Synthesis Of Molybdenum Disulfide Based Nanocomposite Photo-catalyst And Study On Its Performance Of Photoreduction Of CO₂

China’s energy structure is dominated by coal.The large use of fossil energy such as coal and oil makes the concentration of CO₂ in the atmosphere continue to increase,which leads to various environmental problems.At the same time,the decreasing of fossil energy also causes energy crisis.The conversion of CO₂ into fuel（such as methane,methanol,etc.）can effectively solve the above problems,and the photoreduction of CO₂ has unique advantages such as no secondary pollution,simple operation,and has a broad prospect.In this paper,based on MoS₂,the photoreduction properties of methane and methanol were evaluated by the way of heterostructure modification.（1）SrZrO₃/MoS₂ composites were prepared by hydrothermal method,and investigated the effects of different SrZrO₃ loadings on photocatalytic performance.The results show that Sr,Zr,and O elements are evenly distributed on the surface of MoS₂.SrZrO₃ is closely combined with MoS₂,and the heterojunction structure significantly improves the light absorption ability of MoS₂,reduces the recombination rate of photo-generated electron holes,and extends the electronic life.When the amount of SrZrO₃ is 5wt%,the catalyst shows the highest photocatalytic activity because of its superior carrier separation efficiency and small electron transfer resistance under the light,in which the methane yield can reach 98μmol·h^-1·g^-1,methanol yield reached 36μmol·h^-1·g^-1.（2）In order to solve the problem of difficult catalyst recovery,choose the magnetic perovskite material FeTiO₃combine with Mo S_2.The composite of FeTiO₃ and MoS₂ was constructed by use hydrothermal method and annealing treatment and the photocatalytic performance of different FeTiO₃ loadings was investigated.The results show that the composite material is microsphere-shaped,Fe,Ti,and O elements are evenly distributed on the surface of MoS₂.FeTiO₃and MoS₂ are tightly bound,and the structure of the heterojunction significantly improves the photoresponse range of MoS₂ and the carrier.Transmission rate reduces the recombination rate of photo-generated electrons and holes.When and only when the FeTiO₃loading is 1wt%,the catalyst exhibits higher photocatalytic activity due to its higher carrier separation efficiency under light conditions.The methane and methanol yields are about 76μmol·h^-1·g^-1 and 23μmol·h^-1·g^-1.（3）In order to further improve the photocatalytic performance of magnetic composite materials,a more stable and environmentally-friendly magnetic materialα-Fe₂O₃ and MoS₂were selected for compounding,andα-Fe₂O₃/MoS₂ composite with p-n heterostructure was prepared by secondary hydrothermal method.The effect of different loading amount ofα-Fe₂O₃on the photocatalytic performance was also investigated..The results show that the composite material has a flower-like shape of 1μm,Fe and O elements are evenly distributed on the surface of MoS₂,α-Fe₂O₃ is tightly bound to MoS₂,and the constructed p-n heterostructure significantly improves the light absorption capacity of MoS₂ and reduces photo-generated electrons.The recombination rate of the holes extends the life of the electron.When theα-Fe₂O₃ loading is5wt%,due to its excellent carrier separation efficiency,the photocatalyst exhibits the highest catalytic activity,and the yields of methane and methanol are about 121μmol·h^-1·g^-1and 41μmol·h^-1·g^-1.In summary,the photocatalysis performance can be effectively improved by selecting appropriate semiconductors in order to build heterostructure modification.Choosingα-Fe2O3as the heterogeneous material can not only help the recovery and reuse of catalyst,but also accelerate the transport rate of carrier,reduce the recombination probability of photogenerated electron hole and improve the photocatalytic activity of the composite by forming p-n heterojunction.