Electrochemical Synthesis of a Binary Mn-Co Oxides Decorated Graphene Nanocomposites for Application in Nonenzymatic H2O2 Sensing

In this work, binary metallic oxides of MnO 2 -Co 3 O 4 nanocomposite was electrodeposited on graphene oxide (GO) modified electrode by a facile and one-step electrochemical method. The resultant MnO 2 -Co 3 O 4 /graphene (MnO 2 -Co 3 O 4 /GP) electrode was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to study its morphology and element composition. The as-prepared MnO 2 -Co 3 O 4 /GP modified electrode was employed in fabricating a nonenzymatic H 2 O 2 electrochemical sensor. The cyclic voltammetry (CV) and amperometric experiments demonstrated that the MnO 2 -Co 3 O 4 /GP composites exhibited superior electrocatalytic activities toward oxidation of H 2 O 2 to the monometallic oxide decorated graphene materials (MnO 2 /GP and Co 3 O 4 /GP). The developed nonenzymatic H 2 O 2 sensor showed a high sensitivity of 53.65 μA mM -1 cm -2 , a wide linear range of 5 μM-1.2 mM, and a detection limit of 0.8 μM (S/N = 3). In addition, good selectivity, high detection accuracy and acceptable stability were also obtained for the present sensor. Therefore, this work will open an avenue to construct high-performance electrode materials and expand their applications in various fields such as catalysis and biosensor.