Electrochemical direct air CO2 capture (eDAC) using redox carriers enables sustainable decarbonization but suffers efficiency losses from O2-induced side reactions such as oxygen reduction and carrier oxidation. We introduce a composite electrode BPT-GPL by integrating 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (BPT) with ether oxygen (-O-) enriched gas permeation layer (GPL), forming a tunable gas transport channel that facilitates CO2 diffusion while limiting O2 penetration. Under atmospheric conditions (~400 ppm CO2, 21% O2), the BPT - GPL system demonstrates high eDAC capacity of 3.3 ± 0.2 mmol g-1BPT across 48 cycles with negligible redox carrier degradation. The thiadiazole ring-based BPT molecules increase electron delocalization, exhibiting moderate CO2 binding strength and high O2 tolerance. Moreover, GPL allows CO2 diffusion and suppresses O2 permeation creating low-O2 microenvironment that inhibits side reactions and maintains cycling stability. Molecular dynamics (MD) simulations suggest that ether oxygen's stronger affinity for CO2 than O2 increases CO2 solubility within GPL, resulting in preferential CO2 permeation. The BPT - GPL system favors CO2 delivery and restricts O2 transport, enabling efficient eDAC and highlighting the potential for practical implementation.
Hou et al. (Sat,) studied this question.