Search results for "Titanium"
showing 10 items of 878 documents
Substitution effects on the relaxor properties of lead magnesium niobate ceramics
1999
Abstract The temperature dependence of the dielectric permittivity is studied in different Pb(Mg⅓Nb⅔)O3 based ceramics, in which the ordered region size can be changed by introducing titanium or lanthanum ions. Both the relaxor behaviour and the nonlinear dielectric component are found to be dependent on the impurity content. Especially, the nonlinearity increases strongly as the material exhibits a more conventional ferroelectric behaviour, i.e. as the size of the polar clusters, which develop in the paraelectric matrix, increases.
Structural and in depth characterization of newly designed conducting/insulating TiN O /TiO2 multilayers obtained by one step LP-MOCVD growth
2001
Abstract TiNxOy/TiO2 multilayers have been grown by LP-MOCVD using titanium isopropoxide (TIP) precursor during the whole growth, but with an ammonia flow interrupted for the TiO2 layers. The one step growth process used to grow these structures allowed to stack the conducting and insulating layers without any growth breakdown. SIMS and TEM analyses showed the presence of an alternated insulating/conducting layers structure. Moreover, electrical measurements allowed to measure the dielectric part of insulating TiO2 stacked in these structures, whose permittivity was found to be about 80 for a MOS structure. Thus, such multilayers may lead to very promising applications in the microelectroni…
Optically active titanium complexes containing a tridentate linked amido-cyclopentadienyl ligand
2000
Optically active titanium complexes Ti{η5:η1-C5R4SiMe2NC6H10 (OCH2Ph)-2}Cl2 (R = H, Me), containing a cyclopentadienyl ligand linked to the chiral trans-2-benzyloxycyclohexylamido group, were synthesized and characterized in both enantiomerically pure forms. A single crystal X-ray structure analysis of (−)-(R,R)-Ti{η5:η1-C5H4SiMe2NC6H10(OCH2Ph)-2}Cl2 shows a structure in which the benzyloxy group in the amido sidechain is not interacting with the titanium center. Upon activation with n-butyllithium, these complexes hydrogenate acetophenone N-benzylimine with low enantioselectivity. Chirality 12:472–475, 2000. © 2000 Wiley-Liss, Inc.
Influence on the phase transitions of barium titanate of the manganese valency, introduced as a substituant in the titanium site
1991
Abstract A small amount of manganese introduced in BaTiO3 modifies strongly the vibrational and electronic properties of the pure compound. Dielectric response and EPR measurements are reported in order to study the influence of the manganese valency on the ferroelectric-paraelectric phase transition.
Preparazione e caratterizzazione di fotocatalizzatori a base di TiO2
2011
Photocatalytic solar light H2 production by aqueous glucose reforming
2018
A series of tungsten and nitrogen doped Pt-TiO2 samples were prepared with the aim to extend the TiO2 absorption to the visible light region and to enhance the separation efficiency of the photogenerated electron/hole pairs. The physicochemical features of the powders were characterized by Xray diffraction (XRD), UV/Vis reflectance spectra, specific surface area (SSA) determinations, and transmission electron microscopy (TEM) analyses. The influence of the presence of different doping agents was evaluated, under anaerobic conditions, in the aqueous photo-reforming of glucose to form H2 at ambient pressure and temperature under a halogen lamp or natural solar light irradiation. Arabinose, er…
TiO2-CeO2 based catalysts for photocatalytic oxidation of VOC and water splitting reactions
2016
Photocatalysis with TiO2 is one of the most promising green process for the decomposition of organic pollutants and the hydrogen production . Photo-oxidation of 2-propanol, representative of volatile organic compounds (VOC) and photo-catalytic water splitting for H2 production were investigated over TiO2 catalysts doped with a metal (Au and Ag at 1wt. %) and/or ceria (10 wt.%).
TiO2 photocatalysts prepared by thermohydrolysis of TiCl4 solutions
2010
Red Shift in the Light Absorption Threshold of Anodic TiO2 Films Induced by Nitrogen Incorporation
2014
Abstract Titanium foils were anodized in ammonium containing and ammonium free solutions in order to check the possibility of inducing nitrogen incorporation into anodic TiO 2 films. XPS spectra confirmed the presence of O-Ti-N bonds on the surface of the anodic films prepared in ammonium biborate electrolytes. In order to evidence the effect of nitrogen incorporation on the light absorption threshold, photoelectrochemical behavior of as-anodized and high temperature annealed films as a function of the anodizing electrolyte composition were investigated. A photocurrent tail at energies lower than the mobility gap of TiO 2 appeared for those films prepared in ammonium containing electrolytes…