Electrochemical co-preparation of cobalt sulfide/reduced graphene oxide composite for electrocatalytic activity and determination of H2O2 in biological samples

In this work, we describe a simple approach for the preparation of cobalt sulfide/reduced graphene oxide (CoS/RGO) nanohybrids via single step electrochemical method. The electrocatalytic activity of the CoS/RGO nanohybrids was evaluated towards the detection hydrogen peroxide (H2O2). The physiochemical properties of the prepared composite was characterized by means of field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray powder diffraction patterns. The CoS/RGO modified electrode showed superior electrocatalytic activity towards the detection of H2O2. The amperometric (i-t) studies revealed that the CoS/RGO performed well by attaining a wide linear response range of H2O2 from 0.1 to 2542.4 mu M with a lower detection limit 42 nM and the sensitivity of 2.519 mu M-1 cm(-2). Meanwhile, the CoS/RGO nanohybrids exhibited good selectivity, rapid and stable response towards H2O2. The practical applicability of the sensor was successfully evaluated in human serum and urine samples with satisfactory recoveries. (C) 2017 Elsevier Inc. All rights reserved.