Scientists have developed a new catalyst that uses 75% less platinum while delivering almost the same performance as pure platinum, potentially removing one of the biggest cost barriers facing hydrogen fuel cells.
Researchers at the IMDEA Materials Institute achieved the improvement using an unusual approach: gently compressing the catalyst.
The tiny mechanical change alters the material at the atomic level and makes it much more effective at supporting an important chemical reaction inside fuel cells.
The findings were published in the journal Electrochimica Acta.
Hydrogen fuel cells generate electricity by combining hydrogen with oxygen. Their main byproduct is water, making them attractive for clean-energy applications, particularly in areas where batteries may not be practical.
But fuel cells have an expensive problem: platinum.
Platinum is an excellent catalyst, meaning it speeds up chemical reactions without being consumed. In fuel cells, it is particularly important for accelerating the oxygen reduction reaction, one of the slowest steps involved in producing electricity.
Unfortunately, platinum is rare and costly. Reducing the amount needed without sacrificing performance could therefore make hydrogen fuel cells considerably cheaper to manufacture.
The researchers created a catalyst using an alloy containing copper and platinum. The material, known as Cu₃Pt, contains three copper atoms for every platinum atom and was placed on a nickel-titanium shape-memory material.
They then compressed the catalyst by less than 1%.
Although the physical change was extremely small, it altered the electronic structure of the catalyst and improved how effectively its surface supported the oxygen reduction reaction.
In laboratory tests under highly acidic conditions, the compressed copper-platinum catalyst reached 855 millivolts at a current density of 1 milliamp per square centimeter. Pure platinum tested under the same conditions reached 856 millivolts—an almost identical result.
The direction of the mechanical strain was crucial. When researchers stretched the material by 0.80% instead of compressing it, its catalytic performance dropped significantly.
The results support theoretical predictions that small changes in the spacing and arrangement of atoms can affect how strongly hydrogen-related molecules interact with a catalyst’s surface. By carefully controlling this atomic-scale strain, researchers can potentially tune a catalyst to work more efficiently.
Another helpful change happened during operation.
Some copper atoms naturally dissolved away from the surface during the electrochemical reaction. This left behind an extremely thin outer layer enriched with platinum, only a few nanometers thick.
According to the researchers, this self-organizing platinum-rich surface works together with the mechanical compression to provide strong catalytic performance despite the much lower overall platinum content.
The technology is not yet ready for commercial fuel cells. Researchers still need to determine whether the catalyst can be manufactured economically on an industrial scale and whether its compressed state remains stable during years of operation.
If those challenges can be solved, however, the approach could offer a new way to make hydrogen fuel cells more affordable.
It also demonstrates a broader idea: sometimes improving a material does not require adding more expensive ingredients. A tiny mechanical squeeze may be enough to make the atoms already there work better.
