PrFeO3-MoS2 nanosheets for use in enhanced electro-oxidative sensing of nitrite

The authors describe the synthesis, characterization and electrochemical sensing performance of a PrFeO3-MoS2 nanocomposite. Graphene-like MoS2 sheets and a perovskite-type PrFeO3 were synthesized via a hydrothermal and a sol-gel method, respectively. Finally, PrFeO3-MoS2 nansheets were synthesized by using sodium molybdate as a source for molybdenum and thiourea as the source for sulfur. The nansheets were characterized by transmission electron microscopy and X-ray diffraction. The electrochemical behavior of the nanosheets deposited on a glassy carbon electrode was studied via electrochemical impedance spectroscopy and cyclic voltammetry. The modified electrodes display strong response to nitrite. At a scan rate of 100 mV.s(-1), the current at the oxidation peak at 0.85 V (vs. SCE) increases linearly in the 0.005 to 3 mM nitrite concentration range. The detection limit is 1.67 mu mol.L-1 (S/N = 3). The sensor is selective, stable and reproducible. It was successfully applied to the determination of nitrite in (spiked) real samples, and appropriate recoveries were obtained.