A facile microwave-assisted fabrication of fluorescent carbon nitride quantum dots and their application in the detection of mercury ions.

A facile microwave-assisted solvothermal method was used to prepare fluorescent carbon nitride quantum dots (CNQDs) using oleic acid as the reaction media at moderate reaction temperature in a short time (5 min). Citric acid monohydrate and urea were used as the precursors. The as-prepared CNQDs were characterized by multiple analytical techniques. The CNQDs exhibited an uncommon excitation wavelength-dependent fluorescence with two maximum emission peaks at 450 and 540 nm. The CNQDs with a quantum yield of 27.1% could serve as an effective fluorescent sensing platform for label-free sensitive detection of Hg(2+) ions with a detection limit of 0.14 μM. This method was also applied to the detection of Hg(2+) ions in tap water samples.