Kinetics of hydrogen evolution on submicron size Co, Ni, Pd and CoNi alloy powder electrodes by d.c. polarization and a.c. impedance studies

Elumalai, P and Vasan, HN and Munichandraiah, N and Shivashankar, SA (2002) Kinetics of hydrogen evolution on submicron size Co, Ni, Pd and CoNi alloy powder electrodes by d.c. polarization and a.c. impedance studies. In: Journal of Applied Electrochemistry, 32 (9). pp. 1005-1010.

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Abstract

Submicron size Co, Ni and Co-Ni alloy powders have been synthesized by the polyol method using the corresponding metal malonates and Pd powder by reduction of PdOx in methanol. The kinetics of the hydrogen evolution reaction ( HER) in 6 M KOH electrolyte have been studied on electrodes made from the pressed powders. The d.c. polarization measurements have resulted in a value close to 120 mV decade(-1) for the Tafel slope, suggesting that the HER follows the Volmer-Heyrovsky mechanism. The values of exchange current density (i(o)) are in the range 1-10 mA cm(-2) for electrodes fabricated in the study. The a.c. impedance spectra measured at several potentials in the HER region showed a single semicircle in the Nyquist plots. Exchange current density (i(o)) and energy transfer coefficient (alpha) have been calculated by employing a nonlinear least square-fitting program.

Item Type:	Journal Article
Publication:	Journal of Applied Electrochemistry
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	a.c.impedance;d.c.polarization;hydrogen evolution;submicron size particles
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	19 Jul 2011 09:39
Last Modified:	19 Jul 2011 09:39
URI:	http://eprints.iisc.ac.in/id/eprint/39255

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