Tris-(2-aminoethyl)amine-Intercalated Graphene Oxide as an Efficient 2D Material for Cerium-Ion Fluorescent Sensor Applications.

In this work, we report the covalent functionalization of tris(2-aminoethyl)amine (tren) onto the graphene oxide surface by the ring opening of epoxide with primary amine moieties. The effect of intercalation creates the covalent coordinating moieties in between the basal planes of graphene oxide by increasing the interlayer spacing of 1.08 nm from 0.75 nm and thereby decreasing 2θ of 8.17 deg from 10.46 deg. Because of the intercalation of tren, the aminoalcohol moieties are formed in the GO planes and the intercalated material is characterized by the spectroscopic (IR, XPS, UV, and Fluorescence) and microscopic techniques. The DFT calculation shows the newly formed C-N bond length of 1.484 Å and enhanced energy gap due to functionalization. The intercalated material shows a good selective fluorescent chemosensor for the cerium ion in aqueous solution. The reversibility and its interference with other competing metal ions have been studied. The enhanced fluorescence upon the addition of cerium ions is due to the intramolecular charge transfer and photoinduced electron transfer processes in the sp2- and sp3-hybridized carbon networks.