Copper-Gold Nanoparticles Convert CO2 into Fuel

ScienceDaily (Apr. 11, 2012) — Copper — the stuff of pennies and tea kettles — is also one of the few metals that can turn carbon dioxide into hydrocarbon fuels with relatively little energy. When fashioned into an electrode and stimulated with voltage, copper acts as a strong catalyst, setting off an electrochemical reaction with carbon dioxide that reduces the greenhouse gas to methane or methanol.

Various researchers around the world have studied copper’s potential as an energy-efficient means of recycling carbon dioxide emissions in powerplants: Instead of being released into the atmosphere, carbon dioxide would be circulated through a copper catalyst and turned into methane — which could then power the rest of the plant. Such a self-energizing system could vastly reduce greenhouse gas emissions from coal-fired and natural-gas-powered plants.

But copper is temperamental: easily oxidized, as when an old penny turns green. As a result, the metal is unstable, which can significantly slow its reaction with carbon dioxide and produce unwanted byproducts such as carbon monoxide and formic acid.

Now researchers at MIT have come up with a solution that may further reduce the energy needed for copper to convert carbon dioxide, while also making the metal much more stable. The group has engineered tiny nanoparticles of copper mixed with gold, which is resistant to corrosion and oxidation. The researchers observed that just a touch of gold makes copper much more stable. In experiments, they coated electrodes with the hybrid nanoparticles and found that much less energy was needed for these engineered nanoparticles to react with carbon dioxide, compared to nanoparticles of pure copper.

A paper detailing the results will appear in the journal Chemical Communications; the research was funded by the National Science Foundation. Co-author Kimberly Hamad-Schifferli of MIT says the findings point to a potentially energy-efficient means of reducing carbon dioxide emissions from powerplants.
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Reprinted from materials provided by Massachusetts Institute of Technology. The original article was written by Jennifer Chu.