Progress of sensitive materials in chemiresistive sensors for detecting chemical warfare agent simulants: A review

Abstract Chemical warfare agents (CWAs) are chemical substances intended for use in military operations to kill, injure, or incapacitate an enemy. It is very important to detect toxic CWAs at trace levels on site. Compared with traditional CWA analysis instrument methods, chemiresistive gas sensors present advantages of being small, fast, and inexpensive. Chemiresistive gas sensors are still an important research topic with the development of nanofabrication technology and new kinds of sensing materials, including carbon nanotubes, graphene, and black phosphorus (BP). Chemiresistive gas sensors are divided into three categories according to the type of sensitive materials: carbon- and BP-based materials, conductive polymers, and metal oxide semiconductors. A brief analysis was carried out on fabrication strategies using sensitive materials, including hydrogen bonding strategies, nanostructures, morphology, doping effects, composite materials, and other material application methods, and the sensitive materials and detection effects are summarized in this study. This review aims to provide guidance in the development of chemiresistive sensors for the detection of CWAs. Graphical abstract