Simultaneous degradation of non-emissive and emissive dyes on visible light illuminated TiO2 surface

Simultaneous photocatalytic degradation of non-emissive dye, acid blue1 (AB1) and emissive dyes (eosinY or thionine) in air-equilibrated aqueous suspension of TiO2 semiconductor photocatalyst has been achieved at ambient conditions. Under visible light irradiation AB1 undergoes appreciable degradation in presence of a sensitizing dye (eosinY or thionine). However, concomitant decoloration of eosinY (EY) or thionine (Th) due to self-sensitized degradation was also noticed. Mechanistic proposals for the photocatalytic degradation of AB1 using a 150 W Xe lamp with a UV-filter (λ > 420 nm) as well as without a UV-filter, are discussed. Formation of reactive O2−/HO2 radicals is proposed to be responsible for the degradation of the selected dyes, AB1, EY and Th.

Graphical abstractUnder visible light irradiation acid blue1 undergoes appreciable degradation in presence of a sensitizing dye (eosinY or thionine). However, concomitant disappearance of eosinY or thionine due self-sensitized degradation was also noticed. Figure optionsDownload full-size imageDownload as PowerPoint slide