The next generation of low-cost fuel cells could take your home off the grid and free your car from the gas pump with clean, renewable energy, and researchers at Pacific Northwest National Laboratory have brought us one step closer to that future. The team has deployed a biomimicry-based hydrogen production process that combines high speed with high energy efficiency, thanks to a catalyst that “lights up like a rocket.”
An obstacle for low-cost fuel cells
Hydrogen is the most abundant material on the planet, but hydrogen fuel cells are relatively expensive in part because separating hydrogen from water molecules typically involves the use of a pricey platinum catalyst, and partly because it can be an energy-hungry process.
So far, researchers have found ways to make cheaper nickel-based catalysts work more quickly, or use less energy, but not both at the same time.
A fast, efficient hydrogen catalyst from biomimicry
To achieve a catalytic twofer, the PNNL team used a type of natural protein called a hydrogenase as their model. A hydrogenase is an enzyme that plays a role in anaerobic (oxygen-free) digestion. Its key role is to create an energy-storing chemical bond between two hydrogen atoms.
In its initial form, the team’s “imitation” hydrogenase catalyst could produce hydrogen molecules at a snail’s pace of about 1,000 per second.
It could also produce at the rate of 100,000 per second, but only under energy-intensive conditions.
The breakthrough came when the team dissolved the catalyst in a solution of salts called an ionic liquid. When they slowly added water to the mix, the catalyst began to light up “like a rocket” according to PNNL chemist John Roberts.
At its best rate, the catalyst cranked out 53,000 molecules of hydrogen per second without a loss of energy efficiency.
Next steps for biomimicry fuel cells
In addition to achieving a better ratio of speed to efficiency, the PNNL team also came away with a better understanding of how the catalyst interacts with its ionic bath. The team plans to develop those clues into further improvements.
For now, the team will continue to study the catalyst in its dissolvable form, but for real-world applications they will eventually need to bind it to a fixed surface.