Chemisorption of NO2 to MoS2 Nanostructures and its Effects for MoS2 Sensors

The special interactions with NO2 make MoS2 promising sensors. Effective gas adsorption and active sites of MoS2 are crucial for high performance sensors. However, studies of the interactions of MoS2 with gas have been focused on the physisorption of basal planes. In this article, chemisorption modes, with O,O-bidentate or N-monodentate bonding, on the (1-1 0) surfaces of MoS2 structures have been explored in addition to physisorption. The active sites of MoS2 nanosensors have been predicted to be edge sites of (1-1 0) surfaces and further confirmed by the different sensing performances of vertically and parallelly aligned MoS2 hybrids. Chemisorption mode with N-monodentate bonding has also been calculated to be effective for MoS2 nanosensors by a two-probe system simulation and further confirmed by in-situ Raman and in-situ diffuse reflectance infrared Fourier transform experiments. High sensitivity and selectivity have also been obtained by the vertical aligned MoS2 hybrids.