Nanocomposite of Pd–polyaniline as a selective methanol sensor

Palladium nanoparticles were obtained by a reflux method. A Pd–polyaniline nanocomposite was synthesized by oxidative polymerization of a 0.1 M aniline (stabilizer) solution containing palladium nanoparticles. The synthesized nanocomposite was subjected to different aliphatic alcohol vapours such as methanol, ethanol and isopropanol. The results showed that the nanocomposite was highly selective and sensitive to methanol vapours. The sensor responded rapidly and reversibly in the presence of methanol vapours. The selectivity of the nanocomposite was further investigated by exposing it to mixtures of methanol–ethanol and methanol–isopropanol. The nanocomposite is found to exhibit exactly identical response to that for pure methanol except for the response time. The sensing mechanism has been explained on the basis of FT-IR spectroscopy.