Synthesis and structural characterization of rGO–Fe ₃ O ₄ nanocomposites via a simple chemical method

Reduced graphene oxide-iron oxide (rGO-Fe ₃ O ₄ ) nanocomposites were successfully synthesized via a rapid, room-temperature chemical reduction method using NaBH ₄ , offering a green alternative to conventional high-temperature synthesis routes. X-ray diffraction (XRD) analysis confirmed the formation of cubic spinel Fe ₃ O ₄ with high crystallinity and average crystallite size of ∼17 nm. FTIR spectroscopy revealed characteristic Fe-O vibrational bands (455-711 cm ^-1 ) and indicated partial reduction of graphene oxide to rGO. SEM and TEM analyses showed spherical Fe ₃ O ₄ nanoparticles (10-40 nm) uniformly anchored onto wrinkled rGO sheets. EDX analysis confirmed elemental composition with C (53.9 wt%), O (33.4 wt%), and Fe (11.6 wt%) as major constituents. UV–Vis spectroscopy exhibited strong absorption in the UV region, with a maximum at 198 nm, a shoulder at 223 nm, and a weak band at 277 nm; Tauc analysis identified two optical transition energies at 4.52 and 5.55 eV, assigned to n → π* and π → π* transitions of the reduced graphene oxide framework. Zeta potential measurements showed exceptional colloidal stability with a surface potential of -43.2 mV, significantly higher than typical literature values (-20 to -30 mV). These findings confirm the successful synthesis of structurally stable, optically active rGO-Fe ₃ O ₄ nanocomposites with superior colloidal stability, providing a well-characterised platform for further investigation in environmental and optoelectronic applications.