Effect of alloys modified by sodium borohydride alkaline solutions on the kinetics of hydrogen evolution reaction at Mm(Ni3.6Co0.7Mn0.4Al0.3)(1.15) hydride electrodes

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Sequeira, CAC (Author) Other; Lobo, RFM (Author) Other

Journal

Title: International Journal of Hydrogen Energy

Vol. 35 No. 18

Pages: 9901-9909

ISSN: 0360-3199

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 8 Citations

Scopus - 7 Citations

Other information

Authenticus ID: P-003-3GD

DOI: 10.1016/j.ijhydene.2009.11.015

Abstract (EN): The effects of treating the alloy powder of an electrode with 6 M sodium hydroxide solution containing y M (y = 0.0, 0.005, 0.01, 0.02, 0.03, 0.05) sodium borohydride (NaBH4) on the kinetics of hydrogen evolution reaction (HER) at the Mm(B-5)(1.15) hydride electrode (Mm = cerium-rich mischmetal; B-5 = Ni3.6Co0.7Mn0.4Al0.3) are described. Several kinetic parameters are considered, including Total, Volmer and Tafel overpotentials, exchange current densities and activation energies of the elementary reactions. Such parameters are investigated by measuring the overpotential decay immediately after the interruption of an applied cathodic current. The effects of NaBH4 treatment and temperature on the mechanism of the HER are analysed on the basis of the dependence of the Volmer and Tafel overpotentials on current density. The effect of the NaBH4 concentration on the performance of the hydrogen storage alloy as a negative electrode material in nickel-metal hydride batteries and/or alkaline fuel cells is discussed from the standpoint of relative velocity of the elementary reactions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9