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Microstructural and photocatalytic properties of Cr-doped hematite (𝛂-Fe2O3) nanorods

Hematite (-Fe2O3) is a semiconducting material (Eg = 2.1 eV) that has found various applications in traditional and advanced technologies. The chemical and physical properties of -Fe2O3 highly depend on the particles size, morphology, crystallinity as well as on synthesis route. Additionally, some specific -Fe2O3 properties can be pronounced by its doping with foreign metal cations. The synthesis of hematite nanoparticles of various morphology and sizes have been reported.1 In the present research, we have focused on the effects of chromium on the microstructural, magnetic, and photocatalytic properties of hematite nanorods synthesized by combination of hydrothermal procedure and thermal decomposition of hydrothermally obtained precipitate. The nominal concentration of chromium varied in the range 3, 5, 10 and 20 mol %. The Cr-doped -Fe2O3 nanorods were characterized with XRPD, 57Fe Mössbauer spectroscopy at RT and liquid N2 temperatures, FT-IR, UV/Vis and FE SEM. The Mössbauer spectra of Cr-doped -Fe2O3 nanorods recorded at room temperature showed the presence of sextet and central quadrupole doublet which intensity increased with increasing the Cr content. Mössbauer spectra recorded at 80 K were resolved into one sextet with the parameters corresponding to hematite crystal structure. The calculated hyperfine field of -Fe2O3 decreased gradually as the content of Cr fraction increased. The incorporation of Cr ions into -Fe2O3 crystal structure was confirmed by XRPD analysis. The investigation of solid solutions (CrxFe1-x)2O3, 0 ≤ x ≤ 1, prepared by traditional ceramic procedures, also showed great affinity to Cr3+ incorporation into -Fe2O3 crystal structure.2 A significant effect of Cr-doping on the optical and photocatalytic properties of hematite nanorods was measured.

hematite nanorods ; Mössbauer spectroscopy ; photocatalysis

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