Jacqueline Mullin

The power of the sun is again being harnessed to help reduce greenhouse gas emissions, but this time it is not through solar panels. Instead, a breakthrough achieved by a team of scientists from around the world is offering a way to recycle carbon dioxide using solar power by using less energy than what was originally needed to create the greenhouse gas.

A naturally occurring gas, carbon dioxide is very prevalent in the Earth’s atmosphere. It is a byproduct of various processes including breathing, decomposition of organic matters and the burning of fossil fuels. While the volume of the gas was once regulated by naturally occurring processes, the increased production of carbon dioxide through human activity has transformed the vital life-sustaining gas into a damaging greenhouse gas.

Alternatively, “carbon monoxide is an important raw material in a lot of industrial processes. It’s also a way to store energy as a carbon-neutral fuel since you’re not putting any more carbon back into the atmosphere than you already removed. You’re simply re-releasing the solar power you used to make it,” explained lead researcher, Liang-shi Li of Indiana University to Science News.

The process of extracting carbon dioxide from the Earth’s atmosphere and converting it in to carbon monoxide already exists. The excitement surrounding the discovery made by Li and his team stems from the minimal amount of energy required to make the process occur. Previously, the act of recycling carbon dioxide was made moot by the fact that an equal amount of energy was required to create the carbon neutral fuel source. Li’s molecule changes that by eliminating the need to have a connecting step between the absorption of solar power and the production of carbon monoxide.

The key to the molecule efficiency is nanographene (one billionth of a meter of graphite), due to the material’s dark color being able to absorb a large amount of sunlight.

Li’s explanation of the new molecule included an identification of its make-up: a nanographene-rhenium complex connected via bipyridine (an organic compound.) Comprised of two components designed to work together, the molecule creates the reaction required to recycle carbon dioxide within itself. Electrons obtained from solar power but without the use of solar panels, are bound together and converted into carbon monoxide. Understanding that sunlight is attracted to darker objects, in the case of Li’s molecule the tiny sliver of graphite, has enabled scientists to identify a way to reduce greenhouse gas while creating a carbon neutral fuel source.

This new discovery may not seem significant now, yet it could be a real part of the equation when developing fuel of the future. It also makes it clear that the battle against climate change continues to grow in strength and wisdom each day.