An Electrochemical Sensor for Cd²⁺ in Water Based on rGO-CoMnCNF Screen-Printed Electrodes

Cadmium ions (Cd 2+ ), as ubiquitous water contaminants, pose severe threats to human health due to their irreversible toxicity even at trace levels. The development of precise quantification methods for aqueous Cd 2+ is therefore critical for environmental monitoring and public health protection. In this work, cobalt-manganese carbon nanofibers (CoMnCNFs) were synthesized through electrostatic spinning followed by high-temperature carbonization. These CoMnCNFs were integrated with reduced graphene oxide (rGO) to construct an electrochemical sensor using screen-printed electrodes for Cd 2+ detection in aquatic systems. The sensor’s performance was systematically characterized through microscopic techniques (scanning electron microscopy and X-ray photoelectron spectroscopy) and electrochemical analyses (cyclic voltammetry and square-wave voltammetry). Quantitative Cd 2+ detection demonstrated a linear response range of 0.05–100 μg l −1 with a low detection limit (LOD) of 0.043 μg l −1 , outperforming many reported sensors. The sensor also demonstrated good selectivity and stability. By integrating rGO and CoMnCNFs as co-modification materials on portable screen-printed electrodes, this work provides a feasible strategy for on-site detection of cadmium ions in aquatic environments.