For nearly two decades, scientists have been puzzled by the corrosion of negatively polarized platinum electrodes, a costly issue for water electrolyzers used in hydrogen production and electrochemical sensors.
Now, researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Leiden University have identified the culprit, paving the way for cheaper hydrogen energy and more reliable sensors.
Electrolyzers and many electrochemical devices often use negatively polarized platinum electrodes in an electrolyte, essentially saltwater. Despite being a durable and stable option, platinum electrodes degrade under these conditions.
“For most metals, being negatively polarized protects against corrosion. But platinum electrodes can rapidly break down under these conditions,” explained Dimosthenis Sokaras, a Stanford Synchrotron Radiation Lightsource (SSRL) senior scientist and the SLAC team’s principal investigator.
Scientists discovered something unexpected about Platinum
The research revealed that the rapid breakdown of platinum electrodes is due to platinum hydrides not previously considered. Two theories have tried to explain this corrosion, pointing to either sodium ions or a combination of sodium and hydrogen ions. However, the research team observed platinum corroding in real-time using high-energy-resolution X-ray spectroscopy techniques at SSRL.
The researchers developed a special “flow cell” to clear hydrogen bubbles that form during the electrode’s operation, enabling them to focus on the subtle changes in the platinum electrode. After years of data analysis, they confirmed that only platinum hydride could explain the observed corrosion patterns.
“By advancing the frontiers of X-ray science, SSRL has developed operando methods that, combined with modern supercomputing, now allow us to tackle decades-old scientific questions,” Sokaras said.
With these new insights, the team hopes to develop solutions to prevent platinum corrosion in electrolyzers and other devices. The project highlights the importance of collaborative expertise in solving complex scientific questions.
The research was funded in part by the International Whaling Commission’s Southern Ocean Research Partnership.
Journal Reference:
- Hersbach, T.J.P., Garcia-Esparza, A.T., Hanselman, S. et al. Platinum hydride formation during cathodic corrosion in aqueous solutions. Nat. Mater. (2025). DOI: 10.1038/s41563-024-02080-y
