Low-cost bimetallic FeNi alloy nanoparticles loaded on nitrogen-doped carbon nanotubes for electrochemical sensing of copper ions

Abstract

The monitoring of heavy metals is of paramount significance for environmental conservation and the safeguarding of public health. In this study, a novel electrochemical sensor based on low-cost, highly active bimetallic FeNi alloy nanoparticles coupled with nitrogen-doped carbon nanotubes (N-CNTs) was developed for the sensitive detection of Cu²⁺. The FeNi/N-CNT nanocomposites, which were synthesized through a straightforward sol–gel method, were systematically characterized to confirm their structure and morphology. The sensor based on the FeNi/N-CNT nanocomposites exhibited outstanding analytical performance, with a wide linear range spanning from 1 to 435 μM and a low detection limit of 0.08 μM, by employing differential pulse anodic stripping voltammetry under optimized experimental conditions. Moreover, this sensor demonstrated a set of highly desirable attributes, including favorable selectivity, stability, and reproducibility. The practical applicability of the sensor was validated by accurately quantifying Cu²⁺ in spiked lake water samples, resulting in recovery rates ranging from 97.6% to 103.6%.