0000000000046246
AUTHOR
María José López-muñoz
Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home prepared titanium dioxide: 2. Intrinsic and surface features of catalysts
Some intrinsic electronic properties of home prepared (HP) TiO2 catalysts were investigated by diffuse reflectance spectroscopy and quasi-Fermi level measurements. These powders were used for carrying out the photocatalytic oxidation of benzyl alcohol to benzaldehyde and CO2 in water; the selectivity for aldehyde formation was enhanced by the addition of small amounts of ethanol, a typical hole trap. The values of band gap, valence band and conduction band edges are almost identical for all the HP samples in which anatase phase is predominant, whereas appreciable differences can be noticed for an HP sample containing high amount of rutile phase. A comparative ATR-FTIR study of the HP cataly…
Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home-prepared titanium dioxide
Abstract Oxygenated aqueous suspensions of home-prepared (HP) and commercial TiO2 catalysts were used in a batch photoreactor for carrying out the oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) under different operative conditions. HP catalysts were synthesized from TiCl4 and underwent a hydrolysis treatment of different times under mild conditions. The textural characterization of catalysts was carried out with XRD, SEM observations, BET surface area and porosity measurements. For both alcohols the main oxidation products were the corresponding aromatic aldehydes and CO2. The HP catalysts exhibited selectivity values towards the aldehyde production up to 28% (BA convers…
Home-prepared anatase, rutile, and brookite TiO2 for selective photocatalytic oxidation of 4-methoxybenzyl alcohol in water: reactivity and ATR-FTIR study
5th European Meeting on Solar Chemistry and Photocatalysis -- OCT 04-08, 2008 -- Palermo, ITALY
ESR study of photo-oxidation of phenol at low temperature on polycrystalline titanium dioxide
The formation of oxygen radicals on hydrated TiO 2 (anatase) samples irradiated at 77 K in the near-UV region and their interaction with adsorbed phenol molecules have been studied by electron spin resonance. The results indicate that the irradiation determines the generation of O 2 H · and O − radicals which react with adsorbed phenol molecules. Phenol-derived radicals are generated after warming the sample at room temperature. A reaction mechanism is proposed on the basis of the observed species.
Photocatalytic Oxidation of Cyanides in Aqueous Titanium Dioxide Suspensions
The photocatalytic oxidation of free cyanides in aqueous suspensions containing polycrystalline TiO2(anatase) powders irradiated in the near-UV region has been investigated. The rate of cyanide photooxidation has been studied by varying the following operative parameters: (i) initial cyanide concentration; (ii) catalyst concentration; (iii) initial pH; (iv) power of irradiation; and (v) chloride ion concentration in the reacting mixture. Under the used experimental conditions the photoreaction proceeded at a measurable rate until the complete disappearance of cyanides. The kinetics of cyanide photooxidation is affected by the catalyst concentration, the chloride ion concentration, and the p…
Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home prepared titanium dioxide
In this paper some intrinsic electronic properties of home prepared (HP) TiO2 catalysts were investigated by diffuse reflectance spectroscopy and quasi-Fermi level measurements. These powders were used for carrying out the photocatalytic oxidation of benzyl alcohol to benzaldehyde and CO2 in water; the selectivity for aldehyde formation was enhanced by the addition of small amounts of ethanol, a typical hole trap. The values of band gap, valence band and conduction band edges are almost identical for all the HP samples in which anatase phase is predominant, whereas appreciable differences can be noticed for an HP sample containing high amount of rutile phase. A comparative ATR-FTIR study of…