Mechanically exfoliated MoS 2 nanosheets decorated with SnS 2 nanoparticles for high‐stability gas sensors at room temperature

Abstract Due to its unique physical, chemical and surface electronic properties, molybdenum disulfide (MoS 2 ) nanosheets open up a new avenue for nitrogen dioxide (NO 2 ) detection at room temperature. Nevertheless, the gas sensing properties of pure MoS 2 nanosheets are inevitably degenerated by the adsorption of atmospheric oxygen, which results in weak stability for MoS 2 ‐based gas sensors. Reducing surface defects and constructing heterojunctions may be effective strategies to improve the gas sensing properties of MoS 2 nanosheets. In this work, we design a novel nanocomposite based on MoS 2 nanosheets decorated with tin disulfide (SnS 2 ) nanoparticles (MoS 2 /SnS 2 ) via combining the mechanical exfoliation method with the facile hydrothermal method. The experimental results indicate that, after surfaces decoration with SnS 2 nanoparticles, the as‐prepared gas sensor based on MoS 2 /SnS 2 nanocomposites exhibits reliable long‐term stability with the maximum response value drift of less than 3% at room temperature. Moreover, the MoS 2 /SnS 2 sensor also possesses desirable gas sensing properties upon NO 2 at room temperature, such as high sensitivity, rapid response/recovery speed (28 s/3 s, 5 × 10 −6 NO 2 ), satisfactory selectivity, favorable repeatability and reversibility. The improved gas sensing properties of MoS 2 /SnS 2 nanocomposites can be attributed to the unique electronic properties of MoS 2 nanosheets with the fewer layers structure and the competitive adsorption effect of SnS 2 nanoparticles. This work elucidates that SnS 2 nanoparticles serving as an effective antioxidative decoration can promote the stability of MoS 2 nanosheets, providing a promising approach to achieve high‐stability NO 2 gas sensors at room temperature.