Preparation Of MoS₂-based Composite Materials And Photocatalytic Degradation Of Organic Dyes

In recent years,the energy crisis and environmental pollution become increasingly serious.Photocatalytic technology has attracted much attention because it can directly use clean light energy to effectively degrade pollutants in the environment.The design and preparation of new friendly,efficient and easy to recycle photocatalysts that can respond in the visible light range are the key to the development of photocatalytic technology.Due to the unique structure and excellent photoelectric performance,molybdenum disulfide（MoS₂）has a wide range of applications in energy storage,catalysis and electrochemistry.However,photo-generated electron-hole pairs are likely to recombine in MoS₂,thus reducing the photocatalytic efficiency.Therefore,this thesis aims to prepare MoS₂-based semiconductor heterojunction photocatalytic composites:CuS/MoS₂,ZnO/MoS₂,and TiO₂-C/MoS₂ and to study their catalytic degradation of methylene blue（MB）In the first part of the thesis,CuS/MoS₂ heterojunction composite catalyst with two different morphologies were prepared and used to degrade MB solution.It was found that the photocatalytic efficiency of lamellar CuS/MoS₂ composite catalyst for MB was higher,and the degradation rate reached 93%in 90 minutes.The results showed that when the mass ratio of CuS to MoS₂ is 1:10,the catalytic effect is the best.The recycling measurements showed that CuS/MoS₂ composite has a very good recycling performanceIn the second part of the thesis,three types of ZnO with different morphologies were prepared and and were used to degrade MB solution.Among them,the thin strip mixed irregular lamellar ZnO has the best catalytic degradation effect.The MB solution can be completely degraded in 40 minutes.ZnO/MoS₂ heterojunction composite was prepared by combing short rod ZnO and MoS₂.Under the same experimental conditions,the degradation rate of MB solution was 97%,which was 12%higher than single ZnO and 55%higher than single MoS₂ at 50 minutes.Therefore,ZnO/MoS₂ heterojunction composite photocatalyst can effectively enhance the photocatalytic activity of the systemIn the third part of the thesis,C/TiO₂ nanofibers were prepared by electrospinning technology.The FE-SEM characterization indicated that the heat treatment has little effect on the morphology of MoS₂.The photocatalytic activity of C/TiO₂ nanofibers treated at different carbonization temperatures were compared.The experimental results showed that the C/TiO₂ nanofibers carbonized at 400℃ have better catalytic degradation performance for MB.The recycling performance measurements showed that C/TiO₂ as a photocatalytic material has a good recycling performance.TiO₂-C/MoS₂ composite photocatalyst was prepared by combining the flower ball MoS₂ and TiO₂.Compared with single material,the photocatalytic degradation efficiency of composite TiO₂-C/MoS₂ material for MB was improved.