Wool-Based Carbon Fiber/MoS(2) Composite Prepared by Low-Temperature Catalytic Hydrothermal Method and Its Application in the Field of Gas Sensors

Under the background of the Paris Agreement on reducing greenhouse gases, waste wools were converted into wool carbon fiber (WCF) and WCF–MoS(2) composites by low-temperature catalytic hydrothermal carbonization. Their structures and gas-sensing performances were studied for the first time. Due to the existence of heterojunctions, the responses of the WCF–MoS(2) composite to the five analytes were 3–400 times those of MoS(2) and 2–11 times those of WCF. Interestingly, because of the N, P, and S elements contained in wools, the WCF prepared by the hydrothermal method was realized the doping of N, P, and S, which caused the sensing curves of WCF to have different shapes for different analytes. This characteristic was also well demonstrated by the WCF–MoS(2) composite, which inspired us to realize the discriminative detection only by a single WCF–MoS(2) sensor and image recognition technology. What’s more, the WCF–MoS(2) composite also showed a high sensitivity, a high selectivity, and a rapid response to NH(3). The response time and the recovery time to 3 ppm NH(3) were about 16 and 5 s, respectively. The detection of limit of WCF–MoS(2) for NH(3) was 19.1 ppb. This work provides a new idea for the development of sensors and the resource utilization of wool waste.