Polypyrrole nanocomposites as promising gas/vapour sensing materials: Past, present and future prospects

Abstract

Development of highly efficient gas/vapour sensor is an urgent necessity because of rapidly increasing emission of various hazardous and highly flammable gases/vapours. The chemical detection and quantification are extremely important to control and monitor the pollutant or toxins and flammable gases/vapours to ensure the safety of eco-system. Nano sensors have fascinated massive interest owing to their excellent performance along with being compact, easy to fabricate and cost effective. Over the years, polypyrrole (PPy) is one of the con- ducting polymers (CPs), proved to be excellent materials for gas/vapour sensing application at room temperature operations. But pristine PPy has some drawbacks such as poor selectivity & reversibility and poor long-term stability. However, these sensing properties can be significantly improved by making nanocomposites of PPy by adding semiconductor metal oxide and/or carbon nanomaterials which amplify adsorption, catalytic reaction and charge transport behaviour. Hence, PPy nanocomposites have been employed as the gas/vapour sensing materials for detection and monitoring of various gases such as ammonia (NH3), liquefied petroleum gas (LPG), hydrogen disulphide (H2S), carbon oxides (CO & CO2), nitrogen oxides (NO & NO2), hydrogen (H2) and different volatile organic compounds (VOCs) such as acetone, ethanol, methanol, formaldehyde, toluene etc. Current review is focused on the gas/vapour sensing properties of PPy nanocomposites along with future prospects for the development of new PPy nanocomposites for the fabrication of highly efficient sensors.