Highly efficient catalytic direct air capture of CO₂ using amphoyeric amino acid sorbent with acid‐base bi‐functional 3D graphene catalyst

Direct air capture (DAC) of CO₂ is vital for combating global climate change, but DAC technologies have a low absorption efficiency due to the low concentration (∼400 ppm) of atmospheric CO₂. A novel DAC technology was developed to solve this issue using lysine (an amino acid) as a sorbent and N-doped 3D graphene as an absorption/desorption-enhanced bifunctional catalyst. Introducing only 500 ppm N-3DG catalyst increased the working time (≥90% CO₂ absorption efficiency) by 233% and its absorption capacity by 197%. The catalyst also significantly accelerated the CO₂ working desorption capacity and rate by ∼280% and ∼338% at 70 °C, enabling regeneration of the sorbent by utilizing low-temperature waste heats. Furthermore, the excellent stability of the system was confirmed by 50 cyclic tests. The chemical mechanism driving catalytic CO₂ capture was postulated and confirmed by density functional theory computations. This study provides a new strategy for developing next-generation DAC technologies.