Acetaminophen Sensing Using NiFe₂O₄ Nanoparticle/Reduced Graphene Oxide Nanosheet Composites

High Resolution Image Download MS PowerPoint Slide Graphene oxide (GO), an oxygen-rich, chemically reactive carbon nanomaterial, offers a versatile platform for catalytic and sensing applications. In this work, we report a high-performance electrochemical sensor for acetaminophen detection based on nickel ferrite (NiFe 2 O 4 ) nanoparticles anchored onto partially reduced graphene oxide (rGO). GO was synthesized via the Tour method and partially reduced with ethylene glycol during hydrothermal treatment. Two sensor configurations were fabricated: one with pristine NiFe 2 O 4 nanoparticles and the other with a NiFe 2 O 4 /rGO nanocomposite. Scanning electron microscopy revealed that GO facilitates the formation of smaller, uniformly dispersed NiFe 2 O 4 nanoparticles on its surface. The N 2 adsorption–desorption isotherm confirmed a mesoporous structure with narrow slit-like pores, enhancing the surface area. Electrochemical impedance spectroscopy and differential pulse voltammetry analyses revealed that the incorporation of rGO significantly reduces the charge-transfer resistance from 167.5 Ω for pristine NiFe 2 O 4 to 121.7 Ω in the composite and increases the density of the electroactive sites. The NiFe 2 O 4 /rGO sensor exhibited an exchange current density of 365.9 μA/cm 2, a sensitivity of 673.25 μA/cm 2 ·mM, and a detection limit of 0.14 μM, representing improvements of nearly 2 orders of magnitude over the pristine NiFe 2 O 4 sensor. These enhancements have been attributed to the synergistic combination of the high redox activity of NiFe 2 O 4, the nanoscale particle size, and the superior conductivity of rGO at the electrode–electrolyte interface.