MOF-carbon fiber composites for electrically driven CO2 regeneration under direct air capture conditions

초록

Electrically driven temperature swing adsorption (ETSA) is a promising alternative to conventional temperature swing adsorption (TSA) for direct air capture (DAC), enabling rapid regeneration and reduced energy consumption through Joule heating. However, its application to metal-organic frameworks (MOFs) remains largely unexplored. Herein, a modular MOF/carbon fiber (CF) composite optimized specifically for ETSA is developed, combining rapid thermal response, high CO2 adsorption capacity, and long-term humid stability. The composite was synthesized by functionalizing Mg2(dobpdc) with N,N '-dimethylethylenediamine (mmen) and formulated into a printable ink using a polystyrene-polybutadiene-polystyrene (SBS) binder. Membrane-type mmen-MOF90 and mmen-MOF80 demonstrated notable adsorption capacities of 2.89 and 2.32 mmol g-1 at 400 ppm CO2, respectively. Under practical DAC conditions, mmen-MOF80/CF composites reached target desorption temperatures within 30 s via Joule heating, achieving complete CO2 desorption in 4 min. The developed ETSA platform exhibited a significant 66.4% improvement in regeneration efficiency over conventional TSA. Thus, this modular composite shows promising potential to address key DAC challenges such as humidity tolerance, rapid regeneration kinetics, and long-term cycling stability, indicating its feasibility for practical continuous operation under ambient conditions.

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