Turning carbon dioxide into fuel — it is what plants do

In a new study from the U.S. Department of Energy’s Argonne National Laboratory and the University of Illinois at Chicago, ­researchers were able to convert carbon dioxide into a usable energy source using ­sunlight. The process is similar to how trees and other plants slowly ­capture carbon ­dioxide from the atmosphere, converting it to sugars that store energy.

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.

While plants use their catalysts to make sugar, the Argonne ­researchers used theirs, a metal compound called tungsten diselenide, to convert ­carbon dioxide to carbon monoxide. Scientists already have ways of ­converting ­carbon monoxide into usable fuel, such as methanol.

Although the reaction to transform carbon dioxide into carbon ­monoxide is different from anything found in nature, it requires the same basic inputs as photosynthesis. “In photosynthesis, trees need energy from light, water and carbon dioxide in order to make their fuel; in our ­experiment, the ingredients are the same, but the product is different,” said Curtiss.

The research team was able to construct an “artificial leaf” that could complete the entire three-step reaction pathway. The reaction occurs with minimal lost energy. “The less efficient a reaction is, the higher the energy cost to recycle carbon dioxide, so having an efficient reaction is crucial,” Zapol said.

Source: Jared Sagoff Argonne National Laboratory

U.S. Department of Energy