MoS2-xSex lamellae assembled with lotus-leaf-like structures for sensitive NO2 gas sensors at room temperature

Transition metal disulfides (TMDs) have been the subject of extensive research interest in the field of gas sensors due to their distinctive physical and chemical characteristics. However, the insufficient stability and poor moisture resistance, is the two major challenges of these materials in practical applications. In this work, pristine Mo-S bonds were partially transformed into Mo-Se bonds by thermal selenization treatment under H2(5%)/Ar atmosphere conditions to form 3D MoS2-xSex alloy nanocomposites, which the surface of the composites possess a nanoscale and dense convex structure (100-400 nm), similar with the bionic structure of the lotus leaf in morphology. The fabricated MoS2-xSex sensor with lotus-leaf-like structure and large number of sulfur defects revealed high sensitivity (S = 71.2), fast response (4.7 s) and lower limit (50 ppb) to NO2 at room temperature (RT, 25 degrees C). Notably, the unique lotus leaf-like structural design of the MoS2-xSex alloy nanocomposite considerably improves the moisture resistance and enhances its stability in humid environments.