Role of cooperative factors in the photocatalytic activity of Ba and Mn doped BiFeO₃ nanoparticles

Abstract

The escalated photocatalytic (PC) efficiency of the visible light absorber Ba-doped BiFe0.95Mn0.05O3 (BFM) nanoparticles (NPs) as compared to BiFeO3 (BFO) NPs is reported for the degradation of the organic pollutants rhodamine B and methyl orange.

Mono‐, Di‐, and Tri‐Valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts

“…According to our previous work, lowering the pH value to 2.2 helps to improve the PC rate by reducing dispersion settling. [22] We also noticed similar results for MDT-doped BFM NPs, where at a pH of 2.2 the PC rate is higher than at pH = 4.4. Figure S8 (Supporting Information) shows the absorption spectra of the RhB dye in the process of photo-stimulated degradation in the presence of various NPs.…”

“…To quantify the variation of the piezoresponse in respect to the chemical composition, we compare between particles showing the maximum VPFM amplitude signal (Figure 5j). The data for the BFO and BFM samples are taken from our previous publica-tions, [23,22] and the VPFM amplitude is normalized to the probe voltage. Here we have considered that the longitudinal piezoresponse depends on the crystallographic orientation of the particles with respect to the laboratory coordinate system.…”

“…This might be one of the major factors influencing the magnetic properties of BFM NPs. [22,23] Upon monovalent Ag doping into BFM NPs, the shorter BiO distances (BiO (1.1) 3 and (1.2) 3 ) slightly increase by 1% and 2%. However, the longer BiO distances (BiO (1.3) 3 and (1.4) 3 ) significantly decrease to 19% and 8% to BFM NPs, which alters the distorted-cuboctahedron and corresponds to an increment in polarization.…”

“…A large number of studies on the optical properties of BFO have been carried out by substituting Fe 3+ , since dopants at the Fe-site directly affect the electronic structure by participating in molecular orbital energy levels of FeO 6 octahedra. [20,21] Doping of Mn (up to 5 mol%) into the Fe-site not only enhances the light absorption of BFO NPs via contributions from d-d transitions, [22] while maintaining its ferroelectric polarization. [23,24] A large surface to volume ratio of material is needed for fast PC.…”

“…[ 23,24 ] A large surface to volume ratio of material is needed for fast PC. [ 22 ] However, it has been reported that a reduction of particle size leads to a decrease in the ferroelectric polarization of BFO. [ 25 ] To find a balance between the smaller size of NPs and large polarization, we have decided to substitute dopants into BFM NPs at the Bi‐site.…”