Nanostructures and optical, electrical, magnetic, and photocatalytic properties of hydrothermally and sonochemically prepared CuFe2O4/SnO2

Abstract

The hydrothermal preparation of CuFe₂O₄/SnO₂ yields nanospindles of a high aspect ratio bound to nanoblocks. The nanospindles grow to about 800 nm with a diameter of ∼110 nm. The sonochemically obtained CuFe₂O₄/SnO₂ nanocomposite lacks a regular shape and is about 40 nm in size. X-ray diffractograms (XRD) and selected area electron diffractograms (SAED) show tetragonal SnO₂ and tetragonal CuFe₂O₄ as the components of the hydrothermally prepared nanostructure. Although the XRD of the sonochemically obtained CuFe₂O₄/SnO₂ shows the presence of tetragonal CuFe₂O₄ only the SAED reveals the existence of tetragonal SnO₂ also. The sonochemically prepared composite lacks a perfect nanocrystalline surface. The hydrothermally obtained nanostructure is rich in SnO₂ (80% mol.) and the other is rich in CuFe₂O₄ (91% mol.). Both the nanostructures absorb visible light and exhibit emission at 600 nm. The solid state complex impedance spectra display truncated semicircular arcs, which is similar to that of SnO₂. The hydrothermally synthesized CuFe₂O₄/SnO₂ is superparamagnetic, while both the nanostructures exhibit bactericidal activity the visible light-photocatalytic activity of the hydrothermally prepared nanostructure is much larger than that of the other. The contrasting photocatalytic activities are explained in terms of the nanostructures. The present study shows that the sonochemical method provides a coating of SnO₂ on CuFe₂O₄ nanoparticles, whereas it is an ordered growth of SnO₂ on CuFe₂O₄ in the hydrothermal preparation.