New insights into the role of nitrogen-bonding configurations in enhancing the photocatalytic activity of nitrogen-doped graphene aerogels.

Nitrogen (N)-doped graphene aerogels (GAs) have recently emerged as a promising class of photocatalytic materials for a multitude of environmental applications. Their photocatalytic activity depends strongly on the type of N bonding configurations created in the host lattice, which in turn relies on the choice of nitrogen sources employed as molecular precursors. However, there is still no systematic assessment of the photocatalytic activity of N-doped GAs (NGAs) synthesized using different nitrogen containing precursors. Herein, we developed a series of NGAs using different kinds of amine, such as primary and secondary amines, as nitrogen precursors and rigorously evaluated their photocatalytic activity toward degradation of acridine orange under visible light irradiation. The bonding state of N atoms in the NGAs could indeed be effectively modulated by a judicious selection of an appropriate nitrogen precursor. Primary amines resulted mainly in pyridinic N structures whereas pyrrolic N was predominantly obtained from secondary amines. Irrespective of the source of nitrogen, the photocatalytic efficiency of the NGAs was directly correlated to the concentration of pyrrolic N defects in their constituent graphene building blocks. Further, the photodegradation byproducts did not present any significant antibacterial activity, reflecting the ecofriendly nature of the as-prepared novel photocatalysts.