Preparation and characterisation of N-doped SiO2 at TiO2 core-shell structural materials and its photocatalytic property

N-doped SiO₂ at TiO₂ core-shell structural materials has been synthesised successfully via a simple two-step method. First, SiO₂ spheres were obtained by using a slightly modified Stöber process. Then, N-doped SiO₂ at TiO₂ were prepared via coating SiO₂ template with TiO₂ layers, followed by N-doping using NH₄NO₃ as the N source. According to Kato et al. the as-obtained products were well characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis absorption spectra. The photocatalytic activity of the as-prepared products was evaluated by photocatalytic decolourisation of rhodamine B aqueous solution at ambient temperature under UV and visible-light irradiation. The experimental results showed that the diameter of N-doped SiO₂ at TiO₂ spheres was about 250 nm and the thickness of the TiO₂ shell was 10-20 nm, the products exhibited a high photocatalytic activity because N atoms were incorporated into the titanium dioxide planes to decrease the bandgap energy.