Anisotropic Core-Shell Nanoparticles Using Silica Templates for Ammonia Gas Detection

Abstract

Ammonia is one of the essential components of life formation. It plays a wide role in biological processes and physiology. It widely used in chemical industries, fertilizers, a precursor to nitrogenous compound, textiles, refrigeration etc. But it is irritating, inflammable and extremely hazardous in concentrated form. Various types of ammonia sensors are available but they subject to limitations. Composites of conducting polymer and core-shell Gold-metal oxide nanoparticles prove to be the promising material for gas sensing. Gold as a bulk does not interact with gases but its nanoparticles and composites show excellent gas sensing properties. Gas sensing properties of these materials depend on chemical composition, morphology, and method of preparation. Our attempt was to synthesize a material for the sensor, selective to only ammonia gas using Nano-composites of conducting polymer (Polyaniline, Polypyrrole) and two morphologies (spherical and rod) of anisotropic gold coated silica core-shell nanoparticles. It is found that composite of Polypyrrole and Au coated Spherical SiO2 nano-particles shows better sensing properties for ammonia gas as compared to other composites.