Spatially selective visible light photocatalytic activity of TiO2/BiFeO3 heterostructures

Heterostructures of thin titania films on BiFeO3 substrates were grown by pulsed laser deposition. The heterostructures, when excited by visible light with energies between 2.53 and 2.70 eV, photochemically reduce aqueous silver cations from solution in patterns that mimic the structure of the ferroelectric domains in the substrate. Under the same conditions, titania by itself reduces insignificant amounts of silver. The observations indicate that electrons generated in the substrate are influenced by dipolar fields in the ferroelectric domains and transported through the titania film to reduce silver on the surface.