Sensing behavior of flower-shaped MoS 2 nanoflakes: case study with methanol and xylene.

Recent research interest in two-dimensional (2D) materials has led to an emerging new group of materials known as transition metal dichalcogenides (TMDs), which have significant electrical, optical, and transport properties. MoS2 is one of the well-known 2D materials in this group, which is a semiconductor with controllable band gap based on its structure. The hydrothermal process is known as one of the scalable methods to synthesize MoS2 nanostructures. In this study, the gas sensing properties of flower-shaped MoS2 nanoflakes, which were prepared from molybdenum trioxide (MoO3 ) by a facile hydrothermal method, have been studied. Material characterization was performed using X-ray diffraction, Brunauer-Emmett-Teller surface area measurements, elemental analysis using energy dispersive X-ray spectroscopy, and field-emission scanning electron microscopy. The gas sensing characteristics were evaluated under exposure to various concentrations of xylene and methanol vapors. The results reveal higher sensitivity and shorter response times for methanol at temperatures below 200 °C toward 200 to 400 ppm gas concentrations. The sensing mechanisms for both gases are discussed based on simulation results using density functional theory and charge transfer.