eV for CelloZIFPaper_In Situ (Fig. ). XPS analysis indicates a stronger interaction between TOCNF and ZIF-8 crystals inside CelloZIFPaper_In Situ than CelloZIFPaper_Ex Situ. This was further sustained by observing the leaching of white particles upon touching the papers synthesized via ex-situ synthesis procedure, probably, due to loosening binding to cellulose particles. The crystal morphology and particle size in dispersion and CelloZIFPaper were evaluated using TEM (Fig. ) and SEM imaging (Fig. ). The in-situ growth of ZIF-8 in CP gives rise to smaller particles (average crystal particle size of 40 nm) than the ZIF-8 crystals grown in the presence of TOCNF (average crystal particle size 250 nm, Fig. ). ZIF crystals can be in-situ synthesized on the cellulose fibrils of CP (Figure ). SEM images of CelloZIFPaper_In Situ show homogenous crystal distribution within the membrane (Fig. ). Additionally, the amount of ZIF-8 crystals increases with the increase of the loading of CP/TOCNF and ZIF-8 (i.e., higher ratio values) from 1:0.5 (Fig. ) to 1:4 (Fig. ). TEM and SEM images show mesoporous structure inside the ZIF-8 crystal, indicating that the synthesis procedure yields hierarchical porous ZIF-8.