Development of a doped titania immobilised thin film multi tubular photoreactor

This paper describes a novel doped titania immobilised thin film multi tubular photoreactor which has been developed for use with liquid, vapour or gas phase media. In designing photocatalytic reactors measuring active surface area of photocatalyst within the unit is one of the critical design parameters. This dictate greatly limits the applicability of any semi-conductor photocatalyst in industrial applications, as a large surface area equates to a powder catalyst. This demonstration of a thin film coating, doped with a rare earth element, novel photoreactor design produces a photocatalytic degradation of a model pollutant (methyl orange) which displayed a comparable degradation achieved with P25 TiO2. The use of lanthanide doping is reported here in the titania sol gel as it is thought to increase the electron hole separation therefore widening the potential useful wavelengths within the electromagnetic spectrum. Increasing doping from 0.5% to 1.0% increased photocatalytic degradation by ∼17% under visible irradiation. A linear relationship has been seen between increasing reactor volume and degradation which would not normally be observed in a typical suspended reactor system.

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► Development of a thin film photoreactor, doped with a rare earth element.
► Photoreactor produced degradation of methyl orange equal to that of P25 TiO2.
► Degradation rate of 95% after 90 min under UV irradiation and 70% under visible irradiation.
► Use of lanthanide doping is thought to increase the electron hole separation.
► Increasing doping from 0.5% to 1.0% increased photocatalytic degradation by ∼17%.