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Magnetism in graphene oxide nanoplatelets: The role of hydroxyl and epoxy bridges

2021; Elsevier BV; Volume: 541; Linguagem: Inglês

10.1016/j.jmmm.2021.168506

1873-4766

J. J. Prías‐Barragán, Rafael González‐Hernández, F.A. Hoyos-Ariza, Juan Gabriel Ramírez, M. R. Ibarra, P. Prieto,

Magnetic Properties and Synthesis of Ferrites

This work investigates the role of hydroxyl and epoxy bridges in room-temperature ferromagnetism (FM) of pyrolytic graphene oxide nanoplatelets (GOs). Graphene oxide nanoplatelets were synthesized from bamboo pyroligneous acid (BPA), varying oxide coverage (OC) from 5.3% to 13.0%. The amount of hydroxyl and epoxy functional groups in all the GO samples were estimated from results analysis of X-ray photoelectron spectroscopy (XPS). An FM signal was identified, measured at room temperature, which scaled with oxide coverage. Decreased oxide coverage results in enhanced FM. A combination of results from high-resolution transmission electron microscopy (HR-TEM), XPS, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Fourier transform infrared (FTIR), Raman, and electrical characterization allowed constructing an atomic model for each graphene oxide (GO) structure. First-principles calculations of the atomic model suggest that FM is induced by the adsorption of –OH and –O– atoms on graphene nanoplatelets; therefore, their magnetism is a response to the number of uncompensated spins due to topographic defects. These results suggest future possibilities of the magnetism approach of pyrolytic GO in spintronics of advanced sensors and devices.