Titanium Oxyacetylacetonate Research Articles

Effect of the Carbon Source on the Electrochemical Properties of Li4Ti5O12/C Composites Prepared by Solid-State Synthesis

Li4Ti5O12/C composite anode materials have been prepared by solid-state reactions using lithium- or titanium-containing reagents (lithium lactate, acetate, and acetylacetonate or titanium oxyacetylacetonate) not only as precursors for the synthesis of lithium titanate but also as carbon sources. In addition, two surfactants, Pluronic 123 (P123) and cetyltrimethylammonium bromide, have been used as carbon sources. The composites have been characterized by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy, and their electrochemical properties have been studied. The results demonstrate that the best electrochemical performance is offered by the materials prepared using P123. In particular, the discharge capacity of the Li4Ti5O12/C material prepared using TiO2/P123 and lithium lactate is 119 and 44 mAh/g at current densities of 200 and 3200 mA/g, respectively. The materials prepared using lithium and titanium acetylacetonates have high carbon content and undergo more severe degradation during cycling at high current densities.

Modification of anatase using noble-metals (Au, Pt, Ag): Toward a nanoheterojunction exhibiting simultaneously photocatalytic activity and plasmonic gas sensing

A new and original method, based on a non-aqueous sol–gel process, has been successfully established to produce quasi-spherical monodispersed TiO2 nanoparticles (NPs) and also noble metals (NM) @TiO2 heterostructures (NM=Au, Pt, Ag, 2wt%), in one-pot and at low temperature. This has been achieved by using titanium oxyacetylacetonate as new single source precursors. This system has been deeply investigated by advanced characterization techniques. By using NMR, we have demonstrated the relatively complex mechanism behind this apparently simple synthesis, mediated by the reaction of the solvent and generated species, with many separate organic and organometallic molecules identified as being involved in the mechanism. The morphology and structure of the NM@TiO2 heterostructures were investigated by advanced scanning transmission electron microscopy while the chemical state of the noble metal nanoparticles was check by X-ray photoelectron spectroscopy (XPS). Undoped and noble metal (Au, Pt, Ag) decorated quasi/spherical TiO2 nanoparticles worked also as sensing interfaces, leading to the development of a highly sensitive conductometric NO gas sensor under both dark and UV–vis light irradiation, in the first result of its kind. Furthermore, the photocatalytic activity (PCA) was also evaluated, in the gas–solid phase, by monitoring the degradation of NOx under solar-light irradiation. Au-modified TiO2 showed improved photocatalytic efficiencies, compared to unmodified TiO2.

Ellipsometric studies on TiO 2 thin films synthesized by spray pyrolysis technique

TiO 2 thin films were synthesized on quartz substrates at substrate temperatures of 350 °C and 450 °C by thermal spray pyrolysis technique using titanium oxy-acetyl acetonate as a precursor. The optical properties of the thin films were characterized by a Spectroscopic Ellipsometer (SE). The surface morphology of the thin films was studied using Atomic Force Microscopy (AFM). The surface roughness values obtained using AFM and SE was compared. The refractive indices of the films were computed using a point by point ellipsometric data extraction procedure. The porosity of the films were modeled from the optical data by effective medium approximation and corroborated from empirical relations. Using Forouhi–Bloomer optical dispersion model, further treatment of SE data was carried out. The experimental investigations and modeling of the data were directed towards optical benchmarking of spray pyrolyzed titania thin films.

Dye adsorption and ζ-potential for activated carbon fibers obtained from metal complexes containing pitch

The adsorption of acid and direct dyes (Acid Red 88 and Direct Yellow 11) on activated carbon fibers (Y-ACF, Al-ACF, and Ti-ACF) obtained from pitch containing metal complexes, viz., yttrium acetylacetonate, aluminumacetylacetonate, and titanium oxyacetylacetonate has been investigated in terms of pore size and ζ-potential. The ζ-potentials of Al-ACF, Ti-ACF, and Y-ACF possessed the isoelectric points at pH about 4.4, 4.4, and 6.7, respectively.The adsorption of Acid Red 88 on Y-ACF, Al-ACF, and Ti-ACF was lower than that on the metal-free ACF (A-20) in pH regions from 2 to 12. The adsorption of Direct Yellow 11 on Y-ACF with a large amount of mesopores was higherthan those on other microporous Al-ACF, Ti-ACF, and A-20 in acidic pH regions. On the other hand, the adsorbedamount of Direct Yellow 11 on Y-ACF decreased steeply withincreasing pH from the isoelectric point at pH 6.7. This suggests that the adsorption of dyes on ACF strongly depends on pore size of ACF and electrostatic interactionsbetween dye molecules and carbon surface.