Fabrication of highly (110)-Oriented ZIF-8 membrane at low temperature using nanosheet seed layer

Abstract Preferred orientation represents a main concern for microstructure control and performance optimization of MOF membranes. To date, it remains a challenging task to precisely control preferred orientation of ZIF-8 membrane. Herein, we prepared highly (110)-oriented ZIF-8 membrane by oriented secondary growth. Among various elements, preparation of uniform ZIF-8 nanosheet seeds through thermal conversion of identically shaped ZIF-L precursors, spin-coating-assisted oriented deposition of (110)-oriented ZIF-8 seed layer, and controlled in-plane secondary growth at low temperature were found crucial for obtaining well-intergrown (110)-oriented ZIF-8 membrane whose H2/CO2 ideal selectivity exceeded H2/N2 and H2/CH4 under ambient conditions, owing to preferential CO2 adsorption capacity of not only PEI but also ZIF-8 nanosheets compared with their bulk counterparts. Our research highlighted the significance of preferred orientation regulation in tailoring the gas permeation behavior of MOF membranes.