In situ analysis of copper electrodeposition reaction using unilateral NMR sensor

Area of Science:

• Electrochemistry
• Nuclear Magnetic Resonance (NMR) Spectroscopy
• Materials Science

Background:

• High-resolution NMR spectroscopy and MRI are valuable for in situ electrochemical studies but often confined to specialized labs.
• Existing benchtop NMR systems have limitations in cell size and compatibility with standard electrochemical setups.
• Previous work demonstrated benchtop NMR for monitoring copper electrodeposition and Lorentz force effects.

Purpose of the Study:

• To demonstrate the feasibility of using a unilateral NMR sensor (UNMR) for in situ monitoring of electrodeposition.
• To assess the impact of magnetic fields on electrodeposition reaction rates using UNMR.
• To compare the advantages of UNMR for in situ electrochemical analysis against conventional NMR spectrometers.

Main Methods:

• In situ monitoring of copper electrodeposition using a unilateral NMR sensor (UNMR).
• Measurement of Cu(2+) concentration via transverse relaxation rate (R2) using the Carr-Purcell-Meiboom-Gill pulse sequence.
• Comparison of reaction rates in the presence (in situ) and absence (ex situ) of the UNMR magnetic field.

Main Results:

• UNMR successfully monitored copper electrodeposition in situ, with Cu(2+) concentration measured over three hours.
• The electrodeposition reaction rate increased fourfold when conducted in the presence of the UNMR magnetic field (in situ) compared to ex situ.
• The enhanced reaction rate was attributed to magnetohydrodynamic (FB) and magnetic field gradient (F∇B) forces, with F∇B being dominant.

Conclusions:

• Unilateral NMR sensors provide a versatile, cost-effective, and portable solution for in situ electrochemical reaction monitoring.
• UNMR overcomes the sample size and cell compatibility limitations of traditional NMR spectrometers.
• The technology facilitates adaptation to standard electrochemical cells and large industrial reactors, opening new avenues for research and application.