A5028463208- Catalytic Processes in Materials Science
- Catalysis and Hydrodesulfurization Studies
- Aerogels and thermal insulation
- Mesoporous Materials and Catalysis
- TiO2 Photocatalysis and Solar Cells
- Semiconductor Quantum Structures and Devices
- Advanced oxidation water treatment
- Silicone and Siloxane Chemistry
- Advanced Photocatalysis Techniques
- Quantum and electron transport phenomena
- Layered Double Hydroxides Synthesis and Applications
- Water Quality Monitoring and Analysis
- Quantum Dots Synthesis And Properties
- Catalysis and Oxidation Reactions
- Gas Sensing Nanomaterials and Sensors
- Chemical Synthesis and Reactions
- Pigment Synthesis and Properties
- Catalysts for Methane Reforming
- Zeolite Catalysis and Synthesis
- Nanomaterials for catalytic reactions
- Carbon dioxide utilization in catalysis
- Pharmaceutical and Antibiotic Environmental Impacts
- Electrochemical sensors and biosensors
- Material Selection and Properties
- Chalcogenide Semiconductor Thin Films
Universidade Federal do Rio Grande do Sul
2009-2019
Computational Intelligence and Information Systems Lab
2003
Institut des Sciences des Plantes de Montpellier
1999
University of Bari Aldo Moro
1988-1992
Max Planck Society
1990
Max Planck Institute for Solid State Research
1990
The photoactivated degradation reaction of rhodamine B (RB) was studied using P-25 TiO2 (Degussa) as catalyst. Three process variables - temperature, initial pH, and catalyst concentration were evaluated. Temperature had a slight effect on rate; however, the combined pH greater. affected particle's adsorption RB, altering rate. significant only up to 0,65 g L-1. temperature at optimum 50ºC found be operational temperature. presence surfactant (sodium dodecylsulfate, SDS) ionic contaminants...
The Pt/TiO2, Pt/ZrO2, and Pt/Al2O3 catalysts submitted to low-temperature reduction (LTR, 200 °C) high-temperature (HTR, 500 exposed hydrogen carbon monoxide at room temperature were studied by infrared spectroscopy. There is a strong loss of transmission in the entire spectra on Pt/TiO2 after its exposure hydrogen, which related reducibility support. A typical SMSI behavior (strong metal−support interaction), such as decrease adsorption capacity, was detected Pt/ZrO2 even for LTR treatment....
SILICA BASED HYBRID MATERIALS OBTAINED BY THE SOL-GEL METHOD.This review deals with silica based hybrid materials obtained by the sol-gel method.It involves concepts, classifications and important definitions regarding method that allows obtaining organic inorganic components dispersed in a molecular or nanometric level.We discuss properties characteristics of related to experimental synthesis conditions.We devote special attention nanostructured materials, where self-organization is imposed...
PHOTOCATALYTIC ACTIVITY OF NANOSTRUCTURED TiO 2 CATALYSTS DOPED WITH METALS.Titanium dioxide nanostructured catalysts (nanotubes) doped with different metals (silver, gold, copper, palladium and zinc) were synthesized by the hydrothermal method in order to promote an increase their photocatalytic activity under visible light.The characterized X-ray diffraction, diffuse reflectance spectroscopy, transmission electron microscopy specific area pore volume determination.The materials' was...
The radiative recombination processes of the electron-hole plasma in a series GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As multiple-quantum-well (MQW) heterostructures have been studied by means space-resolved high-excitation-intensity luminescence and optical-gain spectroscopy. spontaneous emission dramatically changes depending on actual MQW heterostructure configuration, which determines degree optical confinement epilayer. consisting 100 quantum...
The dynamics of the interacting excitonic states in GaAs/${\mathrm{Al}}_{\mathrm{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$As quantum wells has been investigated by spatially resolved and time-resolved luminescence spectroscopy. combination these techniques allows us to determine radiative recombination processes generated inelastic biexciton-biexciton exciton-electron collisions under high-excitation density. Our experimental results demonstrate that are comparable those bulk...
The aqueous styrene photocatalytic degradation reaction was evaluated using TiO2 P-25 (Degussa) as a catalyst. These experiments were accomplished in batch slurry reactor with temperature control and UV lamp. effects of the initial concentration, catalyst hydrogen peroxide addition pH solution on evaluated. experimental results showed that 90 min, 95% degraded by photocatalysis. It verified rate fits pseudo-first-order kinetics for concentrations between 15.27 57.25 ppm, at 30ºC....
AbstractIn this paper, we assessed aqueous solutions of glutaraldehyde (GA), a chemical used for the disinfection hospital materials, using advanced oxidative processes, O3, and UV, combination latter two. Assays with different ozone concentrations at distinct pH levels were conducted to determine best treatment process. GA before after each measured by spectrophotometry. The was that which combined O3 yielding degradation 72.0–75.0% in relation initial concentration between 4 9. Kinetics...
γ-Nitroesters are synthesized by the<italic>one pot</italic>domino process. GABA derivatives phenibut and baclofen were readily accessed.
ANIONIC CONTAMINANTS IN WATER.In this work the adsorption features of hydrotalcites (Al, Mg-CO 3 ) and magnetic properties iron oxides have been combined in a composite to produce adsorbent.These composites can be used as adsorbents for anionic contaminants water subsequently removed from medium by simple process.The were characterized XRD, magnetization measurements, N 2 isotherms Mössbauer spectroscopy.These show remarkable capacity water.
The influence of acetic acid on the pore structure and surface area silica prepared by sol-gel method was investigated. Experimental conditions synthesis, such as gelation temperature solvents, were also studied. N2 adsorption isotherms samples type 1, typical microporous materials, explaining high values (BET) observed. simultaneous addition hydrochloric acids catalysts acetone solvent, together with use a 20 ºC, made it possible to prepare amorphous materials up 850 m² g-1. value these...
Abstract Infrared spectroscopy, using carbon monoxide as probe molecule, was utilized to detect the electronic metal–support interactions on platinum dispersed silica modified with different titania amounts. The spectral features produced by effects were observed only for materials that present a high content and they are related crystal lattice. Copyright © 2002 John Wiley & Sons, Ltd.
A new approach based on multicomponent/domino combined reactions for the synthesis of γ-nitroesters promoted by a mixed aluminium-magnesium oxides derived from hydrotalcite-like material was developed.Different were synthesized in 15-95% yield using Meldrum's acid, aromatic aldehydes, nitromethane and different alcohols as reagents solvents.The γ-aminobutyric acid derivatives, Phenibut Baclofen, prepared 63 61% overall yield, respectively, through two steps synthetic strategy.A mechanistic...
We report the results of a systematic investigation structural and optical properties polydispersed semiconductor microcrystals in glass. Transmission electron microscope experiments reveal existence different radii size dispersion around average radius. A simple method is proposed to extract parameters by Gaussian deconvolution histogram. The presence dot distribution accounts very well for observed absorption spectra which exhibit excitonic features corresponding estimated microcrystal...