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.

中文翻译：

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膨胀石墨负载的 CeO2 纳米材料上环境 Cd2+ 和 Pb2+ 离子的形态控制电化学传感

重金属离子（如 Cd2+ 和 Pb2+）广泛存在于环境中，毒性很强。因此，它们方便、灵敏和选择性的测定是可取的。在这项研究中，使用负载在膨胀石墨上的 CeO2 纳米材料的复合材料作为敏感材料开发了一种新型的电化学传感界面。通过水热法制备的 CeO2 纳米材料具有不同的形态（例如，纳米立方体、纳米多面体和纳米棒形状）。该界面的电催化能力和监测 Cd2+ 和 Pb2+ 离子的传感性能取决于所用 CeO2 纳米材料的形态和结构。使用纳米棒状 CeO2 纳米材料负载在膨胀石墨上的界面表现出优异的电化学活性，即用于监测 Cd2+ 和 Pb2+ 离子的显着信号增强。使用这种 r-CeO2/EG 复合材料作为敏感材料开发的电化学传感器对 Cd2+ 和 Pb2+ 离子的检测限分别为 0.39 和 0.21 μg L-1。