Preparation Of MoS₂/Fe₃O₄ And Its Sensing Applications

In recent years,2D molybdenum disulfide?MoS₂?,as an emerging type of inorganic graphene analogs,had developed rapidly in the field of photoelectric and sensing.In this paper,the structural properties,preparation methods and enzymatic properties of MoS₂ nanomaterials with different morphologies were studied.The MoS₂ nanoflowers were decorated with Fe₃O₄ nanoparticles to obtain MoS₂/Fe₃O₄ composite with ethanol as solvent.MoS₂/Fe₃O₄ composite had the advantages of easy separation during preparation,high peroxidase-like activity,high yield and a greatly reduced cost compared with the MoS₂modified by noble metals such as platinum or gold.Several MoS₂/Fe₃O₄-based detection platforms had been developed when the MoS₂/Fe₃O₄ was applied in the field of colorimetric sensing,and several good linear relationships were obtained.The main contents were as follows:?1?The MoS₂ nanosheets were prepared by ultrasonic assisted stripping method,and the SEM image showed obvious lamellar structures.The XRD spectrogram showed that the corresponding peaks intensity of the c-axis crystal plane of MoS₂ nanosheets were weaker than the bulk MoS₂.The exfoliated MoS₂ nanosheets possessed enzyme-like catalytic activity.In addition,the MoS₂ nanoflowers were prepared by one-step hydrothermal method.The morphology and crystal structure of MoS₂ nanoflowers were affected by synthesis temperatures?140-220°C?.It was noteworthy that the edges of the petals become more unclear and all of the XRD peaks are significantly broadened with decreased synthesis temperature,suggesting the increased number of defects and decreased crystallinity.Taking the enzyme activity as the objective,the highest enzyme-like activity belongs to the MoS₂nanoflowers prepared at 180°C.?2?MoS₂/Fe₃O₄ composite was prepared by one-step solvothermal method with FeCl₃·6H₂O as the precursor.The synthesis conditions were optimized with the aim of enzyme activity:m?MoS₂?/m?FeCl₃·6H₂O?=1/2.4,ethanol as the reaction solvent,and the synthesis temperature at 200°C.Mo S₂/Fe₃O₄ was characterized by SEM,TEM,XPS and XRD.The results showed that the Mo S₂/Fe₃O₄ was successfully compounded and the Fe₃O₄nanoparticles grew on the edge of the MoS₂ nanopetals.The modification of Fe₃O₄ decreased the Fermi level of catalyst and improved the rate of electron transfer,resulting in the improvement of the catalytic activity.?3?MoS₂/Fe₃O₄ was applied in the field of colorimetric sensing,and the detection platforms of H₂O₂ was constructed first.The linear range and detection limit were 20mM-220 mM and 0.73 mM respectively;Secondly,based on the principle of glucose oxidase specific catalytic oxidation glucose to produce H₂O₂,a detection platform of glucose was constructed with a linear range and detection limit of 0.05 mM-1.25 mM and 0.006 mM,respectively.Third,a detection platform of PFOS was constructed based on the hydrophobic interaction and electrostatic interaction between MoS₂/Fe₃O₄ and PFOS,resulting PFOS adsorbed on the surface of MoS₂/Fe₃O₄ and the enzyme activity was inhibited.The linear range and detection limit were 0.1?M-12.5?M and 0.0086?M.Finally,based on the coordination of Cu²⁺with the nitrogen atom in the TMB molecule of the system,the process of TMB oxidated to oxTMB was inhibited,a detection platform of Cu²⁺was constructed with a linear range and detection limit of 1.0?M-50.0?M and 0.1?M.In this paper,the enzyme-like activity of MoS₂ with different morphology were studied.Furthermore the MoS₂/Fe₃O₄ composite with high enzyme activity was prepared,and was successfully applied in the field of colorimetric sensing.This provided a new idea for the construction of sensing platform based on enzyme-like materials.