Double-shell structural polyaniline-derived TiO 2 hollow spheres for enhanced photocatalytic activity

Polyaniline (PANI) is a conducting polymer which has been employed as a photosensitizer for enhancing the performance of a number of photocatalysts. Herein, we describe the synthesis of organic–inorganic hybrid materials in order to enhance the photocatalytic activity of double-shell TiO2/PANI hollow spheres (TAHSs), which were fabricated by means of sol–gel and in situ polymerization processes. The physicochemical properties of the PANI-modified TiO2 hollow spheres were investigated by a variety of techniques. The effect of the PANI shell layer on the photocatalytic activity of TAHSs was elucidated. With the optimal PANI content, the resultant TiO2/PANI hybrid materials exhibited remarkably enhanced UV and visible light photocatalytic degradation of aqueous methyl orange, far exceeding the activity of bare TiO2 hollow spheres. The synergistic effect between TiO2 and PANI is explained in terms of the improved separation of photogenerated electron–hole pairs.