Designing Synthesis And Photocatalytic Performance Analysis Of Hollow Copper Oxides And Copper Sulfides

Photocatalytic oxidation technology can be used to treat toxic,harmful and hard-degradable pollutants in waste water as a green,efficient and convenient scientific and technological method,which has attracted much attention of many researchers.Hollow micro-nanomaterials can provide much more inner space due to a large number of pore structures in their interior,which make them have a larger specific surface area and a smaller skeleton density,leading more and more people to studying their applications in the field of photocatalysis.Cu₂O has the characteristics of low preparation cost,non-toxicity and shape-controlled morphology.It can be used as a sacrificial template to synthesize the target product with controllable morphology,and the hollow structures can be easily obtained by using ammonia or acid solution to remove Cu₂O cores.In this thesis,the Cu₂O microcrystals with different morphologies were prepared by hydrothermal synthesis method,and the Cu₂O microcrystals with 14-pods morphology were used as sacrifice templates to synthesize the hollow micro/nano-structure Cu₇S₄ with 14-pods morphology.The suitable preparation conditions were discovered via experiments.The photocatalytic performance and the reaction mechanism of hollow micro/nano-structure Cu₇S₄catalysts were investigated.At the same time,the Cu₂O-CuO composite micro-frameworks with14-pods morphology were synthesized,and the light absorption performance was characterized by solid UV-vis.The main results are summarized as follows:1.In hydrothermal conditions,using Cu?Ac?₂ as the copper source,EDTANa₂ as both reducing agent and surfactant,the Cu₂O microcrystals with 8-pods morphology,14-pods morphology and 6-pods morphology with particle size of about 5?m were prepared by adjusting the ratio of n-butanol to water in the reaction solvent.2.Hollow micro/nano-structure Cu₇S₄ crystals with 14-pods morphology were synthesized by using the 14-pods morphology of Cu₂O microcrystals as the template.Combining experimental data with the characterizations of XRD and SEM,the appropriate reaction time was20 min,the reaction temperature was 35?,and the dosage of 2 M Na₂S?aq?was 1.0 mL.The photocatalytic activity of 14-pods hollow micro/nano Cu₇S₄ crystals was investigated by degradation of methylene blue?MB?solution with visible light.With irradiation for 120 min,the degradation rate of MB solution without catalyst was 28.9%,the degradation rate of MB solution with the catalyst of 14-branch morphology Cu₇S₄ with smooth surface was 94.3%,and the degradation rate of MB solution with 14-branch morphology of Cu₇S₄ covering with naosheet layered structures reached 98.6%,almost all the MB solution was degraded.It proved that the hollow Cu₇S₄ particles with 14-pods morphology had good catalytic activity,and the photocatalytic performance of Cu₇S₄ particles covering with nano-sheet layered structure was better than that of Cu₇S₄ particles with smooth surface.The photoluminescence?PL?and electrochemical impedance?EIS?were tested and the photocatalytic mechanism of Cu₇S₄ was discussed.3.The Cu₂O-CuO composite micro-frameworks were synthesized by using the Cu₂O microcrystals with 14-pods morphology as templates.Combining experimental data with the characterizations of XRD and SEM,the appropriate reaction time was determined to be 12 h,the reaction temperature was 150?,and the concentration of NaOH?aq?was 0.05 mol/L and 0.10mol/L.According to characterization of solid UV,the synthesized Cu₂O-CuO composite micro-frameworks had absorption in visible region and had potential to be good photocatalytic material.