Study On The Synthesis Of Inorganic Hollow Nanoparticles By Using CaCO₃ Template

Inorganic nano hollow-strucured materials are new functional materials,which are provided with different geometric structures and different physical and chemical properties from the traditional inorganic nano materials.Inorganic nano hollow materials have extensive potential application in the catalyst,drug delivery,insulation materials,lightweight filler etc.This is because the materials have low density,large specific surface and hollow cavity structure characteristic.Therefore,it becomes the focus of research on all kinds of inorganic nano hollow material preparation and regulation.In this paper nano hollow-strucured particles of TiO2,Al2O3 and ZrO2 are prepared by the template of nano-sized CaCO3 by self-made.The main factors that effects on the inorganic hollow nano material microstructure are investigated.And the prepared inorganic nano hollow particles under the optimal conditions are analysed and characterized by TEM,SEM,XRD,IR,and BET.Moreover,The mechanism of different inorganic nano hollow particle coating is proposed.1)In the ethanol-water system,hollow-strucured TiO2 nanoparticles are prepared by mixing tetrabutyl titanate.The main factors are investigated,The optimum conditions for synthesis of the hollow-strucured Ti02 nanoparticles are as follows:the ratio TBOT/H2O was 1/20,Ca/Ti was 4,the dissolve time was 72h in dilute hydrochloric acid of 0.02mol/L.The characterization results showed that the hollow-strucured TiO2 nanoparticles preparaed under the optimum condition has good agreement with the morphology of the template,the coating is uniform and integrity,the size of hollow nanoparticles is about 80nm,the thickness of shell is 15nm and the small amount CaTiO3 crystalline phase is formed.It is supposed that the mechanism of coating is chemical bonding mechanism.2)Hollow-strucured Al2O3 nanoparticles are prepared by the process of heterogeneous deposition with Aluminum Sulfate as aluminum precursor.The optimal conditions of the reaction are given as follows:10%(mass fraction)of urea was added as precipitant;in the beginning the pH of reaction system was adjusted to 12-13,after reaction finished the pH should adjusted to 8-9;the aging time was 24h;and the dissolve time was 120h in buffer solution of pH=5.The hollow Al2O3 nnoparticles with spherical and uniform are prepared,the size is about 60-70nm,the shell is amorphous.The analysis indicates that the mechanism of coating is degree of supersaturation mechanism.3)Hollow-strucured ZrO2 nanoparticles are obtained by the process of heterogeneous deposition with Zirconium Oxychloride as precursor.By optimizing the conditions,the experimental conditions are as follows:10%(mass fraction)of urea was added as precipitant;the aging time was 24h;and the dissolve time was 120h in buffer solution of pH=4.5.At these conditions,the synthesis of hollow ZrO2 nanoparticles is spherical and uniform,the thickness of the shell is about 15nm and the shell is amorphous,the size is 80nm.According to the analysis,the mechanism of coating is degree of supersaturation mechanism.On the basis of preparation and study on the mechanism of the above three kind of inorganic nano hollow-strucured nanoparticles,it shows that the thinking of the preparation of inorganic nano hollow particles by the template of nano CaCO3 is feasible.