High-efficiency electrochemical air capture enabled by thiadiazole redox carrier with tunable gas-selective channels

Electrochemical direct air CO 2 capture (eDAC) using redox carriers enables sustainable decarbonization but suffers efficiency losses from O 2 -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 CO 2 diffusion while limiting O 2 penetration. Under atmospheric conditions (~400 ppm CO 2 , 21% O 2 ), the BPT − GPL system demonstrates high eDAC capacity of 3.3 ± 0.2 mmol g –1 BPT across 48 cycles with negligible redox carrier degradation. The thiadiazole ring-based BPT molecules increase electron delocalization, exhibiting moderate CO 2 binding strength and high O 2 tolerance. Moreover, GPL allows CO 2 diffusion and suppresses O 2 permeation creating low-O 2 microenvironment that inhibits side reactions and maintains cycling stability. Molecular dynamics (MD) simulations suggest that ether oxygen’s stronger affinity for CO 2 than O 2 increases CO 2 solubility within GPL, resulting in preferential CO 2 permeation. The BPT − GPL system favors CO 2 delivery and restricts O 2 transport, enabling efficient eDAC and highlighting the potential for practical implementation.