| Fenton-like reaction is one of the effective environmental remediation processes for the degradation of organic pollutants.Layered MoS2 with large specific surface has strong adsorption capacity and is a potential catalyst with excellent performance.By introducing small-size noble metal nanoparticles on its surface to form semiconductor/metal heterojunction structure,it can not only increase the defects on the material surface and produce more catalytic active sites,but also improve the ability of electron-hole separation,which is beneficial to catalytic reaction.The SERS detection system of Au nanoparticle monolayer film/semiconductor/metal heterojunction was constructed.This dissertation focused on the preparation of heterojunction structure and the construction of heteromaterial stacking structure.With SERS as the detection means,the following studies were carried out mainly around the Fenton-like reaction of organic methylene blue(MB)degradation:1.MoS2/Au heterojunction materials with high catalytic performance were prepared.The material structure was optimized,and the SERS detection system of Au film/MoS2/Au was constructed.The effects of natural light and pH value of Fenton-like reaction were studied.The results showed that natural light could promote the degradation of MB by MoS2/Au.The catalytic degradation process of MB at three pH values was investigated in a wide pH range.The results showed that MB could be effectively degraded at pH between 1.4-11.1,which widened the application range of traditional Fenton reaction.In addition,the reaction rate constants and reaction orders defined from the perspective of kinetics.The Fenton-like reaction mechanism of MB degradation catalyzed by MoS2/Au based on free radicals(hydroxyl radical and superoxide radical)was proposed.2.MoS2/Au/Pt bimetallic heterojunction materials were prepared.The material structure was optimized,and the effects of natural light and pH value and kinetic process of the Fenton-like reaction were studied.It is found that MoS2/Au/Pt also has a wide pH application range.The degradation of MB by MoS2/Au/Pt followed the second-order kinetic characteristics.In addition,the degradation of malachite green(MG)was studied and the universality of the catalyst was also verified.Combined with electron spin resonance(ESR)technology,the degradation mechanism of Fenton-like reaction catalyzed by MoS2/Au/Pt was proposed.3.The SERS detection system of MoS2/molecule/gold nanostructure was constructed.Taking p-mercaptobenzoic acid(MBA)as the probe molecule for adsorption study,the SERS properties of MoS2/MBA/three gold nanostructures were compared.The results showed that the detection limits of MBA in the three structures were different.The enhancement effect order of SERS was MoS2/MBA/gold cube>MoS2/MBA/gold nanorod>MoS2/MBA/gold nanosphere.The effects of different shapes of gold nanoparticles on the coupling reaction of p-aminothiophenol(PATP)catalyzed by surface plasmon(SPR)were studied.It was found that the coupling reaction of PATP catalyzed by MoS2/PATP/gold nanospheres was difficult to occur in anhydrous system with the maximum power of the instrument.At the same time,the structures of gold nanorods and gold cubes can catalyze the reaction because of their own hot spots.By covering a layer of water film on the surface of the above nanostructures,the characteristic peaks of the coupling product 4,4’-dimercaptoazobenzene(DMAB)can be detected under any power provided by the instrument.This was due to the fact that liquid water provides more probability of hot spots caused by collision and the participation of oxygen.The results showed that the hot spot distribution,crystal surface structure and the participation of ambient oxygen can greatly affect the SPR catalytic coupling efficiency. |
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