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

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 similar to 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.