A collaboration between two chemical scientists has yielded valuable insights into graphene, a sheet of pure carbon just one atom thick that is used to create useful products such as batteries and solar cells.
The collaboration began when Ange Nzihou, an expert in converting society’s waste into valuable products, sought the advice of Claire White, associate professor of civil and environmental engineering. Nzihou had developed an approach to transform waste biomass into graphene that offered advantages over existing methods relying on hazardous chemicals, precious metals, or fossil fuels. But Nzihou wanted to understand the nano- and atomic scale mechanisms involved during the process that enabled iron to help convert waste biomass into graphene.
“Ange had shown that it was possible to use iron as a catalyst,” White said. “But the real question was in trying to understand how iron was providing this catalytic behavior.”
Using a host of techniques, including X-ray total scattering, the researchers found that over the course of the heating process, the iron oxide catalyst first broke down to form nanoparticles within the biomass. As the cellulose-rich biomass began to dissolve at higher temperatures, it precipitated as layers of graphene sheets onto the surface of the iron particles.
“Now that we have an understanding of the mechanism, we can figure out how to improve the process and optimize the properties of the graphene sheets compared to the conventional chemical vapor deposition method, and even consider ways to scale it in the near future,” Nzihou said.