Room temperature operable ultra-sensitive ammonia sensor based on polyaniline-silver (PANI-Ag) nanocomposites synthesized by ultra-sonication

This paper reports a novel, highly sensitive room temperature operable and reusable ammonia (NH3) gas sensor based on Polyaniline-silver nanocomposite (PANI-Ag). The nanocomposite was synthesized by in-situ, sono-chemical oxidative polymerization methods by using ammonium persulphate. Aniline was used as a dispersant and stabilizer, D-glucose was chosen as an efficient reducing agent for the formation of Ag nanoparticles in the sol. The structural and optical properties of PANI-Ag nanocomposite were studied by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Morphological analysis of PANI-Ag nanocomposites revealed a cluster of PANI nanofibers with uniformly distributed silver nanoparticles having an average particle size of about 6 nm. The performance of PANI-Ag based sensor was evaluated at different concentrations of aqueous ammonia at room temperature. The sensor is highly sensitive at low ammonia concentration (less than 100 ppm). The sensor showed fast response and recovery time in the range of 30-120 s from 1 ppm to 100 ppm of ammonia concentration. The sensor showed an optimum response of 57% for 100 ppm ammonia. Due to excellent reversibility, reusability and long term environmental stability, PANI-Ag sensor provides a promising simple and efficient sensor system for wide-range ammonia concentration detection at room temperature.