Advances in chemiresistive methane gas sensors based on nanostructured metal oxide semiconductor

Abstract

Methane is the main cause of safety accidents in coal mines and household natural gas leaks, posing huge safety risks and even leading to serious consequences. Timely and efficient monitoring and early warning of methane using high-performance gas sensors can effectively reduce gas safety threats and ensure human safety. Metal oxide sensors have advantages such as high sensitivity, fast response speed, good stability, low cost, and simple structure that is easy to operate. Compared to other types of sensors, the application prospects of metal oxide sensors are more suitable for household use and industrial production. Although targeted development of various nanostructured metal oxide-based chemiresistive methane gas sensors has been widely pursued, there remains a lack of comprehensive summary regarding their performance-enhancing fabrication methods and associated sensitization mechanisms. The classical metal oxide semiconductor methane gas-sensitive materials are introduced in this article. Their basic principles and advantages for methane gas sensing are analyzed. And four main directions for improving the gas-sensitive performance of metal oxide semiconductor materials which are morphology control, noble metal functionalization, constructing heterojunctions, and ultraviolet light excitation are summarized. Currently, further optimization and preparation are needed around the three enhancement mechanisms of surface-resistance controlling, chemical sensitization, and electronic sensitization. Overall, the research on metal oxide semiconductor gas-sensitive materials lays the foundation for developing high-performance gas sensors and will become a favorable line of defense for industrial production and home safety assurance.