Enhanced photocatalytic activity of Bi4Ti3O12 nanosheets by Fe3+-doping and the addition of Au nanoparticles: photodegradation of phenol and bisphenol A

Pure Bi4Ti3O12 (BTO) and Fe-doped Bi4Ti3O12 (Fe/BTO) nanosheets with exposed {001} facets were synthesized by a one-step molten salt method. Au nanoparticles with a diameter range of 20–50 nm were loaded on 2%Fe-doped Bi4Ti3O12 (Au-2%Fe/BTO) nanosheets via a room-temperature hydrogen peroxide reduction method. The UV–vis diffuse reflectance spectra showed that the Fe/BTO and Au-2%Fe/BTO samples exhibit an obvious red shift in visible light absorption band in comparison with the pure BTO. Phenol and bisphenol A solutions were chosen as model organic pollutants to verify the influence of Fe3+-doping and plasmonic effect of Au nanoparticles on the photocatalytic activity of the catalyst. The Au-2%Fe/BTO sample exhibited the highest photocatalytic activity compared with other samples. The high photocatalytic activity of Au-2%Fe/BTO rises from two contributions: i) the Fe3+ ion acts as an efficient scavenger to trap electrons, and hence promotes the separation of photo-induced electron-hole pairs; ii) the visible light response of the catalyst is enhanced by the surface plasmon resonance effect from the Au nanoparticles.