Effection of pH and molar ratio of formaldehyde and urea on preparation of mesoporous SiO2 microspheres with polymerization induced colloidal aggregation method

Mesoporous SiO2 microspheres were prepared via polymerization induced colloidal aggregation (PICA) method. Particle size of the mesoporous microspheres was about 6 μm. Mesoporous microspheres with various surface morphology and pore structure were obtained via varying the pH and molar ratio of formaldehyde/urea in PICA process. While pH = 1.2 and molar ratio of formaldehyde/urea = 3, the obtained mesoporous SiO2 microspheres had the most uniform pore size distribution and the largest specific surface area.