Gas-Sensing Performances of Metal Oxide Nanostructures for Detecting Dissolved Gases: A Mini Review

Abstract

Gas sensors have been wildly used in various fields related to people's lives. Gas sensor materials were the core factors that affected the performances of various gas sensors, and these have attracted much attention from scientific researchers due their high sensitivity, high selectivity, adjustable reliability, low cost, and other advantages. The preparation of nanostructures with a highly specific surface area was a useful method to improve the gas-sensing performance of a metal oxide semiconductor. Meanwhile, lots of research has focused on preparing nanostructures with a highly specific surface area. This paper has explored some fabricated sensors with high sensitivity, good selectivity, and long-term stability, which has also made them promising candidates for toxic gas detection. Besides, this paper has reviewed the development status of metal oxides used as gas sensors.

Review: Influences of Semiconductor Metal Oxide Properties on Gas Sensing Characteristics

“…Upon exposure to a reducing gas, the target molecules react (via oxidation) with the adsorbed oxygen species on the surface, leading to the release of the trapped electrons back to the conduction band, which then increases the sensor resistance as a result of the hole accumulation layer becoming thinner. If the target gas is an oxidizing one, it will get reduced by taking electrons from the conduction band and thus resulting in the decrease of resistance (Kim and Lee, 2014;Wei et al, 2020).…”

Metal-Oxide Based Nanomaterials: Synthesis, Characterization and Their Applications in Electrical and Electrochemical Sensors

“…Recently, there was an increased interest towards the applications of gas sensors based on semiconductor MOX. For instance, TiO 2 , SnO 2 and ZnO have been successfully applied for the detection of combustible and toxic gases, principally for monitoring the environmental pollution and to secure the home/industrial ambient [ 20 , 64 , 65 ]. In details, for the sensing of hydrocarbons, oxygen, CO, H 2 and NO 2 , devices based on ZnO have been adopted in a real-time fashion, with a particular enhancement for doped nanostructures by Al, Ga, In and Sn [ 66 ].…”

Use of nanostructured and modified TiO2 as a gas sensing agent

“…Significant progress has been made in recent years in the development of nanostructured materials for sensor applications [42][43][44][45][46]. In addition to the advantages inherent to the TiO 2 , its nanostructures due to the large surface-to-volume ratio can significantly improve the sensors' sensitivity and selectivity compared to traditional materials, as their high surface area promotes an increase in the concentration of active sites for adsorption of oxygen [47].…”