Visible Light TiO2 Photocatalysts Assessment for Air Decontamination

Abstract

Different visible light responses of commercial TiO2photocatalysts are assessed for theirapplication in air decontamination. To do that the modified TiO2catalysts were immobi-lized on borosilicate glass plates according to a dip coating method. Then, the photocatalyticperformance of these plates was evaluated in a continuous gas flat plate photoreactor irra-diated with visible light lamps using two representative air pollutants: nitrogen oxide andacetaldehyde. Working under visible light, the modified TiO2catalysts were compared bymeans of efficiency parameters: the true quantum efficiency, which relates the moles ofdegraded pollutant with the moles of the absorbed photons, and the apparent photonicefficiency, which relates the moles of degraded pollutant with the moles of incident pho-tons. Also, the photocatalytic pollutants degradation by immobilized modified TiO2could berelated with their optical properties, finding a clear correlation between them. These resultsare useful to decide which TiO2will be more efficient for a full scale air decontaminationprocess under visible light illumination.