Transmission Mode 2D-IR Spectroelectrochemistry of In Situ Electrocatalytic Intermediates

Area of Science:

• Physical Chemistry
• Spectroscopy
• Electrochemistry

Background:

• Electrocatalytic mechanisms and intermediate dynamics require high-resolution spectroscopy.
• Nonequilibrium conditions in electrochemistry pose challenges for traditional methods.
• Two-dimensional infrared (2D-IR) spectroscopy is a powerful tool, but its application in spectroelectrochemistry (SEC) faces technical hurdles.

Purpose of the Study:

• To adapt 2D-IR spectroscopy for spectroelectrochemistry (2D-IR-SEC).
• To monitor the Re(bpy)(CO)3Cl CO2-reduction electrocatalyst using the developed technique.
• To gain mechanistic insights into electrocatalytic processes and catalyst degradation.

Main Methods:

• Development of a transmission-mode, optically transparent thin-layer electrochemical (OTTLE) cell for 2D-IR-SEC.
• Application of 2D-IR-SEC to study the Re(bpy)(CO)3Cl electrocatalyst.
• Analysis of spectral diffusion and inhomogeneity of the catalyst and its reduced forms.

Main Results:

• Demonstrated successful adaptation of 2D-IR spectroscopy for spectroelectrochemistry.
• Observed significant differences in spectral diffusion and inhomogeneity between the pristine and singly reduced catalyst ([Re(bpy)(CO)3Cl]•−).
• Identified catalyst-degrading dimerization pathways through cross-peak analysis in 2D-IR spectra.

Conclusions:

• 2D-IR-SEC provides unprecedented insights into electrocatalytic mechanisms.
• The technique elucidates the structural dynamics of intermediates and reaction pathways.
• This advancement is crucial for developing future energy conversion and CO2 reduction technologies.