Spinel ferrite magnetic nanostructures at the surface of graphene sheets for visible light photocatalysis applications

Highlights: • Rare earth Er³⁺-substituted Cobalt-Zinc Nano-ferrites were prepared. • XRD confirmed the FCC structure of all compositions. • Graphene@ ferrite composites exhibited better photocatalytic properties. - Abstract: In this work erbium (Er³⁺) substituted cobalt zinc ferrite having general formula Co_0.70Zn_0.30Er_xFe_2-xO₄ (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) were fabricated using micro-emulsion technique. The substitution of Er was done for the purpose of tuning the optical band gap. Er⁺³ substituted nanoparticles were annealed at 700 °C for 7 h. A typical composition of Co_0.70Zn_0.30Er_xFe_2-xO₄ was utilized to make the nanocomposites material with reduced graphene oxide (rGO), that was prepared by facile chemical route. The main purpose of graphene was to enhance the conductivity of ferrite particles. All these ferrite particles and a composite were characterized by X-rays diffraction (XRD), UV–Visible spectroscopy and SEM for structural elucidation and morphology studies. Single phase spinel structure was confirmed by XRD analysis and crystallized size calculated by Scherer formula was found in the range 35–60 nm. SEM confirmed the well dispersed ferrite particles among graphene sheets. All the Er-substituted ferrite particles were subjected to dielectric parameters study. One typical composition of Co_0.70Zn_0.30Er_xFe_2-xO₄ particles and its composites with rGO were utilized for photocatalysis study using methylene blue as model organic compound in the presence of visible light. Current-voltage (I-V) measurements of ferrites nanoparticles and their composites with graphene were also studied. The results of all these techniques were agreed with each other and suggested the various potential applications of these nanoparticles.