A novel voltammetric p-nitrophenol sensor based on ZrO2 nanoparticles incorporated into a multiwalled carbon nanotube modified glassy carbon electrode

Abstract

Herein, we report the incorporation of zirconium oxide (ZrO₂) nanoparticles into functionalized multiwalled carbon nanotubes (fMWCNTs/ZrO₂) to form a nanocomposite film via a simple and clean in situ method based on the electrochemical redox reaction of zirconyl chloride (ZrOCl₂). The electrocatalytic properties and surface morphology of the as-prepared nanocomposite were studied using cyclic voltammetry, electrochemical impedance spectroscopy and field emission scanning electron microscopy. The as-prepared fMWCNTs/ZrO₂ nanocomposite-modified glassy carbon electrode shows a prominent electrocatalytic activity towards the voltammetric determination of p-nitrophenol. The presence of fMWCNTs in the film enhances the surface coverage concentration and also increases the electron transfer rate constant of the ZrO₂ nanoparticles. The modified electrode has a linear range of 2–26 μM for p-nitrophenol. The proposed film was also used successfully for the voltammetric determination of p-nitrophenol in river and tap water samples with a linear range of 0–24 μM. A well-defined peak for the detection of p-nitrophenol in water samples has proved this fMWCNTs/ZrO₂ nanocomposite-modified electrode to be a successful sensor material. The proposed film has long-term stability.