Nickel-Palladium-Based Electrochemical Sensor for Quantitative Detection of Formaldehyde

Abstract

A journal article by Dr. Naumih M. Noah a lecturer at United States International University - Africa.Formaldehyde is asmall organic molecule that has awide range of uses in societydespite its toxicity.Formaldehyde is classified as a“known carcinogen”byInternational Agency for Research on Cancer (IARC). Formaldehyde electrooxidation has become asubject of major interest in the recent past due to its potentialapplication in fuel cell technologyand the need for its detection at trace levels because of its toxicity.Many studies have been conducted on formaldehyde electrooxidation, most of which suffer electrode passivation as aresult of adsorbed intermediates such as carbon monoxide adsorbed (COads) and formic acid adsorbed (H2COOads) formed from electrooxidation of formaldehyde. In this study aNickel Palladium nanoparticles modified glassy carbon electrode (Ni@Pd/GCE) was fabricated for electrooxidation of formaldehyde. Palladium nanoparticles were electrochemically deposited onto abare Glassy Carbon Electrode (GCE) from 2mMPdCl2 in 0.1 MH 2 SO4 supporting electrolyte, at acontrolled [email protected] Vfor 240 seconds. The Nickel nanoparticles were electrochemically deposited onto the PdGCE from 0.5 MNiSO4 in 0.1 MH 2 SO4 supporting electrolyte, at acontrolledpotential of @1.25 Vfor 40 seconds. The modified glassycarbon electrode (Ni@Pd/GCE) was conditionedin0.5 MNaOH for about 50 cycles or more to obtain a reproducible voltammogram. The fabricated electrode was characterized using Cyclic Voltammetry (CV) and Chronoamperometry (CA). The resultsshowedthat the electrode had good electrocatalytic properties with respect to formaldehyde electrooxidation as aresult of the synergistic effect of Ni and Pd nanoparticles combined with the glassy carbontechnology.A sensitiveoxidation peak for 1mMformaldehyde was observed at about 0.43 Vv s. Ag/AgCl/KCl (3 M) in 0.5 MNaOH, with a current density of 17 mA/cm2.Ithad alinear detection range from 10 mMto1mM (R=0.9985) and adetectionlimit of 5.4 mM. The electrode showedsignificant electrocatalytic activity towardst he electrooxidation of formaldehyde in aqueous solution,was selective,reproducible and stable, hence can be used to detect formaldehyde at trace levels and can find application in fuel cells