Facile synthesis of porous nitrogen doped carbon dots (NCDs)@g-C3N4 for highly efficient photocatalytic and anti-counterfeiting applications

A novel porous nitrogen doped carbon dots (NCDs)@g-C 3 N 4 composite was successfully synthesized by a facile hydrothermal approach. The surface area of NCDs@g-C 3 N 4 can reach up to 60.9 m 3 /g, and pores with diameter between 20–50 nm are the most widely distributed. The photocatalytic activity of NCDs@g-C 3 N 4 toward the degradation of Methylene blue (MB) under visible light irradiation was remarkably higher than that of g-C 3 N 4 and NCDs. The improved photocatalytic activity can be attributed to the fact that the addition of NCDs not only broadens the photo-response range, but also suppresses the photo-generated electrons and holes recombination of g-C 3 N 4 . Degradation rate of 2.0 wt% NCDs@g-C 3 N 4 is about twice than that of pristine g-C 3 N 4 at 60 min under the same conditions. In addition, at 120 min, MB was almost degraded completely by 2.0 wt% NCDs@g-C 3 N 4 with the degradation rate as high as 97.9%, while the pristine g-C 3 N 4 was only 69%. NCDs@g-C 3 N 4 can be used as a potential catalyst for organic contaminants degradation considering its high photo-response range and excellent photocatalytic activity. Moreover, NCDs, g-C 3 N 4 and NCDs@g-C 3 N 4 also can be used as fluorescent inks for anti-counterfeiting.