Mechanically exfoliated MoS2 nanosheets decorated with SnS2 nanoparticles for high-stability gas sensors at room temperature

Abstract

Due to its unique physical, chemical and surface electronic properties, molybdenum disulfide (MoS2) nanosheets open up a new avenue for nitrogen dioxide (NO2) detection at room temperature. Nevertheless, the gas sensing properties of pure MoS2 nanosheets are inevitably degenerated by the adsorption of atmospheric oxygen, which results in weak stability for MoS2-based gas sensors. Reducing surface defects and constructing heterojunctions may be effective strategies to improve the gas sensing properties of MoS2 nanosheets. In this work, we design a novel nanocomposite based on MoS2 nanosheets decorated with tin disulfide (SnS2) nanoparticles (MoS2/SnS2) via combining the mechanical exfoliation method with the facile hydrothermal method. The experimental results indicate that, after surfaces decoration with SnS2 nanoparticles, the as-prepared gas sensor based on MoS2/SnS2 nanocomposites exhibits reliable long-term stability with the maximum response value drift of less than 3% at room temperature. Moreover, the MoS2/SnS2 sensor also possesses desirable gas sensing properties upon NO2 at room temperature, such as high sensitivity, rapid response/recovery speed (28 s/3 s, 5 × 10−6 NO2), satisfactory selectivity, favorable repeatability and reversibility. The improved gas sensing properties of MoS2/SnS2 nanocomposites can be attributed to the unique electronic properties of MoS2 nanosheets with the fewer layers structure and the competitive adsorption effect of SnS2 nanoparticles. This work elucidates that SnS2 nanoparticles serving as an effective antioxidative decoration can promote the stability of MoS2 nanosheets, providing a promising approach to achieve high-stability NO2 gas sensors at room temperature.