Nickel oxide nanoparticles (nano-NiOx) of peculiar shape are prepared by sol-gel technique and its electrocatalytic activity is evaluated at different conditions. The thus prepared nanoparticles are annealed at three different temperatures, i.e., 200, 400 and 600 degrees C and anchored on glassy carbon (GC) electrode. Nano-NiOx modified GG (nano-NiOx/GC) electrodes are subjected to surface analysis techniques such as field emission scanning electron microscopy (FE-SEM) high resolution transmission electron micrograph (TEM) and X-ray diffraction (XRD). Electrochemical characterizations are performed using cyclic voltammetry and chronoamperometric techniques. The effects of annealing temperature on the morphological structure, surface concentration and subsequently on the electrochemical properties of nano-NiOx/GC are examined. Experimental results indicate that the grain size and electrochemical characteristics of the nano-NiOx/GC are significantly affected by the annealing temperature. The electrocatalytic oxidation of glucose at nano-NiOx/GC electrode is significantly enhanced especially with nano-NiOx annealed at 200 degrees C compared to those annealed at 400 and 600 degrees C. Nano-NiOx is believed to play a crucial role as a catalytic mediator to facilitate the charge transfer during the oxidation of glucose. (C) 2015 Elsevier B.V. All rights reserved.