Polypyrrole and associated hybrid nanocomposites as chemiresistive gas sensors: A comprehensive review

The detection of toxic and flammable gases entwines a wide diversity of application purposes, such as medical diagnosis, food quality monitoring, environmental tracking, and so forth. In recent, polypyrrole (PPy) nanostructure and its hybrid composite have been emerged as an auspicious gas sensing element because of their unique physicochemical attributes. This review article demonstrates a comprehensive outlook of rapid progress in polypyrrole (PPy) and associated hybrid composite based chemiresistive gas sensors till now. Furthermore, the role of PPy nanostructures and organic or inorganic additives (CNT, graphene or its derivative, metal nanoparticle, metal oxides, metal sulfides) in PPy matrix towards improved gas sensing performance are discussed hereunder. The detailed and systematic discussion on the synthesis strategies, gas sensing principle of the PPy nanostructures, and its composites along with the development of sensor device configuration provide an in-depth understanding of the aforesaid topic to the readers. However, some relevant limitations of PPy and associated composites based gas sensor are addressed after investigating the thorough literature survey. Finally, this article will promote an advanced as well as focused direction to the readers for further development of PPy based high-performance gas sensing devices.