A solar cell is great if you want electricity right now, but what if you could get a solar panel that pulled CO2 from the air and used sunlight to turn it into burnable fuel? It might sound fantastic, but that’s just what plants do when they photosynthesize, and it’s also the promise of a new device from researchers at the University of Illinois.
"Instead of producing energy in an unsustainable one-way route from fossil fuels to greenhouse gas," lead author Amin Salehi-Khojin said in a news release, "we can now reverse the process and recycle atmospheric carbon into fuel using sunlight."
Instead of storing generated electricity in batteries, this artificial photosynthesis uses the sun to convert atmospheric carbon dioxide into fuel. It sounds magical, like cold fusion, but artificial photosynthesis isn’t even new. Wikipedia lists attempts dating back to the beginning of the 20th century.
Salehi-Khojin and his team are calling their device an "artificial leaf," and its output is a mixture of hydrogen and carbon monoxide, called syngas. Syngas can be burned, or converted to something like diesel, for use in cars and so on.
The catch with this process has been poor efficiency. Making fuel from sunlight and air was possible, but not practical. By using a new catalyst to promote the conversion of CO2, the team says it has made a device that is 1,000 times faster and 20 times cheaper than before.
But that catalyst alone wasn’t enough. The nano-material they used breaks down quickly in the harsh environment of the conversion, so they also had to protect it in an ionic liquid bath.
Theoretically, the process could be used in large-scale power plants, turning water, salt, air, and sunlight into usable fuel, all without having to manufacture batteries to store any energy. While proof in a lab is very different from practical mass production, this does look like the best effort yet at making an artificial plant. And because burning the resulting fuel does no more, emissions-wise, than recreating the CO2 that made it in the first place, the whole cycle would be more or less carbon neutral.
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