A Water-Splitting Catalyst That Lasts Longer Near 0°C
October 21, 2026
New low-temperature electrochemical behavior discovered in supercooled water
Researchers at the RIKEN CSRS have discovered that cooling water enables a manganese oxide catalyst used for water electrolysis to achieve its longest lifetime near 0°C.
Water electrolysis is attracting attention as a technology for producing hydrogen and oxygen from water. However, the oxygen evolution reaction (OER) involved in water electrolysis takes place under harsh chemical conditions, causing catalysts to deteriorate over time and posing a challenge to their long-term stability.
The research group used manganese oxide as a model catalyst and investigated the temperature dependence of the oxygen evolution reaction and catalyst degradation. They found that as the temperature decreased, the oxygen evolution reaction slowed down, while the catalyst degradation reaction slowed down even more significantly. Surprisingly, upon further cooling below 0°C, they discovered that catalyst degradation accelerated again. In other words, catalysts do not necessarily last longer as the temperature decreases; instead, they achieve their longest lifetime near 0°C. Further experiments revealed that the electrolyte could remain liquid below its freezing point of approximately −6.5 °C, a phenomenon known as supercooling, under which catalyst degradation becomes more pronounced. These findings reveal an unusual temperature dependence in low-temperature electrochemistry that differs from the general Arrhenius law, which describes how reaction rates decrease with decreasing temperature.
These findings are expected to advance our understanding of electrochemical reactions at low temperatures, particularly in supercooled water, an area that has not been extensively investigated. They may also contribute to understanding electrochemical phenomena in cold regions and polar environments, as well as on extraterrestrial bodies, where further research is expected to open up new possibilities.
The electrolyte's measured freezing point is −6.5 °C, so 0 °C is not literally just before ice formation.
- Original article
- Nature Chemistry DOI: 10.1038/s41557-026-02274-8
- A. C. Wardhana, H. Ooka, T. Lim, A. Li, K. Adachi, C. Chen, D. Hashizume, R. Nakamura,
- "Cooling Water to Near Freezing Breaks the Activity-stability Trade-off of Water Oxidation Electrocatalysis".
- Contact
- Ryuhei Nakamura; Team Director
Hideshi Ooka; Senior Visiting Scientist
Aufandra Cakra Wardhana; Postdoctoral Researcher
Biofunctional Catalyst Research Team
