Co3O4 nanoparticles/MWCNTs composites: a potential scaffold for hydrazine and glucose electrochemical detection

Abstract

We report the successful formation of cobalt oxide (Co₃O₄) nanoparticles/multi-walled carbon nanotubes (Co₃O₄/MWCNTs) composites as efficient electrocatalytic materials for chemical sensing. Co₃O₄/MWCNTs composites were synthesized via a straightforward hydrothermal treatment and comprehensively characterized. Working as effective electron mediators, the prepared Co₃O₄/MWCNTs composites were used for the fabrication of hydrazine (N₂H₄) and glucose sensors. The electrochemical impedance spectroscopy (EIS) studies confirmed Co₃O₄/MWCNTs/glassy carbon electrode (GCE) exhibited higher conductivity than bare GCE and Co₃O₄/GCE, endorsing a faster electron transfer rate and a higher electrocatalytic activity. The addition of MWCNTs can not only improve the dispersion of Co₃O₄ nanoparticles but also facilitate the electron transfer rate. The sensitivity, selectivity, repeatability, reproducibility, linear range and detection limit of the fabricated sensors were systematically investigated. The fabricated hydrazine sensor displayed a great sensitivity of 120.26 μA mM⁻¹, a wide linear range of 1.0–187.4 μM, and a rather low detection limit of 0.449 μM, and the fabricated glucose sensor exhibited a high sensitivity of 63.27 μA mM⁻¹, a wide linear range of 1.70–554 μM, and a low detection limit of 0.95 μM. We demonstrated that such fabricated Co₃O₄/MWCNTs composites may have favorable applications in the establishment of fast and effective determination of environmental pollutants.