Investigation of structural, magnetic, optical and photocatalytic properties of zinc ferrite nanowires/bismuth vanadate composite

Abstract

In this paper, zinc ferrite nanowires with an average length of 6.3 µm and an average diameter of 38 nm, bismuth vanadate nanoparticles, and zinc ferrite nanowires/bismuth vanadate composites were fabricated by AC pulse electrodepositing, co-precipitation, and hydrothermal methods, respectively. In order to study the samples, XRD analysis, FESEM, FTIR spectroscopy, EDS spectroscopy, UV-Vis spectroscopy, PL spectroscopy, and VSM were used. XRD patterns of the samples revealed that they did not contain any impurities and that zinc ferrite nanowires and bismuth vanadate nanoparticles had cubic spinel and monoclinic structures, respectively. The optical gap energy of all the samples was in the range of visible light. According to the magnetic hysteresis loops, the composites exhibited paramagnetic behavior. The intensity of the photoluminescence spectrum of the composites (especially those containing 20 wt% of zinc ferrite) was less than the intensity of the photoluminescence spectrum of bismuth vanadate and zinc ferrite. The weaker the intensity of the photoluminescence spectrum, the longer the separation of electron-hole pairs and this leads to an increase of photocatalytic activity. The photocatalytic activity of the composites for decomposing Congo red under visible light was improved as compared to zinc ferrite and bismuth vanadate and the highest degradation rate was related to nanocomposite containing 20 wt% zinc ferrite. These results were obtained because the probability of recombining photogenerated electrons and holes was reduced and there were nanowires in the composite samples, leading to an increase of the contact surface. According to the results of this study, zinc ferrite nanowires/bismuth vanadate nanocomposite with 20 wt% of zinc ferrite is a good choice for the degradation of organic matter under sunlight.