Decoupling Morphological and Electronic Effects of Ni-Doped Ruthenium Oxide Oxygen Evolution Catalysts for PEM Water Electrolysis
8 affiliations
- 1Institute of Chemistry
- 2University of Tartu
- 3Institute of Physics
- 4Department of Physics and Astronomy
- 5University of Turku
- 6Institute of Ecology and Earth Sciences
- 7Department of Materials and Environmental Technology
- 8Tallinn University of Technology
Abstract
Proper assessment of oxygen evolution reaction (OER) catalyst performance requires recognising that doping can introduce simultaneous changes to structure, morphology, and electronic properties that together influence the observed electrochemical behaviour. In this study, Ni-doped RuO2 is used as a model system to systematically investigate how dopant concentration and synthesis temperature affect catalyst morphology and electronic structure. These trends are correlated with OER mass activity (MA), intrinsic activity, and stability enabling the morphological and intrinsic electronic contributions to catalyst performance to be distinguished. The acid-stable limit for bulk Ni incorporation in RuO2 is found to be approximately 10 mol%. Ni incorporation affects the rutile structure and inhibits particle growth, while lower synthesis temperatures decrease particle size. The best-performing Ni-doped RuO2 catalyst here shows up to a tenfold increase in OER MA compared with undoped RuO2. Surface area-based normalisation of MA reveals that this enhancement is partly caused by increased accessible surface area and includes an additional contribution from increased intrinsic OER activity. X-ray photoelectron spectroscopy reveals Ni-dependent changes in the Ru 3d and O 1s regions (electronic effect), which correlate with the increase in intrinsic OER activity. S-number measurements further indicate an approximately twofold improvement in catalyst stability caused by doping.
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BibTeX
@misc{berziņs2026decoupling,
title = {{Decoupling Morphological and Electronic Effects of Ni-Doped Ruthenium Oxide Oxygen Evolution Catalysts for PEM Water Electrolysis}},
author = {Mairis Bērziņš and Peeter Valk and Tavo Romann and Priit Möller and Jekaterina Kozlova and Kuno Kooser and Sari Granroth and Jaan Aruväli and Peeter Paaver and Marian Külaviir and Valdek Mikli and Rutha Jäger and Enn Lust and Jaak Nerut},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008551/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008551/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Decoupling Morphological and Electronic Effects of Ni-Doped Ruthenium Oxide Oxygen Evolution Catalysts for PEM Water Electrolysis
AU - Mairis Bērziņš
AU - Peeter Valk
AU - Tavo Romann
AU - Priit Möller
AU - Jekaterina Kozlova
AU - Kuno Kooser
AU - Sari Granroth
AU - Jaan Aruväli
AU - Peeter Paaver
AU - Marian Külaviir
AU - Valdek Mikli
AU - Rutha Jäger
AU - Enn Lust
AU - Jaak Nerut
PY - 2026
DA - 2026/09/09
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008551/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008551/v1
AB - Proper assessment of oxygen evolution reaction (OER) catalyst performance requires recognising that doping can introduce simultaneous changes to structure, morphology, and electronic properties that together influence the observed electrochemical behaviour. In this study, Ni-doped RuO2 is used as a model system to systematically investigate how dopant concentration and synthesis temperature affect catalyst morphology and electronic structure. These trends are correlated with OER mass activity (MA), intrinsic activity, and stability enabling the morphological and intrinsic electronic contributions to catalyst performance to be distinguished. The acid-stable limit for bulk Ni incorporation in RuO2 is found to be approximately 10 mol%. Ni incorporation affects the rutile structure and inhibits particle growth, while lower synthesis temperatures decrease particle size. The best-performing Ni-doped RuO2 catalyst here shows up to a tenfold increase in OER MA compared with undoped RuO2. Surface area-based normalisation of MA reveals that this enhancement is partly caused by increased accessible surface area and includes an additional contribution from increased intrinsic OER activity. X-ray photoelectron spectroscopy reveals Ni-dependent changes in the Ru 3d and O 1s regions (electronic effect), which correlate with the increase in intrinsic OER activity. S-number measurements further indicate an approximately twofold improvement in catalyst stability caused by doping.
ER -