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-CO 2 stoichiometric penalty. Here, we overcome this bottleneck by engineering a point defect-mediated proton trapping network into ESA sorbents, enabling a 1:1 amine-CO 2 stoichiometry. Our engineered sorbent achieves a CO 2 uptake of 6.57 mmol g −1 from 400 ppm CO 2 , 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 CO 2 release rate 48% faster than conventional thermal methods. N 5- d GA 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 CO 2 target. This work presents a sorbent design and ESA process, establishing a scientifically rigorous and economically viable pathway towards gigaton-scale DAC deployment.