Developing a process to produce graphene from CO₂

Chemical engineers at Southwest Research Institute produced gram quantities of graphene and other carbonaceous materials by bubbling carbon dioxide through a bed of liquefied alkaline earth metals. Graphene, a carbon allotrope, is used for everything from biomedical devices to sensors and electronics. The project advances the lab-scale conversion of CO₂ into graphene which, like diamonds, another form of carbon, is both valuable and useful for a variety of applications.

Many people are familiar with graphite, which is made of multiple layers of graphene, and often erroneously referred to as lead in pencils. Composed of carbon atoms arranged in a honeycomb-like lattice, graphene is stronger than diamonds, highly flexible, conductive and one of the lightest materials available. Its unique properties make it useful for coatings, lubricants and batteries, among other things.

"With almost unlimited potential uses for graphene, it's understandable why the market continues to grow year over year," said Miles Salas, the project lead. "We're advancing this technology to support industrial clients looking for ways to create value-added products from their industrial CO₂ waste."

In the first phase of the project, SwRI scientists and engineers used a chemical reactor the size of a mini fridge to conduct a lab-scale experiment to gather data, test the graphene yield and identify the best reaction conditions.

"Redefining CO₂ as a feedstock instead of a pollutant or sequestered product is key to increasing carbon capture projects around the globe," said Michael Hartmann, manager of SwRI's Carbon Capture and Utilization Process Development Section. "We are exploring graphene and other targeted CO₂ utilization markets with a focus on scalability and commercialization pathways through lab-to-pilot demonstration projects."

During phase two, engineers will create a small-scale pilot plant to further refine the process. For every 200 grams of alkaline earth metal, which is inexpensive and abundant, the team can produce roughly 6 grams of graphene-containing material.

"Financial incentives for capturing carbon dioxide emissions are crucial. All solutions for reducing global CO₂ emissions must be economical or they are unlikely to be adopted. Providing a high-value product from CO₂ will certainly drive support for future markets in carbon materials," said Eloy Flores III, director of SwRI's Chemical Engineering Department.

"We continue to support efforts for industrial decarbonization in all areas to push the envelope in scaling new reactor designs for our government and industry clients."

Provided by Southwest Research Institute