Using sunlight for energy, researchers at the University of Illinois in Chicago (UIC) have successfully devised a method to convert atmospheric carbon dioxide into usable hydrocarbon fuel, much like the way plants photosynthesize sunlight into sugars.
“The new solar cell is not photovoltaic—it’s photosynthetic,” says UIC assistant professor of mechanical and industrial engineering and senior author on the study Amin Salehi-Khojin.
The cheap and efficient new process hits two birds with one stone: generating energy and eliminating significant amounts of carbon dioxide in the atmosphere, which as we know, constitutes a huge percentage of the green house gases we produce, which are known to contribute to global warming.
“Instead of producing energy in an unsustainable one-way route from fossil fuels to greenhouse gas, we can now reverse the process and recycle atmospheric carbon into fuel using sunlight,” Salehi-Khojin adds.
Synthesis gas, or syngas, is produced by a process opposite of oxidation or combustion, called reduction reactions, which result in a mixture of hydrogen gas and carbon monoxide. These can then be either burned straight away or converted into other hydrocarbon fuels.
Through the years, engineers have been looking for CO2 reduction methods, but have been unable to find cheap catalysts and required precious metals. The researchers developed a new catalyst: a nano-structured compound called nanoflake tungsten diselenide, a transition metal dichalcogenide (TMDC), and paired it with an unconventional ionic liquid as the electrolyte inside a two-compartment, three-electrode electrochemical cell.
Not only is the nanoflake tungsten diselenide 20 times cheaper than precious metals, it is also 1,000 times faster at catalysis.
With the low cost and high efficiency of producing syngas, we are closer to eradicating fossil fuels. Salehi-Khojin says large-scale adaptation will not be a problem, and neither are small-scale applications.