Effect of different synthesis routes on the electrocatalytic properties of NiOx nanoparticles

Nanoparticles of nickel oxide (nano-NiOx) have been synthesized using electrochemical and sol-gel routes. Impacts of the synthesis route on the structural and electrochemical properties of NiOx nanoparticles modified glassy carbon electrode (nano-NiOx/GC) are studied. Cyclic voltammetry (CV), field emission scanning electron microscopy (FE-SEM), X-ray diffraction and transmission electron microscopy (TEM) have been used for the characterization of nano-NiOx/GC. The size of the particles using the sol-gel technique (NiOx-SG) is uniform and have smaller particle size (similar to 20 nm) than that obtained using the electrochemical route (NiOx-El, similar to 80 nm). The specific activity (given in mA per mg of the NiOx) of the Ni(OH)(2)/NiOOH redox couple of the NiOx-SG is higher with higher reversibility compared with the NiOx-EL. Impacts of the synthesis route on the electrocatalytic properties of the thus prepared NiOx-SG and NiOx-El are tested by the glucose oxidation in alkaline solution as a probing reaction for the electrocatalytic activity. Enhancement of glucose electrocatalytic oxidation is discussed in the light of the difference in structural and electrochemical characteristics of both catalysts. (C) 2016 Elsevier B.V. All rights reserved.