Optimal Pore Environments for Effective NF3/N2 Separation in Robust Metal–Organic Frameworks

Nitrogen trifluoride (NF 3 ) is indispensable for semiconductor manufacturing but is also a potent greenhouse gas, demanding energy-efficient capture technologies. While open metal site (OMS)-containing MOFs exhibited exceptional NF 3 /N 2 selectivity, strong OMS-NF 3 interactions caused irreversible framework collapse, rendering them unsuitable for industrial applications. Herein, we systematically investigated NF 3 adsorption and separation performance across an OMS-free isonicotinate-based ultramicroporous MOF family. Comprehensive analyses revealed Ni(IN) 2 and Ni(AIN) 2 achieved simultaneous high NF 3 uptakes (~55 cm 3 g -1 ) and NF 3 /N 2 selectivities (~25 by IAST at 298 K and 101.33 kPa), while larger-pored Ni(pba) 2 underperformed—demonstrating precise pore size matching as the key performance determinant. Ni-series MOFs also exhibited excellent structural stability post-NF 3 exposure. Notably, Ni(AIN) 2 breakthrough experiments (NF 3 /N 2 1:99, v/v) demonstrated exceptionally high dynamic uptake, excellent separation efficiency, moisture stability via -NH 2 hydrogen-bonding networks, and multi-cycle regenerability for OMS-free MOFs. This work establishes Ni(AIN) 2 as a structurally robust, industrially viable adsorbent, prioritizing pore size engineering over OMS strategies for NF 3 gas capture.