Optical, Photocatalytic, Electrochemical, Magnetic, Dielectric, and Ferroelectric Properties of Cd- and Er-Doped BiFeO 3 Prepared via a Facile Microemulsion Route.

A series of Cd- and Er-doped bismuth ferrites were synthesized using a simple microemulsion technique. The influence of Cd and Er doping on the structural, ferroelectric, photocatalytic, and dielectric properties of bismuth ferrite (BFO) was examined in this research. The prepared materials were examined by X-ray diffraction, Raman, scanning electron microscopy, and UV-vis techniques. The XRD patterns reflected the formation of a monophasic rhombohedral structure with the space group R 3 - c and an average crystallite size calculated to be in the range of 29 to 32 nm. The saturation polarization ( P s ), coercivity ( H c ), and retentivity ( P r ) of the materials were investigated by a hysteresis loop (P-E), and it was perceived that increasing the dopant contents improved the P s and P r values, which may be due to the variation of metal cation valence states. In accordance with the photoluminescence (PL) spectra, a highly substituted material displayed lower recombination and increased charge separation rate (e - -h + ), which eventually contributed to a higher photocatalytic degradation performance of the prepared NMs. Furthermore, as the frequency and dopant concentration increased, the dielectric loss decreased, which could be due to different types of polarization. Bi 1 -  x Cd x Fe 1 -  y Er y O 3 showed well-saturated hysteresis loops (P-E) with enhanced saturation polarization near 9.7 × 10 -4 μC·cm -2 . The remnant polarization of the BFO and BFOCE NPs was 2.26 × 10 -4 and 8.11 × 10 -4 μC·cm -2 , respectively, under a maximum electric field, which may be due to the variation of the metal cation valence states. The improved ferroelectric and dielectric properties of Bi 1 -  x Cd x Fe 1 -  y Er y O 3 NPs are attributed to the reduced concentration of defects, the different domain behavior, and the valence state of Cd and Er ions. The electrochemical (crystal violet (CV) and I - V ) properties of Bi 1 -  x Cd x Fe 1 -  y Er y O 3 were all influenced by the dopant concentrations (Cd and Er). The synergistic effects of Cd and Er on the substituted material enhanced the specific capacitance in comparison to undoped BiFeO 3 . The photocatalytic activity to degrade CV under visible irradiation increased in BFOCE as the dopant ( x , y ) concentration increased from 0 to 0.25 by showing 84% dye degradation in comparison to pristine BiFeO 3 (53% only) within 120 min under visible light. Moreover, the stability of these prepared nanoparticles was confirmed using recycling experiments, with the results indicating that the synthesized nanomaterials demonstrated promising stability and reusability.