Facile Fluorescent Nanoplatform Based on N,B-Doped Carbon Dots Carbon Dots for Highly Selective Sensing of Dichromate Ions

Abstract

A novel heteroatom-doped carbon dots (named as APDP-CDs) were synthesized by using a simple hydrothermal treatment, and used for dichromate ions sensing. The chemical and physical structures of APDP-CDs were characterized by TEM, XRD, FT-IR, and XPS. An average particle size of APDP-CDs was 3.91 nm characterized by transmission electron microscopy. It showed absorbance peaks at 207 and 290 nm, fluorescence wavelength was 425 nm when excited at 370 nm. When treated the quinine sulfate (QS) as the standard sample for reference, quantum yields (QYs) of APDP-CDs reached as high as 37.6%. APDP-CDs showed two linear ranges of 300 nM – 80 µM and 80 µM – 1 mM, and the detection limit was found to be 0.48 µM. Furthermore, APDP-CDs exhibited excellent selectivity and anti-interference to dichromate in the case of different interfering species being present. The quenching process mechanism could be assigned to the surface electron transform between the functional groups and Cr2O72- ions, as well as the inner filter effect. APDP-CDs have been used for actual water sample analysis with satisfactory results, which indicated that the carbon dots-based fluorescence sensor has potential application value.

Keywords: Fluorescence sensing, N, B-doped carbon dots, Cr2O72-, surface electron transfer, inner filter effect