New York, Aug 2 (IANS): Taking a cue from the mechanism that trees use to convert carbon dioxide into sugars, researchers have found a similar way to turn the gas produced by the burning of fossil fuels in power plants and car engines into a usable energy source using sunlight.

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.

"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 one of the study authors Larry Curtiss from US Department of Energy's Argonne National Laboratory.

While plants use their catalysts to make sugar, the 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.

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, showed the study published in the journal Science.

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," Curtiss said.

To make carbon dioxide into something that could be a usable fuel, Curtiss and his colleagues from University of Illinois at Chicago 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 maximise the surface area and to expose its reactive edges and ultimately create carbon monoxide.