THE CHEAT SHEET. When carbon goes clean

You mean carbon dioxide? Yes. The colourless, odourless greenhouse gas that’s a big contributor to global warming.

How does it go clean? Scientists have just found a new material that converts CO ₂ into a simple, clean fuel.

Where, who? The material — made from microscopic (read very very thin) layers of pure cobalt metal and a cobalt oxide-cobalt metal mix — is developed by a team of scientists led by Shan Gao at the Hefei National Laboratory for Physical Sciences in Hefei, China.

Interestingly, China is the world’s largest emitter of green house gases. The researchers have published their results in the recent issue of Nature .

They say the material can convert CO ₂ gas into formate, a fuel that can be burned with no poisonous by-products and used as a clean energy source.

Impressive. This is quite a breakthrough, I’d say. Indeed. Scientists have been struggling for decades to come up with an energy-efficient way to transform CO ₂ into a useful entity. Now the Chinese invention offers a lot of hope on that front. Scientists say the material help us better deal with the 36 gigatonnes of CO ₂ we release into the atmosphere each year while burning fuels.

But, is the process of conversion simple? Yes. It is called electro reduction — which we all studied in school.

I’m sorry, I had bunked those classes. Can you elaborate? Put simply, electro reduction is a process in which we add electrons to a substance near the cathode of an electrolytic cell.

This takes nothing more than a small amount of electric current.

But how does this conversion exactly work? Well, that’s a bit of science you may not fully digest — if you bunked science classes.

Translate it into English then. Let me try. When electric current goes through it, the material interacts with the CO ₂ molecules running through it. Basically, a hydrogen atom — remember, it has one electron and one proton — gets linked to the carbon atom of the CO ₂ molecule.

And as this happens, an extra electron is “flung” into one of the oxygen atoms in CO ₂ . With that — lo and behold! — the CO ₂ becomes CHOO, aka formate. And formate can be used as fuel in a fuel cell, which ‘burns’ hydrogen and oxygen to produce power, with water as a byproduct!

Superb! But this is just a lab result. When will it hit the street? Of course it will take years of further research for the new material to be ready for commercialisation and the road to the market is still bumpy.

Still, researchers are much more hopeful about this new product than they were about other similar products in the past.

Why? See, this is not the first material scientists have found could convert CO ₂ into clean fuel. They all faced a problem called ‘over-potential’. Which basically deals with the extra energy one needs to deal with this process.

This wasted energy needs to be kept as low as possible. But what happens in most cases is when the over-potential is brought down, it also pulls down the pace at which CO ₂ is being converted into formate. The material from China seems to have overcome this jinx. It can keep the over-potential significantly down while maintaining a robust pace of conversion. To top it all, it remains stable throughout the process.

Yay! Scientists believe if commercialised, this material can make a significant difference in our fight against global warming. If this material can convert a decent chunk of the CO ₂ generated at the world’s biggest power stations, that’s in itself is a big deal.

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