Influence of particle size on the photoactivity of Ti/TiO2 thin film electrodes, and enhanced photoelectrocatalytic degradation of indigo carmine dye

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoeletrocatalytic oxidation of anionic surfactant used in leather industry on nanoporous Ti/TiO2 eletrodes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Removal of sunscreen compounds from swimming pool water using self-organized TiO2 nanotubular array electrodes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Highly ordered TiO2 nanotube arrays and photoelectrocatalytic oxidation of aromatic amine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Degradação fotoeletroquímica de corantes dispersos em efluente têxtil utilizando fotoanodos de Ti/TiO2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoelectrocatalytical degradation of basic blue 41 dye using nanoporous semiconductor of Ti/TiO2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NIR luminescent Er3+/Yb3+ co-doped SiO2-ZrO2 nanostructured planar and channel waveguides: Optical and structural properties

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cerâmicas eletrônicas à base de SnO2 e TiO2

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electronic ceramics based on polycrystalline SnO2, TiO2 and (Sn xTi1-x)O2 solid solution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis, characterization and catalytic properties of nanocrystaline Y2O3-coated TiO2 in the ethanol dehydration reaction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An ab initio study of oxygen vacancies and doping process of Nb and Cr atoms on TiO2 (110) surface models

We theoretically investigated how the formation of oxygen vacancies and the addition of niobium and chromium atoms as dopants modify the varistor properties of TiO2. The calculations were carried out at the HF level using a contracted basis set, developed by Huzinaga et al.. to represent the atomic centers on the (110) surface for the large (TiO2)(15) cluster model. The change of the values for the net atomic charges and band gap after oxygen vacancy formation and the presence of dopants in the lattice are analyzed and discussed. It is shown that the formation of oxygen vacancies decreases the band gap while an opposite effect is found when dopants are located in the reduced surface. The theoretical results are compared with available experimental data. A plausible explanation of the varistor behavior of this system is proposed. (C) 1997 John Wiley & Sons, Inc.

TiO2 films organofunctionalized with 2-aminothiazole ligand and adsorbed Pd(II) ions applied in the photocatalytic degradation of phenol in an aqueous medium

This paper describes the preparation of thin titanium films via sol-gel route and their subsequent chemical modification by anchoring with 2-aminothiazole ligand and Pd(II) ion sorption, aiming to maximize the photocatalytic activity. The material was characterized by diffuse reflectance infrared Fourier transform spectroscopy, ultraviolet and visible spectrometry, X-ray diffractometry, and scanning electronic microscopy. The amount of palladium adsorbed on the film's surface, determined by graphite furnace atomic absorption spectrometry, showed a value of 2.69 x 10(16) atoms CM-2. The photocatalytic tests indicated that the functionalization with 2-aminothiazole and the adsorption of palladium (II) were determinants in the semiconductor's enhanced photocatalytic activity. (c) 2007 Elsevier B.V. All rights reserved.

A theoretical analysis on electronic structure of the (110) surface of TiO2-SnO2 mixed oxide

Mixed oxide compounds, such as TiO2-SnO2 system are widely used as gas sensors and should also provide varistor properties modifying the TiO2 surface. Therefore, a theoretical investigation has been carried out characterizing the effect of SnO2 on TiO2 addition on the electronic structure by means of ab initio SCF-LCAO calculations using all electrons. In order to take into account the finite size of the cluster, we have used the point charge model for the (TiO2)(15) cluster to study the effect on electronic structure of doping the TiO2 (110) Surface. The contracted basis set for titanium (4322/42/3), oxygen (33/3) and tin (43333/4333/43) atoms were used. The charge distributions, dipole moments, and density of states of doping TiO2 and vacancy formation are reported and analysed. (C) 2003 Elsevier B.V. All rights reserved.

Nanostructured films employed as sensing units in an electronic tongue system

Nanostructured films of lignin (macromolecule extracted from sugar cane bagasse), polypyrrole (conducting polymer) and bis butylimido perylene (organic dye) were used in the detection of trace levels of fluorine (from H2SiF6), chlorine (from NaCIO), Pb+2, Cu+2, and Cd+2 in aqueous solutions. Langmuir monolayers on ultrapure water were characterised by surface pressure-mean molecular area (II-A) isotherms. Langmuir-Blodgett (LB) films were transferred onto gold interdigitated electrodes and used as individual sensing units of an electronic tongue system. Impedance spectroscopy measurements were taken with the sensor immersed into aqueous solutions containing the ions described above in different molar concentrations. Fourier transform infrared absorption (FTIR) was employed to identify possible interactions between the LB films and the analytes in solution, and no significant changes could be observed in the FTIR spectra of BuPTCD and Ppy. Therefore, the results for lignin point to an interaction involving the electronic cloud of the phenyl groups with the metallic ions.

Sintering mechanisms of ZrO2 center dot MgO with addition of TiO2 and CuO

Substitutions of Ti and Cu in ZrO2.MgO (Z), cause transformation from monoclinic (m) to cubic (c) and tetragonal (t). According to the vacancy model and solid Solution formation models, neither CuO nor TiO2 cause zirconia stabilization, which derives front other phenomena. Data analysis by TMA using the CRH (constant rate of heating) method shows a solid state reaction of ZrO2.MgO.TiO2 (Z.TiO2) demonstrating a dominant mechanism of volume diffusion (n = 1). However, the sintering of ZrO2.MgO.CuO (Z.CuO) shows a viscous flow mechanism (n = 0), a similar phenomena to that of by sintering of glass. Transformations, such as: CuO to Cu2O at 1000 degreesC, ZrO2 (m) to ZrO2 (t) at 1100 degreesC and Cu2O (s) to Cu2O (l) at 1230 degreesC cause successive rearrangements of microstructure inside of region I (sintering process) and lead to interpretation errors when the Bannister equation is used. (C) 2003 Elsevier Ltd and Techna Group S.r.l. All rights reserved.