Electro-, photo-, and photoelectrochemical degradation of chloramphenicol on self-doping Ti nanotubes.

In this work, the photo-, electro-, and photo-electro-oxidation of chloramphenicol was investigated. The photo-experiments were carried out with different irradiation sources (an ultraviolet and a simulated solar source) using self-doped titanium nanotubes (SDTNT), a very promising and innovative material that deserves further investigations in the degradation of different pollutants. The photo-electrooxidation (j = 15 mA cm) under simulated solar irradiation presented the best efficiency, with ca.

Effect of the Random Defects Generated on the Surface of Pt(111) on the Electro-oxidation of Ethanol: An Electrochemical Study.

In the present work, the Pt(111) surface was disordered by controlling the density of {110}- and {100}-type defects. The cyclic voltammogram (CV) of a disordered surface in acid media consists of three contributions within the hydrogen adsorption/desorption region: one from the well-ordered Pt(111) symmetry and the other two transformed from the {111}-symmetry with contributions of {110}- and {100}-type surface defects. The ethanol oxidation reaction (EOR) was studied on these disordered surfaces.

Photolysis of parabens using medium-pressure mercury lamps: Toxicity effects in MCF7, Balb/c 3T3 cells and Ceriodaphnia dubia.

Degradation studies of the propylparaben (PrP), butylparaben (BuP) and of the propylparaben-butylparaben mixture (PrP-BuP) in deionized water and surface river water was investigated as a function of pH and initial concentration of the reactants using a medium-pressure mercury lamp. The photolysis of parabens (concentration ranging from 5 to 30 mg L) followed apparent pseudo-first-order kinetics, with rate constants (k) in deionized water and surface river water changed from 1.80 × 10 to 3.

How do random superficial defects influence the electro-oxidation of glycerol on Pt(111) surfaces?

The glycerol electrooxidation reaction (GEOR) has attracted huge interest in the last decade due to the very low price and availability of this polyol. In this work, we studied the GEOR on Pt(111) electrodes by introducing different densities of random defects. Our results showed that the generation of defects on Pt(111) slightly modified the GEOR onset potential, however it generates changes in the voltammetric oxidation charges and also in the relative production of CO to carbonyl containing compounds, C[double bond, length as m-dash]O.

New insights into the formation mechanism of Ag, Au and AgAu nanoparticles in aqueous alkaline media: alkoxides from alcohols, aldehydes and ketones as universal reducing agents.

In this report we present new insights into the formation mechanism of Ag, Au and AgAu nanoparticles with alcohols, aldehydes and ketones in alkaline medium at room temperature. We selected methanol, ethanol, glycerol, formaldehyde, acetaldehyde and acetone to demonstrate their capability of reducing gold and silver ions under the above-mentioned conditions. We showed that the particles are also formed with potassium tert-butoxide in the absence of hydroxides.

Influence of substrate steps on the catalytic properties of Pt layers: the ethanol electrooxidation reaction.

The ethanol oxidation reaction (EOR) is investigated on Pt/Au(hkl) electrodes. The Au(hkl) single crystals used belong to the [n(111)x(110)] family of planes. Pt is deposited following the galvanic exchange of a previously deposited Cu monolayer using a Pt(2+) solution.

Surface restructuring of Pt films on Au stepped surfaces: effects on catalytic behaviour.

In this paper, the reconstruction of Pt films deposited on stepped Au(hkl) surfaces belonging to the [n(111) × (110)] family of planes has been studied. Pt films were deposited using the galvanic displacement procedure of a pre-deposited Cu monolayer. We experimentally found that the Pt film deposition onto Au(hkl) surfaces is not fully epitaxial suggesting an atomic arrangement different from the underlying substrate.

Glycerol electro-oxidation over glassy-carbon-supported Au nanoparticles: direct influence of the carbon support on the electrode catalytic activity.

Glycerol is at present abundantly co-produced in the biodiesel fabrication and can be used as fuel in Direct Glycerol Fuel Cells (DGFC) for cogeneration of electricity, value-added chemicals and heat. With this motivation, in the present work, we investigated at a fundamental level the oxidation of glycerol over glassy carbon (GC) supported Au nanoparticles in alkaline medium using cyclic voltammetry. By controlling the Au deposition time, we varied the GC supported Au coverage from 0.

Poly(imide)/Organically-Modified Montmorillonite Nanocomposite as a Potential Membrane for Alkaline Fuel Cells.

In this work we evaluated the potentiality of a poly(imide) (PI)/organically-modified montmorillonite (O-MMT) nanocomposite membrane for the use in alkaline fuel cells. Both X-ray diffraction and scanning electron microscopy revealed a good dispersion of O-MMT into the PI matrix and preservation of the O-MMT layered structure. When compared to the pure PI, the addition of O-MMT improved thermal stability and markedly increased the capability of absorbing electrolyte and ionic conductivity of the composite.

The ethanol electrooxidation at Pt layers deposited on polycrystalline Au.

The ethanol electro-oxidation reaction was evaluated using a polycrystalline Au substrate modified with two different amounts of Pt using the galvanic exchange methodology. FTIR results suggest that Pt deposits have a greater ability to break the C-C bond present in the ethanol molecule. However, under potentiostatic conditions both modified Au surfaces undergo faster deactivation in comparison with polycrystalline platinum as indicated by the chronoamperometric results.

Electrochemical and spectroscopic studies of ethanol oxidation on Pt stepped surfaces modified by tin adatoms.

Ethanol oxidation on platinum stepped surfaces vicinal to the (111) pole modified by tin has been studied to determine the role of this adatom in the oxidation mechanism. Tin has been slowly deposited so that the initial stages of the deposition take place on the step, and deposition on the terrace only occurs when the step has been completely decorated. Voltammetric and chronoamperometric experiments demonstrate that tin on the step catalyzes the oxidation.

The role of the steps in the cleavage of the C-C bond during ethanol oxidation on platinum electrodes.

Ethanol oxidation has been studied on stepped platinum single crystal electrodes in acid media using electrochemical and Fourier transform infrared (FTIR) techniques. The electrodes used belong to two different series of stepped surfaces: those having (111) terraces with (100) monoatomic steps and those with (111) terraces with (110) monoatomic steps. The behaviors of the two series of stepped surfaces for the oxidation of ethanol are very different.

Surface structure effects on the electrochemical oxidation of ethanol on platinum single crystal electrodes.

Ethanol oxidation has been studied on Pt(111), Pt(100) and Pt(110) electrodes in order to investigate the effect of the surface structure and adsorbing anions using electrochemical and FTIR techniques. The results indicate that the surface structure and anion adsorption affect significantly the reactivity of the electrode. Thus, the main product of the oxidation of ethanol on the Pt(111) electrode is acetic acid, and acetaldehyde is formed as secondary product.