Enhanced electrochemiluminescence of ZnO nanoparticles decorated on multiwalled carbon nanotubes in the presence of peroxydisulfate

A glassy carbon electrode was modified with a nanohybrid material consisting of zinc oxide (ZnO) nanoparticles deposited on the surface of multiwalled carbon nanotubes. The nanohybrid was prepared by the use of a rapid, solvent-less and reductant-less thermal decomposition method. The modified electrode yielded a strongly enhanced electrochemiluminescence (ECL) signal at an applied potential of -1.65 V (versus Ag|AgCl|KClsat) in KOH solution containing peroxydisulfate. The increase in ECL signal intensity (with a peak at 570 nm) is attributed to an electron transfer reaction that occurred between the species formed by the reduction of peroxydisulfate and ZnO nanoparticles. The ECL signal is stable and reproducible, indicating that the nanohybrid can be used as a viable ECL luminophore. A linear relationship was found between ECL signal and peroxydisulfate concentration in the range between 0.5 and 300 mM. Conceivably, the method can be applied for the determination of species which introduce enhancement or an inhibition effect on the ECL signal of ZnO nanoparticles and peroxydisulfate.