Homoelemental effect boosted stable ZIF-8 membrane with super high H2 permeance

Abstract

Fabricating stable MOF membranes with high permeance for H2 separation and purification faces significant challenges primarily due to the heterogeneous nucleation of MOF on substrate. Herein, we propose a simple but effective homoelemental strategy by choosing the Zn-based ZIF-8 and Zn foam substrate. Without any chemical or physical modification, a serials of highly stable and compact ZIF-8 membranes are assembled on the Zn foam which exhibit high H2 permeance both for H2/CH4 and H2/CO2 separation. Especially, the 1-Zn-Foam/ZIF-8-24 membrane displays the high H2 permeance close to 104 GPU, surpassing most MOF membranes for H2/CH4 and H2/CO2 separation. Further, the excellent stability displays steady H2 permeance and selectivity, even after 96-hour test, high temperature of 100 °C, or high pressure. This is the first exploration by adopting Zn foam as a substrate for gas separation, not only demonstrating the Zn foam is an ideal carrier for assembling the Zn-based MOF membranes, but also implying the potential of the homoelemental strategy in fabricating other MOF membranes.