Highly sensitive and selective electrochemical sensor based on porous graphitic carbon nitride/CoMn2O4 nanocomposite toward heavy metal ions

Abstract

The combination of semiconductors and binary transition metal oxides has drawn growing interest in terms of their enhanced electrochemical analysis performance in electrochemical sensing. A new type of highly sensitive and selective sensor was designed and developed by constructing a nanocomposite system of porous graphitic carbon nitride and CoMn2O4 (pg-C3N4/CoMn2O4) to detect heavy metal ions of Cd(II) and Pb(II). The morphological and structural characteristics of pg-C3N4/CoMn2O4 nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The optimized current responses obtained through the square wave anodic stripping voltammetry (SWASV) of Cd(II) and Pb(II) increased linearly with their concentration in wide linear dynamic ranges of 0.5–7.0 μM and 0.2–4.4 μM, respectively, as well as low detection limits of 0.021 μM for Cd(II) and 0.014 μM for Pb(II). Further, the proposed sensor was successfully applied for the determination of Cd(II) in actual water samples accomplished with the value of recoveries ranging from 93.0%–106.0%. In addition, good anti-interference, favorable reproducibility, excellent stability and repeatability of the sensor enable it feasible for the detection of heavy metal ions.