In the present work, a reduced graphene oxide and multiwalled carbon nanotube (RGO/MWCNTFe3O4) composite decorated with Fe3O4 magnetic nanoparticles was prepared as an electrochemical sensor. The surface morphology of the prepared composite
was identified by scanning electron microscopy and X-ray diffraction. The electrochemical properties of the GCE/RGO/MWCNT-Fe3O4 electrode were investigated by electrochemical impedance spectroscopy, cyclic voltammetry and amperometry. The GCE/RGO/MWCNT-Fe3O4
electrode exhibited higher electrocatalytic performance towards the oxidation of hydrazine. In the optimal conditions, the GCE/RGO/MWCNT-Fe3O4 electrode showed a wide linear range (0.15–220 μM), low limit of detection (LOD) (0.75 μM), and high
sensitivity (2.868 μA μM−1 cm−2). The prepared GCE/RGO/MWCNT-Fe3O4 electrode also had excellent repeatability, selectivity, and reproducibility. The practical application of the electrode was confirmed with various
spiked water samples and demonstrated acceptable recovery.