Normally, fuel cells use platinum for the catalyst in splitting water into hydrogen and oxygen, but platinum is expensive and rare, and after the latest calculations, it also isn’t enough for sustaining a worldwide hydrogen-based economy for long.
A group of researchers from France revealed some tests in this week’s issue of the journal Science that shows how platinum can be substituted with nickel, by mimicking the process going on in anaerobic-living algae. These have an enzyme, called hydrogenase, and use it to metabolize hydrogen. “They use exactly the same process as fuel cells to stay alive,” says Vincent Artero, one of the scientists, working for the Commissariat i l’Énergie Atomique near Paris.
Fuel cell electrodes made of nickel are 20 percent cheaper than those made of platinum. Since platinum counts for about one third of the cost of a fuel cell, replacing it with something 20% cheaper could lower the entire fuel cell’s price by a significant amount.
Nate Lewis, a professor of chemistry at Caltech, agrees. “This is an important step toward the development of a full system that splits water from sunlight,” he says. But Lewis notes that finding a way to attach the catalysts to a surface so that they can be used in an electrode is just one piece of the puzzle.
John Turner, a research fellow in energy sciences at the National Renewable Energy Laboratory in Golden, CO adds that, “the major barrier for hydrogen production from water and fuel cells for transportation is not hydrogen catalysis, but oxygen catalysis.”
Nickel-based catalysts are already used in large multi-megawatt commercial electrolyzers, but these catalysts are much less efficient than platinum ones and therefore have to be very large–typically at least 10 square meters.
Turner notes that the current produced by Artero’s catalyst is still orders of magnitude less than can be achieved with platinum. Artero says this can be fairly easily remedied. He notes that the nanotubes used in his team’s experiments received only a low loading of the catalytic material. Increasing this should boost the current: “It’s a gap that we can fill,” he says.
Replacing the expensive platinum with something else inside fuel cells isn’t something new: many scientists have invented various methods of obtaining the same effects with much lower-priced materials, but it still remains to be seen who is going to win by inventing the most feasible technology, and when this technology is going to be applied for the sake of electric car owners out there, who can hardly wait their vehicle to drive for as long as their gasoline one does, and to have the same price it has.
