Speaker
Description
Electrochemically mediated amine regeneration (EMAR) is a promising approach for the regeneration of amine-based solvents that are typically used for CO$_2$ capture in the carbon capture and storage (CCS) system. By operating at lower temperatures, EMAR reduces energy consumption and solvent degradation, which are critical challenges of conventional CCS methods with amine-based solvents. In this process, electrochemically generated Cu ions bind to CO$_2$-rich amines, forming Cu-amine complexes that are later transported and reduced in a separate compartment, effectively regenerating the amine for further CO$_2$ capture. While recent advances in reactor design and amine chemistry have improved EMAR performance, a detailed understanding of the electrode|electrolyte interface remains limited.
Therefore, we employed in situ soft and hard X-ray absorption spectroscopy (XAS) to investigate interfacial processes during EMAR operation. In situ Soft XAS at the Cu $L_3$-edge provided insight into surface interactions, while hard XAS at the Cu $K$-edge revealed bulk speciation of Cu species. Experiments were performed under N$_2$- and O$_2$-saturated conditions to evaluate the impact of oxygen on EMAR efficiency. In situ XAS analysis indicates that under O$_2$ environment, cathodic EMAR process: deposition of Cu$^{(0)}$ from Cu-amine complex, is only observed at more negative potential. These spectroscopic results and complementary ex-situ analysis suggest that oxygen exposure negatively affects EMAR efficiency. These findings give a deeper understanding of the electrode|electrolyte interface in EMAR systems and provide a foundation for optimizing the process for industrial implementation. This work is carried out as a part of the Helmholtz Sustainability Challenge project DACStorE.
