Scientists accidently convert CO2 into ethanol
Carbon dioxide in the atmosphere is a really big problem, and although we have a number of possible solutions to our impending climate-change crisis, none of them show great promise on the kind of scale we need yet. So it’s a pleasure to report that scientists at Oak Ridge National Laboratory have come up with another possible solution that could potentially scale up beyond the lab. And what’s more, they discovered it by mistake.
“We discovered somewhat by accident that this material worked,” explained Adam Rondinone, lead author of the study published in ChemistrySelect. “We were trying to study the first step of a proposed reaction when we realised that the catalyst was doing the entire reaction on its own.”
The catalyst in question? Copper nanoparticles embedded into nitrogen-laced carbon spikes, around 50-80 nanometres tall (that’s around 0.00008mm, so pretty damned small.) Applying an electric current of 1.2 volts converted a solution of CO2 dissolved in water into ethanol, with a whopping yield of 63 to 70%.
It’s no wonder they didn’t see that result coming: they essentially reversed the combustion process with an exceptionally high yield and without the use of expensive or rare metals. “We’re taking carbon dioxide, a waste product of combustion, and we’re pushing that combustion reaction backwards with very high selectivity to a useful fuel,” Rondinone explained.
Ethanol is an incredibly useful end product. While researchers have been trying to neutralise carbon dioxide for years, the best bets were going to be products that the world doesn’t really use much of at the moment: think alternative fuels such as methanol or hydrocarbon fuel.
While we could – with the political will – rethink society to utilise these byproducts, it’s far easier to imagine business sticking to what we know, and ethanol is pretty useful – chiefly in fuel, but also with medical applications. In other words, this is a great, if unexpected result. “Ethanol was a surprise – it’s extremely difficult to go straight from carbon dioxide to ethanol with a single catalyst,” said Rondinone.
“By using common materials, but arranging them with nanotechnology, we figured out how to limit the side reactions and end up with the one thing that we want. They are like 50nm lightning rods that concentrate electrochemical reactivity at the tip of the spike,” he continued.
It potentially gets better: it’s relatively inexpensive, operates at room temperature and could potentially be scaled up for industrial use. But it’s important to remember how big a problem we’re dealing with – the EU alone emitted 3,420,000,000 tonnes of CO2 in 2014, so you would need a lot of these little spikes to make a difference.
Nonetheless it is, if nothing else, scientifically interesting. The next step is to refine the approach and production rate. Watch this space, planet Earth.