Enhanced Gas-Sensing Performance of Atomically Dispersed Binary Co-Zn Doped Mos2 Nanosheets Toward Ppb-Level No2 at Room Temperature

Molybdenum disulfide (MoS2), a transition metal dichalcogenides (TMDs), is conventionally regarded as a promising room-temperature (RT, 25 °C) gas-sensing material due to its unique physical and chemical properties. However, the gas sensors based on pristine MoS2 films do not seem to achieve the expectation. In this study, we fabricated the unique structure of atomically dispersed (AD) Co and Zn atoms anchored on the MoS2 lattice (i.e., AD binary Co/Zn-doped MoS2). We find that the sensor based on the AD binary Co-Zn/MoS2 nanosheets shows high responses toward NO2 gas ( = ~1.3 at 50 ppb and ~5.2 at 5 ppm) at RT, which is significantly higher than that of the pristine MoS2 sensor. Additionally, the AD binary Co-Zn/MoS2 sensor has a low limit of detection (LOD) of 6.2 ppb, fast response-recovery times (120/310 s toward 1 ppm NO2), and long-term stability. Compared with other gases, including NO, NH3, H2, CO, and ethanol, the sensor exhibits good selectivity toward NO2 due to its lower activation energy. Furthermore, the enhanced gas-sensing performance for NO2 can be attributed to the dual atomic synergetic effects and the enriched oxygen adsorption. This work may open a new avenue to achieve NO2 sensors with absolutely competitive performance at RT.