Fabrication of nitrogen-doped graphene oxide for detection of mercury(Ⅱ) by electrochemically modified electrodes

Abstract

Nitrogen-doped reduced graphene oxide (N-rGO) was synthesized by a single-step facile hydrothermal method to modify glassy carbon electrode (GCE) for detection of Hg(II) in water. The electronic properties of graphene and N-rGO were modified using experimental and molecular modelling data. Compared to graphene, N-rGO modified GCE shows enhanced response for detection of Hg(II) with sensitivity of 19.38 μA μM-1 and limit of detection (LOD) of 9.29 nM. X-ray photoelectron spectroscopic (XPS) data evidenced the intimate chemical interactions between Hg(II) and N-rGO surface sites. The band structure, bandgap and density of states (DOS) of solid substrates were calculated by density functional theory. The chemical interference of Cd(II), Cu(II), and Pb(II) for detection of Hg(II) by N-rGO modified GCE sensor was minimal. By combining experimental and theoretical data, an efficient method is proposed in materials fabrication required for electrochemical sensors.