Controllable Synthesis And Electrocatalytic Performances Of MoS₂ And Cu₂MoS₄

With the progress of society and the development of science and technology,the energy crisis has been put on the agenda.The electrochemical hydrogen production is an important and effective way to solve the energy crisis.Pt-based noble metal catalyst with best performance is difficult to be widely used because of its high cost and non renewable resource.In recent years,low-cost transition metal sulfides have attracted much attention due to their unique electronic structure and the associated electrochemical properties.However,most of the transition metal sulfides have less active sites and poor conductivity.Based on these considerations,in this dissertation,the electrochemical performance of transition metal sulfides was enhanced through the edge engineering and metal atoms and ions-double-doped strategies.The main contents include the following aspects:（1）MoS₂ nanospheres were synthesized through a facile hydrothermal route on a large scale,using thiourea and ammonium molybdate as raw materials.Then Cu atoms and Cu²⁺ ions were doped into the as-synthesized MoS₂ nanospheres through a disproportionation reaction of tetrakis（acetonitrile）copper（I）hexa-fluorophosph.The resultant products were characterized by XPS,XRD,SEM,TEM,EDX,BET,and contact angle analyzer in detail.A series of experimental results on electrochemical performance show that the doping can significantly improve hydrogen evolution activity of MoS₂.In addition,from a practical point of view,MoS₂ nanosheets arrays were grown on stainless steel mesh wires substrate.The electrocatalytic activity of MoS₂ nanosheets arrays and Cu-doped MoS₂ nanosheets arrays were comparatively studied.The experimental results showed that Cu-doped powder MoS₂ nanospheres and MoS₂ nanosheets arrays could significantly enhance the electrocatalytic properties of MoS₂.The present study provides a new strategy for the preparation of highly efficient electrocatalysts.（2）Edges often play a role as active centers for catalytic reactions in some nanomaterials.Therefore it is highly desirable to enhance catalytic activity of a material through modulating the microstructure of the edges.Cu₂MoS₄ nanospheres were synthesized through a facile hydrothermal route on a large scale,using sodium chromate,cuprous oxide and thioacetamide as raw materials.Then the Cu₂MoS₄ nanosheets with indented edges can be fabricated through a simple chemical etching route at room temperature,using Cu₂MoS₄ nanosheets with flat ones as sacrifice templates.Taking the electrocatalytic hydrogen evolution reaction（HER）and photocatalytic degradation of rhodamine B（RhB）as examples,the catalytic activity of Cu₂MoS₄ indented nanosheets（INSs）obtained through edge engineering was comparatively studied with those of Cu₂MoS₄ flat nanosheets（FNSs）without any modification.The photocatalytic and HER tests revealed that the catalytic active sites of Cu₂MoS₄ nanosheets were associated with their edges rather than basal planes.The present work shows that the edge engineering strategy can significantly enhance the light and electrocatalytic activity of the material.