Near room temperature synthesis of rGO-Fe3O4 nanosheets: Structural, magnetic ordering, charge transport, dye degradation properties and hydrogen evolution reaction

Abstract

Abstract Reduced graphene oxide (rGO)-Fe3O4 nanosheets were synthesized at near room temperature stirring method. X-ray diffraction results showed the formation of Spinel structure of Fe3O4 with a broad diffraction pattern of reduced graphene oxide sheets. Vibrating sample magnetometery was employed to investigate the superparamagnetic behavior of Fe3O4 nanoparticles decorating rGO sheets. The estimated size of superparamagnets obtained 11 nm which was in well in agreement with XRD analysis (14 nm) and FESEM images (13 nm). A new splitting feature in high magnetic files were observed in the hysteresis curve of samples. A dipole-dipole magnetic interaction was employed to estimate the interparticle separation for the first time. The results obtained roughly 3 nm which was in good agreement with the results mean pore diameter from BET-BJH analyses. The effective surface area was obtained 97 m2 g−1 and 20 m2 g−1 for Fe3O4 and rGO-Fe3O4, respectively. Cyclic voltamettery and impedance spectroscopy revealed the significant enhancement of charge transfer for rGO-Fe3O4 hybrid nanosheets. The polarized light off-on measurement obtained a net current of 0.05 mA cm−2 which is comparable to metal chalcogenide nanostructures. Linear sweep voltamettery and corresponding Tafel plot analysis revealed an exchange current density of 210 μA cm−2 and Tafel slope of 100 mV decade−1 for rGO-Fe3O4 optimized sample. Moreover, it showed a superior methylene blue degradation of 98% and pseudo-linear degradation rate constant of 78 × 10−3min−1 which is much higher than the value of 27 × 10−3 min−1 for Fe3O4 nanoparticles. Cyclic photocatalyst activity of rGO-Fe3O4 demonstrates only 3% degradation of its performance after 5 cycles.