Reduction of Graphite Oxide Using Ammonia Solution and Detection Cr(VI) with Graphene-Modified Electrode

Abstract

Graphene (reduction of graphite oxide, rGO) was successfully prepared by using ammonia solution (NH3·H2O) as a reductive agent. The molecular structure and electrochemical properties of rGO were characterized by FTIR, XRD, Raman, SEM, EIS, and cyclic voltammetry (CV). The electrochemical sensing of chromium (Cr(VI)) at graphene-modified electrode (rGO/GCE) was investigated by differential pulse cathodic stripping voltammetry. The result showed that the charge transfer resistance of [Fe(CN)6]3−/4− at rGO/GCE was 75.02 Ω·cm2 decreased by about nine times comparing as that of GCE. The reduction peak potential of Cr(VI) at rGO/GCE was shifted positively by 116 mV and the peak current increased by about eight times. Meanwhile, the detection limit was 1.5 × 10−7 mol/L. It was worth noting that the synthesis of rGO by reducing GO with NH3·H2O was more friendly to environment and human health relative to hydrazine hydrate (NH2-NH2·H2O) or other poisonous reductants.