A facile solvothermal synthesis of 3D magnetic MoS2/Fe3O4 nanocomposites with enhanced peroxidase-mimicking activity and colorimetric detection of perfluorooctane sulfonate

Recently, two-dimensional (2D) layered structural MoS2 has emerged as novel inorganic nanomaterials with excellent characteristics especially of its tunable bandgap applicable to the field of catalysis. Owing to the inherent basal surface catalytic inertia and instability of 2D MoS2, methods of coupling with other functional materials or exploiting three-dimensional (3D) structure have been developed. Here, we report a facile preparation process of 3D MoS2-based nanomaterials with remarkably enhanced peroxidase-like catalytic activity, magnetic separation, cost-effective and high yield, which is of great significance for the construction of colorimetric sensors. All SEM and TEM images showed a 3D flower-shaped morphology of our prepared MoS2 with Fe3O4 nanopartides (NPs) anchored on the "petals", so called MoS2/Fe3O4 nanocomposites. The absorbance plots confirmed higher catalytic property of nanocomposites, taking MoS2, Fe3O4 NPs and a blend of the two by physical method as comparison. And this robust catalytic activity was utilized to achieve hypersensitive colorimetric sensing method for detecting perfluorooctane sulfonate (PFOS) with the linear relationship between absorbance and PFOS concentrations, ranging from 0.1 to 12.5 mu M, and the limit of detection (LOD) was 8.6 nM (3 sigma/k).