Synthesis method for silica needle-shaped nano-hollow structure

Silica needle-shaped nano-hollow structure with high specific surface area was prepared by a sol-gel approach using needle-shaped calcium carbonate (CaCO₃) nanoparticles as novel template and sodium silicate as the silica source, followed by washing in acidic solution to remove the CaCO₃ sacrificial template. The sample was characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and BET. The results show that regular uniform silica nano-hollow tubes are obtained: the length of the hollow tubes ranges from 200 nm to 300 nm with a inside diameter about 20 nm, the thickness of the tubes is around 10 nm, the specific surface area of the sample is up to 321.4 m²/g, the average pore diameter is 63.83 Å and the total pore volume is 0.5128 cm³/g.