Preparation Of Molybdenum Disulfide-based Nanomaterials And Research On Their Photocatalytic And Electrocatalytic Properties

In the 21st century,the situation of energy crisis and environmental pollution has become more and more severe,and the development of new energy and the treatment of environmental pollution have received increasing attention.These problems can be solved by the high-efficient catalysts.2D transition metal sulfides(TMDs)represented by MoS₂ have a wide range of applications in many fields such as electrochemical energy storage and conversion,optics,and electrical devices due to their special energy band structure,semiconductor or superconducting properties,and good thermal stability,and have aroused the interest of many researchers.However,MoS₂ has defects such as poor conductivity,few active sites,and easy agglomeration and stacking,which limit its application.In this paper,we modified MoS₂ by phase engineering,doping,and formation of heterojunction with two-dimensional materials to improve the photocatalytic and electrocatalytic properties of MoS₂.The main research contents are as follows:1.High 1T content of MoS₂ nanomaterials was prepared by using pyridine ionic liquid[BPy]Br-assisted hydrothermal method.The steric hindrance effect of the ionic liquid and the mutual stacking interaction of aromatic rings promote the transformation of MoS₂ from 2H phase to 1T phase during the preparation process,thereby increasing the content of metal 1T crystal form in MoS₂,so that the content of metal 1T crystal form in MoS₂ can reach 91.9%.In addition,the electrocatalytic hydrogen evolution reaction activity of MoS₂ is improved.The over potential of MoS₂ synthesized by ionic liquid(at a current density of 10 m A·cm^-2)can reach 259 m V,which is lower than the overpotential of 422 m V of pure MoS₂.2.The heterojunction structure of MoS₂ and g-C₃N₄ composite was prepared by hydrothermal method and has been used to photo-catalytically degrade the simulated wastewater.Experiments have proved that the degradation rate of methylene blue and rhodamine B dyes at 40 mg/L can reach 99%and 92%.3.Through the combination of P and g-C₃N₄ with MoS₂,the P-MoS₂/g-C₃N₄composite formed has high electrocatalytic hydrogen evolution activity.The overpotential can reach 187 m V at a current density of 10 m A·cm^-2,Tafel slope can reach 39 m V·dec^-1,and the composite has good stability.