Orientation Control of Metal–Organic Framework Membranes Through Magnetic Induced Room‐Temperature Growth

Precise orientation regulation represents an important pathway for microstructure optimization and performance enhancement of metal–organic framework (MOF) membranes, which remains challenging to achieve. In this study, a magnetic field is employed to prepare Co‐based zeolitic imidazolate framework‐L (Co‐ZIF‐L) membranes with controlled orientation. The application of a magnetic field promotes the ordered migration of Co 2+ ions along the magnetic field lines and enables Co 2+ ions to orderly coordinate with ligands along the easy magnetization axis of MOF crystals, exposing the lowest energy crystal plane and promoting selective growth of MOF crystals. Resulting (200)‐oriented Co‐ZIF‐L membrane with a thickness of ≈40 nm exhibits H 2 /CH 4 separation factor of 59.1 with H 2 permeance of 2275 GPU. This work provides a facile and efficient strategy to accurately regulate the preferred orientation of MOF membranes toward superior gas separation.