Preparation Of Molybdenum Disulfide/Functionalized Graphene Composites And Study On Electrocatalytic Hydrogen Evolution Properties

Due to the large-scale development and consumption of fossil fuels,the energy crisis and environmental pollution problems have become increasingly prominent.The urgent need to develop green and sustainable new energy sources to replace fossil energy has become a hot spot in global research.Among them,a series of advantages of hydrogen energy have been known and valued,and along with,many hydrogen production technologies have been produced.Hydrogen produced by electrolyzed water is widely used due to its advantages of simple operation and no pollution.Therefore,experts and scholars have carried out a lot of research on the cathode catalyst in the process of electrocatalytic hydrogen evolution,and found that the Pt-based precious metal catalyst has extremely excellent electrocatalytic hydrogen evolution performance,but because of its high price,small reserves and other problems limit its large-scale use,it is necessary A non-Pt-based precious metal cathode catalyst was designed to replace the precious metal catalyst.Among many non-precious metal catalysts,transition metal sulfides with molybdenum disulfide as a typical representative have attracted attention.Theoretical and experimental calculations show that there are hydrogen evolution active sites at the edge of molybdenum disulfide nanosheets,but due to the weak van der Waals force between MoS₂ layers,agglomeration is easy to occur,the structure is unstable,and the number of active sites for hydrogen evolution is reduced.MoS₂ has poor conductivity and reduces the hydrogen evolution performance of molybdenum disulfide.Therefore,in combination with the existing research results at home and abroad,in order to make the MoS₂ catalyst simple to prepare,at the same time versatile and efficient in use,it is necessary to prepare MoS₂ with good conductivity and a large number of hydrogen evolution active sites.Based on the above analysis,we use the non-Pt-based precious metal material MoS₂ as the main catalytic material,Nitrogen-doped graphene quantum functionalized graphene（N-GQDs-GR）and ionic liquid functionalized graphene（ILs-GR）were used as carrier materials respectively.The morphology and structure of the material are characterized.The electrocatalytic hydrogen evolution performance of the composites was investigated by electrochemical tests.The performance parameters such as hydrogen evolution onset potential,Tafel slope,current density at the same potential,exchange current density,and switching frequency were compared.The main contents of this paper are:1.The three-dimensional molybdenum disulfide/nitrogen-doped graphene quantum functionalized graphene（MoS₂@N-GQDs-GR）composite was successfully synthesized by one-step hydrothermal method.The addition of nitrogen-doped graphene quantum dots not only disperses the agglomerated graphene,but also enhances its water solubility.It also provides more stable binding sites for the adhesion of molybdenum disulfide and controls the molybdenum disulfide.Morphology and crystallization state,which affects the hydrogen evolution performance of the composite.2.Molybdenum disulfide is used as the molybdenum source,thiourea is the sulfur source,graphene is used as the substrate,and ionic liquid is added to regulate the synthesis of MoS₂@ILs-GR composite material.Nitrogen dimethylformamide（DMF）is used as the solvent.Molybdenum disulfide/graphene（MoS₂/GR）composites without ionic liquid were prepared by solvent thermal method,and the influence of the presence of ionic liquid on the structure and morphology of the product was studied.