Solid oxide cells are important for clean energy. These devices work at high temperatures and can do two jobs. They can be fuel cells that make electricity from hydrogen. They can also use electricity to split water and make hydrogen gas. To make these reactions happen quickly, engineers use tiny helpers called nanocatalysts.
Scientists used to think these metal helpers were simple and did not change. But researchers in South Korea have found they have a hidden, active behavior. A new study shows that silver nanocatalysts actually move their active areas depending on the job they are doing.
The journal Energy & Environmental Science featured this research. The team tested metals like cobalt, palladium, and platinum. They found silver worked best for oxygen reactions. The surprise was how the silver worked differently for different tasks.
When a solid oxide cell makes electricity, it needs to reduce oxygen. Silver particles help move electrons to oxygen molecules. The scientists saw the most activity where the silver touched the electrode.
But when the device made hydrogen, it released oxygen. Silver particles helped join oxygen atoms. In this case, the main activity moved to the outer surface of the silver.
To see this, the researchers created a special testing environment. They used powerful equipment and computer models to watch the silver change the electrode's surface.
Experts from Seoul National University, the Korea Advanced Institute of Science and Technology, and the Korea Basic Science Institute worked together. Professor WooChul Jung from Seoul National University said the discovery is important. He explained that the research shows where nanocatalysts work and how they operate.
This changing behavior means engineers must think differently about catalysts. The researchers suggest a new way to build clean energy devices. By improving the catalyst's outer shell and its connection to the electrode, better machines can be made. This could lead to more efficient hydrogen fuel production and better power for homes and factories.