Fig. 1. Preparation of MOF-in-COF membrane and morphological characterization.
a Scheme depicting ZIF-67-in-TpPa-1 membrane synthesis and schematic of single pore structure. Top-view (b–d) and cross-sectional (e–g, i) SEM images of porous α-Al2O3 substrate (b, e), supported TpPa-1 layer (c, f) and ZIF-67-in-TpPa-1 membrane (d, g, i). h Optical photograph of membranes. j EDXS mapping and elemental distributions corresponding to (i).