Highly active composite TiO2-polypyrrole nanostructures for water and air depollution under visible light irradiation

Engineering photocatalytic materials for solar energy harvesting and environmental remediation is a very promising prospect to solve energy and environment issues. Here we report the preparation of a nanocomposite formed by TiO2 with nanostructured polypyrrole (PPyNS-TiO2) and its photocatalytic properties. We show that this nanocomposite is very active for water and air treatment under UV and visible light irradiation. This activity is higher than that of bare TiO2 and PPyNs, and much improved compared to that of TiO2-bulk polypyrrole (PPybulk-TiO2). The nanostructuration of the conjugated polymer is a key factor for the photocatalytic activity of the composite. The large enhancement of the photocatalytic activity is ascribed to the heterojunction between PPyNs and TiO2, which broadens the absorption of visible light and facilitates the charge carriers' separation. These results foresee the composite PPyNS-TiO2 photocatalyst for water and air purification in environment remediation.