Electrochemical and theoretical investigation of functionalized reduced graphene aerogel modified electrode for lead ions sensing

Abstract

In this work, we have incorporated 4,4′-methylenedianiline into reduced graphene oxide (F-rGO Aerogel) with high surface area and increased conductivity. The modified electrode with F-rGO Aerogel presents a sensitive Pb(II) sensor performance with good properties, such as excellent conductivity, high effective surface area and high adsorption ability for lead (II) ions. After the deposition process, the amount of lead on the working electrode surface can be increased due to easily coordination of the –NH2 groups present in F-rGO Aerogel/CPE with Pb(II). Molecular geometry optimization, structural calculations, as well as molecular system electronic state were carried out to obtain suitable information about adsorption process. The range of interaction energies in the cationic complexes (−659.80 kJ mol−1 to −763.15 kJ mol−1) represents the establishment of a covalent bond, by sharing π-electron with d-orbitals of lead cations. The strong cation-π interaction with high adsorption energy helps to remain the Pb2+ ions on the graphene surface through chemical adsorption that do not collapse with time. This strong chemisorption interaction allows the graphene species, especially the newly presented one, to be one of the most powerful adsorbent for adsorbing lead cation atoms. Under optimized condition, the built active electrode system could present a low detection limit of 0.03 μM concentration and a detection range of 0.01–0.3 μM. Furthermore, the reproducibility and stability of the sensor exhibited satisfactory results.