Electrochemical Deposition of Nickel Oxide Nanocatalyst on Anodically Pretreated Glassy Carbon and its Electrocatalytic Activity

The effects of anodic oxidation of glassy carbon (GC) in H2SO4 and NaOH electrolytes on the electrodeposition of nickel oxide nanoparticles (NiOx) and on the electrocatalytic activity of the GC/NiOx electrode are studied. Cyclic voltammetry (CV), Tafel Plot, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) are used for characterization of the electrodes. The structural and electrochemical characteristic of GC/NiOx (GC is unoxidized), GC(OX-AC)/NiOx (GC is oxidized in acid (0.1 M H2SO4)) and GC(OX-AL)/NiOx (GC is oxidized in alkali (0.1 M NaOH)) are different. While NiOx nanoparticles deposited on GC(OX-AC) reveal a bird-like shape, it shows semi-spherical shape with larger size when it is deposited on either GC or GC(OX-AL). Glucose electrooxidation in alkaline medium is used as a probe reaction to study and compare the electrocatalytic activity of the GC/NiOx with GC(ox) (GC is oxidized in acid or alkali). Enhancement of glucose oxidation on either GC(OX-AC)/NiOx or GC(OX-AL)/NiOx is evident. While glucose oxidation on either GC(OX-AC)/NiOx or GC(OX-AL)/NiOx, shows higher peak currents, it shows negative shifts in both the peak and onset potentials only on the GC(OX-AL)/NiOx. The enhancement and the difference in the catalytic activity on both GC(OX-AC) /NiOx and GC(OX-AL)/NiOx are discussed in the light of surface analysis of both electrodes compared to GC /NiOx.