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.