Temperature triggers distinct RhRu鈧僌鈧� reaction mechanisms, offering clues for better water-splitting catalysts
Sadie Harley
scientific editor
Robert Egan
associate editor
The oxygen evolution reaction is more relevant to your daily life than you would think. It is used in many electrochemical devices, such as batteries. However, this reaction still has a lot of room for improvement that would allow for it to be applied at a larger scale in next-gen technology.
To achieve this, researchers at Tohoku University demonstrated an effect that influences the stability of catalysts鈥攖he key to making this oxygen evolution reaction more efficient.
were published in Nature Communications.
The research team used a home-made operando differential electrochemical mass spectrometry system to examine how RhRu3Ox behaves in the oxygen evolution reaction. Their findings showed a temperature-dependent mechanism evolution effect, which means that a certain stage of the reaction is triggered by temperature.
The revelation of this effect will help researchers understand how to manipulate this pathway in order to create more stable catalysts.
"We found that this catalyst tends toward different reaction mechanisms at high versus low temperatures, which we can now use to our advantage to try and get the outcome that we want," explains Heng Liu (Advanced Institute for Materials Research, WPI-AIMR).
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Photograph (a) and Schematic illustration (b) of the operando TC-DEMS set up. Triangular potential applied at room temperature (c) and 60 掳C (d) and corresponding MS signal. The upper panel shows the potential (black, left axis) and current density (red, right axis) in relation to time. The lower panel shows the MS signals for 32O2 (m/z = 32, orange) and 34O2 (m/z = 34, blue). The integrated peak area of m/z = 32 (e) and m/z=34 (f) at different cycles and different temperatures. (g) Ratio of peak area of 34O2: 32O2. Credit: Heng Liu et al. -
Calculated 1D surface Pourbaix diagram as a function of potential vs. RHE (pH 1; temperature=298.15 K) (a) and 2D surface Pourbaix diagram as a function of potential vs. SHE and pH (temperature: 298.15 K) (b) of RuO2 (110). AEM and LOM OER mechanisms illustration (c) and relevant free energy diagrams of these two mechanisms on RhRu3Ox and undoped RuO2 (d). Credit: Heng Liu et al.
Since practical implementation is also important, they evaluated the stability of RhRu3Ox. Remarkably, it remained stable for over 1,000 hours at room temperature (current density: 200 mA cm鈭�2).
To advance this research further, future work should focus on optimizing the F doping levels to systematically enhance catalytic performance and durability under commercial-scale PEM electrolyzer conditions.
This work represents considerable advancement in the fundamental research of TMPs-based hydrogen evolution reaction (HER) catalysts, which paves the way for the rational design of novel highly efficient, non-noble metal-based cathodes for commercial applications.
These catalysts hold tremendous potential as a way to help reduce our reliance on fossil fuels and generate energy in an environmentally friendly manner.
More information: Ming-Rong Qu et al, Temperature-dependent mechanism evolution on RhRu3Ox for acidic water oxidation, Nature Communications (2025).
Journal information: Nature Communications
Provided by Tohoku University
