Remarkably Enhanced Gas Separation by Partial Self-Conversion of a Laminated Membrane to Metal-Organic Frameworks

Separation methods based on 2D interlayer galleries are currently gaining widespread attention. The potential of such galleries as high‐performance gas‐separation membranes is however still rarely explored. Besides, it is well recognized that gas permeance and separation factor are often inversely correlated in membrane‐based gas separation. Therefore, breaking this trade‐off becomes highly desirable. Here, the gas‐separation performance of a 2D laminated membrane was improved by its partial self‐conversion to metal–organic frameworks. A ZIF‐8‐ZnAl‐NO3 layered double hydroxide (LDH) composite membrane was thus successfully prepared in one step by partial conversion of the ZnAl‐NO3 LDH membrane, ultimately leading to a remarkably enhanced H2/CH4 separation factor and H2 permeance. From LDH to MOF: The partial transformation of a ZnAl‐NO3 layered double hydroxide (LDH) membrane to a ZIF‐8 metal–organic framework (MOF) top layer led to the formation of the composite membrane ZIF‐8‐ZnAl‐NO3 LDH. This membrane is characterized by remarkably enhanced H2/CH4 gas separation and H2 permeance.