Weird Science: Artificial Photosynthesis

by Sue Lange


And why would we need such a thing? I mean, I’m envisioning what? some new kind of diet? You no longer eat, you make your own food by using SlimFast’s fast-acting photosynthetic day cream. Slather it on, head outdoors on a sunny day, and you’ll never need to eat again. You’ll have all the glucose your body needs without the messy fat. Slim down the natural way!

The reality is not nearly as fun (and weird) as that, but it is interesting nonetheless.

The point of artificial photosynthesis is to create fuel using CO2 and sunlight, the same way plants create fuel (carbohydrates) using CO2 and sunlight.

To propel you on your merry way, your car or truck or personal airplane burns carbohydrates in the engine, driving the pistons. The process gives off CO2 in the process. Photosynthesis does the opposite. It uses up CO2 in the air to create carbohydrates (fuel). Plants photosynthesize naturally; it’s how they create food for themselves. Artificial photosynthesis would mimic natural photosynthesis.

Since CO2 is a greenhouse gas, and in fact, the number one bad guy in the story of climate change, we need to find ways of getting rid of it. Using it up only to produce more of it when we fly our personal airplanes seems like we’re just treading water. But treading water is what we want. We crave a cycle that creates no byproducts, that is, excess CO2. Right now we don’t have that cycle. We’re creating CO2 from materials that have sequestered it for thousands of years: our oil reserves. That’s what oil amounts to: sequestered CO2.

Besides we’re supposedly running out of our oil. Utilizing excess CO2 may be the only way to shore up our fast-fading fossil fuel economy.

This seems like a no-brainer; we should have been doing this yesterday, right? Apparently it’s not all that easy to do. It’s another one of those processes that requires a higher energy input than what you get out of it.

To reduce the energy requirement, researchers have been experimenting with various elements such as iridium and cobalt and something called an “ionic liquid,” to catalyze the reactions and make them more efficient.

For those interested, an ionic liquid is defined by wikipedia as “a salt in the liquid state.” When they say “salt”, they’re not necessarily talking about table salt with a melting point of 1,474 °F. Obviously that’s not going to be particularly easy to maintain in a liquid state. There are better candidates that are closer to liquid at room temps. Unfortunately they all seem to have obscenely long names. Here’s one that won’t be too taxing on the bandwidth: 1-butyl-3-methylimidazolium tetrafluoroborate. If you’re interested in the chemistry of the more profane ionic liquids head over to wikipedia for details.

Suffice it to say, there are people working on this strange phenomenon called artificial photosynthesis. There are even some cheeky startups jumping into the mix. New companies like Dioxide Materials whose graphic I grabbed to illustrate this post. I wish them luck and a total monopoly when their process gets approved. Maybe we should keep Exxon’s oily fingers out of the pie this time.

Hang in there!

Sue Lange’s latest ebook, Tritcheon Hash, is full of lapses of logic and weird science. Get your copy  or read a couple of free chapters right here at Book View Cafe.

This essay was originally posted 12/3/2011 at the Singularity Watch blog.



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