Transmuting a powerful poison

When used to power fuel cells, methanol and other hydrocarbon fuels release carbon monoxide, which can contaminate the expensive platinum electrodes now used to extract electrons from hydrogen gas. A common practice for eliminating that electrode “poison” requires high temperatures, which make it impossible to get rid of all the carbon monoxide, says chemical engineer James A. Dumesic of the University of Wisconsin–Madison.

Now, he and his colleagues have developed a way to eradicate the contaminant at room temperature. The new approach, described in the Aug. 27 Science, promises to improve fuel cell performance while lowering costs and to wring energy from the decontamination.

In the novel process, before carbon monoxide gas can clog the electrodes, the poison reacts with an aqueous solution containing the acid polyoxometalate and catalytic nanoparticles. The reaction converts carbon monoxide into carbon dioxide, a compound that doesn’t hinder the cell’s performance. It also ionizes polyoxometalate compounds and hydrogen atoms in the solution, thus storing energy from the once-threatening gas.

The researchers report a bonus effect: A fuel cell that uses the solution would require less platinum in its electrodes, Dumesic notes.

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