Facile synthesis of graphene anchored rare earth doped mixed metal ferrite nanorods: A potential candidate for azo dye mineralization

• Published in: Journal of rare earths Vol. 42; no. 5; pp. 907 - 916
• Main Authors: Kousar, Tehmina, Aadil, Muhammad, Zulfiqar, Sonia, Ibrahim, Sobhy M., Mubeen, Sidra, Hassan, Warda, Shafiq, Kashuf, Mahmood, Farzana
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2024
• Subjects: azo-dye; Composite; Dy-doped; Graphene; Nanotechnology; Rare earths; azo-dye; Composite; Graphene; Rare earths; Dy-doped; Nanotechnology
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2023.07.002

Bandgap tuning using rare earth metals as dopants in ferrite-based photocatalytic materials has received a lot of interest because the Fermi 4f energy of these metals generates a sub-energy state in the bandgap generated by the overlapping of Fe-3d and O-2p orbitals. Herein, dysprosium-doped cobalt-nickel mixed ferrite (D-CNFO) and its graphene-reinforced composite (D-CNFO@G) were prepared and an ideal photocatalyst material for azo dye mineralization was proposed. A cost-effective combination of wet-chemical and ultrasonication methods was used to prepare the doped and composite samples. Advanced characterization methodologies were used to scrutinize the optical, compositional, structural, morphological, and photocatalytic characteristics of as-prepared materials. The X-ray diffraction analysis identified the spinel phase's (cubic) structure, while the electronic spectroscopy examination confirmed the prepared samples' rod-like morphology. The UV/visible absorbance spectrum shows the higher light harvesting behavior of the D-CNFO@G in the visible region. The mineralization performance of the D-CNFO and D-CNFO@G composites was analyzed using Congo-red (an anionic dye), a well-known azo dye. The D-CNFO@G sample removes Congo-red dye at a rate almost 2.4% faster than the D-CNFO sample. The experiment involving trapping free radicals indicates that hydroxyl radical plays a crucial role in dye degradation. Since the D-CNFO@G catalyst is magnetic and can be isolated easily from the photocatalytic system, it shows an awkward cycle activity of more than 96% after five mineralization tests. The as-prepared D-CNFO@G composite is proved as an excellent option for azo dye mineralization because of the combined impacts of rare earth doping, graphene reinforcement and nanotechnology. The novel graphene-reinforced dysprosium-doped cobalt-nickel mixed ferrite composite exhibits exceptional Congo red dye mineralization activity under solar irradiation. Compared with the just doped cobalt-nickel mixed ferrite, the composite sample mineralized the dye at a 2.45 time faster rate. The composite sample retains 96% of its initial photocatalytic efficiency after five cyclic tests. [Display omitted] •Dy-doped and graphene reinforced mixed metal ferrite was prepared via facile route.•Doping and composite formation synergistically improve the catalytic activities.•Optical analysis confirms the positive impact of doping.•Composite sample mineralizes Azo dye at faster rate.•Due to magnetic nature catalyst also recovers completely at the end of reaction.