Electrochemical determination of semicarbazide on cobalt oxide nanoparticles: Implication towards environmental monitoring

Abstract

The electrochemical determination of semicarbazide (SCB) executed by using cobalt oxide (Co3O4) nanoparticle modified electrode which was fabricated by using simple precipitation method. The as-synthesized nanoparticles have been well characterised by X-ray diffraction (XRD), Furrier transform infra-red (FTIR), UV-visible (UV-Vis) spectroscopic techniques, energy dispersive analysis of X-ray (EDAX), BET surface area, thermogravimetric (TG) analysis and transmission electron microscopic (TEM) techniques. The XRD shows face centred cubic (FCC) structure, the FTIR demonstrated a major bands appeared at 574 cm−1 and 669 cm−1 are suggesting the (Co-O) vibrational mode of Co3O4. The TEM of Co3O4 NPs has been confirmed its ultra-small particle size is of ∼2 nm ± 0.5 nm. Whereas, EDAX shows the only cobalt and oxygen are available confirms Co3O4 having high BET surface area. The fabricated Co3O4 acted as a highly sensitive electrochemical sensor for the determination of SCB by using linear Sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) in 0.5 M KOH solution. Significantly, anodic onset potential observed at 0.2 V vs. SCE, linear range of scan rate and concentration (1 mM–100 mM) with (LOD 0.13 and LOQ 0.46) and high current and potential stability with pH dependent behaviour confirms Co3O4 based electrocatalytic system is good for oxidative determination of SCB. The selectivity of the sensor also tested by using mixture of other environmental active species with SCB by using LSV measurements. This proposed system is applicable in food and pharmaceutical industries for the determination of SCB as an amperometric sensor.