Preparation of SiO_2 Microspheres by Two-step Catalytic Sol-Gel Method

Micrometer SiO2 microspheres were prepared by two-step catalytic Sol-Gel method with tetraethoxysi-lane(TEOS) as starting material and N,N-Dimethylformamide(DMF) as template.The effects of some factors on the diameter and particle size distribution of the SiO2 microspheres were discussed,such as H2O quantity and etha-nol quantity during the first catalytic process,the electrolyte concentration and stirring speed during the secondary catalytic process.SiO2 microspheres were characterized by SEM,Zetasizer,BET measurements and micro-scope-particle image analysis system.Results show that SiO2 microspheres are mostly regular-ball with no particle agglomeration.The mean particle size(D50) is 8.9μm,and the particle size distribution follows typical Gaussian distribution.The specific surface area is 546.67m2/g,and pore volume is 0.7142m3/g,with a narrow pore size varied from 2nm to 8nm.Also the particle size increases with water quantity,ethanol quantity and NaCl concentration in-creaing,but decreases with stirring speed acceleration.