Synthesis and characterization of SnS2 2D nanomaterial in gas sensing applications. (a) Schematic illustration of the hydrothermal synthesis of SnS2 and subsequent fabrication of the gas sensor using the drop-casting method. (b) SEM image of stacked SnS2 2D nanolayers. (c) TEM image and HRTEM image (inset) of the hexagonal structure of an SnS2 single nanolayer. (d) Fast Fourier transform (FFT) pattern of the SnS2. (e) X-ray diffraction (XRD) pattern of the SnS2 confirming its 2H structure.