Morphology-controlled electrochemical sensing of environmental Cd2+ and Pb2+ ions on expanded graphite supported CeO2 nanomaterials.

Heavy metal ions (e.g., Cd2+ and Pb2+) are widely existed in environment and highly toxic. Their convenient, sensitive, and selective determination is thus desirable. In this study, a novel electrochemical sensing interface is developed using the composite of CeO2 nanomaterials supported on expanded graphite as the sensitive materials. As-prepared CeO2 nanomaterials through a hydrothermal method feature different morphologies (e.g., nanocube, nanopolyhedra, and nanorod-shape). Electrocatalytic ability of this interface and sensing performance towards the monitoring of Cd2+ and Pb2+ ions rely on the morphology and structure of used CeO2 nanomaterial. The interface using nanorod-shape CeO2 nanomaterials supported on expanded graphite exhibits superior electrochemical activity, namely remarkable signal enhancement for the monitoring of Cd2+ and Pb2+ ions. The developed electrochemical sensor with this r-CeO2/EG composite as the sensitive material delivers the detection limits of 0.39 and 0.21 μg L-1 for Cd2+ and Pb2+ ions, respectively.