Synthesis and characterization of the thermally reduced graphene oxide in argon atmosphere, and its application to construct graphene paste electrode as a naptalam electrochemical sensor

Abstract

New insight into the preparation of sensitive carbon-based electrochemical electrode is provided by examining the properties of thermally reduced graphene oxide (TRGO). In this paper, TRGO was prepared by thermal reduction of graphene oxide (GO) in argon atmosphere, and characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and atomic force microscopy (AFM). Results showed that thermal reduction in argon was effective to remove oxygen-containing functional groups in GO, and graphene sheets were obtained. Furthermore, TRGO was used to prepare thermally reduced graphene oxide paste electrode (TRGOPE) which showed excellent conductivity and fast electron transfer kinetics confirmed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrode was applied to determination of the pesticide naptalam (Nap) in square-wave voltammetric (SWV) mode. The corresponding current at approx. +1.0 V increased linearly with the Nap concentration within two linear dynamic ranges (LDR) of 0.1-1.0 μmol L^-1 (LDR₁) and 1.0-10.0 μmol L^-1 (LDR₂). The limits of detection (LOD) and quantification (LOQ) for Nap were calculated as 0.015 μmol L^-1 and 0.051 μmol L^-1, respectively. In comparison to the carbon paste electrode (CPE) the results showed that the TRGOPE possesses advantages in terms of linearity, sensitivity and detectability.

Keywords: Electrochemical sensor; Graphene; Naptalam; Paste electrode; Reduced graphene oxide; Square–wave voltammetry.