Three-dimensional flower-like Mg(OH)2@MoS2 nanocomposite: fabrication, characterization and high-performance sensing properties for NOx at room temperature

Abstract

A three-dimensional (3D) flower-like hierarchical Mg(OH)₂@MoS₂ nanocomposite was fabricated using ordinary hydrothermal technology. On adjusting the ratio of MoS₂ and Mg(OH)₂, the morphology could be readily controlled. The Mg(OH)₂@MoS₂ nanocomposite comprises Mg(OH)₂ nanosheets (NSs), which serve as an alkaline center and benefit the adsorption and diffusion of acidic NO_x gas. In addition, the 3D hierarchical 2-Mg-MoS₂ (the content of MoS₂ in Mg(OH)₂@MoS₂ is 33.3 mol%) is not only beneficial for NO_x adsorption on the surface but also strengthens the interaction between the target gas molecules and the active sites. As a result, 2-Mg-MoS₂ exhibits excellent sensing properties; its response to 100 ppm NO_x could reach 4.73, and the response time was 3 s. In addition, the detection limit of 2-Mg-MoS₂ is 0.1 ppm at room temperature (RT). These results demonstrate that this nanocomposite shows outstanding selectivity and stability at RT. This 2-Mg-MoS₂ sensor has significant implications for monitoring polluted air.