Yet another use for the important greenhouse gas.
Scientists at Rice University have devised an environmentally friendly way to take carbon dioxide and turn it into liquid fuel. The device uses a catalytic reactor to transform the greenhouse gas into formic acid, an important chemical reagent that is also found in bee and ant venom.
“The big picture is that carbon dioxide reduction is very important for its effect on global warming as well as for green chemical synthesis,” says lead researcher Hoatian WangWang, a chemical and biomolecular engineer at Rice, in a press statement. “If the electricity comes from renewable sources like the sun or wind, we can create a loop that turns carbon dioxide into something important without emitting more of it.” Tests revealed that the formic acid produced can store nearly half of the energy created during the reaction.
Formic acid can be used in a number of ways. The pungent, colorless liquid has antibacterial qualities and can be used as a preservative, according to the National Center for Biotechnology Information. Most importantly, it can be used as a fuel-cell fuel that, when burned, will emit carbon dioxide that can be recaptured and used to produce more fuel. It essentially creates a closed loop.
Two innovations allowed the scientists to better develop this technology. First, they used a catalyst made of bismuth atoms, which are far more stable than the atoms from transition metals such as cobalt, iron, or cadmium. Additionally, this type of catalyst can be reproduced at a much larger scale.
Next, the researchers developed a type of a new type of solid-state electrolyte that doesn’t require salty water. Typically, in order to reduce carbon dioxide, water laced with salts like sodium chloride or potassium bromide is used as an electrolyte. This method is less effective because the formic acid bonds with the salt, and it can be extremely expensive and time intensive to remove these salts later.
When tested, the reactor successfully ran for 100 hours without degrading, according to the release. How fast water is pumped through the reactor determines how concentrated the formic acid solution will be. Wang hopes that in the future, the technology could produce other useful products like ethanol and acetic acid.
This article was written by Jennifer Leman and was published by Popular Mechanics on 04/09/2019
Cover image: Pexels