Facile synthesis of N, P-doped carbon dots from maize starch via a solvothermal approach for the highly sensitive detection of Fe3.

Nitrogen/phosphorus-doped carbon dots (N, P-CDs) with a quantum yield as high as 76.5% were synthesized by carbonizing maize starch via a facile ethanol solvothermal approach. Transmission electron microscopy (TEM) measurement shows that the as-prepared N, P-CDs displayed a quasi-spherical shape with a mean size of ca. 2.5 nm. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy disclosed the presence of -OH, -NH2, -COOH, and -CO functional groups over the surface of N, P-CDs. On the basis of excellent fluorescent properties with strong blue fluorescence emission at 445 nm upon excitation at 340 nm, these N, P-CDs were adopted as a fluorescent probe towards the effective detection of Fe3+ ions in water. The limit of detection (LOD) was as low as 0.1 µmol L-1 and showed a better linear relationship in the range of 0.1 ∼ 50 µmol L-1. In conclusion, these synthesized N, P-CDs can be efficiently used as a promising candidate for the detection of Fe3+ ions in some practical samples.