Study On Alcohol Directed Synthesis Of Thermostable Ordered Nanostructured Zirconia

The thermostable of the ordered lamellar nanostructured crystalline zirconia was synthesized by reflux-mixed solvothermal（R-MST）hybrid method with ZrOCl₂·8H₂O as zirconium source,sodium hydroxide as precipitating agent,isopropanol as supermolecular template.The thermostable ordered lamellar nanostructured zirconia was characterized by XRD,SEM and TEM.Firstly,the experimental results show that a mixed cubic phase and monoclinic phase of ordered lamellar nanostructured crystalline zirconia was obtained from R-MST,only a mixed cubic phase and monoclinic phase of zirconia was obtained from mixed solvothermal method（MST）,and amorphous zirconia was obtained from reflux method（R）.Moreover,degree of crystallinity of zirconia decreased from MST to R-MST to R.R-MST well promoted the zirconia nucleation,controlled 2-D growth and ordered self-assembly induced by isopropanol supermolecular template.By comparison,isopropanol and ethanol have the similar supermolecular template roles.The preparation of samples was placed in the muffle furnace 2 h under 500℃calcination in air,and the samples were characterized before and after calcination,and the results showed that study on isopropanol directed synthesis of ordered lamellar nanostructured zirconia have the good hierarchical thermostabilities from the crystal structure to an ordered lamellar nanostructure.Secondly,we use to establish structural model based on density functional DMol3package in Materials Studio simulation software,the synthesis of ordered lamellar nanostructures crystalline zirconia structure is optimized by density functional theory calculations.In the process of isopropanol template directed synthesis of thermostable ordered lamellar nanostructured zirconia,zirconia and isopropanol molecule by molecule Zr-O coordination bond can form a stable complex,and formed a bond with a bond length of 2.39?,bond energy of 25.5 kcal/mol.Thus isopropanol template directed synthesis of thermostable ordered lamellar nanostructured zirconia has a very effective template guide.Calculated by isopropanol template molecule and the（100）,（110）and（111）crystal plane of zirconium oxide crystal lattice formed different layer structures,the isopropanol molecule and the（111）crystal plane of zirconium oxide crystal lattice formed layer structure has the lowest energy,and the layer structure is the most stable,so it can be obtained a stable plane from the（111）crystal plane of zirconium oxide crystal lattice.Finally,by the Gibbs free energy of nucleation theory,we successfully explained the role of isopropanol template and the synthesis mechanism of isopropanol directed synthesis of thermostable ordered lamellar nanostructured zirconia from the thermodynamic.