Effect of TiO2 on the Gas Sensing Features of TiO2/PANi Nanocomposites

A nanocomposite of titanium dioxide (TiO(2)) and polyaniline (PANi) was synthesized by in-situ chemical polymerization using aniline (ANi) monomer and TiCl(4) as precursors. SEM pictures show that the nanocomposite was created in the form of long PANi chains decorated with TiO(2) nanoparticles. FTIR, Raman and UV-Vis spectra reveal that the PANi component undergoes an electronic structure modification as a result of the TiO(2) and PANi interaction. The electrical resistor of the nanocomposite is highly sensitive to oxygen and NH(3) gas, accounting for the physical adsorption of these gases. A nanocomposite with around 55% TiO(2) shows an oxygen sensitivity of 600-700%, 20-25 times higher than that of neat PANi. The n-p contacts between TiO(2) nanoparticles and PANi matrix give rise to variety of shallow donors and acceptor levels in the PANi band gap which enhance the physical adsorption of gas molecules.