Research On Design And Structure-property Relationship Of Au-transition Metal Sulfide Heterostructure

Constructing metal-semiconductor heterostructure is one of the effective ways to improve the physicochemical properties of materials.The research on the design,preparation of metal-semiconductor heterostructure,and structure-property relationship,is of great significance to the understanding of the influence of heterostructures on nanomaterials,guiding the design of heterostructure nanoparticles and promoting the development of nanoscience.Transition metal sulfide is an important candidate system in the fields such as catalysis,energy,optics and devices.It is of great scientific significance for the preparation,structure,performance and application of noble metal-transition metal sulfide heterostructure.This paper aims to explore new strategies for the preparation of Au-transition metal sulfide,research the influences of interface structure,morphology and composition on the properties of the products,and the relationship between physicochemical properties and heterostructure.Based on the heterostructure of Au-transition metal sulfide,a series of nanoparticles/nanorods of core-shell,yolk-shell structure with single crystal shell and oligomer-like with single structure were designed and constructed.The specific contents are as follows:1.Three kinds of Au-NiSx heterostructure nanoparticles with different interface structures such as core-shell,yolk shell,and oligomer structure were prepared by solvothermal method.Among these three heterostructures,the core-shell and yolk-shell structure nanoparticles possess single crystal shells,and the oligomer structure also have single crystal structures NiSx nanoparticles.Based on the analysis of the electronic structure of the materials,it is concluded that the introduction of Au NPs causes the charge separation of the nanoparticles,and the core and shell possess different charges respectively.The core-shell structure was formed by seeded growth and the yolk-shell structure was formed by in-situ transformation method combined with Kirkendall effect.To study the influence of interface structure on physicochemical properties of materials,the HER performance of Au-NiSx heterostructure was characterized.Au-NiSx core-shell structure has better performance due to the largest degree of charge separation and the highest electrical conductivity.The interface structure has a significant impact on the performance of heterostructure nanoparticles.Controlling the interface structure can optimize the performance of metal-semiconductor heterostructure nanoparticles.2.Au@NiCo2S4 and Au@CoNi2S4 bimetallic sulfide core-shell heterostructure nanoparticles were prepared seeded growth method.The electronic structure and chemical state of the products were characterized.The introduction of Au particles improved the atomic ratio of Co3+ and Ni3+ in the Au-bimetallic sulfide core-shell structure nanoparticles.To investigate the effects of the component of heterostructures on the properties of materials,the OER catalytic properties of the as-prepared samples were characterized.Owing to better conductivity and higher proportion of Co3+and Ni3+,the catalytic properties of Au@NiCo2S4 and Au@CoNi2S4 core-shell nanoparticles were superior to those of Au@NiS,Au@Co3S4,NiCo2S4,and CoNi2S4 nanoparticles.Due to the metal-semiconductor heterostructure and bimetallic structure,the catalytic performance of Au@NiCo2S4 and Au@CoNi2S4 nanoparticles has an obvious improvement.The physicochemical properties of materials can be enhanced by combining various means,such as the combination of optimized composition and electronic structure.3.Three kinds of Au@NiS core-shell nanorods with different lengths were prepared by solvothermal method.Reaction time,reaction temperature and reaction steps were important to the length of nanorods.In order to study the influence of morphology of heterogeneous components on physicochemical properties of materials,the catalytic properties of HER of the products were tested in both acid and alkaline solution.The best performance was achieved with the shortest length of Au@NiS core-shell nanorods,and the morphology of the components had an important influence on the performance of heterostructure.Regulating the morphology of components is an effective way to improve the physicochemical properties of heterostructures.