Hydrothermal synthesis of nanostructures Bi12TiO20 and their photocatalytic activity on acid orange 7 under visible light

Bismuth titanate (Bi12TiO20) nanostructures with different morphologies were synthesized hydrothermally using Bi(NO3)3 and Ti(SO4)2 in the presence of polyethylene glycol (PEG). X-ray diffraction (XRD) proved that the samples were in pure cubic phase. UV–visible diffuse reflection spectra showed the band gap of Bi12TiO20 is about 2.7 eV. Brunauer–Emmett–Teller (BET) analysis proved that the Bi12TiO20 samples have higher surface areas than samples prepared by methods reported previously. Photocatalytic degradation of acid orange 7 (AO7) under visible light illumination was used to evaluate the photocatalytic ability of samples. The photocatalytic results showed Bi12TiO20 could degrade AO7 very efficiently and had higher photocatalytic activity than traditional N-doped TiO2. In addition, we have also discussed factors that have major effect on reaction efficiency. BET surface area played the most important role in the photocatalytic degradation of AO7. The crystallinity of the samples is another important factor which can also influence photocatalysis results.