Electrochemically reduced graphene oxide with enhanced electrocatalytic activity toward tetracycline detection

Abstract An electrochemically reduced graphene oxide sample, ERGO -0.8V , was prepared by electrochemical reduction of graphene oxide (GO) at –0.8 V, which shows unique electrocatalytic activity toward tetracycline (TTC) detection compared to the ERGO -1.2V (GO applied to a negative potential of –1.2 V), GO, chemically reduced GO (CRGO)-modified glassy carbon electrode (GC) and bare GC electrodes. The redox peaks of TTC on an ERGO -0.8V -modified glass carbon electrode (GC/ERGO -0.8V ) were within 0–0.5 V in a pH 3.0 buffer solution with the oxidation peak current correlating well with TTC concentration over a wide range from 0.1 to 160 mg/L. Physical characterizations with Fourier transform infrared (FT-IR), Raman, and X-ray photoelectron spectroscopies (XPS) demonstrated that the oxygen-containing functional groups on GO diminished after the electrochemical reduction at –0.8 V, yet still existed in large amounts, and the defect density changed as new sp 2 domains were formed. These changes demonstrated that this adjustment in the number of oxygen-containing groups might be the main factor affecting the electrocatalytic behavior of ERGO. Additionally, the defect density and sp 2 domains also exert a profound influence on this behavior. A possible mechanism for the TTC redox reaction at the GC/ERGO -0.8V electrode is also presented. This work suggests that the electrochemical reduction is an effective method to establish new catalytic activities of GO by setting appropriate parameters.