Search results for "TiO2"
showing 10 items of 283 documents
2D slab models of TiO2 nanotubes for simulation of water adsorption: Validation over a diameter range
2020
Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2019/2 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under Grant Agreement No. 739508, project CAMART 2 .
Syntheses of TiO2 anatase nanocrystals with controlled size distribution. Influence of the crystallites size on the Raman spectrum and investigation …
2006
The determination of the size and the size distribution of anatase TiO2 nanopowders using Raman spectroscopy is presented. Several synthesis methods (soft chemistry, water-in-oil microemulsion, continuous hydrothermal synthesis) are used in order to control the size (from 3 to 20 nm), shape, phase and size distribution. The shift and width of the anatase Eg peak are often used to obtain the nanoparticles size. Homever, this peak is also sensitive to nonstoichiometry and others parameters. Low-frequency Raman scattering does not suffer from this problem. Size distibutions obtained by Raman spectroscopy and MET micrographs are compared. Finally, in situ Raman spectroscopy is used to study the…
Initial stages of metal oxides thin films growth by MOCVD: physicochemical characterisation of the film/substrate interface
2006
The initial stages of Metalorganic Chemical Vapour Deposition (MOCVD) of TiO2 thin films on Si(100) were studied in situ by surface analyses (XPS, ARXPS, AES). An original experimental set-up was built for this purpose and developed. Information obtained from these in situ experiments was completed by ex situ characterisations (HRTEM, SIMS, GIXRD...).The formation of an interfacial SiOy<2 layer resulting of the interaction of the precursor Ti(OCH(CH3)2)4 with the substrate takes place before the formation of stoichiometric TiO2 and leads to the presence of carbon at the interface. At the deposition temperature, 675 °C, silicon diffusion within the TiO2 external layer was also revealed. Conc…
Study of TiO2 nanostructures grown in a MOCVD reactor in presence of metallic catalysts. Valorization of these TiO2 nanostructures
2017
Within the Nanoform Theme, Ax Nanosciences, ICB, we realize the growth of 1D, 2D and 3D hybrid nanostructures based on TiO2 by MOCVD. Our work deals with the theoretical aspect of the formation of these nanostructures (growth and kinetic models, structure and texture) and the study of photoelectric, optical and physicochemical properties as well as the development of applications of these structures in physics (random laser), photocatalysis, energy (solar cells). Under certain perfectly controlled conditions, we obtain original TiO2 structures not yet described in the literature: membranes, rods , canals, crucibles, COHN (COaxiales Heterostructures Nanowires). Our previous work made it poss…
ZnO(core)/TiO2(shell) composites : influence of TiO2 microstructure, N-doping and decoration with Au nanoparticles on photocatalytic and photoelectro…
2017
The aim of the thesis is to study the influence of microstructure of ZnO/TiO2 composites on their properties in photocatalytic degradation of organic pollutants, and in photoassisted water oxidation. To realize such study we chose the design based on ZnO nanorods supported on ITO (Indium Tin Oxide)-coated glass electrode. The ZnO nanorods were then covered with a layer of TiO2 under different conditions. The composition and microstructure of the obtained ZnO(core)/TiO2(shell) composites were modified in the aim to elucidate how these parameters influence their photocatalytic activity. The results of studies lead to elaboration of two most distinctive variants of sol-gel procedure that allow…
Réseaux métalliques pour le couplage dans des guides en dioxyde de titane
2016
National audience; Nous montrons la fabrication de réseaux métalliques enterrés entre deux couches de dioxyde de titane. En utilisant un supercontinuum, nous démontrons expérimentalement une efficacité de couplage supérieure à -8 dB pour une bande passante à 3 dB supérieure à 80 nm.
Photocatalytic oxidation of acetonitrile in gas–solid and liquid–solid regimes
2005
Il programma NON mi ha consentito di scaricare il PDF di questo articolo. Se lo volete ditemi come inviarlo ABSTRACT Photocatalytic degradation of acetonitrile was carried out in both gas–solid and liquid–solid regimes using two commercial TiO2 catalysts (Merck and Degussa P25). For the gas–solid regime, a continuous annular photoreactor was used. The influence on photodegradation kinetics of the gas flow rate and concentrations of acetonitrile, oxygen, and water was investigated. Acetonitrile degradation products detected in the gas phase included carbon dioxide and hydrogen cyanide. The same photoactivity was exhibited in the presence and in the absence of water vapour. The liquid–solid reg…
Photodegradation of lincomycin in aqueous solution
2006
Aqueous solutions of lincomycin were irradiated with UV light in homogeneous and heterogeneous systems. Lincomycin disappeared in both systems but the presence ofTiO2noticeably accelerated the degradation of the antibiotic in comparison with direct photolysis. The rate of decomposition was dependent on the concentration of lincomycin and followed a pseudo-first-order kinetics. Photolysis involved only the oxidation of lincomycin without mineralization. Differently, the treatment withTiO2and UV light resulted in a complete mineralization of the antibiotic. The degradation pathways involved S- and N-demethylation and propyldealkylation. The mineralization of the molecule led to the formation …
Raman spectral identification of phase distribution in anodic titanium dioxide coating
2017
Growing need for cleaner environment and energy production has brought about a hunt for perspective materials. One of such perspective materials is titanium dioxide (TiO2, titania) due to its chemical stability and photocatalytic properties. Titania can be synthesized through many methods but anodization process is one of the prevailing methods to produce high active surface nanostructured titania. Various anodization electrolytes produce different polymorphs of TiO2. Uniform phase distribution on the surface is crucial for higher photocatalytic activity. In this research, the influence of two electrolytes on polymorph phase distribution of TiO2 was investigated. Phase distribution correlat…
WO 3 as Additive for Efficient Photocatalyst Binary System TiO 2 /WO 3
2021
The financial support provided by Scientific Research Project for Students and Young Researchers No. SJZ/2018/9 implemented at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the Euro-pean Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART².