Proton trap engineered electric swing adsorption for scalable and cost-effective direct air capture.

Abstract

Direct air capture (DAC) is critical to achieve carbon neutrality, yet current technologies face significant barriers to widespread, cost-effective deployment. Amine-based electric swing adsorption (ESA) offers a promising low-energy, steam-free pathway, but its efficiency is fundamentally limited by an inherent 2:1 amine-to-CO₂ stoichiometric penalty. Here, we overcome this bottleneck by engineering a point defect-mediated proton trapping network into ESA sorbents, enabling a 1:1 amine-CO₂ stoichiometry. Our engineered sorbent achieves a CO₂ uptake of 6.57 mmol g^-1 from 400 ppm CO₂, a 28.8% improvement over the state-of-the-art sorbents. Regeneration is achieved with a low energy input of 3.4 GJ t^-1 and exhibits a CO₂ release rate 48% faster than conventional thermal methods. N5-dGA remains stable under 0-80% relative humidity fluctuations and at a gas velocity of 1 m s^-1. Techno-economic analysis projects DAC operating costs of $48-62 t^-1 using renewable electricity, up to 78% lower than temperature swing adsorption DAC and below the $100 t^-1 CO₂ target. This work presents a sorbent design and ESA process, establishing a scientifically rigorous and economically viable pathway towards gigaton-scale DAC deployment.