Mechanistic Organic Electrochemistry for the Electrochemical Capture of Carbon Dioxide from Air

[Geoengineering News]

https://iopscience.iop.org/article/10.1149/MA2026-01452229mtgabs

Authors: Oana Luca

DOI 10.1149/MA2026-01452229mtgabs

Abstract

Electro-swing carbon capture relies on modulating the redox state of an organic sorbent so that CO₂ is bound at one potential and released after a shift to another. Because this process is governed by electron transfer and the reactivity of reduced organic intermediates, it offers a direct interface with renewable electricity and avoids the thermodynamic penalties of thermal or pressure-swing systems. Mechanistically, an effective sorbent must undergo clean, reversible reduction, form a thermodynamically strong CO₂ adduct, and do so at potentials mild enough to avoid oxygen reduction—an essential requirement for direct air capture (DAC).

This work integrates synthetic molecular design with mechanistic organic electrochemistry to develop improved quinone-based sorbents. Computational free energies of CO₂ addition were correlated with quinone reduction potentials, establishing a structure–reactivity relationship that guided the synthesis of new candidates. A quinone-annulated imidazolium scaffold was selected for its intrinsic charge and favorable redox profile, eliminating the need for supporting electrolyte. Experimental studies confirm CO₂ adduct formation and enable identification of degradation pathways under repeated redox cycling. Targeted synthetic modifications were then introduced to tune electronic properties, modulate the nucleophilicity of the reduced quinone, and disrupt solid-state packing to generate room-temperature ionic-liquid derivatives that lower oxygen solubility and remove the need for solvent.

Together, these results demonstrate how synthetic strategy and mechanistic electrochemical insight reinforce one another, enabling the rational design of next-generation sorbents for electro-swing DAC.

Source: IOP Science