Preparation of graphene nanoflakes and its application for detection of hydrazine

This work reports the synthesis of graphene nanoflakes (GNF) and its electron transfer characteristics towards hydrazine electro-oxidation. GNF is prepared by a simple chemical route using cationic-surfactant mediated exfoliation of graphite. The flakes are formed as a stable colloidal suspension in N, N-dimethyl formamide. Surface morphology and corresponding number of layers are measured using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and laser Raman spectroscopy. In addition, electrochemical techniques like cyclic voltammetry, amperometry and electrochemical impedance spectroscopy (EIS) are used to quantify electron transfer kinetics and electrochemical properties of GNF. These results inveterate that edge plane sites in GNF promote electron transfer characteristics in graphene nanostructures. GNF modified glassy carbon electrode (GCE) shows hydrazine oxidation at lower overpotential with higher selectivity, sensitivity and stability. Thus, a novel hydrazine sensor is presented using GNF modified GCE. The regression coefficient (R-2) value is found to be 0.99 with a response time less than 3 s. The above observations revealed that these results are the finest reports to scrutinize the electrochemical properties of GNF produced using liquid phase exfoliation with surfactant. Further, it serves as an important benchmark in the development of inexpensive graphene based electrodes for electrochemical hydrazine sensor. (C) 2015 Elsevier B.V. All rights reserved.