ZnO nanofiber skeleton induced robust zeolitic imidazolate framework membranes for gas separation

Rationally designing compact metal-organic framework (MOF) membrane is highly desired but challenging. Herein, we proposed a ZnO nanofiber skeleton induced zeolitic imidazolate framework (ZIF) membrane inspired by the reinforced concrete structure. In this process, the ZnO nanofiber skeleton was employed as active anchor sites to assist the heteroepitaxial growth of continuous membranes, like the reinforcing steel in structure. The formed ZIFs particles were tightly embedded in the skeleton like the concrete. With this approach, highly compact Co-based ZIF-9 membrane and Zn-based ZIF-8 membrane were successfully achieved and exhibit effective H2 separation performance. For ZIF-9 membrane, the H2 permeance and the ideal selectivity of H2/CO2 are 2.19 × 10−7 mol m−2 s−1 Pa−1 and 15.3, respectively. For ZIF-8 membrane, the H2 permeance and the ideal selectivity of H2/CH4 are 2.26 × 10−6 mol m−2 s−1 Pa−1 and 9.7, respectively. More importantly, benefiting from the novel structure, the membrane showed a highly robust architecture under different pressures, good durability against rubbing, and separation stability of 100 h. This strategy provides a new approach toward other compact and robust MOF membrane.