Fenton And Simulated Enzyme Catalytic Properties Of Bimetallic Sulfide Fe_xNi_yS₂

In recent years,advanced oxidation technologies（AOPs）are more and more widely used in pollution control,and Fenton technology,which has the most potential,has become the focus of researchers.Although the free radicals produced by Fenton reaction are fast,the conversion speed of Fe3+/Fe2+ in the speed determination step is slow,which limits the continuous degradation of organic pollutants.The catalyst that can carry out Fenton-like reaction also has peroxidase-like activity,which can be applied to the colorimetry of practical monitoring.The core of colorimetric detection is enzyme.Artificial simulated enzyme has similar catalytic activity with natural enzyme,but it has higher activity and stability,easy preparation and low cost.It is an ideal substitute.How to improve the activity of mimetic enzyme and prepare mimetic enzyme with better performance is also a research hotspot.Compared with classical ferrite,transition metal sulfide has lower band gap,excellent stability,good conductivity and rich active sites,and there is synergy between the two metal elements of bimetallic sulfide,which can improve the redox rate.It is an excellent choice for Fenton-like research or simulated enzyme detection.In this paper,the bimetallic sulfide FexNiyS2 was prepared,and then it was compounded with graphene（GO）to obtain a more stable and better catalyst.After a series of characterization of its structure and morphology,its Fenton-like properties and enzyme-like activities were studied,and the possible reaction mechanism was explained.The research content of this paper is mainly divided into three parts:1.Effect of metal cation synergy on catalytic activity of Fenton reaction.Spherical FexNiyS2 particles were synthesized by solvothermal method for Fenton degradation of Rhodamine B（RhB）.Compared with other similar catalysts reported in the literature,Fe1.4Ni0.6S2 has higher degradation efficiency,such as low concentration of catalyst and H2O2,fast reaction speed and high decolorization rate.After reuse,the zeta potential of the catalyst becomes negative,the specific surface area increases,the adsorption capacity of cationic dyes is improved,and the degradation effect becomes better,which has good practical application value.2.The bimetallic sulfide FexNiyS2 has peroxidase like activity.In this chapter,two-dimensional FexNiyS2 nanosheets were synthesized by hydrothermal method,and Fe0.8Ni0.2S2 was selected for subsequent experiments according to enzyme-like activity experiments.The addition of ≡Ni2+accelerates the rate of transformation from=Fe3+to≡Fe2+,thus improving the activity of the nano-enzyme.Fe0.8Ni0.2S2 has strong affinity for H2O2 and can be used as a nano-enzyme to quickly detect H2O2 and ascorbic acid（AA）within 1.0 min at room temperature.3.On the basis of the previous chapter,compound sulfide with GO with strong conductivity and high stability to improve the stability and dispersity of nano-enzyme,and its enzyme-like activity is also improved.Fe0.8Ni0.2S2/GO showed peroxidase-like activity in the range of pH 3.0-6.0,and the optimal pH range was 3.5-4.0.With the addition of GO,the affinity of the nano-enzyme to H2O2 was enhanced again.Fe0.8Ni0.2S2/GO can also quickly detect H2O2 and AA,and has higher sensitivity due to the reduction of the detection limit.