In Situ Quantification of Cu(II) during an Electrodeposition Reaction Using Time-Domain NMR Relaxometry

Abstract

The use of a low-cost benchtop time-domain NMR (TD-NMR) spectrometer to monitor copper electrodeposition in situ is presented. The measurements are based on the strong linear correlation between the concentration of paramagnetic ions and the transverse relaxation rates (R(2)) of the solvent protons. Two electrochemical NMR (EC-NMR) cells were constructed and applied to monitor the Cu(2+) concentration during the electrodeposition reaction. The results show that TD-NMR relaxometry using the Carr-Purcell-Meiboom-Gill pulse sequence can be a very fast, simple, and efficient technique to monitor, in real time, the variation in the Cu(2+) concentration during an electrodeposition reaction. This methodology can also be applied to monitor the electrodeposition of other paramagnetic ions, such as Ni(2+) and Cr(3+), which are commonly used in electroplating.

Measuring the solubility product constant of paramagnetic cations using time-domain nuclear magnetic resonance relaxometry

“…Recently, we used the CPMG sequence and the T 2 values to measure the Cu 2+ concentration in situ during electrodeposition reactions [11][12][13].…”

Monitoring Electrochemical Reactions in Situ with Low Field NMR: A Mini-Review

“…In 2012 Nunes et al [7] published the first article showing that it is possible to monitor the electrodeposition reaction of Cu 2+ ions by coupling the electrochemical experiment to a low-field bench-top NMR spectrometer (0.23 T). They measured the T 2 of the solution using the CPMG pulse sequence and were able to track the consumption of the copper ions in real-time ( Figure 3) despite the fact that the noise in the NMR signals was increased.…”

“…The instruments used for these analyses are normally based on permanent magnets which produce a magnetic field intensity usually below 0.6 T (25 MHz for 1 H) with a low homogeneity (above 100 ppm) which means that the relevant information can only be extracted from the intensity of the free induction decay signal (FID), the spin echo or by measuring the relaxation times T 1 and/or T 2 or the diffusion coefficient of the sample. In this review we show the application of time domain NMR (TD NMR-also known as low-field NMR) to an increasingly popular research field which is the in situ monitoring of electrochemical reactions (EC-NMR) [7][8][9]. The first published paper which detailed the use of TD NMR for such an application was published as recently as 2010 [10] (which is a 40 year delay from the first paper detailing the use of high-field NMR for the same application [11]).…”

Desenvolvimento de um sensor de RMN (ímã e sonda) para aplicações espectroeletroquímicas

“…In 2012 Nunes et al showed that low resolution NMR can be used to monitor the concentration change of paramagnetic species during electrodeposition (16). The researchers monitored the concentration of Cu 2+ using the idea developed by Bloembergen, Purcell and Pound in 1948 that T 2 is inversely proportional to the concentration of the paramagnetic species present in the solution (17).…”

“…b) Variation of the Cu 2+ concentration (◻) and the potentiostat current (∎) during the electrodeposition reaction. (a) (b)Source: Adapted with permission from Nunes et al 2012(16). Copyright 2012 American Chemical Society.…”