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Validating NiOxHy as the HER promoter for Ni electrodes with in-situ Dip-and-Pull XPS

Brige, Amandine ; Oshchepkov, Alexandr G. ; Bochs Cruz, Ángel ; Bournel, Fabrice ; Bonnefont, Antoine ; Yaroslavtsev, Alexander LU ; Temperton, Robert LU ; Shavorskiy, Andrey LU ; Gallet, Jean Jacques and Asset, Tristan , et al. (2026) In Electrochimica Acta 554.
Abstract

Nickel-based catalysts are the most promising alternative to replace platinum in hydrogen conversion devices in alkaline media. One approach to narrowing the performance gap between Pt and Ni is to fine-tune the nickel surface coverage by (hydr) oxide (NiOxHy) species, which determines its electrocatalytic activity for the hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions. As Ni easily oxidizes when exposed to air, probing the amount and the nature of oxidized surface sites present under reaction conditions using ex-situ methods is challenging. In this work, we used dip-and-pull X-ray photoelectron spectroscopy (XPS) to study in-situ the evolution of the surface NiOxHy layer on a... (More)

Nickel-based catalysts are the most promising alternative to replace platinum in hydrogen conversion devices in alkaline media. One approach to narrowing the performance gap between Pt and Ni is to fine-tune the nickel surface coverage by (hydr) oxide (NiOxHy) species, which determines its electrocatalytic activity for the hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions. As Ni easily oxidizes when exposed to air, probing the amount and the nature of oxidized surface sites present under reaction conditions using ex-situ methods is challenging. In this work, we used dip-and-pull X-ray photoelectron spectroscopy (XPS) to study in-situ the evolution of the surface NiOxHy layer on a polycrystalline nickel electrode. We followed its growth as a function of the applied potential and subsequent transformation during HER. The analysis of XPS spectra enabled us to estimate the thickness of the NiOxHy layer and to hypothesize about the evolution of its nature. We show that the concentration of the metastable NiOxHy species under HER is linked to the potential at which the surface was initially oxidized and confirm by dip-and-pull XPS that the Ni/NiOxHy ratio to maximize HER activity corresponds to ∼ 70/30.

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type
Contribution to journal
publication status
published
subject
keywords
Dip-and-pull, Hydrogen evolution reaction, In-situ, Nickel, X-ray photoelectron spectroscopy
in
Electrochimica Acta
volume
554
article number
148296
publisher
Elsevier
external identifiers
  • scopus:105029064037
ISSN
0013-4686
DOI
10.1016/j.electacta.2026.148296
language
English
LU publication?
yes
id
f7195e3a-f612-4d0a-85e8-3da337375205
date added to LUP
2026-02-18 10:55:53
date last changed
2026-02-18 10:57:01
@article{f7195e3a-f612-4d0a-85e8-3da337375205,
  abstract     = {{<p>Nickel-based catalysts are the most promising alternative to replace platinum in hydrogen conversion devices in alkaline media. One approach to narrowing the performance gap between Pt and Ni is to fine-tune the nickel surface coverage by (hydr) oxide (NiO<sub>x</sub>H<sub>y</sub>) species, which determines its electrocatalytic activity for the hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions. As Ni easily oxidizes when exposed to air, probing the amount and the nature of oxidized surface sites present under reaction conditions using ex-situ methods is challenging. In this work, we used dip-and-pull X-ray photoelectron spectroscopy (XPS) to study in-situ the evolution of the surface NiO<sub>x</sub>H<sub>y</sub> layer on a polycrystalline nickel electrode. We followed its growth as a function of the applied potential and subsequent transformation during HER. The analysis of XPS spectra enabled us to estimate the thickness of the NiO<sub>x</sub>H<sub>y</sub> layer and to hypothesize about the evolution of its nature. We show that the concentration of the metastable NiO<sub>x</sub>H<sub>y</sub> species under HER is linked to the potential at which the surface was initially oxidized and confirm by dip-and-pull XPS that the Ni/NiO<sub>x</sub>H<sub>y</sub> ratio to maximize HER activity corresponds to ∼ 70/30.</p>}},
  author       = {{Brige, Amandine and Oshchepkov, Alexandr G. and Bochs Cruz, Ángel and Bournel, Fabrice and Bonnefont, Antoine and Yaroslavtsev, Alexander and Temperton, Robert and Shavorskiy, Andrey and Gallet, Jean Jacques and Asset, Tristan and Savinova, Elena R.}},
  issn         = {{0013-4686}},
  keywords     = {{Dip-and-pull; Hydrogen evolution reaction; In-situ; Nickel; X-ray photoelectron spectroscopy}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Electrochimica Acta}},
  title        = {{Validating NiO<sub>x</sub>H<sub>y</sub> as the HER promoter for Ni electrodes with in-situ Dip-and-Pull XPS}},
  url          = {{http://dx.doi.org/10.1016/j.electacta.2026.148296}},
  doi          = {{10.1016/j.electacta.2026.148296}},
  volume       = {{554}},
  year         = {{2026}},
}