A highly sensitive hydrazine sensor was successfully fabricated based on Co-CeO2 modified nanocomposites by employing a simple, cost effective and versatile electrodeposition technique. The surface morphology and the elemental composition were examined from SEM, FESEM and EDAX analysis. The oxidation states of Co and CeO2 nanoparticles were characterized using XPS. The crystallite structure and the preferred orientation were analyzed with XRD patterns. FESEM images showed the hierarchical cobalt nanoflakes morphology in which the spherical shaped CeO2 nanoparticles were embedded over the electrode surface. The electrochemical determination of hydrazine was characterized using cyclic voltammetry and chronoamperometric methods. Interestingly, compared with pure Co, the modified Co-CeO2 electrode minimizes the overpotential at 0.28 V and largely enhances the oxidation peak current (2.6 mA) for hydrazine electro-oxidation. Amperometric experiments for hydrazine exhibited two linear ranges from 0.005 mM to 0.1 mM and from 0.13 mM to 0.37 mM. In particular the detection limits obtained for the Co-CeO2 modified electrodes were 6 and 12 nit respectively. The extreme sensitivity and selectivity of the proposed senor material could be due to the porous nature of the material. The analytical parameters revealed that Co-CeO2 nanocomposites are the promising electrocatalyst for hydrazine sensing. (C) 2017 Elsevier B.V. All rights reserved.