The Preparation And Photocatalytic Performances Of The Up-conversion Materials Pr³⁺:Y₂SiO₅/semiconductor Catalysts

In order to solve the problem of low photocatalytic efficiency of semiconductor photocatalyst,this paper study the composites of using the conversion materials Pr3+:Y2SiO5 to modify of TiO2 and ZnO.The composite catalyst of Pr3+:Y2SiO5/TiO2 and Pr3+:Y2SiO5/ZnO was preparation by Sol-Gol method and water fluid method,and determine the best reaction conditions and the best technological process.We degrade the simulate wastewater of nitrobenzene solution under visible light to evaluate the photocatalytic activity of these composites.(1)The transformation materials Pr3+:Y2SiO5 were prepared by sol-gel method and hydrothermal method,and the effects of adding surfactant on Pr3+:Y2SiO5 crystal growth and micromorphology were studied in the hydrothermal method.The samples were characterized by XRD,SEM,EDS and Fluorescence Spectrum,it is concluded that the hydrothermal preparation of Pr3+:Y2SiO5 material has better transformation on the luminescence properties,and PVP and CTAB as surfactant added,the shape of the sample is changed to a smaller microsphere with a uniformly dispersed particle size.(2)The composite catalyst of Pr3+:Y2SiO5/TiO2 were prepared by sol-gel method and hydrothermal method,The composite materials prepared by hydrothermal method are better than sol-gel method though the characterization and analysis,Pr3+:Y2SiO5 and TiO2 have been successfully combined,and some TiO2 crystals are transformed from ruiti to rutile;15%doped compound catalyst Pr3+:Y2SiO5/TiO2 degradation of 15mg/L nitrobenzene in weak acid solution has the best catalytic performance,after 6h the optimum catalytic performance can reach up to 96%in visible light of 140W,and the four times after using still can reach 82%,the degradation process concides the pseudo-first order reaction,through the study on reaction of TOC removal at the same time,the solution in the process of nitrobenzene removal rate is identical with the change of total C.(3)The composite catalyst of Pr3+:Y-SiO5/ZnO and ZnO were prepared by sol-gel method and hydrothermal method,through characterization analysis using weak base source preparation of ZnO is better,the hydrothermal preparation of composite materials is better than that of sol-gel method,the cross-coated nuclear shell structures of Compound materials can be prepared by adding surfactant;In the neutral solution environment 10%doped compound catalyst has the best catalytic performance of 98.9%to degradated 15mg/L nitrobenzene exposed in the visible light of 105W,and the four times after using still can reach 82%,the degradation process concides the pseudo-first order reaction;Contrast the TOC,liquid chromatography and ultraviolet spectrophotometry analysis result,the change of total C in the reaction process is consistent with the removal rate of nitrobenzene,In the end,the nitrobenzene can be completely converted into CO2 and H20.