▎ 摘　　要

A composite electrode material based on graphene oxide (GO) and polyvinyl alcohol (PVA) containing electrodeposited Ni-Co species was electrochemically characterized in alkaline medium (0.1 M NaOH). The well distinct I-a/I-c redox couple shifts to the cathodic potentials in presence of Co oxide species contained in the active deposit. The effect of the potential scan rates (nu) on the I-a/I-c redox couple was studied in the range comprised between 10 mV s(-1) and 250 mV s(-1). The plots of the log(peak current) vs log(nu) gave straight lines with slopes between 0.65 and 0.75, showing a diffusive character of the redox currents. Continuous potentiostatic charge/discharge process between 0.4 V and 0.1 V vs SCE were carried out in alkaline medium in order to ascertain the supercapacitor performance of the investigated GC/GO/PVA/Ni-Co electrode. The composite electrode shows significantly higher capacitance (3.1-10(-4) F). Admitting the only Ni-Co oxide as active electrode material, a specific capacitance of about 2100 +/- 200 F g(-1), was evaluated. During the charge/discharge process in alkaline medium, the electrode system shows, after an initial physical stabilization, a good electrochemical stability (< 0.5%). Under cyclic voltammetry, the GC/GO/PVA/Ni-Co electrode shows good catalytic activity (0.5 V vs SCE) toward electrooxidation of several hydroxylated organic molecules. The sensitivities are related to the number of OH groups per molecule according to the following order: glucose > sorbitol > glycerol > methanol. Flow injection analysis (FIA), performed under flowing 0.1M NaOH solution and an applied constant potential of 0.5 V, show well-defined symmetrical and reproducible peaks in a wide range of concentration of investigated analytes. (C) 2017 Elsevier Ltd. All rights reserved.