If scientists can figure out how to convert atmospheric carbon dioxide into fuel – and do it at an industrial scale – it would, quite literally, change the world. Last month, we hit the highest levels of atmospheric CO2 in 4 million years, and it’s now permanent, meaning we’ll never be able to drop to ‘safe’ levels again.
But if we can turn CO2 into a fuel source, we can at least slow things down a bit, and now researchers have developed a process that can achieve this with a single catalyst.
“We discovered somewhat by accident that this material worked,” said one of the team, Adam Rondinone, from the US Department of Energy’s Oak Ridge National Laboratory.
“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.”
Rondinone and his colleagues had put together a catalyst using carbon, copper, and nitrogen, by embedding copper nanoparticles into nitrogen-laced carbon spikes measuring just 50-80 nanometres tall. (1 nanometre = one-millionth of a millimetre.)
When they applied an electric current of just 1.2 volts, the catalyst converted a solution of CO2 dissolved in water into ethanol, with a yield of 63 percent.
This result was surprising for a couple of reasons: firstly, because it’s effectively reversing the combustion process using a very modest amount of electricity, and secondly, it was able to do this while achieving a relatively high yield of ethanol – they were expecting to end up with the significantly less desirable chemical, methanol.
As Colin Jeffrey explains for New Atlas, this type of electrochemical reaction usually results in a mix of several different products in small amounts, such as methane, ethylene, and carbon monoxide – none of which are in particularly high demand.