Scientists have discovered a way to convert carbon dioxide into usable energy source.

Researchers from the U.S. Department of Energy's Argonne National Laboratory and the University of Illinois at Chicago conducted a study on how to turn carbon dioxide into a usable energy source with the use of sunlight.

Carbon dioxide is relatively chemically unreactive, which makes the compound difficult to convert into something else, the researchers said in a press release.

Argonne chemist and author of the study Larry Curtiss, together with his colleagues, addressed this inherent challenge by finding a catalyst - a compound that could make carbon dioxide more reactive. The researchers used a metal compound called tungsten diselenide, fashioned into tiny flakes to maximize the surface area and to expose its reactive edges.

While plants make use of an organic catalyst called enzyme to convert carbon dioxide into a sugar, the researchers also used their catalyst to turn carbon dioxide into carbon monoxide.

"Making fuel from carbon monoxide means travelling 'downhill' energetically, while trying to create it directly from carbon dioxide means needing to go 'uphill,'" Peter Zapol, Argonne physicist, said in a statement.

Although carbon monoxide is considered a greenhouse gas, it is more reactive that carbon dioxide and the researchers already know how to convert carbon monoxide into usable energy.

According to the scientists, transforming carbon dioxide into carbon monoxide requires the same basic inputs as natural process of 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," Curtiss said.

The setup for the reaction was similar to nature, and the scientists were able to construct an "artificial leaf" that would complete the whole three-step reaction pathway.

First, the researchers converted the incoming photons (packets of light) into pairs of negatively-charged electrons protons and oxygen molecules were created from the reaction between the holes and water molecules. Lastly, the protons, electrons and carbon dioxide react together to form carbon monoxide and water.

"We burn so many different kinds of hydrocarbons -- like coal, oil or gasoline -- that finding an economical way to make chemical fuels more reusable with the help of sunlight might have a big impact," Zapol said.

The study also demonstrated that the reaction occurs with minimal lost energy, which means that the reaction is efficient.