Imagine sucking carbon dioxide from the air and making it into fuel for a car with nothing but the power of the sun. That’s what researchers at the University of Illinois at Chicago did, and they’re now bringing that vision into reality.
“The new solar cell is not photovoltaic—it’s photosynthetic,” says Amin Salehi-Khojin, assistant professor of mechanical and industrial engineering at UIC and senior author on the study, which was published in the July 29 issue of Science. Indeed the artificial leaf they designed creates chemical reactions.
Instead of converting the sun’s rays into electricity as in photovoltaics, the device built by researchers is using a photosynthetic process to convert the sun’s rays into a usable fuel. As such it takes carbon dioxide out of the atmosphere. The result is a syngas as opposed to the sugar that natural photosynthesis creates to keep plants alive.
“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,” said Salehi-Khojin.
The artificial leaf actually uses triple-junction silicon photovoltaic cells to harvest light. Then nano-structured compounds called transition metal dichalcogenides—or TMDCs—are paired with an unconventional ionic liquid as the electrolyte inside a two-compartment, three-electrode electrochemical cell.
When average intensity light reaches the device it energizes the cell and hydrogen and carbon monoxide gas bubble up from the cathode, while free oxygen and hydrogen ions are produced at the anode. “The hydrogen ions diffuse through a membrane to the cathode side, to participate in the carbon dioxide reduction reaction,” explained postdoctoral researcher Mohammad Asadi, first author on the paper.
Researchers anticipate that the technology could be used on the large-scale like solar farms but also for small-scale applications as well. For instance, Salehi-Khojin observed that it could be useful on Mars if it has water.
The research was supported the National Science Foundation (NSF) and the Department of Energy’s SunShot Initiative. “The results nicely meld experimental and computational studies to obtain new insight into the unique electronic properties of transition metal dichalcogenides,” said NSF program director Robert McCabe.Tweet