▎ 摘　　要

In this work, a high-speed dispersive homogenizer as an exfoliating device, and graphite oxide was used to prepare graphene and graphene oxide metal-free composite materials (GR/GO composites) for electrochemical detection of cadmium ions (Cd2+) present in water. Glassy carbon electrode was modified with GR/GO composite by placing a suspension of the composite on the electrode and evaporating the solvent. The fabricated GR/GO composite had a sheet-like structure in which the presence of GO enhanced the hydrophilicity, whereas the presence of GR improved the conductivity. The higher hydrophilicity in a wide pH range of the composite electrode made it favorable to have better contacts with Cd2+ and the good conductivity; these enhanced the response of electrochemical signals. As a result, the assembled electrochemical Cd2+ sensor with GR/GO composite electrode exhibited superior analysis performances than those with GR and GO respectively, which exhibited wide linear range (0-10 mu M), low value of detection limit (0.087 mu M), reliable stability and selectivity. Moreover, the sensor based on GR/GO composites showed satisfactory detection accuracy for tap water samples, suggesting that the GR/GO composites are promising materials for electrochemical heavy metal ion sensors.