Studies On The Preparation Of Nanometer Tin Dioxide Particles

Nanometer material is a new multifunction stuff developed lately, the special performances of nanometer material make it better than common material in magnetism, catalysis, light absorbability and heat blocking. Nanometer tin dioxide is a typical n type semiconductor material. it has many characteristics, such as higher specific surface area, higher activeness, lower melting point, better thermal conduction. It is used widely in gas sensing, wet sensing, optics technology, electricity conduction and so on, moreover it is an important chemical industrial material.The uniformity nanometer-size SnO₂ particles were prepared by sol-gel method, with tin tetra-chlorine as the main starting material. The method had simple equipment, easily controlled process, low cost, high productivity. The influences of preparation technics were seen about including concentration of raw material, temperature of reaction, the pH of termination, manner of drying, temperature of calcination. In the process of experiment IR and thermal analysis were used to analyse changes of the hydrous cassiterite during being heated, chemical bonds on the surface of hydrous cassiterite and the mechanism of antiaggregation. TEM, XRD, BET were used to characterize the final particle shape and size distribution, phase and so on.The corresponding antiaggregation methods were introduced aiming at the problem of Aggregation in liquid preparation of nanometer tin dioxide. Two measures were adopted to dehydrate afterward, one was that the wet gelatin was washed by grain alcohol, the other was that azeotropic distillation was used to dehydrate freely water. The equipment of azeotropic distillation was built up. The result of azeotropic distillation showed the effect of antiaggregation was better. The mechanism of antiaggregation of two dehydration was pilot studied. The result of IR showed organism radicle come into being using azeotropic distillation, It had separate domino offect which can reach antiaggreation.The results showed the specific surface area of particles was 28.72 m²/g under following conditions: SnCl₄ as 0.2mol/L, NH₃ · H₂O as 8¹0 percent, 2.5 as the final pH, reaction temperature 65℃, calcination temperature 500℃ for 3h. The specific surface area of particles...