Optical, magnetic and photocatalytic properties of magnetically separable Fe3O4-doped ZnO and pristine ZnO nanospheres

This work focussed on the optical, magnetic and photocatalytic properties of sol–gel-synthesized Fe3O4-doped ZnO nanospheres and was compared with pristine ZnO nanospheres. The crystalline phase of Fe3O4-doped ZnO nanospheres was studied with X-ray diffraction analysis and was well matched with standard pattern. Surface morphology was studied with HR-SEM images and EDAX spectrum. Furthermore, elemental mapping analysis was carried out to confirm the presence of Fe3O4 phase in Fe3O4-doped ZnO nanospheres. FT-Raman spectral studies show that a strong intense peak at 670 cm−1 indicates the presence of Fe3O4 in Fe3O4-doped ZnO nanospheres. The mean crystallite size of Fe3O4-doped ZnO nanospheres was 34 nm as calculated by Debye–Scherrer’s formula which confirmed with HR-TEM image. The SAED pattern shows the presence of (100), (101), (102) and (202) of ZnO phase and (400) of Fe3O4 phase, confirming the crystalline nature of Fe3O4-doped ZnO nanospheres. The vibrating sample magnetometer (VSM) result shows that Fe3O4-doped ZnO nanospheres possess superparamagnetic nature and the composite nanospheres are magnetically separable. The optical properties have been studied by diffuse reflectance spectroscopy and time-resolved photoluminescence spectra. Implantation of Fe3O4 in ZnO nanospheres modifies the UV absorption edge, and it displays near-band gap emission and deep-level emission. The photocatalytic activity of Fe3O4-doped ZnO nanospheres studied against rhodamine B dye is found higher than that of pristine ZnO nanospheres which shows that Fe3O4-doped ZnO nanospheres are a promising photocatalyst.