Hydrothermal synthesis and structure evolution of metal-doped magnesium ferrite from saprolite laterite

Abstract

Spinel metal-doped magnesium ferrite (MgFe2O4) was synthesized using an atmospheric hydrochloric acid leaching process and hydrothermal synthesis process from saprolite laterite.

Zn2+ substituted superparamagnetic MgFe2O4 spinel-ferrites: Investigations on structural and spin-interactions

“…A satellite peak is present at 715.38 eV separating Fe 2p 3/2 and Fe 2p 1/2 peaks that confirm the presence of Fe 3+ ions corroborating well with XRD results [50]. Deconvolution of Fe 2p 3/2 peak in Fe 3+ (B) and Fe 3+ (A) peaks revealed the existence of Fe 3+ ions at B and A sites respectively as a result of partial-inversion of the spinel structure [51,52]. O 1s spectra deconvolved in two peaks at 530.8 and 529.46 eV that show the contribution of oxygen in different environments.…”

Evaluating spinel ferrites MFe2O4 (M = Cu, Mg, Zn) as photoanodes for solar water oxidation: prospects and limitations

“…Yan et al attributed these signals to the presence of Mg 2+ in different environments. 50 The most intense signal at lower binding energy can be assigned to Mg 2+ in tetrahedral sites, whereas the weaker signal could be linked to a partial migration of cations to octahedral sites or magnesium bonded to -OH groups. 51 In the case of ZFO, the single band at 1021.0 eV for the Zn 2p3/2 signal confirms the divalent state of Zn within the material in agreement with previous reports.…”

“…52 Note that the Fe 2p3/2 peak can be deconvolved into two bands at approximately 711-712 eV (stronger) and 714-715 eV (weaker) consistent with Fe 3+ cations in octahedral and tetrahedral sites, respectively, due to the partial inversion of the structures. 50,53 Indeed, the relative intensities of these peaks clearly shows that the degree of inversion in CFO is higher compared to MFO or ZFO. Likewise, the contributions at around 724-727 eV were assigned to the chemical state Fe 3+ .…”

Stabilization of nanosized MgFe2O4 nanoparticles in phenylene-bridged KIT-6-type ordered mesoporous organosilica (PMO)

“…During extraction, the powder gets in contact with the acidic solution and the template molecules were dissolved and washed out of the silica [7,16,22]. This Soxhlet extraction procedure might lead to leaching out of the ferritic species from the silica due to the low stability of MgFe 2 O 4 NPs in acidic media [26,39]. In case of our assyn-MgFe 2 O 4 @phe-PMO the ferritic species is still present after Soxhlet extraction with acidic ethanolic solution (31 mL conc.…”

“…Hence, the development of stabilization strategies against undesired magnetic interaction like precipitation on the vessel bottom is important to make ferrite NPs suitable for catalytic application and to achieve in general stable dispersion for several applications. Another huge problem besides the magnetic behavior is the low chemical stability of ferritic NPs in acidic solutions [26,39]. A third reason for stabilization of ferritic NPs in solution is to minimize the risk of dust exposure while handling and processing.…”