Synthesis and visible-light photocatalysis capability of BiFeO3–(Na0.5Bi0.5)TiO3 nanopowders by a sol–gel method

Multiferroic BiFeO3–(Na0.5Bi0.5)TiO3 (BFO–NBT) nanopowders were successfully synthesized by a sol–gel method, and the visible-light photocatalytic and magnetic properties of BFO–NBT nanopowders were investigated. X-ray diffraction results indicated that the adding of NBT and the excess of natrium source could suppress the formation of secondary phases and made it easier to obtain single perovskite phase. High photoactivity of this catalyst for Rhodamine B (RhB) degradation under visible-light irradiation was detected, which is due to narrow band gap energy of 2.08 eV, higher surface area and pure phase compounds with no or less amounts of impurities. The BFO–NBT nanopowders showed a weak ferromagnetic order at room temperature, which should be attributed to the size-confinement effects of the nanostructures. It is suggested that BFO–NBT is a kind of new narrow band gap semiconductor visible-light photocatalyst with broad application prospects, in addition to potential applications for novel magnetoelectric devices.

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► Perovskite-type BFO–NBT nanopowders were synthesized by a sol–gel method.
► NBT and the excess of sodium source could suppress the secondary phases.
► BFO–NBT nanopowders showed excellent visible-light photocatalytic properties.
► Ferromagnetic order was detected indicating potential magnetoelectric applications.