A novel luminol chemiluminescence system induced by black phosphorus quantum dots for cobalt (II) detection

Black phosphorus quantum dots (BP QDs) were prepared through a solvothermal exfoliation method in alkaline N -methyl-2-pyrrolidinone. The BP QDs induce distinct chemiluminescence (CL) of alkaline luminol directly. A possible reaction mechanism is proposed by the study of CL spectrum, ultraviolet–visible absorption spectra, electron paramagnetic resonance spectra as well as radical scavenging experiments. The presence of BP QDs significantly increases generation of active oxygen species, which oxidize luminol and lead to intense CL emission at 425 nm. The reaction of luminol with BP QDs are specifically catalyzed by cobalt (II) ion, this presents a sensitive CL method for cobalt (II) ion. A linear response range extends from 2.5 to 2000.0 pmol/L cobalt (II) ion and a detection limit of 0.7 pmol/L (3 s b ) is acquired. The method displays a good precision approved by a relative standard deviation of 1.9% at 100.0 pmol/L cobalt (II) ion solution (n = 11). A preliminary application of the method was conducted by successful determination of cobalt amount in silica gel and rain water samples. • Intense chemiluminescence is produced between alkaline luminol and BP QDs in absence of an oxidant. • BP QDs significantly increases generation amount of active oxygen species. • The luminol-BP QDs reaction was observably catalyzed by cobalt (II) ion. • A sensitive chemiluminescence method is developed for cobalt (II) ion assay.