Post-synthetic Covalent Grafting of Amines to NH2-MOF for Post-Combustion Carbon Capture

Herein, we report a post-synthetic modification strategy to covalently graft polyamines, including ethylenediamine (ED), diethylenetriamine (DETA), tris(2-aminoethyl)amine (TAEA), and polyethyleneimine (PEI) to the amino-ligand of a Cr-MOF, NH2-Cr-BDC, for post-combustion carbon capture applications. X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) reveal that ~45% of the MOF ligands are grafted with polyamines. Also, after assessment of CO2 uptake, CO2/N2 selectivity, isosteric heats of CO2 adsorption, separation performance during humid CO2/N2 (15/85) breakthrough experiments, and cyclability, the study reveals an enhanced performance for the polyamine composites and the following performance trend: NH2-Cr-BDC