A New Leaf: Scientists Turn Carbon Dioxide Back into Fuel

As scientists and policymakers around the world try to combat the increasing rate of climate change, they have focused on the chief culprit:  carbon dioxide.

Produced by the burning of fossil fuels in power plants and car engines, carbon dioxide continues to accumulate in the atmosphere, warming the planet.  But trees and other plants do slowly capture carbon dioxide from the atmosphere, converting it to sugars that store energy.

In a new study from the U.S. Department of Energy's Argonne National Laboratory and the University of Illinois at Chicago, researchers have found a similar way to convert carbon dioxide into a usable energy source using sunlight.

One of the chief challenges of sequestering carbon dioxide is that it is relatively chemically unreactive.  "On its own, it is quite difficult to convert carbon dioxide into something else," said Argonne chemist Larry Curtiss, an author of the study.

To make carbon dioxide into something that could be a usable fuel, Curtiss and his colleagues needed to find a catalyst -- a particular compound that could make carbon dioxide react more readily.  When converting carbon dioxide from the atmosphere into a sugar, plants use an organic catalyst called an enzyme; the researchers used a metal compound called tungsten diselenide, which they fashioned into nanosized flakes to maximize the surface area and to expose its reactive edges.

While plants use their catalysts to make sugar, the Argonne researchers used theirs to convert carbon dioxide to carbon monoxide.  Although carbon monoxide is also a greenhouse gas, it is much more reactive than carbon dioxide and scientists already have ways of converting carbon monoxide into usable fuel, such as methanol.

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