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Updated: Jun 28, 2026
10:51
The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
12.9K
Suppress Ru Over-Oxidation Through Oxygen Vacancy Engineering - Showcase With Ni-Modified RuO2 via Molten-Salt
Ebrahim Sadeghi1,2, Hee Jung Kwon3, Celine Maynau4
1Department of Green Technology, University of Southern Denmark, Odense, Denmark.
Small (Weinheim an Der Bergstrasse, Germany)
|April 5, 2026
Summary
This study introduces a novel, iridium-free nickel-incorporated ruthenium oxide (RuO2) catalyst for proton exchange membrane (PEM) electrolyzers. Moderate nickel content enhances activity and durability for the oxygen evolution reaction (OER).
Area of Science:
- Materials Science
- Electrochemistry
- Catalysis
Background:
- Proton exchange membrane (PEM) electrolyzers require efficient and stable anode electrocatalysts for the oxygen evolution reaction (OER).
- Iridium-based catalysts are currently dominant but expensive, necessitating the development of alternative materials.
- Developing iridium-free catalysts is crucial for the economic viability of green hydrogen production.
Purpose of the Study:
- To develop and characterize an iridium-free electrocatalyst for the oxygen evolution reaction (OER) in PEM electrolyzers.
- To investigate the effect of nickel incorporation into ruthenium dioxide (RuO2) on catalytic activity and durability.
- To understand the structure-property relationships governing the performance of Ni-incorporated RuO2.
Main Methods:
- Solid-state, molten-salt synthesis (MSS) for preparing Ni-incorporated RuO2.
- X-ray diffraction (XRD) and density functional theory (DFT) analyses to study material structure and bonding.
- High-resolution microscopy for elemental distribution analysis.
- Electrochemical studies to evaluate catalytic activity and long-term stability.
Main Results:
- Moderate Ni incorporation into RuO2 optimizes Ru oxidation state and favors the adsorbate-evolving mechanism (AEM), enhancing activity.
- Higher Ni content leads to instability via the lattice oxygen oxidation mechanism (LOM).
- Ni2+ substitutional doping at Ru4+ sites was confirmed, inducing lattice contraction and electronic interactions between Ni and Ru.
- The optimized catalyst (Ru0.75Ni0.25Ox) retained 56% activity after 6000 cycles and showed only a 4% potential increase after 50 hours of OER at 10 mA cm-2.
Conclusions:
- Ni-incorporated RuO2 prepared via MSS is a promising, scalable, and iridium-free electrocatalyst for acidic OER.
- Controlled Ni doping is essential to balance activity and stability, with moderate doping favoring AEM and high doping promoting LOM.
- The developed catalyst demonstrates excellent potential for application in PEM electrolyzers.
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