According to statistical figures from a study conducted in 2010, around 33.4 billion metric tonnes of carbon dioxide was produced by fossil fuels and cement industries. This should be coupled with the fact that global CO2 emissions due to fossil fuel use reached 36 gigatonnes in 2013, which was a whopping 61 percent higher than the year the Kyoto Protocol was signed (in 1990). Suffice it to say, the picture is not very pretty – but as always there is science. This time around, a group of researchers at the Hefei National Laboratory for Physical Sciences, China, has devised a new material that basically transforms carbon dioxide gas into clean, usable fuel. This new material in question entails a four-atom thick ‘sandwich’ composed of pure cobalt metal and cobalt-oxygen molecules, and it can convert CO2 into a fuel called formate – which is an anion derived from formic acid.
So how does the scope actually work? Well according to some experts, when electric current is introduced into the cobalt nanomaterial, the material interacts with carbon dioxide molecules that are running freely through the sandwich. This causes the hydrogen atoms (with their individually one electron and one proton) to attach themselves to carbon atoms from the carbon dioxide; which in turn propels the extra electron into the realm of the oxygen atoms (from carbon dioxide). As a result, the CO2 morphs into CHOO-, or formate, also known by its IUPAC name ‘methanoate’.
The method encompassing the application of electricity mentioned here pertains to a process known as electroreduction – which consumes only small amounts of electrical energy. Furthermore in this case, the scope of so-called ‘overpotential’ – the extra energy needed to drive the process, is kept low. But in conventional scenarios, if overpotential is kept low, the rate of carbon dioxide conversion also tends to get slower. However in this particular ambit, the Chinese researchers have apparently found the balanced solution by virtue of the specific cobalt-based material. As a result, the new material not only has low overpotential but additionally maintains a high rate of formate production, while remaining stable. Lab tests conform to such an assessment, with the material maintaining –
…stable current densities of about 10 milliamperes [of formate] per square centimetre over 40 hours, with approximately 90 percent formate selectivity at an overpotential of only 0.24 volts.
Now at last it remains to be seen how fast this material can be adopted in the commercial side of affairs. Of course beyond just the technological scope, that would also entail the logistics part relating to the usage of the material in conjunction with the CO2 salvaged from existing power plants. But this step taken is surely in the right direction, as lauded by Karthish Manthiram, a chemical engineer and electroreduction expert at the California Institute of Technology (note – he was not involved in the project) –
This represents a fundamental scientific breakthrough. Certainly it will be a years-long process before this is worked into a successful, commercial device. But at this stage of development, by all conceivable metrics, this reaction looks very positive.
Concerning the logistics part, he further added –
But I’m very optimistic. Just five or ten years, ago [scientists in this field] assumed it might even be impossible to convert CO2 into formate with such a high rate and low overpotential. We need fundamental breakthroughs of just this sort if we’re going to earnestly tackle problems as big as global warming.
The study was originally published in the Nature journal.