Enhanced electrochemiluminescence behavior of C,N quantum dots embedded g-C_3N_4 nanosheets and its sensing application for copper (Ⅱ)

摘要

Electrochemiluminescence (ECL) is a very sensitive method for trace analysis because of its background interference and high signal-to-noise ratio. In the past decade, the determination of Cu2+ in environment has attracted considerable attention since it plays an essential role in many physiological processes. Herein, a novel ECL sensor based on C,N quantum dots embedded g-C3N4 nanosheets (C,N-QDs@NSs) was constructed for the detection of Cu2+. The nanocomposite was rapidly obtained via the oxidation of normal g-C3N4 in H2O2 solution using sonochemical synthesizing method. Due to the abundant surface defects on C,N-QDs@NSs, the ECL intensity was magnified 2.5 times for using a C,N-QDs@NSs electrode in comparision to a g-C3N4 modified electrode. Besides, C,N-QDs@NSs could accelerate the rate of electron transfer in ECL reaction and thus resulted in the lower cathodic peak potential. Significantly, Cu2+ could effectively quench the ECL of C,N-QD@NSs, which endowed C,N-QD@NSs with a great advantage in the ECL detection of Cu2+. under optimum conditions, C,N-QDs@NSs modified electrode exhibited a linear detection range from 5x10(-4) to 10 mu M with a detection limit of 2x10(-4)mu M (S/N=3) for Cu2+, and was finally applied to detect Cu2+ in real samples with satisfactory results.