  In this paper, the photocatalytic activity of multiferroics BiFeO3 (BFO) and
Bi0.8La0.2FeO3 (BLFO) nanocrystals with two different morphologies which were
synthesized by two different sol-gel (SG) and hydrothermal (HT) methods have
been studied. All the obtained samples were characterized using X-ray
diffractometer, Fourier transform infrared spectroscopy, transmission electron
microscopy, UV-vis spectroscopy and vibrating sample magnetometer. Differential
thermal analysis (DTA) measurements were probed ferroelectric- paraelectric
first-order phase transition (TC) for all samples. Addition of lanthanum
decreases the electric phase transition. For photocatalyst application of
bismuth ferrite, adsorption potential of nanoparticles for methylene blue (MB)
organic dye was evaluated. The doping of La in the BFO structure enhanced the
photocatalytic activity and about 71% degradation of MB dye was obtained under
visible irradiation. The magnetic and ferroelectric properties of BLFO
nanoparticles improve compared to the undoped BiFeO3 nanoparticles. The
non-saturation at high applied magnetic field for as-prepared samples by HT is
related to the size and shape of products. This work not only presents an
effect of lanthanum substitution into the bismuth ferrite structure on the
physical properties of BFO, but also compares the synthesis method and its
influence on the photocatalytic activity and multiferroics properties of all
nanopowders.
