$BiFeO3/TiO2$ core-shell structured nanocomposites as visible-active photocatalysts and their optical response mechanism

Anatase titania-coated bismuth ferrite nanocomposites $(BiFeO3/TiO2)$ have been fabricated via a hydrothermal approach combined with a hydrolysis precipitation processing. Analysis of the microstructure and phase composition reveals that a core-shell $BiFeO3/TiO2$ structure can be formed, which results in a significant redshift in the UV-vis absorption spectra as compared to a simple mechanical mixture of $BiFeO3–TiO2$ nanopowders. The core-shell structured $BiFeO3/TiO2$ nanocomposites exhibit higher photocatalytic activity for photodegradation of Congo red under visible-light $(λ>400nm)$ irradiation, which should be attributed to the enhancement of the quantum efficiency by separating the electrons and holes effectively. The obtained $BiFeO3/TiO2$ nanocomposites can be used as potential visible-light driven photocatalysts.