This New Photocell Turns CO2 into Fuel, Thinks It’s a Plant
Finally, it looks like we might be able to tap into the process that our leafy cohabitants have been mastering for thousands (if not millions) of years. A research team at the University of Illinois at Chicago (UIC) has come up with a new photocell that harnesses the power of artificial photosynthesis, taking carbon dioxide and sunlight and turning it into usable fuel.
Before beginning to even describe this eco-friendly sorcery, let’s touch base on the not-so-eco-friendly problem that’s prompted the invention of such a device: the build up of carbon dioxide and other dangerous gases in our atmosphere causing a plethora of issues for humanity and the rest of the world. From heating our atmosphere above natural levels to acidifying our oceans (the excess CO2 reacts with sea water to form carbonic acid which is wreaking havoc on marine wildlife), CO2 emissions are becoming a major problem.
With roughly 1.2 billion motor vehicles around the world contributing to these emissions, our current use of resources and technology is simply unsustainable. At the rate we’re going, there won’t be much of a world left. But hope still remains, looming on the horizon.
Earlier this summer, researchers at UIC have developed a new solar cell that’s “not photovoltaic — it’s photosynthetic.” As Dr. Amin Salehi-Khojin, the senior author of the study, suggests, “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.”
Just think: a machine that takes carbon dioxide and fashions it back into a usable resource without damaging the environment. Not only does the photocell remove carbon dioxide already in the atmosphere, but provided the technology’s commercialization, it could very well cut out our reliance on greenhouse gas-contributing fossil fuels entirely.
But how exactly does this machine work?
Redefining Solar Power
The easiest explanation harkens back to grade school science, likening the photocell to a plant. In nature, trees, shrubs — really anything green and leafy — have cellular structures called chloroplasts which, in turn, contain pigmets called chlorophyll. These molecules are largely responsible for photosynthesis, the process by which plants harness sunlight and use it to produce their own food.
By combining water soaked up through its roots, carbon dioxide absorbed through small pores in the plant’s leaves (otherwise known as stomata), and light energy from the sun, “reaction centers” filled with chlorophyll begin the conversion of these ingredients into sugars and oxygen gas. Just as we provide plants with carbon dioxide to breathe, they’ve been providing us with life-bearing oxygen all these years.
The photocell works on a similar principle. Instead of sugar (which the plant uses naturally as fuel), this artificial form of photosynthesis yields “Syngas.” Keep in mind, this isn’t the same way conventional solar cells work; solar panels convert electricity from sunlight and store that energy in batteries. Syngas, on the other hand, is a mixture of hydrogen gas and carbon monoxide, which can be burned directly as a fuel or processed further into diesel or other kinds of hydrocarbon fuels.
In addition to the very notion that we can now use carbon dioxide and sunlight as a literal fuel source, what makes this technology most exciting is that it’s cost effective. According to Salehi-Khojin, the cost to covert CO2 to syngas is comparable to a gallon of gasoline. Where other biofuels are a bit more expensive compared to conventional fossil fuel derivatives, syngas, applied at an industrial scale, could effectively make fossil fuels obsolete.
While the prospect of cutting off our crude oil reliance could forever change the economic and environmental conservation playing fields, the photocell’s success isn’t without its own drawbacks. Though the photocell proves fuel synthesis from carbon is possible, making it practical presents a variety of challenges, namely its reliance on rare metallic catalysts:
“Chemical reactions that convert CO2 into burnable forms of carbon are called reduction reactions, the opposite of oxidation or combustion. Engineers have been exploring different catalysts to drive CO2 reduction, but so far such reactions have been inefficient and rely on expensive precious metals such as silver.
Luckily, despite its fancy name, the tungsten catalyst turned out to speed the process, making it 1,000 times faster than using traditional noble-metal catalysts. What’s more is that the new catalyst is also 20 times cheaper.
Bear in mind that since this technology is still so new, it’ll be quite some time before practical market applications emerge. In the meantime, if you’re interested in learning more about this exciting new technology that could potentially due away with fossil fuels forever, the UIC research team’s study was recently published for Science magazine in full detail.
Could this be the ace in the hole we need to take down the ugly behemoth that is global warming? Only time will tell.