Graphitic carbon nitride nanosheets-enhanced chemiluminescence of luminol for sensitive detection of 2,4,6-trinitrotoluene

We report that graphitic carbon nitride (g-C3N4) nanosheets can enhance the chemiluminescence (CL) of luminol and hydrogen peroxide (H2O2) system. The reaction mechanism of the luminol-H2O2-g-C3N4 nanosheets system was investigated by CL spectrum, UV-vis absorption spectroscopy, and radical scavengers. The g-C3N4 nanosheets-enhanced CL mechanism was attributed to the fact that g-C3N4 nanosheets were able to catalyze the decomposition of H2O2 to form reactive hydroxyl radical. The produced hydroxyl radical further reacted with luminol and H2O2 anion, generating a light emission. Moreover, 2,4,6-trinitrotoluene (TNT) was observed to inhibit the CL effectively. On this basis, a sensitive and selective sensing approach was successfully developed for the detection of TNT. The linearity ranged from 1 pM to 1 nM with a detection limit of 0.75 pM based on a signal-to-noise ratio of 3. This sensitivity increased about six orders of magnitude over that of g-C3N4 nanosheets-based fluorescence sensor.