Synthesis Of Au-MoS₂ Nanocomposites And Their Photocatalytic Properties Research

To address the quick growing of the world's energy demands and the serious environmental crisis caused by the consumption of fossil fuels,developing the abundantly clean and renewable energy has been attracted considerable interest in worldwide.Solar energy as a clean renewable resource has attracted more and more attention.Conversion solar energy to chemical energy by ustilizing the technique of semicondurtor photocatalysis is one cutting-edge method for solving energy and environmental problems.Efficient photocatalyst requires strong light absorption,weak charge recombination,and fast charge separation and migration.It is highly desirable to develop photocatalysts with high catalytic activities under visible light.In order to improve the photocatalytic efficiency of photocatalysts,researchers have made considerable efforts.Despite many processes have been made,the efforts invested to well fulfil the commercial requirement for photocatalysts have been far less successful in past decades.With the development of nanotechnology,nanostructuring photocatalyst materials is one of the effective means to improve photocatalytic efficiency.The emergence of metal-semiconductor composite nanomaterials has attracted a large number of scholars'attention.Compared with pure semiconductor materials,the nanocomposite photocatalyst has a wider absorption range of light and the formed heterojunction promoted effective charge separation.The properties of nanocomposites are mainly determined by the composition,structure and morphology.The material composition of nanocomposites should be rational designed,and the material morphology should be precisely controlled according to the high photocatalyst.The work of this paper is mainly focusing on the fabrication of metal-semiconductor nanocomposite materials and exploring their application in the field of photocatalytic.The hydrothermal method,seed-growth method and thermal vapor condensation methods has been used to prepare and construct a series of metal-semiconductor nanomaterials with novel structure and excellent performance for photocatalytic.The structure,morphology,composition and photocatalytic properties of the materials were tested and analyzed by characterization instruments.The main research content includes the following several aspects:?1?Three kinds of Au nanoparticles with different particle size were prepared by sodium citrate reduction method.Au@MoS₂ core-shell structure with unique nanostructures was prepared by hydrothermal method.The structure,morphology and optical properties were tested and characterized by XRD,SEM,UV-vis absorption spectrum.The photocatalytic performance was tested by degradation Rhodamine B solution.?2?the Au@MoS₂-CdS composite structure was synthesized by in-situ growth of CdS nanoparticles on the surface of Au@MoS₂ core-shell nanoparticles.The resultant composite structure exhibited higher photocatalytic activity than CdS and Au@MoS₂ Core-Shell structure in experiments for photocatalytic degradation of rhodamine B solution.The degradation mechanism of organic pollutants over the Au@MoS₂-CdS composite structure was further explored.?3?Gold nanorods were prepared by seed growth method.The aspect ratio of gold nanorods was adjusted by adding different amounts of reactants.The optical properties of gold nanorods were studied.The experimental results show that adjusting the aspect ratio of gold nanorods can modulate its SPR wavelength.?4?The hydrothermal method was used to coat the surface of gold nanorods with MoS₂ shells to form AuNRs@MoS₂ core-shell nanoparticles.The AuNRs@MoS₂ core-shell nanoparticles have a wider spectral range and have a stronger absorption of light compared with bare gold nanrods or pure MoS₂.The photocatalytic activity of the AuNRs@MoS₂ core-shell nanoparticles was evaluated by degrading the organic dyes RhB,under visible-light irradiation.