Nanomaterial-based gas sensors: A review on experimental and theoretical studies

Abstract

Gas sensors play an essential role in various fields such as public safety, environmental monitoring, medical engineering, food monitoring, pharmaceutical industries and clinical diagnostic, to name a few. The need for miniaturized sensors possessing high sensitivity, time response, selectivity, reproducibility, durability, and low cost has driven the discovery of nanomaterials-based gas sensing devices due to their inherent properties such as chemical/physical gas adsorption capabilities and high surface-to-volume ratio. Studies in the literature highlight the development of gas sensors using novel nanomaterials to detect toxic gases. The gas molecules are sensed by the nanomaterial due to adsorption of the gas on the sensor surface, which leads to conductivity change in the nanomaterial. However, the sensing mechanism is quite complicated. Computational studies help the researchers elucidate the physical understanding behind such a complicated mechanism and aid in developing tailored nanomaterials for gas sensing applications. This review outlines different sensor types and the advantages and disadvantages of each sensor for various applications. Different nanostructure-based gas sensors and recent studies are discussed elaborately. The contributions made by theoretical and experimental studies in studying the gas sensing applications of nanomaterials are also discussed.