Synthesis and Characterization of Rutile TiO2Nanopowders Doped with Iron Ions

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5–7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO2into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence

TiO2 doped with nitrogen: Synthesis and characterization

In this study, nitrogen-doped titanium dioxide (TiO2) powders were synthesized in two ways: by heating of titanium hydroxide with urea and by direct hydrolysis of titanium tetraisopropoxicle (TTIP) with ammonium hydroxide. The samples were characterized by structural (XRD), analytical (XPS), optical (UV/Vis absorption/reflection and Raman spectroscopy) and morphological (SEM, TEM) techniques. The characterization suggested that the doped materials have anatase crystalline form without any detectable peaks that correspond to dopants. The absorption threshold of titanium dioxide was moved in the visible range of optical spectrum from 3.2 eV to 2.20 eV. Particle sizes of synthesized powders were obtained from XRD measurements and from TEM data ranging from 6-20 nm. XPS and Raman spectroscopy were used for detection of nitrogen in doped samples.International Workshop on Nanostructured Materials (ANAOMAT 2006), Jun 21-23, 2006, Antalya, Turke

Microstructure, surface properties and hydrating behaviour of Mg-C composites prepared by ball milling with benzene

Mg-graphite composites, suitable for hydrogen storage, have been synthesized by ball milling metallic Mg with different amounts of graphite and benzene. The microstructure and the surface chemical composition have been characterized in order to explain the kinetics of reaction with hydrogen. The presence of benzene in the milled blends induces a finer powder particle size, helps to preserve the structural integrity of the graphite crystals and results to be necessary for a complete transformation of the milled powder to the hydride phase by thermal reaction with hydrogen gas. On the other hand, it induces a more pronounced reaction of the milled Mg-C composites with the air. The transport properties of the resulting surface contamination layer appear to control the kinetics of thermal decomposition of the MgH2 phase, so that the addition of benzene induces a higher reaction temperature owing to a larger thickness of the surface compound. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved

Synthesis and microstructural analysis of benzylthiol-functionalized Au nanocrystals

We report on the synthesis and microstructural and microanalytical analysis of dodecanethiol and benzylthiol-stabilized Au nanoparticles (diameter range between 2 nm and 10 nm). Stable functionalized gold nanoparticles were synthesized by using two different routes: a two-phase liquid-liquid method and a one-phase method. The size, strain, shape and crystalline structure of the nanocrystals were determined by a full-pattern X-ray powder diffraction analysis and high-resolution electron microscopy. The chemical environment of the Au nanocrystals and their interaction with the thiols was investigated by X-ray photoelectron spectroscopy. Photoluminescence spectroscopy measurements show a characteristic IR emission at γ=960 nm of small sized Au nanocrystals (∼3 nm). The origin of this IR emission line seems to be correlated to the Au-S bonding and the size of the nanoparticles. © 2007 Materials Research Society