Electrochemical Detection of 4-Nitrophenol Using A Screen-Printed Carbon Electrode Modified by Rod-Shaped Nickel Oxide Nanoparticles

4-Nitrophenol (4-NP) is a hazardous organic pollutant with detrimental effects on plants, animals, and humans. Detection of 4-NP in the environment is therefore a necessary requirement. We demonstrate a facile green synthesis of nickel-oxide (NiO) nanoparticles employing Brassica oleracea vegetable extract (cauliflower) as a green stabilizing and reducing agent. Green synthesized NiO nanoparticles were used as an efficient electrode material for the highly sensitive electrochemical detection of 4-NP. The abundant polyphenolic component in the vegetable extract of Brassica oleracea is capable of reducing and stabilizing C2NiO4 into NiO nanoparticles. The as-synthesized NiO nanoparticles were characterized by UV-Vis spectroscopy, FTIR spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy (XPS), and the structural phase of NiO nanoparticles was confirmed using powder X-ray diffraction technique. The surface morphology of the NiO nanoparticles was analyzed using scanning electron microscopy (SEM). Linear sweep voltammetry (LSV) and Differential pulse voltammetry (DPV) techniques were adopted to for the electrochemical determination of 4-NP after drop casting the NiO nanoparticles onto the screen-printed carbon electrode (SPCE). The developed sensor (NiO/SPCE) showed a high sensitivity of 1.055 mu A/nM over a wide linear-range from 1 to 10 nM with a detection limit of 0.519 nM for the detection of 4-NP using DPV technique.