SnO₂Nanostructure as Pollutant Gas Sensors: Synthesis, Sensing Performances, and Mechanism

A significant amount of pollutants is produced from factories and motor vehicles in the form of gas. Their negative impact on the environment is well known; therefore detection with effective gas sensors is important as part of pollution prevention efforts. Gas sensors use a metal oxide semiconductor, specifically SnO 2 nanostructures. This semiconductor is interesting and worthy of further investigation because of its many uses, for example, as lithium battery electrode, energy storage, catalyst, and transistor, and has potential as a gas sensor. In addition, there has to be a discussion of the use of SnO 2 as a pollutant gas sensor especially for waste products such as CO, CO 2 , SO 2 , and NO x . In this paper, the development of the fabrication of SnO 2 nanostructures synthesis will be described as it relates to the performances as pollutant gas sensors. In addition, the functionalization of SnO 2 as a gas sensor is extensively discussed with respect to the theory of gas adsorption, the surface features of SnO 2 , the band gap theory, and electron transfer.