Manganese valence in precipitated manganese ferrite

A comparative study about the effects of isomorphous substitution of transition metals (Ti, Cr, Mn, Co and Ni) on the UV/Fenton catalytic activity of magnetite

“…Co 2+ and Ni 2+ , they mainly substituted Fe 3+ and Fe 2+ , respectively, without any iron oxidation or reduction. But for Mn, Mn cations coexisted as Mn 2+ and Mn 3+ , and occupied the tetrahedral and octahedral sites, which was consistent with the previous study by Denecke [26].…”

Electrochemical characterization on MnFe2O4/carbon black composite aqueous supercapacitors

“…6a and b shows respectively the Mn and Fe K-edge XANES spectra of the composite electrode acquainted in situ during a cathodic scan from 0.8 to −0.1 V with respect to Ag/AgCl. The main edge energy is known to increase with increasing valence of the detected metal ion [17]. As shown, the K-edge energies for both Mn and Fe shift to lower energies, suggesting decrease in valence, during the cathodic sweep.…”

The valence and site occupancy of substituting metals in magnetite spinel structure Fe3−xMxO4 (M = Cr, Mn, Co and Ni) and their influence on thermal stability: An XANES and TG-DSC investigation

“…Its XANES spectrum shows a broad preedge peak. In the case of manganese ferrite (MnFe 2 O 4 ), Fe 2þ and Mn 3þ are preferentially located in the octahedral sites while Mn 2þ occupy the tetrahedral sites [33]. A pre-edge peak can be observed, due to its disordered structure.…”