The Synthesis Of Metal-sulfide Composite Materials And The Study Of Their Properties

Energy problem and environmental pollution have become the primary problem in the modeRN human survival and development.Finding more new clean energy and energy storage device is an e:fficient way to solve the problem.Photocatalysis（The core is photocatalyst）has recently attracted enormous research interest due tO its excellent performance in environmental protection.As a new kind of energy storage device,supercapacitor has a lot of excellent advantages such as high energy density,high power density,fast charge/discharge rate,environment-friendly,long cycling time etc.Metal-sulfide nanocomposite is considered as a series of important material because it has important application value in the degradation of heavy metal ions,hydrogen production,supercapacitor,etc.In this paper,we present a series of metal-sulfide nanocomposites preparation and their performance studies,including the following three parts:1.Facile synthesis of the hollow PPy/CdS micro box hetero-structures with improved photoactivity.In this chapter,the hollow PPy/CdS micro box hetero-structures composite was synthesized successfully by in-suit chemical oxidation polymerization of pyrrole,using complex of methyl orange（MO）/（NH4）S₂O8 as a reactive self-degraded soft-template,making the particles on the surface of material by two steps route.The results indicated that PPy/CdS micronbox hetero-structures exhibit the enhanced photocatalytic activity for photocatalytic reduction of Cr（VI）and hydrogen production under visible-light irradiation compared with bare PPy.This is mainly attributed to the hollow structure and the best separation efficiency of the photogenerated electrons-holes by the PPy/CdS heterojunction.2.Facile synthesis of the MoS₂/PANI microflowers with improved electrochemical performanceThe composite of transition metal sulfide and conducting polymer is an attractive material for energy storage because of its unique electronic properties.In this work,a facile hydrothermal route for preparation of a molybdenum disulfide（MoS₂）microflowers/polyaniline（MoS₂/PANI）composite,the surface morphology of the pure MoS₂ was comparatively analyzed by various reaction conditions.The crystal structure and surface morphology of the composite are characterized by SEM,XRD and FT-IR.The electrochemical performances of the pure MoS₂ and the MoS₂/PANI composite electrode materials are evaluated by cyclic voltammogram,galvanostatic charge-discharge and electrochemical impedance spectroscopy.The MoS₂/PANI composite reaches up to 234 F g"1 at a current density of 3 A g-1 and a good rate capability（retention 84.6%at 10 A g-1）.In addition,the MoS₂/PANI composite electrode showed an excellent cycling stability（retention 84%after 500 cycles）.The enhancement in specific capacitance and excellent cyclic stability of the composite electrode is due to the synergetic effect of the pure MoS₂ and PANI.The experimental results demonstrate that the MoS₂/PANI composite is a promising electrode material for potential application in supercapacitor.3.Formation of Ni₃S₄/MoS₂ hetero-nanostructures composite with enhanced electrochemical performanceIn this work,a facile solvothermal route for preparation of a Ni₃S₄/MoS₂ hetero-nanostructures composite,the crystal structure and surface morphology of the composite are characterized by SEM and XRD.The electrochemical performances are evaluated by cyclic voltammogram,galvanostatic charge-discharge and electrochemical impedance spectroscopy.The Ni₃S₄/MoS₂ hetero-nanostructures composite reaches up to 1724 F g-1 at a current density of 2 A g-1.In addition,the Ni₃S₄/MoS₂ hetero-nanostructures composite electrode showed an excellent cycling stability（retention 80%after 500 cycles）.The enhancement in specific capacitance and excellent cyclic stability of the composite electrode is due to the synergetic effect of the Ni₃S₄ and MoS₂.The experimental results demonstrate that the Ni₃S₄/MoS₂ hetero-nanostructures composite is a promising electrode material for potential application in supercapacitor.