Enhanced Photosensitized Degradation of Organic Pollutants under Visible Radiation by (I2)n-Encapsulated TiO2 Films

We report on the preparation of (I 2 ) n -encapsulated TiO 2 (I 2 /TiO 2 ) films with high photosensitized activity via a modified doctor blade technique, in which TiO 2 nanocrystal particles and poly ethylene glycol (PEG) were introduced to improve specific surface area of films and adhesion between the films and the substrate. The as-prepared films were characterized by SEM, XRD, EDS, BET, and diffuse reflectance spectra. The visible-light-induced photoactivity of the films was evaluated by the degradation of organic pollutants containing rhodamine B (RhB), alizarin red S, fluorescein sodium, and 2,4-dichlorophenol in neutral water at ambient conditions. Compared to P25 film and homemade pure TiO 2 film, the I 2 /TiO 2 films exhibited higher photoreaction activity. Furthermore, under an optimized experimental condition i.e. ten wt% I/Ti doping ratio and 10 wt % PEG content, the degradation rate of the I 2 /TiO 2 film was significantly better, with over 95% conversion ratio of RhB after 360 min of visible radiation. Subsequently, cycling degradation assay was taken, and the result showed that the film maintained an effective activity after 3 successive cycling experiments. This work may provide new insights into the design of flat and mechanical stable photocatalyst film with efficient visible light activity toward dyes and small organics degradation.