Sunlight photocatalytic activity of polypyrrole–TiO2 nanocomposites prepared by ‘in situ’ method

A series of polypyrrole–TiO2 (PPy–TiO2) nanocomposites with different PPy:TiO2 ratios were prepared by ‘in situ’deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl3) as oxidant in the presence of ultra fine grade power of anatase TiO2 cooled in an ice bath. The samples were characterized by means of TEM, XRD, XPS and UV–vis-diffuse reflectance spectroscope. Their photocatalytic activities were evaluated by photocatalytic degradation of methyl orange aqueous solution under sunlight. PPy–TiO2 nanocomposites show better photocatalytic activity than that of neat TiO2 nanoparticles, which is partly attributed to the sensitizing effect of polypyrrole.