Facile synthesis of iron oxide/nickel ferrite nanoparticles electrode materials for sensitive electrochemical determination of Pb2+

The iron oxide/nickel ferrite nanoparticles with polycrystalline rhombohedral Fe 2 O 3 and cubic NiFe 2 O 4 phases, and size of 50–100 nm have been obtained by a straightforward hydrothermal approach. X-ray photoelectron spectrum and element mapping show that the obtained nanoparticles are comprised of Ni, Fe and O elements. The formation of the oxide/nickel ferrite nanoparticles was investigated based on the morphology, structure change of the samples from different synthesis parameters. Iron oxide/nickel ferrite nanoparticles act as efficient interface serving as the electrode materials for efficient Pb 2+ detection. Density functional theory (DFT) method was applied to determine the most favorable sites for Pb 2+ adsorption on the iron oxide/nickel ferrite nanoparticles. O atoms of the iron oxide/nickel ferrite nanoparticles are the optimal adsorption sites for Pb 2+ . Standing time, pH value, deposition potential and time are 40 s, pH = 7, –1.5 V and 120 s, respectively. The iron oxide/nickel ferrite nanoparticles-modified electrode shows a linear detection range of 0.001–100 μM, with 0.078 nM detection limit, good stability, reproducibility, and selectivity for Pb 2+ detection. The iron oxide/nickel ferrite nanoparticles-modified electrode shows wider linear range or lower detection limit comparing with other electrodes which can potentially be used for detecting Pb 2+ in practical liquid environment.