A review on nanofiber-based composites for toxic and flammable gas sensing

Nanofibers, due to the characteristics of high porosity, large specific surface area, and high strength and mechanical flexibility, exhibit a great potential for gas sensing as a sensing layer or versatile support. The abundant compositions, specific morphology, and tunable pore size of nanofibers are suitable for the detection of diverse environmental gases, and its excellent flexibility and mechanical properties are convenient for fabricating the smart and wearable electronic devices. Compared with conventional powder materials, these merits of nanofibers mainly can enhance the sensitivity and stability. In this review, we first introduce the main evaluation parameters for gas sensors, the designed principle of sensors, and the advantages of nanofiber materials for gas sensing. Then, the recent advances in nanofiber-based gas sensors for monitoring the different environmental gases, mainly including hydrogen (H₂), methane (CH₄), carbon monoxide (CO), acid gases (H₂S, NO₂, and SO₂), SF₆ and its decomposition products, chemical warfare agents (CWAs), and volatile organic compounds (VOCs), are summarized. Meanwhile, the sensing mechanism and different sensing materials based on noble metals, metal oxides, metal-organic framework, and their composites are discussed comprehensively. Finally, the challenges and perspectives of nanofiber-based gas sensors are also addressed.