Abstract: In this study, electrospinning was used to connect carbon nanofibers (CNFs) with multiple metals. Then, through high-temperature graphitization technology, uniformly sized high-entropy alloy nanoparticles (HEA NPs) were successfully synthesized in situ on CNFs. An electrochemical sensor for the simultaneous and sensitive detection of three heavy metal ions was fabricated based on FeCoNiCrCe/CNFs. In 0.1 mol/L acetic acid-sodium acetate buffer solution at pH 5, at deposition voltage and time of −1.3 V and 300 s, respectively, the limits of detection (LOD) of the electrochemical sensor were 0.06, 0.005 and 0.005 μmol/L (signal-to-noise ratio = 3) for Cd2+, Pb2+, and Cu2+, respectively. The excellent performance was considered to be attributed to the good conductivity and catalytic activity provided by HEA NPs and the higher specific surface area of CNFs exposing more active sites, which were synergistically conducive to the adsorption and desorption of heavy metal ions, thereby promoting the redox reaction and charge transfer of heavy metal ions. The FeCoNiCrCe/CNFs/GCE electrochemical sensor prepared in this study has promising application prospects in the detection of heavy metal ions in vegetables and fruits.

Key words: heavy metal ions; electrochemical sensing; high-entropy alloys; electrospinning; nanofibers