Fuel Cells: We Don't Need No Stinking Platinum

Prices for platinum have dropped more than 30 percent in recent weeks, to around $1,478.80 an ounce, off a high of more than $2,100 an ounce earlier this year. It’s part of an overall slide in commodity prices, from corn to precious metals to crude, taking place as global supply chains respond to a slowing U.S. economy.

But platinum prices are still high and supply isn’t expected to keep up with demand — a major point of concern for fuel cell companies, which use platinum as a catalyst for converting hydrogen gas into electricity and water. It’s also a point of innovation as researchers and firms have scrambled to find a way to replace (or at least reduce) the expensive material in their designs.

Hydrogen fuel cells have two main reactive surfaces: an anode, which splits oxygen, and a cathode, which splits the hydrogen gas. Both electrodes typically use platinum to catalyze the reaction, but a team of Australian researchers has developed a way to outfit the cathode with a conductive, Gore-Tex-like material to replace the platinum. The Monash University researchers told Greener Design they’re optimistic about ditching platinum in the anode as well:

“However, the way the conducting polymer works as [a] catalyst make us believe that it should be possible to design a conducting polymer that suits the hydrogen oxidation reaction,” said Monash’s Dr. Bjørn Winther-Jensen.

The Monash team’s work is related to that of researchers at MIT, who have devised a way to use cobalt in an anode-side reaction that mimics photosynthesis, as well as Japanese automaker Daihatsu Motor, which said last year that it had developed a similar polymer-based approach. (So far the company hasn’t made any additional announcements.)

Other companies are working on the cathode problem: Japanese company Hitachi Maxell is looking to blend platinum with gold as a way to cut prices and boost efficiency. The new catalyst is just 2-3 nanometers in size, allowing the company to pack more reactive surface area into the fuel cell stack. However, the Maxell approach may not be as helpful at cutting costs if the U.S. economy continues to slide, since gold prices tend to go up as the dollar goes down. (Still, we’d take gold’s current $814 per ounce over $1,400 per ounce any day!).

Researchers at Brown are also experimenting with nanotechnology to improve platinum’s performance as a catalyst (this time without adding gold into the mix.) By blending the pure metal with two compounds, the team has created “nanocubes” that, like Maxell’s gold-blend catalyst, boost the platinum’s reactive surface area.

Such initiatives are slow going, however, and platinum is unlikely to become a cost-effective option for fuel cell manufacturers any time soon. Nor for the beleaguered U.S. auto industry, which uses platinum as the active ingredient in catalytic converters; each converter can use four to seven ounces of the pricey material. The auto industry accounts for as much as 50 percent of global demand for the metal, according to Reuters, and growing numbers of cars on the road in China and India are likely to increase pressure on existing resources. Mazda and Nissan have both developed catalytic converters that use nanotechnology to reduce the amount of platinum used by 50 to 90 percent.