Preparation and application of copper hydroxide (oxide) / multi wailed carbon nanotubes nanocomposite-modified glassy carbon electrode as a nitrite sensor

摘要

Copper hydroxide (oxide) / multiwalled carbon nanotubes nanocomposite-modified glassy carbon electrode (Cuu_(hydroxide/oxide)/MWCNTs/GCE) was successfully prepared by a novel film plating/cyclic voltammetry (CV) method, which exhibited marked synergistic catalytic effects on the electro-oxidation of NO_2~-. The preparation process, impedance behavior, and surface morphology of Cu_(hydroxide/oxide)/MWCNTs/GCE were investigated by CV, electrochemical impedance spectroscopy, and scanning electron microscopy (SEM), respectively. The optimum preparation and test conditions for the electrode to have high catalytic activity were acquired. The linear range between the anodic current (Δi_a, μA) and NO_2~- concentration (c, mmol L~(-1)) was 1.0 X 10~(-4) to 14.0 mmol L~(-1), and the corresponding calibration curve was Δi_a = -0.1504 + 57.954c (R -0.9990, n = 32) with a detection limit of 0.03 μmol L~(-1) (S/N = 3). The Cu_(hydroxide/oxide)/MWCNTs/GCE prepared in the optimal conditions showed good stability, high selectivity, low detection limit, and quick response (<0.2 s) to NO_2~- in phosphate buffer (pH 5.29) at 0.78 V, which has been successfully applied to the determination of NO_2~- in pickled vegetables with satisfactory results.