Making carbon dioxide by burning hydrocarbons is easy. A pair of novel catalysts recently made by researchers at the University of Illinois at Chicago could make it far more practical to do the reverse, converting carbon dioxide and water into fuel.
Because running this reaction normally requires large amounts of energy, it has been economical only in rare cases (see “Company Makes CO2 into Liquid Fuel, with Help from a Volcano”). But if the process could be done commercially, liquid fuels could be made from the exhaust gases of fossil-fuel power plants.
The new work, described this week in the journal Nature Communications, improves on a pair of catalysts discovered last year that more efficiently turn carbon dioxide into carbon monoxide, which can then be made into gasoline and other products. Those catalysts produce carbon monoxide slowly, however, and one is made of silver, so it’s expensive. But the Illinois researchers have demonstrated that it’s possible to replace the silver with relatively inexpensive carbon fibers while maintaining about the same efficiency. And the technique produces carbon monoxide about 10 times faster.
The work is still in early stages, says Amin Salehi-Khojin, a professor of mechanical engineering at the University of Illinois at Chicago, who led the work. Salehi-Khojin says it will be necessary to produce larger amounts of the catalysts and find a way to incorporate them into a membrane that helps keep them stable over long periods of time—development work that will require industrial partners.
Salehi-Khojin says it may be possible to incorporate the catalysts into an “artificial leaf.” Right now, if the process were to run on sunlight, it would require at least two pieces of equipment: a solar panel to generate electricity, and then a reactor to form the carbon monoxide. A leaf-inspired system would absorb energy from the sun and use it to drive the chemical reactions directly, rather than making electricity first (see “A Greener ‘Artificial Leaf,’” “Sun Catalytix Seeks Second Act with Flow Battery,” and “Artificial Photosynthesis Effort Takes Root”). This approach would make the process more economical.