The Preparation And Synergistic Photocatalytic Performances Of Long Aftergrow Phosphor Couple With Semiconductor Nanocrystallines

With the development of economy,energy shortage and environmental pollution are becoming more and more serious.Semiconductor photocatalyst has been widely used in the fields of degrading pollutants,waste water,and exhaust gas.The use of semiconductor photocatalysts can directly convert light energy into chemical energy to degrade organic pollutants,and it will not cause secondary pollution,which has aroused the interest of scientists.However,for most semiconductor photocatalysts,narrow range of visible light absorption and high recombination rates of photogenerated electrons and holes,giving rise to low quantum efficiency.In addition,the photocatalytic reaction cannot be performed in the absence of illumination.These defects seriously restrict the practical application of photocatalysis.In order to solve the above problems,on the one hand,the absorption range of visible light is amplified by using gold nanoparticle modified semiconductor.On the other hand,the modified photocatalysts were composited with the long afterglow material.Through the synergistic effect of the light-storing photocatalyst,the preparation of a photoactive photocatalyst that can be self-degraded without light irradation,and then the ability to degrade organic pollutants are explored in the dark.?1?SrAl₂O₄:Eu²⁺,Dy³⁺/TiO₂@Au light-storing photocatalyst:Au nanoparticles was synthesized by standard citric acid reduction method,TiO₂@Au with core-shell structure was formed by a simple acetone bath method after that the light-storing photocatalyst was prepared by the in-situ synthesis method.The crystal phase composition,elemental analysis,morphology,structure,light absorption and degradation performance activity of the composite light-storing photocatalyst were characterized by XRD,XPS,FE-SEM,TEM,UV-Vis DRS.The experimental results show that spherical TiO₂ with coexistence of two phases can be obtained at 600 ^oC and the coexistence of sharp ore and rutile phase not only has high catalytic performance but also has good stability.The visible absorption peak of the diffuse reflectance spectra firstly increases and then decreases with the increasing doping amount of Au nanoparticles.The maximum overlap between the emission peak of Sr Al₂O₄:Eu²⁺,Dy³⁺and the absorption spectrum of TiO₂@Au when the optimal doping concentration is 0.24 wt%.The degradation performance was improved 5times not only in visible light but also in the dark under the conditions of 10 minutes light and 1 hour darkness.The results show that the optical energy of Sr Al₂O₄:Eu²⁺,Dy³⁺is absorbed by TiO₂@Au.The main degradation active material is hydroxyl radical,and the photocatalytic performance were reised by the plasma resonance effect of nano-gold in this work.?2?SrAl₂O₄:Eu²⁺,Dy³⁺/g-C₃N₄@Au light-storing photocatalysts:Graphite Phase C₃N₄ was obtained by calcining urea under the condition of 550 ^oC,g-C₃N₄@Au was formed by citric acid.Finally,light-storing photocatalysts were adopted mechanical ball milling and calcination under argon gas protection.The phase composition,elemental analysis,morphology,structure and absorbency of light-storing photocatalysts were characterized by XRD,XPS,FE-SEM,TEM and UV-Vis DRS.The photoelectric performance and the photocatalytic degradation properties were also tested.The experimental results show that the photocurrent response and the absorption peak in the diffuse reflectance spectra diffuse reflection firstly increases and then decreases,the maximum doping concentration of Nano Au is 0.6 wt%,and the maximum overlap between the emission peak of SrAl₂O₄:Eu²⁺,Dy³⁺and the absorption spectrum of g-C₃N₄@Au have been formed.The efficiency of photocatalytic degradation of RhB is improved under 10 minutes light and 3 hours darkness,The experiments alternate 4 times showed that the degradation was complete finished,while pure g-C₃N₄ and g-C₃N₄@Au had no degradation in darkness.The mechanism is same as SrAl₂O₄:Eu²⁺,Dy³⁺/TiO₂@Au.?3?SrAl₂O₄:Eu²⁺,Dy³⁺/Bi₂MoO₆@Au light-storing photocatalyst:Bi₂Mo O₆ was prepared by hydrothermal method and then Bi₂Mo O₆@Au was synthesized by standard citric acid reduction method.Light-storing photocatalysts were adopted mechanical ball milling and calcination under argon gas protection.The crystallinity,surface morphology,optical absorption,fluorescence and photoelectrochemical properties of the materials were investigated by XRD,UV-Vis DRS,fluorescence spectroscopy,XPS and photocurrent densities.The experimental results show that the largest visible light absorption,the highest photocurrent response,the maximum overlap between the emission peak of SrAl₂O₄:Eu²⁺,Dy³⁺and the absorption spectrum of Bi₂Mo O₆@Au when the optimal doping concentration is 0.9 wt%.Bi₂Mo O₆@Au uniform load on the surface of Long afterglow by FE-SEM,the XRD results validate this fact.The Photocatalysis degradation reaction was enhanced in light and darkness,and the main active ions were cavities,the hydroxyl radicals and superoxide radicals react alternately.Repeating four times showed that the photocatalytic stabilizers can be reused.This novel efficient light-storing photocatalyst through the nano gold plasmon resonance effect and the bridge between Long afterglow and the semiconductor photocatalyst,the excitation energy activity?electronic?can be transfer to Bi₂Mo O₆ catalyst,achieve the goal of photocatalytic degradation of organic pollutants under the condition of the dark.