Trace detection of benzene, toluene and xylene (BTX) by chemiresistive metal oxide-based gas sensors: Recent advances in heterojunction materials design

As the chemical industry expands, the use of benzene, toluene, and xylene (collectively known as BTX) in industrial production has increased greatly. Meanwhile, the toxic nature and potential health hazards of BTX gases cannot be ignored due to low-concentration leaks underline the critical need for rapid and real-time monitoring of these gases. Chemiresistive metal oxide semiconductor (MOS)-based gas sensors, which are extensively used for gas detection in both industrial settings and everyday life, emerge as one of the optimal solutions for trace BTX detection. These sensors are highly valued for their high sensitivity and low detection limits. Nevertheless, the improvement of selectivity towards specific BTX gases to achieve efficient and precise detection still remains challenging. This review summarizes the chemiresistive MOS-based gas sensors designed for BTX detection, categorizing them based on the components of sensing materials-basically into three groups: single-component, single heterojunction, and multiple heterojunctions gas sensing materials. Further, the review proposes the future application prospects of chemiresistive MOS-based BTX gas sensors, with specific emphasis on their significance in promoting industrial safety and environmental monitoring.