Carbon dioxide is kind of painted as the villain of the 21st century, and it's not enough to just reduce our emissions now – we need to remove some of what's already in the atmosphere. Now, researchers at Karlsruhe Institute of Technology (KIT) have developed a simple way to turn the troublesome gas into a useful resource by converting it into the "wonder" material graphene.
For all its use as a superconducting, flexible and strong material, graphene is deceptively basic – essentially, it's just a two-dimensional sheet of carbon atoms. Early on, it was made by peeling layers off of graphite with sticky tape, but in recent years scientists have managed to make it in a range of different ways, like laser-etching it from wood or even food, or chemically reducing it from soy beans or eucalyptus leaves.
But by far the most common method for making bulk graphene is chemical vapor deposition (CVD). In this technique a carbon source, often methane gas, is pumped into a chamber along with other gases, and a thin slice of a material acts like a catalyst and a substrate. The gas in the chamber chemically reacts with the material and forms a thin layer of graphene on the surface.
The KIT team's technique works much the same way but uses CO2 as a carbon source, giving it the potential added benefit of removing this harmful gas from the atmosphere. In this case, CO2 and hydrogen fill the chamber, and the catalyst and substrate is a wafer made of copper and palladium. The process is done at atmospheric pressure and high temperatures of up to 1,000° C (1,832° F).
"If the metal surface exhibits the correct ratio of copper and palladium, the conversion of carbon dioxide to graphene will take place directly in a simple one-step process," says Mario Ruben, lead researcher on the study.
The team managed to show that the technique works, even using it to make graphene that's several layers thick. The next step is to try to make functioning electronic components using this process.
The research was published in the journal ChemSusChem.
Source: KIT
