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Controllable Synthesis And Photocatalytic Performance Of Visible-Light-Driven ZnxCd1-xS/RGO Composite Photocatalysts For Hydrogen Production

Posted on:2016-06-11Degree:MasterType:Thesis
Country:ChinaCandidate:A P MaFull Text:PDF
GTID:2321330536450868Subject:Environmental Engineering
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With the increasingly serious environmental pollution and energy crisis,environmental management and developing new energy has become common concern of all mankind and urgent problems.The semiconductor photocatalytic technology has potential ability in solving environmental pollution and energy regeneration.Especially in use of solar energy for heterogeneous photocatalytic degradation of pollutants and decomposition of water into hydrogen technology has attracted wide concern,because solar energy is utilized directly and the system is simple.But more studied potocatalysts such as TiO2 and ZnS are wide bandgap semiconductor materials,and only can be excited by ultraviolet light,which is only 5% among the solar energy.The ratio of visible light is 43%.So the development of visible-light driven high performance photo-catalyst is a breakthrough to realize the industrialization of solar energy photocatalytic technology in solving the environmental pollution and cleaning energy production.The thesis designed and synthesized a 1D/2D structure of ZnxCd1-xS/RGO visible-light composite photocatalyst.The sample was characterized by transmission electron microscope?TEM?,X-ray photoelectron spectroscopy?XPS?,X-ray diffraction?XRD?,UV-Vis absorption spectroscopy?UV-Vis?and PL and the other test methods.Explores the ZnxCd1-xS/RGO composites as visible light catalyst degradation of organic pollutants and hydrogen photolysis aquatic product performanceThe research content and important conclusions of this paper are as follows:1.Controllable synthesis and optical properties of ZnxCd1-xS photocatalystZnxCd1-xS solid solution was successfully synthesized vis a one-step thermal decomposition method by using Zn?DDTC?2 and Cd?DDTC?2 as precursor.The structure,morphology and performance of ZnxCd1-xS solid solution were adjusted by changing the dosage of precursors?Zn:Cd?.The sample was characterized by transmission electron microscope?TEM?,X-ray photoelectron spectroscopy?XPS?,X-ray diffraction?XRD?,UV-Vis absorption spectroscopy?UV-Vis?and PL and the other test methods.The results indicated that the aspect ratio and bandgap energy of the nanocrystals increased with increasing of Zn content.A linear compression in both the a and c axes was observed throughout the range of compositions?from x =0.125 to x =0.875?,consistent with the expectations for Vegard's law behavior.Zn0.5Cd0.5S nanorods with suitable band gap and aspect ratio display the highest photoresponse.The photocurrent density of Zn0.5Cd0.5S is even 25 times as high as that of Zn0.875Cd0.125 S.2.The synthesis and performance of the visible-light driven ZnxCd1-xS/RGOZnxCd1-xS/RGO visible-light composite photocatalyst was synthesized by a thermal decomposition method.The samples were characterized by TEM,XPS,XRD and the other test methods.The ZnxCd1-xS nanorods were evenly dispersed on the graphene observed by TEM.With different content of RGO ZnxCd1-xS/RGO visible-light composite photocatalyst,the research results show that the Zn0.5Cd0.5S/2wt%RGO has the highest photocatalytic activity.With different Zn:Cd ratio of ZnxCd1-xS/2%RGO,the experimental results also shows that photocatalytic effect of Zn0.5Cd0.5S/2wt%RGO is best.And the cyclic experiments of Zn0.5Cd0.5S and Zn0.5Cd0.5S/2wt%RGO shows that Zn0.5Cd0.5S/2wt%RGO has higher stability than Zn0.5Cd0.5S.The 1D/2D structure of Zn0.5Cd0.5S/2wt%RGO visible-light composite photocatalyst has higher stability and catalytic activity than Zn0.5Cd0.5S This is mainly because that the graphene perfect two-dimensional structure and high specific surface area increased the dispersibility and stability of the catalyst.And its excellent conductivity sped up the transfer rate of the electron and improved the separation efficiency of photogenerated electrons and holes paris,thus greatly improve the visible light catalytic efficiency.The results provides an important basis for the development efficiency and visible light response of photocatalyst.
Keywords/Search Tags:visible-light-driven, metal sulfide, solid solution, graphene, 1D/2D composite
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