Key Words:Electrochemical electrodes;Charge transfer - Cobalt compounds - Cyclic voltammetry - Electrochemical impedance spectroscopy - Electrochemistry - Electron transitions - Electrooxidation - High resolution transmission electron microscopy - Ionic liquids - Lithium compounds - Nanospheres - Rate constants - Scanning electron microscopy - Sulfur compounds - Surface diffusion - Synthesis (chemical) - Transmission electron microscopy - X ray diffraction - X ray diffraction analysis;Apparent diffusion coefficient - Carbon ionic liquid electrode - Charge transfer coefficient - Electrochemical behaviors - Electrochemical parameters - Electrochemical performance - Hexafluorophosphates - Voltammetric determination

Abstract:In this study, LiCoO<inf>2</inf>nanoparticles were synthesized by the hydrothermal method and characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analyses, which exhibited flower-like nanospheres composed of uniform nanosheets. The synthesized LiCoO<inf>2</inf>nanospheres were further used for the modification of 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE). The electrochemical performance of the modified electrode, LiCoO<inf>2</inf>/CILE, was studied by cyclic voltammetry and electrochemical impedance spectroscopy. Electrooxidation of p-methylaminophenol sulfate (metol) on the modified electrode was further tested and electrochemical responses of metol were significantly enhanced owing to the presence of LiCoO<inf>2</inf>nanospheres with large surface area and fast electron transfer rate. The electrochemical parameters such as the charge transfer coefficient, the number of electron transferred, the standard electrode reaction rate constant, and the apparent diffusion coefficient for metol electrooxidation were calculated as 0.51, 0.91, 0.92 s^{- 1}and 7.06 &times; 10^{- 5}cm²/s, respectively. Under the optimized conditions, metol can be linearly detected in the concentration range from 0.4 to 400.0 &mu;mol/L with a detection limit of 2.46 &times; 10^{- 7}mol/L (3&sigma;). The optimized method was further applied to the detection of metol content in artificial wastewater samples with satisfactory results. &copy; 2014 Elsevier B.V.<br/>

Volume:564

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Translation or Not:no