A new rGO@Ni nanocomposite for simultaneous detection of Pb (II) and Cd (II)

Abstract

Heavy metals (HMs) are recognised as major environmental pollutants due to their high toxicity, persistence, and tendency to bioaccumulate in ecosystems. Due to their high accuracy, rapid analysis, and excellent sensitivity, electrochemical detection methods have garnered considerable interest. The focus of this work is to develop a sensitive, selective, and fast electrochemical sensing platform suitable for on-site monitoring of heavy metals. By combining the advantages of graphene oxide and metal nanoparticles, a carbon-based sensor was prepared by integrating reduced graphene oxide with nickel nanoparticles (rGO@Ni) to enhance the detection of Pb(II) and Cd(II) ions. The electrochemical performance of the CPE/rGO@Ni sensor was evaluated using cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). The results demonstrate that incorporating nickel nanoparticles into the graphene matrix significantly improves the electrochemical response toward Pb (II) and Cd (II), both in individual and simultaneous detection. The rGo@Ni nanocomposite enables the resolved and concurrent determination of Pb (II) and Cd (II) with minimal mutual interference, highlighting its suitability for multi-ion analysis. The sensor exhibits limits of detection of 0.039 ppm for Pb (II) with a sensitivity of 533.7 μAppm⁻¹, and 0.012 ppm for Cd (II) with a sensitivity of 273.75 μAppm⁻¹ in single ion analysis. Although the detection limits fall within the ppm range, the ability of the rGo@Ni nanocomposite to maintain stable and distinguished signals in the presence of coexisting ions represents a significant advantage for practical applications. These features indicate promising potential for integration into printed sensing technologies, which may help mitigate the challenges associated with ppm-level detection and further improve analytical performance.