Question: Good day! I am doing a small research to reduce the carbon dioxide from the environment caused by the transportation industry (cars, trucks, etc.) current catalytic convertor has 2 ceramic blocks as a used a filter. My research is to design a third filter in the catalytic converter made of graphene for vehicles which can absorb carbon and nitrogen and release only oxygen and water. Oxygen and water will only passed to exhaust pipe from the third filter and this will make the environment safe with less carbon and nitrogen so my question does graphene absorb carbon and nitrogen when its designed as a third filter in the catalytic convertor in the cars ?

Katherine Manfred answered on 19 Nov 2020:

Hi Ayisha,
That sounds like a great project! I’m not sure what key stage you’re currently at in school, so feel free to get back to me with more question if I use any terms you don’t know.

The first thing that I think is important to mention is that not all forms of these carbon and nitrogen are bad! Many vehicles today include a catalytic converter to react the NOx (pollutant) in the exhaust and transform it into N2 gas – which is perfectly fine to release into the air since the air is 78% N2 anyway.

The other type of catalytic converter reacts carbon-based molecules in the exhaust with oxygen so that everything becomes CO2. This is not great for the climate, but it’s perfectly safe for us to breathe.

Graphene-based materials are being explored for CO2 capture and storage. I say “graphene-based” because the graphene itself just acts as a thin, strong support system for the molecules that actually adsorb the CO2 – kind of like when you have Velcro, there’s always a piece of fabric holding together all the little loops. So there are technologies to remove CO2 via adsorption to graphene-based materials, however if your goal is to adsorb the molecules we can’t technically call it a catalytic converter – that is a term for materials that cause a chemical reaction (changing one substance into another) over and over again without being used up.

But, going back to your filter, my question to you now is – what do we do with it afterwards? The CO2 being adsorbed will essentially park itself in an empty spot on the graphene, but there are only a limited number of parking spaces available. When we try to come up with sustainable solutions to problems like this, don’t forget to think about how long your materials will last and whether there will be significant waste afterwards!

Good luck with your project, and let me know if you want me to clarify any of the explanation!