Study Of Synergistic Manipulation Of Dislocation And Strain MoS₂ For Hydrogen Evolution Application

As a green,low-carbon,high-energy-density secondary energy source,hydrogen energy is considered an ideal energy source to replace traditional fossil resources,build a clean,low-carbon,safe,and efficient energy system,and achieve"carbon peak"and"carbon neutrality".Hydrogen production by water decomposition is one of the effective means to achieve efficient hydrogen production.Its core technology is the development and utilization of catalysts.However,the substrate with the highest proportion in the semiconductor phase（2H phase）MoS₂ exhibits an inert state for hydrogen evolution reaction,and the active sites for hydrogen evolution reaction are only located at the edge positions,which limits its catalytic hydrogen evolution performance.In order to solve the problem of low catalytic activity caused by an inert base surface,researchers found that introducing defects on the MoS₂ surface and interlayer can effectively improve its catalytic hydrogen evolution reaction activity.This thesis focuses on the research of MoS₂ defect engineering,focusing on the influence of MoS₂ dislocation defect on the change of microstructure,local strain,and electronic structure,and exploring the structure-activity relationship between them and catalytic hydrogen evolution reaction performance;Dislocation-strained MoS₂（D-S-MoS₂）nanosheets were designed and synthesized to provide theoretical guidance for the subsequent development of a high-efficiency MoS₂-based hydrogen evolution reaction catalyst through theoretical calculation.The main research contents of this paper are as follows:1.D-S-MoS₂ nanosheets were prepared by controlling the temperature and time of the hydrothermal reaction.The prepared samples were characterized by SEM,TEM,XPS,and ESR for their morphology,structure,elemental composition,valence,and defects.Geometric phase analysis（GPA）is carried out by using Strain++to analyze the local stress at the defect of D-S-MoS₂.The effect of reaction time on the synthesis structure of D-S-MoS₂ was investigated by controlling the low-temperature hydrothermal time.2.The photocatalytic hydrogen production online monitoring system was used to evaluate the catalytic hydrogen production performance of MoS₂/triethanolamine（TEOA）/eosin（EY）dye-sensitized system and D-S-MoS₂/TEOA/EY dye-sensitized system.The experimental results of photocatalytic hydrogen evolution show that under the same experimental conditions,the optimal hydrogen evolution rate of D-S-MoS₂ synthesized by the low-temperature hydrothermal method is as high as 5.85 mmol h^-1 g^-1,which is much higher than the catalytic performance of MoS₂ synthesized by other reaction time.It shows that D-S-MoS₂ can significantly enhance the photocatalytic hydrogen evolution performance of the corresponding system.3.Construct and optimize the atomic structure model of D-S-MoS₂.Based on the first principle calculation of density functional theory,conduct a theoretical analysis of the electronic structure,Gibbs free energy for hydrogen adsorption,and optical properties of D-S-MoS₂,thereby exploring the reason why D-S-MoS₂ nanosheets have high catalytic hydrogen evolution activity.