Photocatalytic enhancement of immobilized TiO 2 -polyaniline bilayer (TiO 2 -PBL) system for decolorization of methyl orange dye

Abstract Immobilized TiO2-polyaniline (PANI) bilayer (TiO2-PBL) was fabricated on a glass plate for decolorization of methyl orange (MO). The thickness of TiO2-PBL was 25.55 μm with the ratio of 0.62:0.38 for TiO2 to PANI layer. It was observed that the TiO2 -PBL system emitted less photoluminescence (PL) intensity than the TiO 2 monolayer corresponding to better •OH radicals production with reduced band gap energy. The removal of MO from the solution after 90 min of treatment was 97% by TiO2-PBL and 53% by TiO2 monolayer which indicates the efficacy of the former system due to the synergistic photocatalytic-adsorption processes. The effect of prewashing (photoetching) of TiO2-PBL plate was pronounced as better removal efficiency of MO was observed for ten cycles under UV–vis and visible light irradiations. The results showed that the TiO2-PBL system has visible light active properties, reduces the recombination of photogenerated active species and enhances the photocatalytic oxidation of MO.