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Platinum Nanoparticles Make Fuel Cells Better

Taking a different approach to an existing solution, researchers from the Energy Materials Center at Cornell University could make proton exchange membrane (PEM) fuels cells a more affordable, cost-effective and stable alternative source of energy.

You probably know about the most advertised feature of the technology. In PEM fuel cells, the anode and cathode are separated by a membrane. A catalyst oxidizes hydrogen at the anode part; the membrane then allows the protons to pass through while the electrons are used to create a current. At the cathode the electrons reunite with the protons and oxygen from the air, forming water. No contributions to climate change or air pollution as a by-product.

PEM fuel cells are touted as good for transportation because of their compact size and better environmental durability compared to other competing setups. However, they require very pure hydrogen and a special catalyst to work. Even low levels of carbon monoxide (CO) contamination will "poison" the catalyst and render the fuel cell inert—a definite no-no if your catalyst requires expensive materials like platinum.

To create a better catalyst, researchers tried depositing platinum nanoparticles on a support material made of titanium oxide, and added tungsten to increase electrical conductivity. Tests show that the new catalyst can work with fuel containing as much as two percent CO with only a five percent loss of efficiency, compared to a 30 percent drop for conventional platinum catalysts.

Héctor Abruña, a professor of chemistry and chemical biology at Cornell University, says that with the new catalyst, one "can now use much less-clean hydrogen, and that’s more cost-effective because petroleum has a very high content of carbon monoxide". Otherwise, "you need to scrape off the carbon monoxide, and that's very expensive to do that", he adds. They are now preparing to ramp up their tests by using the catalyst on real fuel cells. Abruña is optimistic: preliminary experiments show that while a platinum cell was poisoned and gave out early, the new cell "was still running like a champ".