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<p>The innovative construction of an electrochemical sensor for the trace detection of lead (II) and cadmium (II) ions in water is reported. The sensor was fabricated by modifying a glassy carbon electrode with polypyrrole and green-synthesized silver nanoparticles. The silver nanoparticles were prepared using <i>Eucalyptus globulus</i> leaf extract as a sustainable reducing and stabilizing agent and were subsequently incorporated into a polypyrrole nanocomposite. Successful formation of the nanomaterials was confirmed by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The electrochemical performance of the modified electrodes was evaluated using cyclic voltammetry and electrochemical impedance spectroscopy using the Ferricyanide/Ferrocyanide redox probe in 0.1&#xa0;mol L<sup>− 1</sup> potassium chloride. Cyclic voltammetry studies revealed that the silver nanoparticles-polypyrrole modified glassy carbon electrode exhibited enhanced electrocatalytic activity and a larger electroactive surface area, as evidenced by an increased current response in comparison to the bare glassy carbon electrode and electrodes modified with silver nanoparticles or polypyrrole alone. Electrochemical impedance spectroscopy revealed that the polypyrrole-modified electrode exhibited the lowest charge transfer resistance, demonstrating the outstanding electron transfer properties of the polymer. Notably, the silver nanoparticles-polypyrrole modified electrode also showed a significant reduction in charge transfer resistance compared to the bare glassy carbon electrode and the silver nanoparticles modified electrode. The silver nanoparticles-polypyrrole modified electrode exhibited excellent electrochemical stability with only 3.9% signal decrease over 10 cyclic voltammetry scans. Differential pulse voltammetry experiments conducted for the electro-analytical determination of lead (II) and cadmium (II), yielded low limits of detection (LOD) of 92 nmol L<sup>− 1</sup> and 2.37 nmol L<sup>− 1</sup> respectively. The sensor exhibited good selectivity with an average normalised signal decrease of only 0.07 in the presence of 100-fold higher concentration of common metal ions. Applicability studies revealed excellent average recoveries of 96% for cadmium (II), and 102% for lead (II) with good precision (RSD &lt; 5%), demonstrating good potential for environmental monitoring applications.</p> Graphical abstract <p></p>

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Green-synthesized silver nanoparticles supported on polypyrrole for the electrochemical detection of Pb2+ and Cd2+ ions in water

  • 期刊论文

  • 发表日期：

    2026年3月1日

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  • Kgotla Katlego Masibi,
  • Karen J. Cloete,
  • Waheed Saban,
  • Malik Maaza

摘要

The innovative construction of an electrochemical sensor for the trace detection of lead (II) and cadmium (II) ions in water is reported. The sensor was fabricated by modifying a glassy carbon electrode with polypyrrole and green-synthesized silver nanoparticles. The silver nanoparticles were prepared using Eucalyptus globulus leaf extract as a sustainable reducing and stabilizing agent and were subsequently incorporated into a polypyrrole nanocomposite. Successful formation of the nanomaterials was confirmed by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The electrochemical performance of the modified electrodes was evaluated using cyclic voltammetry and electrochemical impedance spectroscopy using the Ferricyanide/Ferrocyanide redox probe in 0.1 mol L− 1 potassium chloride. Cyclic voltammetry studies revealed that the silver nanoparticles-polypyrrole modified glassy carbon electrode exhibited enhanced electrocatalytic activity and a larger electroactive surface area, as evidenced by an increased current response in comparison to the bare glassy carbon electrode and electrodes modified with silver nanoparticles or polypyrrole alone. Electrochemical impedance spectroscopy revealed that the polypyrrole-modified electrode exhibited the lowest charge transfer resistance, demonstrating the outstanding electron transfer properties of the polymer. Notably, the silver nanoparticles-polypyrrole modified electrode also showed a significant reduction in charge transfer resistance compared to the bare glassy carbon electrode and the silver nanoparticles modified electrode. The silver nanoparticles-polypyrrole modified electrode exhibited excellent electrochemical stability with only 3.9% signal decrease over 10 cyclic voltammetry scans. Differential pulse voltammetry experiments conducted for the electro-analytical determination of lead (II) and cadmium (II), yielded low limits of detection (LOD) of 92 nmol L− 1 and 2.37 nmol L− 1 respectively. The sensor exhibited good selectivity with an average normalised signal decrease of only 0.07 in the presence of 100-fold higher concentration of common metal ions. Applicability studies revealed excellent average recoveries of 96% for cadmium (II), and 102% for lead (II) with good precision (RSD < 5%), demonstrating good potential for environmental monitoring applications.

Graphical abstract