Investigation Of The Preparation Of Inorganic-oxide Hollow Spheres And Functionalization Through Melamine-formaldehyde(MF) Template Method

Inorganic oxide functional materials have been widely used in many fields,such as photocatalysis,supercapacitors,drug delivery and fluorescent materials.It is very important to improve the properties of inorganic oxide materials through constructing inorganic oxide as a hollow sphere structure with low density and high specific surface area.At present,all kinds of inorganic oxide hollow spheres have been widely applied in the many fields such as photocatalyst,battery electrodes,gas sensors and other related fields.Due to its limitations of internal energy band or crystal structure,single elementinorganic oxide hollow spheres such as TiO₂,NiO cannot achieve the ideal performance,but elements doping inorganic oxide hollow spheres can enhance the correlation properties even extend its application in other fields.Rare earth elements have excellent optical,electrical and magnetic properties due to their special electronic orbital structure.Rare earth doped inorganic oxide hollow spheres with better properties were prepared via some methods.In this paper,yttrium?Y?and ytterbium?Yb?-doped TiO₂ hollow spheres were prepared by sol-gel template method.Gadolinium?Gd?and yttrium?Y?-doped NiO hollow spheres were prepared by homogeneous precipitation template method.Samples were characterized by Fourier transform infrared spectroscopy?FT-IR?,X ray diffraction?XRD?,UV-Vis diffuse reflectance?UV-DRS?analysis,luminescence spectroscopy?PL?,X-ray photoelectron spectroscopy?XPS?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?.In the some time,researchthe electrochemical performance of?Gd,Y?doped NiO hollow spheres and visible light photocatalytic degradation of organic dye performance of?Y,Yb?doped TiO₂ hollow spheres.The main research results are as follows:Melamine formaldehyde?MF?microspheres were prepared via precipitation polymerization with Formaldehyde Solution and melamine as raw materials.By Using MF microspheres as template,tetrabutyl titanate?TBOT?,Y?NO?₃ solution as raw material.Prepared the TiO₂ hollow spheres?TiO₂HS?and Y doped TiO₂ hollow spheres?Y-TiO₂HS?through sol-gel template method and subsequent calcination process?calcination temperature 500^oC?,The photocatalytic activities of TiO₂HS and Y-TiO₂ with difference Y doped mole ratios?Y:Ti=1%,1.5%,2%Y-TiO₂HS?were estimated by the degradation process of dye methyl orange?MO?under irradiation of visible light??>450 nm?,results show that the degradation effect of Y-TiO₂HS>TiO₂HS>P25,With H₂O₂ and 1%Y-TiO₂HS as promoter and photocatalyst,respectively,the degradation ratio of MO achieved a maximum?70%?after irradiation for 5 h.While excessive Yb-doping resulted in negative effect on photocatalysis.By Using MF microspheres as template,TBOT,Yb?NO?₃ solution as raw material.Prepared the Yb doped TiO₂ hollow spheres?Yb-Ti O₂HS?through the sol-gel template method and subsequent calcination process?calcination temperature500 ^oC?.The photocatalytic activities of Yb-TiO₂HS with difference Yb doped mole ratios?Yb:Ti=0.5%,1%,1.5%?were estimated by the degradation process of dye methyl orange?MO?under irradiation of visible light??>450 nm?,results show that with H₂O₂ and 1%Yb-TiO₂HS as promoter and photocatalyst,respectively,the degradation ratio of MO achieved a maximum?89%?after irradiation for 5 h and the photocatalysis ability of Yb-Ti O₂HS were better the Yb-TiO₂HS.While excessive Yb-doping resulted in negative effect on photocatalysis.On the other hands,based on the crystal structure,band energy structure and morphology of Yb-TiO₂HS,the visible light photocatalytic enhancement mechanism and reaction process of rare earth doped TiO₂ hollow spheres were studied in the paper.By using MF microspheres as template,NiCl₂·6H₂O,Gd?NO?₃ solution as raw material and urea as the precipitating agent.Prepared NiO hollow spheres?Ni OHS?and gadolinium?Gd?doped Ni O hollow spheres?Gd-NiOHS?through homogeneous precipitation method and subsequent calcination process template?calcination temperature 500^oC?,used cyclic voltammetry?CV?,constant current charge discharge test?GCD?and AC impedance test?EIS?electrochemical test methods characterized the electrochemical performance of NiOHS,Gd-NiOHS and NiO powders,the results of CV shown that in the 5 m V/s scan rate,capacity of NiOHS was 130 F/g,higher than 79 F/g of NiO powder.Subsequently,NiO hollow spheres of different doped mole amount of Gd?Gd:Ni=1%,2%,4%,6%Gd-NiOHS?for electrochemical test,the results of CV shown that 4%Gd-NiOHS in 5 mV/s scan rate can achieved the maximum capacity of 260.04 F/g,the GCD test can also be obtained in charge discharge current density of 0.5 A/g,the capacity of 4%Gd-NiOHS was 111.11 F/g,and the 1000 charge/discharge cycles after the capacitance retention rate was 75%.By using MF microspheres as template,NiCl₂·6H₂O,Y?NO?₃ solution as raw material and urea as the precipitating agent.Prepared yttrium?Y?doped Ni O hollow spheres?Y-NiOHS?through homogeneous precipitation method and subsequent calcination process template?calcination temperature 500 ^oC?,used cyclic voltammetry?CV?,constant current charge discharge test?GCD?and AC impedance test?EIS?electrochemical test methods characterized the electrochemical performance of Y-NiOHS with difference Y doped mole ratios?Y:Ni=0.3%,0.5%,1%Y-NiOHS?,the results of CV shown that 0.5%Y-NiOHS in 5mV/s scan rate can achieved the maximum capacity of 320.92 F/g,the GCD test can also be obtained in charge discharge current density of 0.5 A/g,the capacity of 0.5%Y-Ni OHS was 226.2 F/g,and the 1000 charge/discharge cycles after the capacitance retention rate was 85%.The electrochemical performance of 0.5%Y-NiOHS were better than NiOHS and4%Gd-NiOHS.