Metal Oxide Semiconductor Gas Sensors for Amine-Based Carbon Capture: A Mini Review

Carbon capture, utilization and storage (CCUS) is indispensable for achieving global carbon neutrality, and amine-based chemical absorption remains the most mature and widely deployed technology. However, amine emissions during operation result in absorbent loss, secondary pollution and potential public health risks, while conventional offline detection methods are unable to satisfy the requirements of real-time monitoring. This review systematically summarizes recent progress in metal oxide semiconductor (MOS) gas sensors for monoethanolamine (MEA) detection, with particular emphasis on AOx-based systems. The effects of the base material, microstructure and modification strategies, including noble metal decoration and heterojunction construction, on sensing performance are critically compared. Through such modifications, AOx-based sensors have achieved markedly improved sensing performance, and several are capable of detecting MEA at room temperature. The feasibility of existing sensing materials is further evaluated in the context of post-combustion amine capture. Among the reported systems, SnO2-based sensors exhibit clear advantages for MEA detection, including high sensitivity, favorable selectivity, rapid response and recovery, and satisfactory stability and repeatability. In contrast, studies on ABO3 perovskite-based sensors remain limited; although these materials show fast response, they continue to suffer from poor stability and insufficient humidity resistance. Future research should therefore focus on low-temperature operation, enhanced humidity tolerance and long-term durability, so as to accelerate the industrial translation of MOS gas sensors and support the sustainable development of CCUS.