Rapid and high yield synthesis of hollow silica nanoparticles using an NH4F catalyst

- Rapid and high-yield process for hollow silica nanoparticles was developed using NH4OH catalysis.
- TEOS consumption of NH4F reached 100% within 15 min and uniform hollow particles were obtained.
- F− improves hydrolysis and condensation of TEOS and NH4+ is proper for silica coating on CaCO3.