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Microstructural and magnetic properties of electrospun α-Fe2O3/CuFe2O4 nanocomposites

Hematite (α-Fe2O3) is n-type semiconductor with Eg value of ~ 2.1 eV and this material has various applications in traditional as well as advanced technologies. Recently, it has been extensively investigated as photoanode material in the photoelectrochemical (PEC) devices for water and air purification, waste water remediation, etc. A lot of efforts have been made to improve magnetic, electrical, catalytic, photocatalytic, or other properties of hematite. These properties are highly dependent on its crystal structure, particles size and morphology and can be tuned by controlling the synthesis conditions or/and doping with foreign metal ions There is also the increasing number of studies of nanocomposites of hematite and other metal oxides. These hematite materials are specifically interesting since they may exhibit new physical properties overcoming the failing of the single materials. In the present work the nanofibers of α-Fe2O3/ CuFe2O4 have been synthesized using electrospinning method starting from viscous solution of polyvinylpyrrolidone (PVP) containing appropriate molar ratio of Fe(NO3)3 and Cu(NO3)2 solutions. As synthesized electrospun fibres were calcined in air at 500 °C for 1 hour and additionally at 700 °C for 1 hour. The reference electrospun α-Fe2O3 was synthesized at the same experimental conditions. The microstructural, magnetic and optical properties of the synthesized electrospun fibres were characterized by XRD, FE SEM, 57-Fe Mössbauer, FT-IR, UV-Vis-NIR spectroscopies and magnetometric measurements. A small amount of Fe3O4 was detected in the reference hematite fibres obtained at both calcined temperatures. On the other hand, the electrospun fibers containing copper ions obtained by calcination at 500 °C show the presence of α-Fe2O3, CuFe2O4 and γ-Fe2O3 phases. A small amount of Fe3O4 is also present. Additional heating at 700 °C of these fibres lead to the formation of hematite and cuprospinel composite. The α-Fe2O3/CuFe2O4 composite fibres showed enhanced magnetic and optical properties compared to reference α-Fe2O3 electrospun fibres.

α-Fe2O3/CuFe2O4 nanocomposites, electrospinnnig, XRD, FE SEM, 57-Fe Mössbauer, FT-IR, UV-Vis-NIR

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