This work focuses on the optimization of a photocatalyst formulation for the selective oxidation of ethanol to acetaldehyde. VOx/TiO 2 catalysts at different vanadium loading were studied in a gas-solid photocatalytic fluidized bed reactor at high illumination efficiency, in which the bed is constituted by photocatalyst diluted with α-Al 2O3 or silica gel. Photocatalytic tests showed the selective formation of acetaldehyde, with ethylene and carbon dioxide as by-products. Selectivity is influenced by the vanadium loading. For ethanol inlet concentration of 0.2 vol%, maximum conversion and acetaldehyde selectivity of 73% and 97%, respectively, were obtained at 100 °C on catalyst at nominal 5 wt% V2O5 content (53% of surface monolayer) mixed with α-Al2O3. Selective sites were related to surface polymeric vanadates possessing Ti-O-V and V-O-V functionalities while the photoactivity appeared correlated with the catalyst equivalent band gap energy. Increasing the ethanol inlet concentration to 1 vol% and diluting the catalyst with silica gel, total ethanol conversion with about 97% selectivity to acetaldehyde was achieved with a photoreactivity of 0.34 mol m irradiated-3 s-1. This is three times higher than reported for other photoreactors. © The Royal Society of Chemistry and Owner Societies 2009.
A step forwards in ethanol selective photo-oxidation
Ciambelli P.;Sannino D.;Palma V.;Vaiano V.;Mazzei R. S.
2009-01-01
Abstract
This work focuses on the optimization of a photocatalyst formulation for the selective oxidation of ethanol to acetaldehyde. VOx/TiO 2 catalysts at different vanadium loading were studied in a gas-solid photocatalytic fluidized bed reactor at high illumination efficiency, in which the bed is constituted by photocatalyst diluted with α-Al 2O3 or silica gel. Photocatalytic tests showed the selective formation of acetaldehyde, with ethylene and carbon dioxide as by-products. Selectivity is influenced by the vanadium loading. For ethanol inlet concentration of 0.2 vol%, maximum conversion and acetaldehyde selectivity of 73% and 97%, respectively, were obtained at 100 °C on catalyst at nominal 5 wt% V2O5 content (53% of surface monolayer) mixed with α-Al2O3. Selective sites were related to surface polymeric vanadates possessing Ti-O-V and V-O-V functionalities while the photoactivity appeared correlated with the catalyst equivalent band gap energy. Increasing the ethanol inlet concentration to 1 vol% and diluting the catalyst with silica gel, total ethanol conversion with about 97% selectivity to acetaldehyde was achieved with a photoreactivity of 0.34 mol m irradiated-3 s-1. This is three times higher than reported for other photoreactors. © The Royal Society of Chemistry and Owner Societies 2009.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
