Synthesis And Photocatalvtic Activities Of ReS₂-based Composites

With the development of society and economy,human beings are increasingly demanding energy,and the current fossil energy is depleting.Therefore,it is necessary to develop and seek new energy sources to realize sustainable development in human society.Semiconductor photocatalysts can utilize the energy of sunlight to catalytically crack organic pollutants or split water to generate hydrogen energy,which meet the needs of human life.Therefore,the development of high-performance semiconductor photocatalysts is of great significance.ReS2 is a two-dimensional(2D)material that strongly absorbs visible light.It has a direct band gap of(1.6-1.7 eV),whether it is single layer or multiple layer.ReS2 has high carrier mobility,as well as relatively strong surface activity and many active sites.Theoretical studies demonstrate that 2D ReS2 have a suitable energy band position for water splitting to generate hydrogen,from single layer to multi-layer.However there is few experimental photocatalytic report concerning ReS2-based materials.Thus,the development and explore of ReS2-based composite photocatalysts is significant from the perspective of both fundamental understanding and applications.In this thesis,two-dimensional(2D)ReS2 was prepared by liquid phase exfoliation method and was subsequently coupled to one-dimensional CdS nanorod by hydrothermal method to form ReS2/CdS heterojunction.The ReS2/CdS heterojunction exhibits excellent photocatalytic performance.Under a 300 W xenon lamp(420nm cut-off filter),the hydrogen production rate is as high as 81 mmolh-1g-1,which is 40 times that of pure CdS.Its apparent quantum efficiency is as high as 34.7%with a 535 nm light source.In the currently reported CdS-based photocatalytic materials,the performance is at a high level.It is revealed that the formation of heterojunction can greatly increase the number of photogenerated carriers,and on the other hand,improve the separation efficiency of photogenerated charges,and as a result,promote the photocatalytic activity significantly,.Besides,a TiO2 nanorod array film was prepared by hydrothermal method,and the 2D ReS2 was dropped onto the TiO2 nanorod array to form a ReS2/TiO2 heterojunction,and the photo-electrocatalytic activity of ReS2/TiO2 photoelectrode was explored.The results show that after combining with ReS2,the photocurrent of the photoelectrode reaches up to 1.5 mA/cm2,50 times that of the pure TiO2 nanorod array.Adequately,the MoS2/TiO2 photoelectrode was prepared as well.The difference in electrochemical performance of ReS2/TiO2 and MoS2/TiO2 was explored and the underlie mechanism was discussed.