The electrochemical activities of anthraquinone monosulfonate adsorbed on the basal plane of reduced graphene oxide by π–π stacking interaction

Abstract

The electrochemical properties of anthraquinone monosulfonate (AQS) adsorbed on the basal plane of chemically-reduced graphene oxide (RGO) by π–π stacking interaction were investigated. The AQS/RGO nanocomposites were synthesized via a simple reduction–adsorption method and characterized with various techniques, and the surface concentration of AQS on the basal plane of RGO was estimated to be 1.72 × 10−12 mol cm−2. Electrochemical tests showed that the AQS/RGO nanocomposites accelerated the heterogeneous electron transfer, when ferro/ferricyanide was used as a redox probe, and RGO facilitated the electron transfer between AQS and the surface of glassy carbon electrode, producing a well-defined redox couple centered at −0.490 V versus SCE at neutral medium. Compared with AQS and RGO modified glassy carbon (GC) electrode, the AQS/RGO nanocomposites showed better electrocatalytic activity towards oxygen reduction reaction. Rotating disk electrode data showed that the reduction of O2 on AQS/RGO/GC electrode underwent a two-electron process to H2O2 at low overpotential and shifted to four-electron reduction to H2O at relatively high overpotential. The present work demonstrates that AQS can be an efficient catalyst when noncovalently functionalized on the basal plane of RGO for electrochemical applications.