Pore Compartmentalization of CO2 and H2O in a Redox-Active Adsorbent.

Achieving sustainable carbon capture under realistic, humid conditions remains a central challenge for decarbonization technologies. Here we report an ultramicroporous oxofluorovanadate metal-organic framework, Ni(pyrazine)2(VOF4), that dynamically regulates competitive adsorption through reversible redox chemistry. Under humid dilute CO2 streams (4 vol%), water chemisorbs at vanadium centers in the form of hydroxide ligands and induces a reversible V(+4)|V(+5) transformation to an isoreticular phase, Ni(pyrazine)2(VO(OH)F4), while CO2 is engaged in strong physisorption within pyrazine-lined pore regions. This redox-driven compartmentalization of H2O and CO2 results in a dynamic breakthrough CO2 capacity of 2.04 ± 0.07 mmol/g, sustained for up to 50 cycles and showing resilience under intense humidification or steam exposure. These findings establish redox-adaptive adsorption in BVR-X as a unique design paradigm, enabling scalable and durable carbon capture under realistic operating conditions.