Tailorable Multi‐Modular Pore‐Space‐Partitioned Vanadium Metal‐Organic Frameworks for Gas Separation

Abstract

Currently, few porous vanadium metal-organic frameworks (V-MOFs) are known and even fewer are obtainable as single crystals, resulting in limited information on their structures and properties. Here this work demonstrates remarkable promise of V-MOFs by presenting an extensible family of V-MOFs with tailorable pore geometry and properties. The synthesis leverages inter-modular synergy on a tri-modular pore-partitioned platform. New V-MOFs show a broad range of structural features and sorption properties suitable for gas storage and separation applications for C₂H₂/CO₂, C₂H₆/C₂H₄, and C₃H₈/C₃H₆. The c/a ratio of the hexagonal cell, a measure of pore shape, is tunable from 0.612 to 1.258. Other tunable properties include pore size from 5.0 to 10.9 Å and surface area from 820 to 2964 m² g^-1. With C₂H₂/CO₂ selectivity from 3.3 to 11 and high uptake capacity for C₂H₂ from 65.2 to 182 cm³ g^-1 (298K, 1 bar), an efficient separation is confirmed by breakthrough experiments. The near-record high uptake for C₂H₆ (166.8 cm³ g^-1) contributes to the promise for C₂H₆-selective separation of C₂H₆/C₂H₄. The multi-module pore expansion enables transition from C₃H₆-selective to more desirable C₃H₈-selective separation with extraordinarily high C₃H₈ uptake (254.9 cm³ g^-1) and high separation potential (1.25 mmol g^-1) for C₃H₈/C₃H₆ (50:50 v/v) mixture.