title: In situ study of the magnetoelectrolysis phenomenon during copper electrodeposition using time domain NMR relaxometry.
abstract: Although the effect of magnetic field (B) on electrochemical reactions (magnetoelectrolysis phenomenon) has been long known, it has not been considered in electrochemical reactions analyzed in situ by magnetic resonance methods, such as nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), and magnetic resonance imaging (MRI), which are intrinsically performed in the presence of B. In this report, the effect of B on the copper electrodeposition reaction, measured by a low-field (0.23 T) NMR spectrometer, was demonstrated. As expected, an enhancement in the reaction rate in comparison to the ex situ electrodeposition reaction was observed. Such enhancement was not dependent on electrodes/magnetic field orientations. Parallel and perpendicular orientations showed similar electrodeposition rates, which is explained by the cyclotron flows generated by distortions in electric and magnetic field lines near the electrode and the electrode edge. Therefore, NMR spectroscopy is not a passive analytical method, as assumed in preceding in situ spectroelectrochemical studies. Although the magnetoelectrolysis phenomenon demonstrated in this report used a paramagnetic ion, it can also be observed for diamagnetic species, since the magnetoelectrolysis phenomenon is independent of the nature of the species. Consequently, similar convection effects may occur in other electrochemical nuclear magnetic resonance (EC-NMR) experiments, such as the electrochemical reaction of organic molecules, as well as in electrocatalysis/fuel cells, lithium-ion batteries, and experiments that use electrochemical electron paramagnetic resonance (EC-EPR) and electrochemical magnetic resonance imaging (EC-MRI).
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo , Avenida Trabalhador São-Carlense 400, São Carlos, SP CEP 13560-070, Brasil.
authors.forename: Bruna Ferreira
authors.initials: BF
authors.lastname: Gomes
authors.forename: Luiza Maria Silva
authors.initials: LM
authors.lastname: Nunes
authors.forename: Carlos Manuel Silva
authors.initials: CM
authors.lastname: Lobo
authors.forename: Luís Fernando
authors.initials: LF
authors.lastname: Cabeça
authors.forename: Luiz Alberto
authors.initials: LA
authors.lastname: Colnago