nm. SEM results showed the surface morphology of zinc oxide such as rod-like.
关键词： ZnO,sol-gel method,thin layer,crystal structure,optical properties,spin coating
更新于2025-09-10 09:29:36
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Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light
摘要： Titanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO2 samples were prepared by the sol-gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO3 and Fe(NO3)3·9H2O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H2-TPR), chemisorption of NH3 at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mgcatalyst/dm3, and of the organic molecule, between 0 and 15 mg/dm3. The catalysts most active in the degradation of salicylic acid were those having the highest Fe content.
关键词： salicylic acid removal,photocatalysis,sol-gel method,Doped titanium oxide,wet impregnation method
更新于2025-09-09 09:28:46
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Photostriction properties of PLZT (4/52/48) ceramics sintered by SPS
摘要： In this paper, the preparation and sintering process of Lanthanum-modi?ed lead zirconate titanate ceramics (PLZT 4/52/48) powders and ceramics were investigated. The PLZT powders were prepared by co-precipitation and sol-gel methods. It is con?rmed that PLZT powders synthesized by sol-gel method had smaller grains and better dispersion. The atmosphere sintering and spark plasma sintering（SPS）technique were used to sinter the PLZT ceramics separately. After sintering, the physical, electrical, and optical properties of the PLZT ceramics sintered by di?erent methods were tested. The results show that the SPS sintering can increase the densi?cation degree (reaching 99.5%)of the PLZT ceramics, which improved the transparency, ferroelectric, piezoelectric and optical properties of PLZT ceramics. It is found that when the light intensity reached 600 mW/cm2, the max- ?3, which was almost 1.4 imum photo-induced strain of the SPS sintered ceramic was as high as 10. 84 × 10 times larger than that of the atmosphere-sintered sample. Obviously, the sol-gel method and SPS process can enhance the comprehensive performance of PLZT ceramics.
关键词： Photo-induced strain,Ferroelectric/piezoelectric property,Sol-gel method,PLZT,SPS
更新于2025-09-09 09:28:46
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Research on cracking of SiO2 nanofilms prepared by the sol-gel method
摘要： SiO2 nano?lms were prepared by a sol-gel method with TEOS as the precursor, ethanol as the solvent, and hydrochloric acid as the catalyst. The in?uences of H2O, EtOH, and HCl on the surface of SiO2 ?lm were studied by a controlled variable method, and the e?ects of aging time, spin-coating speed, ammonia treatment, heat treatment, and substrate on the ?lms were also determined experimentally. Crack-free SiO2 nano?lms with tens of microns thickness were repeatedly fabricated using the optimizing parameters, and the size of SiO2 nano-particles was in the range of 100–500 nm.
关键词： SiO2 nano?lm,Sol-gel method
更新于2025-09-09 09:28:46
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Structural, Infrared, Magnetic, and Electrical Properties of Ni0.6Cd0.2Cu0.2Fe2O4 Ferrites Synthesized Using Sol-Gel Method Under Different Sintering Temperatures
摘要： Ni0.6Cd0.2Cu0.2Fe2O4 ferrites were synthesized using sol-gel method under different sintering temperatures. XRD patterns with the Rietveld refinement indicate that samples crystallize in the cubic spinel structure. The increase of sintering temperature leads successively to the increase of lattice constant, average crystallite size, intensities of absorption bands, magnetization, and electrical conductivity of the prepared ferrites. Dielectric constants decrease with frequency and their behaviors have been investigated using the interfacial polarization theory predicted by Maxwell. The modulus analysis shows the presence of electrical relaxation phenomenon and non-Debye nature for the samples. An appropriate electrical equivalent circuit was used to analyze the Nyquist plots, and the results show that the conduction mechanism of the synthesized ferrites is mainly due to the grain boundary contribution.
关键词： Ferrites,conductivity,Rietveld refinement,Sol-gel method,Infrared properties,Dielectric properties
更新于2025-09-09 09:28:46
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Optical Characteristics of Strontium Titanate Films Obtained by the Sol–Gel Method
摘要： Using data of multiangle spectrophotometry and spectral ellipsometry in the UV and visible ranges, spectra of the refractive indices and absorption coefficients and width of the forbidden band of one- and five-layer strontium titanate films obtained by the sol–gel method have been calculated. Layer-by-layer deposition of sol on quartz substrates, from one to five layers, leads to an increase in film porosity from 4 to 33%. This causes a decrease in the refractive indices in the middle part of the visible spectrum from 2.33 to 1.87, which leads to a decrease in the reflectance and an increase in the transmittance or transparency of five-layer films. With an increase in the heating temperature of such films from 500 to 750°C, a shift of the absorption band maximum from 239 to 253 nm takes place and the optical width of the forbidden band decreases from 4.63 to 4.20 eV. The absorption band maximum of the single-layer film falls on the wavelength of 252 nm, and its optical width of the forbidden band is 3.96 eV.
