Rapid sonochemical synthesis of spherical silica nanoparticles derived from brown rice husk

The nanoparticles of silica (SiO₂) were synthesized from brown rice husk via the sonochemical process, during which the sonication time was varied from 0 to 50 min so as to modulate the material properties of the nanoparticles. The synthesized SiO₂ nanoparticles were confirmed to have amorphous natures in their structural characteristics. The mean particle sizes of the nanoparticles were increased from 5 to 40 nm with increasing sonication time from 0 to 50 min, respectively. The SiO₂ nanoparticles synthesized with the sonication time of 50 min showed to possess the highest porosity among our samples. Accordingly, the sample exhibited a higher effective surface area of 271.22 m²g⁻¹. In addition, the bandgap of the SiO₂ nanoparticles was decreased from 5.77 to 5.68 eV with increasing sonication time (i.e., 0 → 50 min). The results suggest that the SiO₂ nanoparticles synthesized with an appropriate control of the sonication time (e.g., 50 min) hold promise for future nano-ecosystem applications such as nano-biosensors and energy storage nano-devices.