Preparation And Properties Of Photocatalytic Materials Based On Inorganic Hollow Microspheres

The hollow nano-microspheres have relatively high specific surface area and relatively stable three-dimensional spatial structure.The cavity and spherical shell have many advantages such as reaction binding sites,which are of high research value in catalysis,capacitors,drug carriers and micro reactors.Using hollow microspheres to improve the catalytic effect of materials especially the photocatalytic effect has a broad prospect of research.The monodisperse zinc oxide?ZnO?,yttrium oxide?Y₂O₃?and cerium oxide?CeO2?micro/nano hollow spheres were prepared by hydrothermal method.The hollow ball was prepared by the formwork method and the non-formwork method,and the forming process of the hollow structure was studied.In addition,the performance of photocatalytic degradation of methylene blue and rhodamine B by hollow spheres was investigated as follows:1?Using glucose as raw material to the preparation of carbon ball template,prepared by hydrothermal method out of the hollow structure of ZnO hollow ball,the optimal preparation process as follows:0.25 g Zn?NO₃?₂·6H₂O,preparation of the carbon ball template 1 g,0.2 g PVP,dicating 5 h,180 water samples were 800 calcined 2 hours of hollow ball,the ball about 1 micron in diameter,spherical shell thickness of 50 nm,spherical shell is composed of numerous ZnO grain accumulation,porous surface and aperture more concentrated in 3 to 5 nm.The hollow microspheres showed good performance in photocatalytic degradation of methylene blue.The fuel could be degraded completely in about 90minutes,and the ZnO without hollow structure prepared under the same conditions showed better catalytic effect.2?The hollow Y₂O₃ nano-spheres were prepared by hydrothermal method,which adopts the template-free method.The optimal reactant is Y?NO₃?₃·6H2O with 0.2 g dosage,urea with 0.72g dosage,and 70 ml ethanol aqueous solution.PVP dosage is 0.2 g,the reaction temperature is180 oC,response time is 12 h calcination temperature is 900 ^oC preparation of Y₂O₃ hollow ball,size is relatively uniform,good monodispersity and ball diameter of about 200 nm,spherical shell thickness of about 20 nm surface of spherical shell with a large number of mesoporous crack and pore size on 30 nm,of which 5 nm and 15 nm size of the hole,the most specific surface area of the materials for 27.706 m²g^-13?The hollow CeO₂ nano-spheres were prepared by hydrothermal method,we do not use high temperature calcination reaction,the optimum preparation of reactant dosage is:0.3 g seven hydrated cerium chloride?CeCl₃·7 H₂O?,0.534 g PVP,57 mL deionized water,3 mL formamide and 0.3 mL hydrogen peroxide?H₂O₂?,180?within 24hours of preparation of hollow structure CeO₂ nano ball,ball uniform,monodisperse performance is good Sphere at about 200 nm in diameter,surface uniform spherical shells and spherical shells with large diameter about 5 n in mesoporousIn addition,the photocatalytic activity of powdered CeO₂ was superior to that of commercially available powdery CeO₂,and the highest activity could be increased by twice within the same time.Meanwhile,the degradation effect of powder was finally lower than 70%,while the hollow microsphere was up to 90%...