A Simultaneous Electrochemical Sensor of Triple Heavy Metal Ions Based on Synergistic Catalysis of Copper and Platinum Nanoparticles@Graphene Composites

Heavy metal ions emitted from industrial production continue to accumulate in the environment, posing a major risk to human health. Thus, the development of multiple heavy metal ion simultaneous detection methods will greatly contribute to the prevention and control of heavy metal pollution. Due to the unique electronic structure of bimetallic nanoalloys especially composed of transition metals and precious metals, they regularly have high catalytic activity. Herein, we found that bimetallic nanoparticles composed of copper (Cu) and platinum (Pt) have higher catalytic activity than those composed of Cu and cobalt (Co), nickel (Ni), gold (Au), and palladium (Pd). Accordingly, CuPt bimetallic nanoparticles@graphene (CuPtNPs@rGO) composites have been synthesized by simple one-pot method, and an electrochemical sensor for simultaneous detection of Cd²⁺, Pb²⁺, and Hg²⁺ based on CuPtNPs@rGO has been successfully developed. Differential pulsed anodic stripping voltammetry was used for heavy metal ions sensing. The sensor has wide linear ranges for simultaneous detection of Cd²⁺, Pb²⁺, and Hg²⁺, which are 0.06 ∼ 5.0, 0.01 ∼ 5.0, and 0.06 ∼ 5.0 μM, respectively, and quite low detection limits of 20.0, 3.30, and 20.0 nM, respectively. Furthermore, the proposed method presents outstanding repeatability, stability, and good recovery in real sample tests, emerging a promising prospect for the practical detection of environmental water samples.