Metal based gels as versatile precursors to synthesize stiff and integrated MOF/polymer composite membranes

Abstract

Great advances have been made in metal–organic framework membranes recently. However, preparation of stiff and integrated MOF/polymer membranes still remains a big issue. Herein, metal based gels as versatile precursors were first employed to prepare continuous and integrated MOF/polymer hollow fiber membranes. The metal based gel was put into/on various polymer substrates adequately, which can be transformed into pure MOF crystals and lead to formation of continuous MOF crystals on the surface and in the pores of the hollow fiber easily. By using this method, we can not only fabricate continuous MOF membranes without a conventional activation step but also can greatly enhance the stiffness of the membranes through mutual support of MOFs and substrates. The strategy also has an appropriate level of generality which can be used for preparation of inter-grown MOF membranes on different kinds of substrates. The prepared membranes exhibited excellent gas separation performance with a H₂/N₂ separation factor as high as 22.7.