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Amorphous Ni-Nb-Y Alloys as Hydrogen Evolution Electrocatalysts

Authors
  • Ghobrial, S.1
  • Kirk, D. W.2
  • Thorpe, S. J.1
  • 1 University of Toronto, Department of Materials Science & Engineering, Toronto, Ontario, M5S 3E4, Canada , Toronto (Canada)
  • 2 University of Toronto, Department of Chemical Engineering & Applied Chemistry, Toronto, Ontario, M5S 3E5, Canada , Toronto (Canada)
Type
Published Article
Journal
Electrocatalysis
Publisher
Springer US
Publication Date
Mar 01, 2019
Volume
10
Issue
3
Pages
243–252
Identifiers
DOI: 10.1007/s12678-019-00519-4
Source
Springer Nature
Keywords
License
Yellow

Abstract

Ongoing improvements in the performance of anion exchange membranes (AEM) have renewed interest in alkaline water electrolysis for large-scale hydrogen production. New electrocatalysts are required to interface with such AEM water electrolyzers. Ni-Nb-Y amorphous and amorphous-nanocrystalline alloys were prepared by cryomilling and evaluated as electrocatalysts towards the hydrogen evolution reaction. The roles of microstructure and chemistry on catalytic activity were investigated. Characterization by X-ray diffraction and transmission electron microscopy identified Ni5Y nanocrystals finely dispersed in an amorphous Ni-Nb-Y matrix among the multiphase alloys. Capacitance measurements near open-circuit potential were used to estimate the electrochemically active surface area (ECSA) in order to elucidate the activity of various catalyst morphologies on an intrinsic basis. Enhanced intrinsic activity from these multiphase structures were found in kinetic data from Tafel and impedance spectroscopic measurements. A multiphase Ni81.3Nb6.3Y12.5 catalyst displayed the greatest catalytic activity attributed to the presence of a nanocrystalline Ni5Y secondary phase finely dispersed in the Ni-Nb-Y amorphous matrix with increased yttrium content. These preliminary results demonstrate that ball milled Ni-based amorphous-based materials are promising catalysts for electrochemical hydrogen production. Graphical Abstract

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