Graphene quantum dot implanted supramolecular carbon nitrides with robust photocatalytic activity against recalcitrant contaminants

Abstract

For the purpose of improving the photocatalytic oxidation performance of graphitic carbon nitride (g-C₃N₄) towards recalcitrant organic pollutants, graphene quantum dot implanted supramolecular carbon nitrides (AGSCNs) with an open layered nanostructure are prepared via a supramolecular self-assembly method combined with thermal polymerization. At a suitable addition amount of amino-functionalized graphene quantum dots (AGQDs), AGSCN_0.3 displays many more merits, such as a large BET surface area, rapid charge separation efficiency, and more positive valence band edge potential. The above values enable AGSCN_0.3 to exhibit outstanding visible-light photocatalytic capability for the degradation of p-nitrophenol (PNP), levofloxacin (LEVO), and atenolol (ATN) in water, which is 1.8, 2.1, and 1.3 times faster than that of supramolecular g-C₃N₄ (SCN), and 4.1, 3.9 and 2.2 times faster than that of bulk g-C₃N₄ (BCN), respectively. Combining photoelectrochemical measurements and free radical capture technology, the mechanism by which AGQDs improve the photocatalytic oxidation capability of AGSCN towards organic pollutants is studied in-depth. The design of AGSCN photocatalysts may provide an effective way to develop metal-free photocatalytic technology for sustainable development.