MoO2/MoO3/MXene ternary nanocomposites for high-performance ethanol detection at room temperature

Ethanol, as one of the common volatile organic compounds (VOCs), has serious harm to the human central nervous system. The high-efficiency detection of ethanol gas at room temperature (RT) has attracted widespread attention in the field of current gas-sensing detection. Here, we designed and prepared ternary nanocomposites constructed with two-dimensional MXene and MoO2/MoO3 nanosheets, which can be used in the field of low-concentration ethanol detection at RT. The MoO2/MoO3/MXene nanocomposites make full use of the excellent electrical conductivity and large specific surface area of MXene, which provides more active adsorption sites and reaction centers. Moreover, the construction of n-n heterojunctions between uniformly grown MoO2 and MoO3 nanosheets significantly enhances the response of the sensor. The gas sensing results revealed that MoO2/MoO3/MXene nanocomposites showed high response (Ra/Rg = 19.77 @200 ppm) to ethanol at RT, with a detection limit of 5 ppm (Ra/Rg = 2.07). At the same time, the sensor also has excellent selectivity and fast response-recovery to ethanol (46 s/276 s). Further, the possible gas sensing mechanism of the composites was proposed and discussed. This work suggests the promising applications of metal oxides heterojunctions/2D hybrid materials for VOCs gas sensing detection at RT.