Preparation and characterisation of N-doped SiO 2 at TiO 2 core–shell structural materials and its photocatalytic property

Abstract

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 Stober 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.