Synergistic CNFs/CoS<sub>2</sub>/MoS<sub>2</sub> Flexible Films with Unprecedented Selectivity for NO Gas at Room Temperature
Siyu Hou, Rui Pang, Shulong Chang, Li Ye, Jie Xu, Xinchang Wang, Yingjiu Zhang, Yuanyuan Shang, Anyuan Cao
Abstract
Recently, room-temperature flexible gas sensors have been widely studied because they can operate without being heated and create low-cost, low-power-consumption devices with long-term stability. Here, by designing the active material composition and structure, we report an electrospun carbon nanofiber (CNF) network grafted by two-dimensional MoS2 nanosheets and embedded CoS2 nanoparticles, which serves as a flexible gas sensor for various toxic or hazardous gases working at room temperature. In particular, the CNFs/CoS2/MoS2 hybrid films exhibit very high selectivity toward NO over other gases including NO2 and CH4, with selectivity coefficients (|SNO/SNO2| and |SNO/SCH4|) as high as 43 and 42 (defined as the ratio of responses between two gases). The sensor shows a linear relationship in the gas concentration range of 1–100 ppm and a stable response during repeated bending. Theoretical calculations suggest that MoS2 can be selectively n-doped by NO, while CoS2 can effectively capture NO molecules, leading to enhanced selectivity and sensitivity. Our large-area flexible sensors made by synergistic design have potential applications in biological and environmental areas for low-cost, selective detection of toxic or targeted gases.