Electric-Field Induced Unconventional Flexibility of MIL-Series MOFs and Its Application in Carbon Capture.

Porous materials are of critical importance in applications such as catalysis and separation due to their tailorable pore architectures. Research now encompasses metal-organic frameworks (MOFs), with growing attention to their dynamic structural flexibility in response to external stimuli. While thermal, pressure, and light stimuli provide means of control, their implementation faces limitations such as poor heat transfer efficiency and material compatibility constraints. Comparatively, electric fields (EFs) offer a promising alternative stimulus, circumventing mass/heat transfer barriers and thus enhancing applicability. This study investigates the structural response of Materials of Institute Lavoisier (MIL)Materials of Institute Lavoisier-series MOFs to EFs. Ex situ and in situ X-ray analyses reveal that EFs induce an unexpected framework contraction in MIL-53 (Cr), distinct from its conventional large-pore/narrow-pore transitions triggered by other stimuli. This contraction increases pore charge density and significantly enhances CO2 adsorption and selectivity. Similar responses observed across several MIL MOFs (MIL-53 (Fe), MIL-47 (V), and MIL-101 (Cr)) indicate a universal structural adaptability to EFs. These findings elucidate mechanisms of EF-induced structural changes in MIL-series MOFs and their direct impact on gas adsorption properties, particularly for CO2 capture. It provides a pathway for precise, in situ control of pore structure and functionality using EFs, opening new prospects for designing advanced adsorbents applying in separation and catalysis.