Synthesis and characterization of polypyrrole/Sn-doped TiO 2 nanocomposites (NCs) as a protective pigment

Abstract

We have chemically polymerized pyrrole in the presence of Sn-doped TiO 2 nanoparticles (NPs) and TiO 2 (NPs) which act as a protective pigment. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results show a core–shell structure of pigments in which TiO 2 and Sn-doped TiO 2 NPs have a nucleus effect and caused a homogenous PPy core–shell type morphology leading to coverage of the TiO 2 and Sn-doped TiO 2 NPs by PPy deposit. The XRD results indicate that the crystalline size of polypyrrole/TiO 2 NCs and polypyrrole/Sn-doped TiO 2 NCs were approximately 93.46 ± 0.06 and 23.36 ± 0.06 nm respectively. The electrochemical impedance spectroscopy (EIS) results show that the performance of polypyrrole/Sn-doped TiO 2 NCs is better than polypyrrole/TiO 2 NCs. The results indicate that increasing the area of synthesized polypyrrole in the presence of Sn-doped TiO 2 NPs can increase its ability to interact with the ions liberated during the corrosion reaction of steel in the presence of NaCl. The UV–vis results show that the band gap of TiO 2 NPs increases with doped of Sn in lattice of TiO 2. The increase of the band gap of TiO 2 with doping of Sn can decrease the charge transfer through the coating.