关键词： Strontium titanate films,optical characteristics,forbidden band width,sol–gel method,refractive indices,absorption coefficients
更新于2025-09-09 09:28:46
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Influence of the Heat Treatment on the Particles Size and on the Crystalline Phase of TiO2 Synthesized by the Sol-Gel Method
摘要： Titanium biomaterials’ response has been recognized to be affected by particles size, crystal structure, and surface properties. Chemical and structural properties of these nanoparticle materials are important, but their size is the key aspect. The aim of this study is the synthesis of TiO2 nanoparticles by the sol-gel method, which is an ideal technique to prepare nanomaterials at low temperature. The heat treatment can affect the structure of the ?nal product and consequently its biological properties. For this reason, the chemical structure of the TiO2 nanoparticles synthesized was investigated after each heat treatment, in order to evaluate the presence of different phases formed among the nanoparticles. FTIR spectroscopy and XRD have been used to evaluate the different structures. The results of these analyses suggest that an increase of the calcination temperature induces the formation of mixed-crystalline-phases with different content of anatase and rutile phases. The results obtained by SEM measurements suggest that an increase in the particles size accompanied by a noticeable aggregation of TiO2 nanoparticles is due to high temperatures achieved during the thermal treatments and con?rmed the presence of different content of the two crystalline phases of titanium dioxide.
关键词： titania,sol-gel method,rutile,FTIR,nanoparticles size,anatase
更新于2025-09-09 09:28:46
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Quantum cutting properties of Tb3+/Yb3+ co-doped ZrO2-SiO2 nano-crystalized glasses synthesized via a sol-gel route
摘要： Tb3+/Yb3+ co-doped ZrO2-SiO2 nano-crystallized glasses were prepared by a sol-gel process. The crystal structure and optical properties including down-conversion photoluminescence (or, quantum cutting) of the Tb3+-Yb3+ system with respect to gel heat treatment temperature were investigated by X-ray diffraction (XRD), Raman, photoluminescence (PL), and PL decay curves analysis. The energy transfer efficiency from Tb3+ to Yb3+ ions, which converts one photon to two photons with lower energy, increased with heat-treatment temperature. Furthermore, the oxidation state of Tb4+ ions was suspected to influence the emission intensity of Tb3+ and energy conversion efficiency. Thus, a post-treatment reduction was applied to the sample heated at 1100 oC by annealing it at 1100 oC for 1 h under 5%H2/95%N2 reductive atmosphere. Consequently, the thermodynamically generated Tb4+ ions were reduced to a trivalent state, leading to higher energy transfer efficiency.
关键词： ZrO2 nanocrystals,Sol-gel method,photoluminescence,quantum cutting,Tb3+-Yb3+ pair,Tb4+ ions
更新于2025-09-09 09:28:46
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Improved Hydrophobicity of Polydimethylsiloxane (PDMS) Coating with ZnO Nanostructures
摘要： In this present work, an environmentally safe hydrophobic cotton surface comprising of PDMS and different morphology of Zinc oxide (ZnO) nanostructures via simple dip coating method was developed. ZnO nanosphere and ZnO nanoflakes were synthesized via sol gel method while ZnO nanorods were synthesized via solution precipitation method. The precursors used to prepared ZnO nanospheres, nanoflakes and nanorods are zinc acetate dehydrate, zinc chloride and zinc nitrate tetrahydrate respectively. ZnO nanostructures were analysed using FESEM and XRD. The hydrophobic cotton surface was characterized via FT-IR and WCA analysis. A WCA of 144.15° was achieved when coating the cotton with ZnO nanoflakes (ZnO-NF:PDMS).
关键词： ZnO nanostructures,Polydimethylsiloxane,Solution precipitation method,Hydrophobicity,Sol gel method,Dip coating
更新于2025-09-04 15:30:14
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Nano Structured Ni and Ru Impregnated TiO <sub/>2</sub> Photocatalysts: Synthesis, Characterization and Photocatalytic Degradation of Neonicotinoid Insecticides
摘要： Titania by sol gel and Ni–Ru titania catalysts by wet impregnation methods were prepared and characterized by XRD, UV-DRS, BET and TEM techniques. Catalytic activities of the photocatalysts were evaluated towards the degradation of three widely used neonicotinoids type insecticides namely acetamiprid, imidacloprid and thiamethoxam under UV, Visible and solar irradiations. The reaction parameters such as initial concentration of the insecticide, weight of the catalyst and pH of the system were found to influence the reaction rate. The results indicated that the metal impregnated catalysts were found to be more active than pure TiO2. Ni/TiO2 or Ru/TiO2 catalysts degraded all the insecticides completely even under visible irradiation. The observed visible activity of the catalysts was attributed to their lower band gap values. HPLC and TOC analyses revealed that mineralisation of the insecticides occurred through dearomatization by multiple hydroxylation and oxidation. The degradation pathway and the kinetics were also discussed in detail.
关键词： HPLC,Photocatalysis,Sol–Gel Method,Titania,Neonicotinoids,Insecticides
更新于2025-09-04 15:30:14