A review on tin dioxide gas sensor: The role of the metal oxide doping, nanoparticles, and operating temperatures

Metal oxide gas sensors have many advantages over other solid-state gas monitoring devices, including low cost, ease of manufacture, and small design. However, the shape and structure of sensing materials have a considerable impact on the performance of such sensors, posing a significant challenge for gas sensing properties on materials or dense films to attain high-sensitivity characteristics. Various tin dioxide (SnO2) nanostructures have been devised to increase gas sensing characteristics such as sensitivity, selectivity, and response time, among other characteristics. An overview of the most well-known techniques for synthesizing gas-sensing films, as well as the influence of doping with various metal oxides, nanoparticle size, and operating temperature on the gas-sensing properties of such films, is discussed in this work. The gas sensing mechanisms and the gas detection techniques are presented in detail. The metal oxide doped SnO2 showed a strong response for SO2 and NO2 gases, whereas nanoparticle doping plays a crucial effect in increasing SnO2 sensitivity towards H2, H2S, NO2, CO, Ethanol, etc. Furthermore, the effect of operating temperature on SnO2 response is discussed in this report. SnO2 has a high sensitivity over a wide temperature range (100-350 °C).