Synthesis And Antibacterial Properties Of Molybdenum Disulfide And Its Composites

Molybdenum disulfide?MoS₂?,as a typical two-dimensional materials,is promising in many areas such as catalyst,supercapacitor,the electrode of the lithium-ion battery,photothermal therapy,drug delivery,biosensors and so on.Recently,nano MoS₂ has been produced for antibacterial applications;however,the antibacterial mechanisms of MoS₂ have not been specified.Accordingly,by using hydrothermal processes,we prepared several MoS₂-based composite materials,and their antibacterial mechanisms was studied.The main results are as follows:1.MoS₂ nanosheets were coated on the surface of titanium via a one-step hydrothermal reaction.The MoS₂ nanosheets were vertically aligned on the Ti substrate,exposing more reactive sites on the edges of the nanosheets.The MoS₂nanosheets were bound to the Ti substrate through a thin TiO₂ layer formed at the beginning of the hydrothermal treatment.While the vertically-packed nanostructure was formed by self-assembly of MoS₂ nanosheets.The iron-doped molybdenum disulfide coating can be prepared by adding an iron source to the reactants during hydrothermal treatment.The MoS₂ coatings have excellent antibacterial activity under dark condition.Doping of iron enhances the antibacterial activity of MoS₂,the 6 h antibacterial rate of iron-doped MoS₂ coatings is about 100%while that for MoS₂coatings is only about 82%.The MoS₂ coatings have ion release and reactive oxygen species generation based antibacterial actions.Iron doping promotes both actions;therefore significantly improves the antibacterial activity of the MoS₂.2.The C@MoS₂ particles?with an average diameter of 1?m?were prepared by a two-step hydrothermal reaction.The formation of carbon spheres was the result of the carbonization of glucose.And the diameter uniformity of carbon spheres?average about 500 nm?can be improved by addition of the formaldehyde under weak acidic or alkaline pH.Well-distributed C@MoS₂ microspheres can only be produced by a reasonable ratio of carbon spheres and molybdenum source.Under dark condition,the antibacterial efficacy of C@MoS₂ was higher than that of molybdenum disulfide microspheres,this can be answered by the quantity of reactive sites in C@MoS₂,which is 5 times to that in molybdenum disulfide nanosheets.In addition,pre-irradiation by visible light could double the antibacterial rate of C@MoS₂?almost100%?,and this is likely related to the interface effect of carbon and molybdenum disulfide in the microspheres.3.The PPy@MoS₂ particles?average diameter of 1?m?were prepared by oxidative chemical polymerization of pyrrole to produce PPy spheres and growth of MoS₂ cover layers by a hydrothermal process.Pre-irradiation byvisible light,the antibacterial efficacy of PPy@MoS₂ can be improved by 6 times compared to that under dark condition?antibacterial rate less than 10%?.The antibacterial rate of PPy@MoS₂ reaches about 90%)by continuous irradiation by visible light during the whole process of bacterial culture.It is believed that the antibacterial activity of is PPy@MoS₂ microspheres is stemed from charge separation behavior of PPy under light il umination and the surface reactive sites exposed in MoS₂ nanosheets.