Mono‐, Di‐, and Tri‐Valent Cation Doped BiFe_0.95Mn_0.05O₃ Nanoparticles: Ferroelectric Photocatalysts

Abstract

The ferroelectricity of multivalent codoped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for photocatalysis, exploiting their narrow electronic bandgap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono‐, di‐, or tri‐valent cations (Ag+, Ca2+, Dy3+; MDT) coincorporated BFM NPs are studied under ultrasonication and in acidic conditions. It is found that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono‐ and tri‐valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers, and larger surface area of NPs. A‐site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.

Rare-earth doped BiFe0.95Mn0.05O3 nanoparticles for potential hyperthermia applications

“…The alteration in polarization correlates with a doping induced alteration in crystal lattice parameters of pristine BFO NPs. It should be noted that the polarization of BFM NPs doped with Gd and Nd is larger than that of BFM NPs doped with Ag and alkaline earth metals ( Dubey et al, 2019 ; Dubey et al, 2022 ). This indicates that moderated doping with rare earth elements improves the ferroelectric properties of BFO NPs, although the mechanism of this phenomena is unclear yet.…”

“…The difference in heating efficiencies of RE-doped NPs might be due to their different shapes and saturation magnetization values. Dy-BFM NPs have higher M max value at 300 K than other NPs, and their shape is irregular pentagonal ( Dubey et al, 2022 ), which might be one of the factors behind its heating efficiency.…”

Control of physical properties in BiFeO3 nanoparticles via Sm3+ and Co2+ ion doping

“…To probe the ferroelectricity in the BFO, Sm-BFO and Co-BFO NPs, PFM was applied, which is a trustworthy method for studying ferroelectric and piezoelectric properties at the nanoscale, even within individual NPs [31,32]. The PFM results of the samples under investigation are shown in figure 4.…”

The multiple roles of rare earth elements in the field of photocatalysis

“…[27][28][29][30][31][32] In 1794, the first rare earth element yttrium (Y) was extracted from an ore, and in the following 150 years, a total of 17 rare earth elements were extracted. 33 With the deepening of research, people have discovered that rare earth elements have special electronic structures. The unfilled 4f electron sublayer (4f 0 -4f 14 ) is shielded by the outermost 5s and 5p orbitals, allowing 4f level electrons to localize within the atom.…”