Methanol oxidation on titanium-supported nano-scale Ni flakes

A novel titanium-supported nano-scale nickel catalyst (nanoNi/Ti) with flaky structures was successfully fabricated with the hydrothermal process by using hydrazine hydrate as a reduction agent. It was shown from cyclic voltammograms in alkaline solutions that the oxidation current of methanol on the nanoNi/Ti was much higher than that on a polycrystalline nickel (Ni), and that the oxidation peak current on the nanoNi/Ti was seven times higher than on Ni. It was observed from chronoamperometric measurements that the steady-state current (I-ss) on the nanoNi/Ti was also significantly higher than on Ni, and the I-ss is well linearly proportional to the methanol concentration. Electrochemical impedance spectra on the nanoNi/Ti reveal that the presence of methanol in 1 M NaCH enhances the charge transfer process of the oxidation of Ni(OH)(2) to NiOOH. In the activation range of methanol oxidation, the charge transfer resistance decreases with the increase of anodic potentials and methanol concentrations. This novel nickel electrode can be used repeatedly and exhibits stable electrocatalytic activity for the methanol oxidation. (C) 2008 Elsevier B.V. All rights reserved.