Anchoring platinum nanofibers on nickel hydroxide nanosheets for electrochemical detection of ammonia-nitrogen in the aqueous environment

Abstract

This work introduced a novel electrochemical sensor using platinum nanofibers on nickel hydroxide nanosheets and Ni foam as conductive substrate (Pt-Ni(OH)2-NF) for the detection of high sensitivity of ammonia-nitrogen via differential pulse voltammetry (DPV) technique. This Pt-Ni(OH)2-NF sensor was synthesized using a simple two-step synthesis method. Firstly, Ni(OH)2-NF was synthesized by the solvothermal reaction. And then, the platinum nanofibers (Pt) were electrodeposited on the Ni(OH)2-NF to achieve Pt-Ni(OH)2-NF. The synthesized Pt-Ni(OH)2-NF was detected using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and element map and X-ray photoelectron spectroscopy (XPS). The DPV technique was used to measure the detection ability towards ammonia-nitrogen under optimum conditions of prepared Pt-Ni(OH)2-NF. The detection limit of 2.74 μM and linear range from 5 μM to 500 μM were calculated with high sensitivity of 12.27 µA µM−1 cm−2. The measured results indicated that the fabricated sensor has good repeatability and excellent stability in ammonia–nitrogen determination. This sensor also showed good recoveries in determining ammonia–nitrogen in tap water and lake water samples.