Controllable and eco-friendly synthesis of P-riched carbon quantum dots and its application for copper (II) ion sensing

Eco-friendly phosphorus-doped carbon quantum dots (P-CQDs) have been successfully synthesized by facial hydrothermal treatment of phytic acid (PA) and sodium citrate. PA is selected because of its hexatomic ring structure with firm C-P bonds, abundant phosphate group and completely natural. In this case, the phosphorus content of the as synthesized P-CQDs achieves 8.52 wt.%. The P-CQDs show a narrow size distribution in the range of 2.5-4.5 nm and exhibit excellent sensitivity to Cu2+ with an ultra-low detection limit of 1 nM. Furthermore, the P-CQDs have been applied in water sample to detect Cu2+, and the results are highly consistent with the data measured by inductively coupled plasma optical emission spectrometry. Therefore, the as synthesized P-CQDs display a great potential for applications in the area of Cu2+ ion detection.