toyota fuel cell car

Flexible nanomaterials pave the way for cheap hydrogen vehicles

Image credit: DT

Hydrogen fuel cell cars could become more commercially viable thanks to a newly discovered method of creating flexible, reactive nanomaterials.

“Every material experiences surface strain due to the breakdown of the material’s crystal symmetry at the atomic level. We discovered a way to make these crystals ultrathin, thereby decreasing the distance between atoms and increasing the material’s reactivity,” said Chao Wang, assistant professor of chemical and biomolecular engineering at Johns Hopkins University.

Strain is, in short, the deformation of any material. For example, when a piece of paper is bent, it is effectively disrupted at the smallest, atomic level; the intricate lattices that hold the paper together are forever changed.

In this study, the strain effect was manipulated to cause the material to change dramatically. By making those lattices incredibly thin, roughly a million times thinner than a strand of human hair, the material becomes much easier to manipulate.

“We’re essentially using force to tune the properties of thin metal sheets that make up electrocatalysts, which are part of the electrodes of fuel cells,” said Jeffrey Greeley, professor of chemical engineering at Purdue University. “The ultimate goal is to test this method on a variety of metals.”

“By tuning the materials’ thinness, we were able to create more strain, which changes the material’s properties, including how molecules are held together. This means you have more freedom to accelerate the reaction you want on the material’s surface.”

One example of how optimising reactions can be useful in application is increasing the activity of catalysts used for fuel cell cars. While fuel cells represent a promising technology toward emission-free electrical vehicles, the challenge lies in the expense associated with the precious metal catalysts such as platinum and palladium, limiting its viability to the vast majority of consumers. A more active catalyst for the fuel cells can reduce cost and clear the way for widespread adoption of green, renewable energy, the scientists said.

The team estimates that their new method can increase catalyst activity by 10 to 20 times, using 90 per cent less of precious metals than what is currently required to power a fuel cell.

“We hope that our findings can someday aid in the production of cheaper, more efficient fuel cells to make environmentally-friendly cars more accessible for everybody,” said Wang.

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