Enhanced Photocatalytic Activity in Bi1-xBaxFeO3 Prepared by a PEG400 Assisted Sol–Gel Method

Ferroelectric Bi1-xBaxFeO3 nanoparticles for x = 0, 0.01, 0.03, 0.05 and 0.10 were synthesized by a polyethylene glycol 400 (PEG400) assisted sol–gel method. X-ray diffraction reveals that Bi1-xBaxFeO3 nanoparticles exhibit a distorted rhombohedral structure with the R3c space group, and the diffraction peaks shift upon incorporation of Ba. Transmission electron microscope analysis shows that the particle size of Bi1-xBaxFeO3 nanoparticles is in the range of 30–60 nm, decreasing with an increase in Ba content. Bi1-xBaxFeO3 nanoparticles have band gaps in the range of 1.68–2.0 eV, which are capable of responding to visible light irradiation. The rate of the photocatalytic degradation of Bi1-xBaxFeO3 nanoparticles for x = 0.03 to methyl orange (MO) dye achieves about 81% under visible light irradiation for 3 h, which is higher than that of 66% for pure phase BiFeO3 (BFO). Moreover, the effects of Ba2+ modification on the band gap of BFO crystallites have been investigated and discussed.