A platinum surface during cathodic corrosion.
For almost 20 years, scientists could not explain a strange phenomenon: why do typically stable platinum electrodes run as quickly when used on electrochemical devices?
This question has come out a lot carafor example, in water electrolyzers used for the production of hydrogen and electrochemical sensors, notes, but researchers from the Slac National Accelerator Laboratory and the University of Leiden have just starred in a revolutionary discovery that appears to be the solution to the longtime puzzle.
Electrochemical devices, such as water electrolyzers, use submerged platinum electrodes on an electrolyte, often a salt water solution. Although platinum is a durable material, degraded under negative polarizationthat protects most corrosion metals. Platinum degradation It made no sense: It looked like a contranature that a stable metal decomposed so quickly under these conditions.
Two main theories tried to explain this fact: one proposed that electrolyte sodium ions infiltrate the atomic structure of platinum, and another suggested that both sodium and hydrogen ions were combined to form platinum hydrides, which led to corrosion. But neither theories explains the rapid degradation.
To solve this problem, the team resorted to high-resolution energy X-ray absorption conceoscopy, which allowed to observe platinum to corrode in real time for the first time, despite the interference of hydrogen bubbles that form during electrolysis. The team also developed a special “flow cell” to eliminate hydrogen bubbles, ensuring that x rays could penetrate the electrolyte and focus on the platinum surface.
The team found that the cause of corrosion was not sodium ions, as previously thought, but the platinum.
The discovery will be useful for developing solutions for corrosion and for the emergence of more efficient and more lasting electrochemical production methods, researchers say in the study on January 22 at Nature Materials.
