Nickel phosphide: the effect of phosphorus content on hydrogen evolution activity and corrosion resistance in acidic medium
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Published version
Author(s)
Kucernak, ARJ
Sundaram, VNN
Type
Journal Article
Abstract
Transition metal phosphides possess novel, structural, physical and chemical properties and are an emerging new class of materials for various catalytic applications. Electroplated or electrolessly plated nickel phosphide alloy materials with achievable phosphorus contents <15 at% P are known to be more corrosion resistant than nickel alone, and have been investigated as hydrogen evolution catalysts in alkaline environments. However, there is significant interest in developing new inexpensive catalysts for solid polymer electrolyte electrolysers which require acid stable catalysts. In this paper, we show that by increasing the phosphorus content beyond the limit available using electroplating techniques (∼12 at% P), the nickel based phosphides Ni12P5 and Ni2P with higher levels of phosphorus (29 and 33 at% P) may be utilised for the hydrogen evolution reaction (HER) in acidic medium. Corrosion resistance in acid is directly correlated with phosphorus content – those materials with higher phosphorus content are more corrosion resistant. Hydrogen evolution activity in acid is also correlated with phosphorus content – Ni2P based catalysts appear to be more active for the hydrogen evolution reaction than Ni12P5. Electrochemical kinetic studies of the HER reveal high exchange current densities and little deviation in the Tafel slope especially in the lower overpotential regime for these nickel phosphide catalysts. The electrochemical impedance spectroscopy response of the respective system in acidic medium reveals the presence of two time constants associated with the HER.
Date Issued
2014-08-20
Date Acceptance
2014-08-19
Citation
Journal of Materials Chemistry A, 2014, 2 (41), pp.17435-17445
ISSN
2050-7496
Publisher
Royal Society of Chemistry
Start Page
17435
End Page
17445
Journal / Book Title
Journal of Materials Chemistry A
Volume
2
Issue
41
Copyright Statement
This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/I013032/1
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Energy & Fuels
Materials Science, Multidisciplinary
Chemistry
Materials Science
ALKALINE WATER ELECTROLYSIS
NI-P ALLOYS
H-2 EVOLUTION
ELECTROCATALYTIC BEHAVIOR
ELECTROCHEMICAL IMPEDANCE
ELECTRODES
METALS
NANOPARTICLES
KINETICS
COATINGS
Publication Status
Published