Chloride ion sensors based on low-dimensional α-MnO2–Co3O4 nanoparticles fabricated glassy carbon electrodes by simple I–V technique

Highlights: • Detection of chloride ion based on α-MnO2–Co3O4 NPs using flat GCE. • Low-dimensional NPs (dia. ∼20.2 nm) are processed in tetragonal geometry with ∼4.5421 eV band-gap energy. • Fabrication of efficient chloride ions detection by reliable I–V technique. • It exhibits higher sensitivity (∼1.062 μA cm−2 mM−1) as well as lower detection limit (∼0.35 μM). -- Abstract: In this paper, we have synthesized codoped α-MnO2–Co3O4 nanoparticles (NPs) by a facile solvothermal technique using active reducing agents in alkaline reaction systems. The doped NPs are investigated using UV/vis, FT-IR spectroscopy, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray energy dispersive spectroscopy (XEDS), and field-emission scanning electron microscopy (FESEM). α-MnO2–Co3O4 NPs are fabricated onto a flat-glassy carbon electrode (GCE, surface area, 0.0316 cm2) to give a chemo-sensor with a fast response toward chloride ions (∼10 s) in liquid phase. The chemo-sensor also shows good sensitivity, long-term stability, reproducibility, and enhanced electrochemical responses. The calibration plot is linear (r2 = 0.9794) over the large chloride ions concentration (1.0–0.1 μM) ranges. The sensitivity and detection limit is calculated as ∼1.062 μA cm−2 mM−1 and ∼0.35 ± 0.05 μM (signal-to-noise ratio, at a SNR of 3) respectively. We also discuss the possible future prospective uses of the transition-metal doped semiconductor nanomaterials in terms of chemical sensing