Optical, Dielectric, Magnetic, Photocatalytic, and Antibacterial Properties of Ga-Doped BiGaxFe1-xO3 Synthesized by the Microemulsion Approach.

The effect of Ga-substitution on bismuth ferrite BiGaxFe1-xO3 (x = 0, 0.05, 0.10, 0.15, 0.20, and 0.25) properties was investigated, which was fabricated using a microemulsion route. X-ray diffraction analysis confirmed that specimens had a single-phase rhombohedral structure with space group R3̅c. The concentration of Ga had an impact on various properties such as structural parameters, crystalline size, porosity, and unit cell volume. The samples exhibited notable values for the dielectric constant, tangent loss, and dielectric loss in the low-frequency range, which declined as the frequency increased due to different polarizations. The increment in the AC conductivity was associated with rise in frequency. The P-E loops demonstrated that the samples became more resistive as the Ga concentration increased. The retentivity (Mr) and saturation magnetization (Ms) values reduced as the Ga content increased, although all samples had Hc values within the range for electromagnetic materials. The Ga-substitution had a synergistic effect on the electrochemical characteristics of BiGaxFe1-xO3, resulting in greater conductivity than that of undoped BiFeO3. These enhanced properties contributed to their higher photocatalytic activity in the degradation of crystal violet under visible light irradiation. The doped BiGaxFe1-xO3 exhibited 79% dye degradation after 90 min of illumination compared to 54% for pure BiFeO3. Recycling experiments confirmed the stability and reusability of the synthesized nanoparticles. The antibacterial activity of the samples was certified against various microbes, and the doped BiGaxFe1-xO3 showed promising activity. Thus, doped materials are good candidates for memories, dielectric resonators, and photovoltaics because of their high dielectric constant and AC conductivity, while their higher photocatalytic activity under visible light makes them promising photocatalysts for removing noxious and harmful effluents from wastewaters.

Optical, Photocatalytic, Electrochemical, Magnetic, Dielectric, and Ferroelectric Properties of Cd- and Er-Doped BiFeO3 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 R3-c and an average crystallite size calculated to be in the range of 29 to 32 nm. The saturation polarization (Ps), coercivity (Hc), and retentivity (Pr) of the materials were investigated by a hysteresis loop (P-E), and it was perceived that increasing the dopant contents improved the Ps and Pr 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. Bi1 - xCdxFe1 - yEryO3 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 Bi1 - xCdxFe1 - yEryO3 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 Bi1 - xCdxFe1 - yEryO3 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 BiFeO3. 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 BiFeO3 (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.