Recent Advances in Materials, Parameters, Performance and Technology in Ammonia Sensors: A Review

Importance of ammonia sensors is increasing significantly worldwide in environmental monitoring, control of chemical processes, agricultural, and medical applications. Particularly, the detection of ammonia gas is very important for many industries due to its toxicity and environmental hazards. The hybrid nanostructures formed by blending of nanoparticles of metal/metal-oxides with polymer or its derivatives have been explored which showed improved gas sensing ability and selectivity at room temperature. This article reviews ammonia gas sensors based on semiconducting materials like metals, metal oxides, metal oxide-polymers and carbon nanotubes (CNT's) based hybrid nanostructures for different level of detection of ammonia in various applications. The characteristic performance parameters of these sensors, such as measuring range, sensitivity, selectivity, response/recovery time and the latest technological developments are discussed with detailed analysis in this article.