Titanium-Oxo Cluster Assisted Fabrication of a Defect-Rich Ti-MOF Membrane Showing Versatile Gas-Separation Performance

Although having shown great promise for efficient gas separation, relevant study of Ti-MOF membranes remains very scarce, owing to limited Ti source types and uncertain factors which dominate the separation properties. In this work, we pioneered the use of the Ti₈(μ₂-O)₈(OOCC₆H5)₁₆ cluster as the Ti source of MIL-125 membranes, which led to lower reaction temperature and higher missing-linker number within the framework and therefore, enhanced CO₂/N₂ adsorption selectivity. The MIL-125 membrane prepared by combining single-mode microwave heating with tertiary growth displayed an ideal CO₂/N₂ selectivity of 38.7, which ranked the highest among all pristine pure MOF membranes measured under comparable conditions. In addition, the ideal H₂/N₂ and H₂/CH₄ selectivity was as high as 64.9 and 40.7, thus showing great promise for versatile utility in gas separation.