Transition metal-substituted magnetite minerals have attracted increasing attention for their wide application in industry and environmental protection. In this study, the valence and atomic environment of some substituting metals in magnetites (Fe3-x M (x) O-4, M = V, Co, and Ni) were investigated using X-ray absorption fine structure spectroscopy. The results deduced from X-ray absorption near-edge structure spectroscopy indicated that the valences of V, Co, and Ni in Fe3-x M (x) O-4 were +3, +2, and +2, respectively. The valences did not change as the substitution extent increased. Extended X-ray absorption fine structure spectroscopy suggested that the substituting cations occupied octahedral sites in the magnetite structure. The M-O and M-M/Fe distances were consistent with the Fe-oct-O and Fe-oct-Fe distances, respectively, in the magnetite (Fe3O4) structure. The occupancy of the substituting cations was assessed by crystal-field theory. We also considered the relationship between the chemical environment of substituting cations and their effects on the physicochemical properties of magnetite, including thermal stability, surface properties, and catalytic reactivity.
Liang, XL,He, ZS,Tan, W,et al. The oxidation state and microstructural environment of transition metals (V, Co, and Ni) in magnetite: an XAFS study[J]. PHYSICS AND CHEMISTRY OF MINERALS,2015,42(5):373-383.
Liang, XL.,He, ZS.,Tan, W.,Liu, P.,Zhu, JX.,...&张静.(2015).The oxidation state and microstructural environment of transition metals (V, Co, and Ni) in magnetite: an XAFS study.PHYSICS AND CHEMISTRY OF MINERALS,42(5),373-383.
Liang, XL,et al."The oxidation state and microstructural environment of transition metals (V, Co, and Ni) in magnetite: an XAFS study".PHYSICS AND CHEMISTRY OF MINERALS 42.5(2015):373-383.