Nitrogen-doped graphene oxide monoliths crosslinked by short chain aliphatic amines

Abstract

Nitrogen-doped graphene oxide monoliths (NGOMs) were readily fabricated by crosslinking graphene oxide (GO) using four different short chain aliphatic amines, i.e., ethylenediamine (EDA), dimethylaminopropylamine (DMPDA), N-isopropylethylenediamine (IPEDA), and triethylenetetramine (TETA). Depending on the structure of the amine crosslinkers, the generated monoliths showed various morphologies with different d spacing, layer thickness, and microspore size. Fourier transform-infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses provided evidence for the formation of covalent CN or CN bonds in all cases, indicating that the interaction of GO with amine crosslinkers involved the ring-opening reaction between GO epoxides and amine groups. The formation of both quaternary nitrogen and some nitrogen-containing heterocyclic composition inside the graphene oxide sheet were also suggested. X-Ray Diffraction (XRD) results indicated that the interspatial distance between GO sheets was increased after crosslinking. The fabricated NGOM-TETA demonstrates potential application as an adsorbent material due to its efficient removal of copper ions.