Integrating Catalytic Regeneration with Nonaqueous Absorbents for Low-Temperature CO₂ Capture

Scalable and energy-efficient carbon capture technologies are critical to meeting global climate targets, yet current thermal amine scrubbing is hindered by its high regeneration energy demand. Nonaqueous solvents and catalytic regeneration have independently shown promise in reducing energy penalty, but their combined potential remains underexplored. Here, we investigate the integration of a low-cost, clay-based catalyst with a nonaqueous 2-(2-aminoethoxy)ethanol (DGA)/diethylene glycol monomethyl ether (DEGMME) absorbent to enhance CO₂ desorption. The catalyst was first benchmarked against aqueous monoethanolamine (MEA) under microwave heating, where it improved the observed desorption rates by up to 750%, increased CO₂ release by ∼36%, and reduced regeneration heat duty by 26% under these conditions. In the DGA/DEGMME system, catalytic regeneration achieved an 82% increase in desorbed CO₂ amount and maintained 78% of the cyclic capacity at just 70 °C. Overall, the catalytic DGA/DEGMME system showed substantially lower estimated heat duty compared to aqueous MEA. FTIR and ¹³C NMR analyses suggest that the catalyst may facilitate carbamate decomposition at low temperatures in the nonaqueous environment. These results provide insights into potential approaches for lowering the energy demand in CO₂ capture and highlight the value of combining catalytic and solvent innovations.