Elimination of Grain Boundary Defects in Zeolitic Imidazolate Framework ZIF‐95 Membrane via Solvent‐Free Secondary Growth

Abstract

Metal-organic framework membranes are usually prepared by in-situ or secondary growth in a solution/hydrogel. The use of organic solvents may cause safety and environmental problems, and also produce solvent-induced defects. In this work, highly oriented and permselective ZIF-95 membranes are prepared for the first time via a solvent-free secondary growth method. The solvent-free growth is not only helpful to control the membrane microstructure and thickness, but also to reduce the intercrystalline defects. In case of solvent-free growth, a perfectly oriented structure leads to an outstanding reduction of intercrystalline defects and transport resistances. For the separation of equimolar binary gas mixtures by using the highly oriented ZIF-95 membrane at