Preparation And Properties Of Iron-Based Sulfide Nanozymes

Nanozyme is a kind of nanomaterial with natural enzyme properties.Compared with other artificial enzymes,its catalytic activity has been further improved due to the size effect and unique physicochemical properties of nanomaterials.Among many kinds of nanomaterials,transition metal sulfide nanomaterials exhibit excellent peroxidase-like activity.In particular,FeS₂,a typical representative of transition metal sulfides,was found to have intrinsic enzyme-like activity.To further improve the catalytic activity of the enzyme and expand the preparation method of the enzyme.In this paper,nano-iron-based sulfide peroxidase were derived by the arc-discharge method combined with heat treatment technology and hydrothermal method.And synthesized FeS₂@C/MoS₂with a layered structure,and established a colorimetric sensing platform with high sensitivity and selectivity,which can be used for the detection of hydrogen peroxide and glutathione.The specific research is as follows:In this paper,Fe@C,Fe/FeS₂@C core-shell nanoparticles and FeS₂@C/MoS₂nanocomposites were successfully prepared by the combination of arc-discharge method,heat treatment technology and hydrothermal method.By means of X-ray diffraction,scanning electron microscopy,transmission electron microscopy and X-ray electron spectroscopy,the phase composition of the sample,the morphology and size of microscopic particles,and the elemental composition and valence state of the sample were characterized.The catalytic activity and catalytic mechanism of the samples were tested by UV-Vis spectrophotometer and fluorescence photometer.In the experiment,a combination of arc-discharge method and heat treatment technology was used to prepare Fe@C core-shell nanoparticles with metallic iron as raw material and methane as carbon source.Fe@C core-shell nanoparticles with different mass ratios and sulfur powder were uniformly mixed by heat treatment were obtained the Fe/FeS₂@C core-shell nanoparticles.And Fe/FeS₂@C core-shell nanoparticles were prepared by heat treatment technology.The experimental results show that Fe/FeS₂@C（1:2）core-shell nanoparticles have the best peroxidase-mimicking activity.The K_mof Fe/FeS₂@C for H₂O₂is as low as 0.037 m M.The detection limit for H₂O₂was as low as 0.42μM,and the detection time was 2 min.The detection limit for GSH was as low as 0.23μM.The excellent catalytic activity originates from the synergistic effect between the core Fe/FeS₂and the graphitic C layer which can increase their electron transport capacity,the cycling efficiency between Fe³⁺/Fe²⁺and the exposed active sites of the Fe/FeS₂@C defective core-shell.In the experiment,FeS₂@C/MoS₂nanocomposites were prepared by the combination of arc-discharge method and hydrothermal method using metallic iron as raw material and methane as carbon source.The content of FeS₂@C was controlled by changing the amount of Fe@C added.The results show that the FeS₂@C/MoS₂-150 nanocomposite has the strongest catalytic activity,the K_mvalue for H₂O₂is as low as 0.08 m M,the detection limit for H₂O₂is as low as 0.44μM,and the detection time is 3 min.The detection limit for GSH is as low as 0.19μM.The excellent catalytic activity stems from the synergistic effect of FeS₂@C and MoS₂,the cycling effect between Fe³⁺/Fe²⁺and Mo^6+/Mo⁴⁺and FeS₂@C/MoS₂nanocomposites have better spatial structure and can provide abundant active sites and material shuttle.The research results show that the Fe/FeS₂@C core-shell nanoparticles and FeS₂@C/MoS₂nanocomposites synthesized in this paper both have high peroxidase-like activity.It has the advantages of wide source of raw materials,low preparation cost and easy preservation.The synthesized material is a very promising colorimetric sensing platform.