Smog-eating graphene composite greedily pulls pollution from air

4 Dec 20191.34k Views

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Adding another string to its bow, graphene is now being used to suck up smog at unprecedented levels thanks to a new breakthrough.

The European Graphene Flagship partnership has revealed a new graphene-titania photocatalyst that has enormous potential as a feasible greenhouse gas capture technology. According to the research team, this new composite degrades up to 70pc more atmospheric nitrogen oxides (NOx) than standard titania nanoparticles, based on tests with real pollutants.

When titania is exposed to sunlight, it degrades harmful NOx and volatile organic compounds present at the surface, oxidising them into inert or harmless products. Now with the addition of graphene, it has been supercharged in terms of efficiency.

By performing liquid-phase exfoliation of graphite – the process that creates graphene – in the presence of titania nanoparticles using only water and atmospheric pressure, the team created a new graphene-titania nanocomposite.

This can be coated onto the surface of materials that can passively remove pollutants from the air. If applied to concrete on streets or the walls of buildings, the now harmless pollution can be washed away by rain or wind, or even manually cleaned off.

“It is low maintenance and environmentally friendly, as it just requires the sun’s energy and no other input,” said Marco Goisis, research coordinator at the cement producer Italcementi, which is a partner of the Graphene Flagship group.

Heated concrete

However, there are a number of challenges to deal with before the technology could be produced at a commercial scale, including cheaper production of graphene. Also, interactions between the catalyst and the host material need to be deepened, as well there being a need for more long-term studies of the photocatalyst in real-world environments.

Despite this, Enrico Borgarello, also of Italcementi, described the research so far as “a very significant result”.

Looking to the future, Goisis said the Graphene Flagship group is working on a conductive graphene composite that could potentially make its way into homes.

“You could heat your room, or the pavement, without using water from a tank or boiler,” he said. “This opens the door to innovation for the smart cities of the future, particularly to self-sensing concrete.”

The team’s findings have been published to Nanoscale.

Colm Gorey is a senior journalist with Siliconrepublic.com

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