The team, led by Liang-shi Li at Indiana University (IU) with researchers from Nanchang University and the University of Science and Technology of China, used a nanographene-rhenium complex connected via an organic compound known as bipyridine to trigger a highly efficient reaction that converts carbon dioxide to carbon monoxide.
"If you can create an efficient enough molecule for this reaction, it will produce energy that is free and storable in the form of fuels," said Li, associate professor in the IU Bloomington College of Arts and Sciences' Department of Chemistry. "This study is a major leap in that direction. The ability to efficiently and exclusively create carbon monoxide is significant due to the molecule's versatility. This is 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."
The bipyridine-metal complexes have long been studied to reduce carbon dioxide to carbon monoxide with sunlight but these molecules can use only a tiny sliver of the light in sunlight, primarily in the ultraviolet range, which is invisible to the naked eye. In contrast, the molecule developed at IU takes advantage of the light-absorption nanographene to create a reaction that uses sunlight in the wavelength up to 600 nm, a larger portion of the visible light spectrum.