Electrochemical activation of graphene sheets embedded carbon films for high sensitivity simultaneous determination of hydroquinone, catechol and resorcinol

• The GSEC films were electrochemical activated in KOH solution with CV. • The electrochemical activation mechanisms of GSEC in alkaline solution were clarified. • Activation caused more defective graphene edges and carbonyl functional formation. • Activation greatly improved the electrochemical activity of GSEC film. • Activated GSEC film could be applied in simultaneous detecting HQ, CC and RC sensitivity. In this study, the graphene sheets embedded carbon (GSEC) film was electrochemically activated in KOH solution for high sensitivity simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RC). The electrochemical activation mechanism of GSEC films in alkaline solution was clarified. We found that the embedded graphene sheets were corroded during activation, resulting in the formation of more defective graphene edges and carbonyl functional groups at the surface of carbon film. These corroded graphene edges provided more electrochemical active sites and accelerated the electron transfer. Thus, the activated GSEC film exhibited highly electrocatalytic activity towards the oxidation of HQ, CC and RC. The redox peak separation for HQ and CC decreased from 366 mV to 62 mV and 262 mV to 54 mV, respectively. The oxidation potential of RC also decreased from 714 mV to 590 mV. The electrochemical sensor showed a wide liner response for HQ, CC and RC in the concentration range of 0.5∼200 μM, 0.5∼200 μM and 0.2∼400 μM with detection limit of 0.1 μM, 0.1 μM and 0.05 μM, respectively. These results demonstrate that the KOH-activated GSEC film is a promising electrode material for constructing highly sensitive and selective biosensors.