LAUSR

In this work, the high electrochemical activity induced by doping different contents of oxygen on the surface of graphene sheets embedded carbon (GSEC) film is studied, which is prepared by electron cyclotron resonance (ECR) plasma sputtering system under electron irradiation. Transmission electron microscopy observation and Raman analysis confirm that doping oxygen induced more graphene edges and oxygen‐containing functional groups on the surface. The electrochemical activities of the films are measured in the Fe(CN)64–/3– redox system and the results show that a proper doping content of oxygen is beneficial to reduce the oxidation‐reduction peak separation. The surface O‐doped GSEC film with 5% content realizes the simultaneous detection of uric acid (UA), xanthine (XA) and hypoxanthine (HXA) with high sensitivity. The mechanism could be that the isolated electron at graphene edge and the polar fraction of oxygen‐containing functional groups provide more active sites to accelerate the electron transfer. These results indicate that surface O‐doped GSEC films are promising electrode materials to construct sensitive electrochemical biosensors.