MOS based gas sensor in detection of volatile organic compounds: A review
Chenwei Zhang, Lijun Qian, Wen Zeng
Abstract
Volatile organic compounds (VOCs), as toxic, carcinogenic, and persistent environmental pollutants, chronically contaminate enclosed spaces like indoors and vehicle cabins. Efficient detection is crucial for improving air quality and safeguarding human health. Metal oxide semiconductor (MOS) gas sensors have emerged as the preferred materials to address current detection challenges due to their high sensitivity, low preparation cost and potential for miniaturization. This review systematically examines the sensing mechanisms of MOS materials and recent progress in MOS-based sensors for detecting formaldehyde, acetone, and other common VOCs. Based on the analysis of over a hundred research studies, it has been found that MOS materials suffer from issues such as high operating temperatures, poor selectivity, insufficient long-term stability, and susceptibility to humidity, and we explore how modification strategies such as micromorphology regulation, structural modification, and composite material construction of heterojunctions enhance the sensitivity, selectivity, and operational temperature of MOS sensors. However, challenges persist in achieving synergistic optimization of multiple parameters, hindering practical applications. This review aims to summarize current research methodologies for various MOS materials used in VOC detection, providing design principles and performance benchmarks for developing high-efficiency VOC sensors.