Search results for "Sol-gel"
showing 10 items of 118 documents
TiO2/ORMOSIL Thin Films Doped with Phthalocyanine Dyes: New Photocatalytic Devices Activated by Solar Light
2008
WOS: 000253222200065
Sol–Gel Microcapsulation in Silica-Based Particles: A Comparative Study
2011
Comparison between the two main sol–gel/emulsion methods to prepare microparticles made of organosilica doped with a lipophilic molecule shows that entrapment only takes place starting from O/W emulsions. In this case, however, formation of spherical microcapsules, observed when the sol–gel polycondensation is carried out in a W/O microemulsion, does not take place.
Self-organization of porphyrin units induced by magnetic field during sol-gel polymerization
2007
The use of a magnetic field as a controlling factor during the hydrolysis-polycondensation of porphyrin precursors substituted by Si(OR)(3) groups, induces a self-organization of porphyrin moieties due to the stacking of these units in the hybrid material and this study also confirms the effect of the magnetic field in the nano- and micrometric organization during the kinetically controlled polycondensation process.
The influence of Al doping on the photocatalytic activity of nanostructured ZnO: The role of adsorbed water
2018
Abstract Al doped ZnO nanoparticles (labeled as x% A-ZnO, x = 0.0, 0.5, 1.0, and 1.5) were synthesized by a simple sol-gel method, characterized and tested as photocatalysts for the degradation of a model compound under UV-light irradiation. Diffuse reflectance spectroscopy (DRS) and photoelectrochemical analysis have been performed to evidence their optical and electronic behavior. The structural features of the powders were highlighted by means of specific surface area (SSA) analysis, X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and Raman spectroscopy. Al doping results in enhanced photocatalytic activity of the modified powders with respect to pure ZnO. In particular, the h…
Enhanced Solar Light Photocatalytic Activity of Ag Doped TiO2–Ag3PO4 Composites
2020
Composites comprised of Ag3PO4 and bare TiO2 (TiO2@Ag3PO4) or silver doped TiO2 (Ag@TiO2&ndash
The Luminescence Properties of ZnO:Al Nanopowders Obtained by Sol-gel, Plasma and Vaporization-Condensation Methods
2007
ZnO nanocrystals were synthesized and characterized by XRD and SEM methods. The luminescence spectra and decay kinetics were studied under pulsed laser excitation (266 nm, 8 ns). ZnO and ZnO:Al powders were prepared by sol-gel and plasma chemical synthesis. These powders were used as a raw material for the SPVD (Solar Physical Vapour Deposition) process. In this way, the vaporisation-condensation phenomenon (VC) led to the formation of ZnO whiskers and nanopowders. The luminescence properties of the VC nanopowders were studied and compared to those displayed by the raw material. The Al dopant, present in the raw powders as a solid solution and ZnAl2O4 precipitates, was only present as Al io…
Effect of oxygen deficiency on the radiation sensitivity of sol-gel Ge-doped amorphous SiO2
2008
We report experimental investigation by electron paramagnetic resonance (EPR) measurements of room temperature γ-ray irradiation effects in sol-gel Ge doped amorphous SiO2. We used materials with Ge content from 10 up to 104 part per million (ppm) mol obtained with different preparations. These latter gave rise to samples characterized by different extents of oxygen deficiency, estimated from the absorption band at ~5.15 eV of the Ge oxygen deficient centers (GeODC(II)). The irradiation at doses up to ~400 kGy induces the E'-Ge, Ge(1) and Ge(2) paramagnetic centers around g ~ 2 with concentrations depending on Ge and on GeODC(II) content. We found correlation between Ge(2) and GeODC(II) con…
Effect of Poly(Titanium Oxide) on the Viscoelastic and Thermophysical Properties of Interpenetrating Polymer Networks
2021
The authors thank V. Serga for many useful discussions. The research was (partly) performed in the Institute of Solid State Physics, University of Latvia ISSP UL. ISSP UL as the Center of Excellence is supported through the Framework Program for European universities Union Horizon 2020, H2020-WIDESPREAD-01–2016–2017-Teaming Phase 2 under Grant Agreement No. 739508, CAMART2 project.
Sol-gel entrapped visible light photocatalysts for selective conversions
2014
A general method to heterogenize, stabilize and significantly enhance the activity of selective visible light photocatalysts for aerobic oxidation of glycerol is devised. The new method makes use of the sol-gel encapsulation of photocatalytic species in silica-based matrices to afford leach-proof catalysts capable to afford valued products at low cost with little or no waste generation. In particular, the photocatalytic selective conversion of glycerol is performed in water solvent under ambient conditions with molecular oxygen as oxidant and visible light as the driving energy source, thereby meeting all requirements for a green chemical process. Entrapment of the semiconductor-based photo…
The effect of rare earths deposited on steel surfaces, by different processes (sol/gel, electrophoresis, OMCVD), on high temperature corrosion behavi…
1993
Abstract In this paper, different methods of rare earth oxides deposition on the surface of AISI 304 steel are described: sol/gel, electrophoresis in aqueous or organic medium, OMCVD of rare earth β-diketonates. After the deposition, all the samples were reheated. This treatment was absolutely essential for a strengthening effect of the protective oxide scale. Oxidation of coated and non-coated samples was performed under isothermal and cyclic conditions. The effect of rare earth deposition is significant in isothermal conditions. However, in thermal cyclic conditions, the effect of a rare earth deposited on surface is spectacular. Scale spallation is then completely avoided under the chose…