Monitoring Surface-Enhanced Infrared Absorption Spectroscopy on a Graphitic Electrode for in-Situ Surface-Sensitive Electrochemistry: Designing Electrode Interfaces for Carbon Capture
Authors: Siddiqui Abdur-Rahman , N'Diaye Jeanne , Martin Kristin , Baby Aravind , Dawlaty Jahan M , Augustyn Veronica , Rodriguez Lopez Joaquin 
Published: December 2024

Combining spectroscopy with electrochemistry enables the monitoring of changes in bonding, molecular orientation, and chemical composition during electrochemical processes at the electrode/electrolyte interface. Surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) allows a direct in situ monitoring of electrochemical processes occurring at the electrode interface due plasmonic enhancement by surface plasmon polaritons (SPP).1 Electrochemical ATR-SEIRAS has been used extensively for investigating electrocatalysis2,3, characterizing adsorbed species4, and detecting reaction intermediates5. However, SEIRAS literature has focused on plasmonic metals while the small number of SEIRAS studies reported on graphene surfaces are incompatible with electrochemical experimentation or not considered. Nonetheless, carbon electrodes are ubiquitous in electrocatalysis, sensing, and energy storage6, thus probing their surface chemistries are of particular interest. Thus, there is still a need for a convenient substrate for probing graphitic interfaces using electrochemical SEIRAS.
In our first study1, we expanded the scope of SEIRAS by introducing a robust hybrid graphene on gold (graphene-gold) substrate where we monitored electrografting processes occurring on the graphene/electrolyte interface. The graphene-gold substrate successfully monitored the electrografting of 2,2,6,6-tetremethyl-1-pipperridine N-oxyl (4-amino-TEMPO) and 4-nitrobenzene diazonium (4-NBD) in real-time using SEIRAS and cyclic voltammetry. The graphene-gold substrate is proficient at resolving the spectral responses of the electrografting and redox transformations of the grafted moieties occurring at the graphene interface spectroscopically and electrochemically. We clearly demonstrate highly sensitive SEIRAS in real-time at a graphene interface.
This substrate opens a plethora of possibilities for real-time electrochemical ATR-SEIRAS investigations on graphitic interfaces such as catalysis, battery research, and CO2 capture and conversion, the latter of which our laboratory is exploring using modified electrodes. Electrochemical carbon capture and concentration (eCCC) methods have emerged as a prosing alternative to the current state-of-the-art temperature-pressure swing systems.7 Redox-active organic (RAO) molecules such as quinones have been reported to reversibly capture and release CO2.
7 However, they suffer from low solubility in solution. New approaches have explored immobilizing these molecules on electrode interfaces for increased CO2 adsorption capacities.11 Our graphene-gold allows a unique opportunity for an in situ mechanistic investigation of the immobilization and carbonization of RAOs. Our current work investigating immobilized aminoanthraquinone and a riboflavin derivative will be presented.

References:

(1) Siddiqui, A.-R.; N’Diaye, J.; Martin, K.; Baby, A.; Dawlaty, J.; Augustyn, V.; Rodríguez-López, J. Monitoring SEIRAS on a Graphitic Electrode for Surface-Sensitive Electrochemistry: Real-Time Electrografting. Anal. Chem.
2024, 96 (6), 2435–2444. https://doi.org/10.1021/acs.analchem.3c04407.
(2) Jiang, T.-W.; Qin, X.; Ye, K.; Zhang, W.-Y.; Li, H.; Liu, W.; Huo, S.; Zhang, X.-G.; Jiang, K.; Cai, W.-B. An Interactive Study of Catalyst and Mechanism for Electrochemical CO2 Reduction to Formate on Pd Surfaces. Appl. Catal. B Environ.
2023, 334, 122815. https://doi.org/10.1016/j.apcatb.2023.122815.
(3) Li, T.; Han, S.; Wang, Y.; Zhou, J.; Zhang, B.; Yu, Y. A Spectroscopic Study on Nitrogen Electrooxidation to Nitrate. Angew. Chem. Int. Ed.
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(4) Siddiqui, A.-R.; N’Diaye, J.; Santiago-Carboney, A.; Martin, K.; Bhargava, R.; Rodríguez-López, J. Spectroelectrochemical Determination of Thiolate Self-Assembled Monolayer Adsorptive Stability in Aqueous and Non-Aqueous Electrolytes. Analyst
2024. https://doi.org/10.1039/D4AN00241E.
(5) Pang, L.; Zhao, Z.; Ma, X.-Y.; Cai, W.-B.; Guo, L.; Dong, S.; Liu, C.; Peng, Z. Hyphenated DEMS and ATR-SEIRAS Techniques for in Situ Multidimensional Analysis of Lithium-Ion Batteries and Beyond. J. Chem. Phys.
2023, 158 (17), 174701. https://doi.org/10.1063/5.0144635.
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(10) Stampi-Bombelli, V.; van der Spek, M.; Mazzotti, M. Analysis of Direct Capture of CO2 from Ambient Air via Steam-Assisted Temperature–Vacuum Swing Adsorption. Adsorption
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