Simple Synthesis of Iron Oxide Nanoparticles and Sensitive Pb Ion Detection
Heng Liu, Chenxu Feng, Yuetong Chang, Zhengyu Cai, Mengyan Pei, Hui Zhang, Junzhe Li, Xuexiang Ge, Lizhai PeiBackground:
Lead ions are highly toxic heavy metal ions, widely used in ceramics, batteries, mining, and paint industries, and thus pose a major environmental threat in air, liquid, and soil. Exposure to Pb ions can pose severe risks to human health. Therefore, it is vital to sensitively detect Pb ions in a liquid environment due to health concerns.
Methods:
Iron oxide nanoparticles with a single crystalline rhombohedral Fe2O3 phase, sphereshaped morphology, and a size of 50–100 nm were fabricated via a simple hydrothermal method using cetyltrimethylammonium bromide (CTAB) as a surfactant. The iron oxide nanoparticles serve as an effective electron transfer interface. Density functional theory (DFT) was used to identify the preferred adsorption sites for Pb2+ on the iron oxide nanoparticles-modified glassy carbon electrode (GCE).
Results:
O-Pb-O of the Pb2+-Fe2O3 (001) is the optimum adsorption site. The optimal measurement parameters for Pb2+ detection using the iron oxide nanoparticles-modified GCE are as follows: a standing time of 60 s, a solution pH of 7, a deposition potential of +1.5 V, and a deposition time of 90 s.
Discussion:
The direct utilization of earth-abundant single-crystalline iron oxide nanoparticles effectively addresses the socioeconomic demand for sustainable toxic-pollutant screening. The integration of interfacial electrochemical analysis with DFT-based investigation of the adsorption behavior elucidates the microscopic origin of the surface chemical affinity. These mechanistic insights offer a powerful strategic framework for the rational design of next-generation high-performance metal-oxide interfaces, with potential applications in the field of environmental monitoring to targeted electrocatalysis.
Conclusion:
The iron oxide nanoparticle-modified GCE demonstrates a linear detection range of 0.001–100 μM and a detection limit of 0.22 nM for Pb2+ detection, with good stability, reproducibility, and selectivity. The iron oxide nanoparticle-modified electrode shows good electrocatalytic performance for detecting Pb2+. The enhanced sensing performance can be attributed to the superior electron-transfer capability and stronger adsorption ability of Pb2+ on the iron oxide nanoparticles. This work highlights a simple yet effective strategy for constructing low-cost electrochemical sensors. It provides in-depth insights into the structure- performance relationship of the iron oxidebased materials, offering promising potential for the environmental monitoring of trace heavy metal ions.