How to make graphene greener

Since the very beginning of the Graphene Flagship, one of our core priorities has been to investigate and develop new ways to sustainably produce graphene and layered materials, as well as the products made from them. The Graphene Flagship is committed to working towards the UN’s Sustainable Development Goals and the EU Green Deal, with many of our Work Packages targeting the use of graphene and layered materials to generate clean energy, water, air and more.

Now, Graphene Flagship partner Empa, Switzerland, has published a ‘life cycle assessment’ of graphene and layered materials. The study considers the environmental impacts of a range of production methods and suggests ways to make them more sustainable. Its conclusions could help scientists to develop greener ways to make graphene and graphene-based products.

In the study, Didier Beloin-Saint-Pierre and Roland Hischier, both scientists at Graphene Flagship partner Empa, considered three different classes of material: pristine graphene, graphene oxide, and other types of layered material. They evaluated their sustainability, conducting a full assessment of each material’s whole life cycle, combining quantitative comparison, modelling and detailed statistical analysis.

“At each step, we considered the different interactions of the three classes of material with the world around us,” begins co-author Beloin-Saint-Pierre. “The more we know about the environmental impacts of different production methods, the better equipped we are to design greener alternatives or improvements,” he explains.

“We quantified the environmental impacts of each of these interactions, such as how the extraction of natural resources results in pollution. Then, we translated this data to determine the effects of each type of material on climate change, human health and the ecosystem,” he continues.

In their study, the Graphene Flagship scientists evaluated the environmental impacts of graphene and layered materials throughout every step of the value chain, from material extraction to manufacture to the end of a product’s life. They identified the key routes to make the production of graphene and layered materials cleaner and more sustainable.

For pristine graphene, energy is key. Epitaxial growth and chemical vapour deposition are energy-intensive processes. Powering them with clean energy, or conducting them in regions with decarbonised energy economies, will reduce the carbon footprints of devices based on these materials.

On the other hand, for graphene oxide, green chemistry principles are most important. Energy is less of an issue, and the main focus should be avoiding the use of hazardous substances and pollutants. For other layered materials, it depends on the fabrication method – but they all need a careful balance between energy efficiency and green chemistry.

Overall, for all types of graphene, using decarbonised energy sources will naturally reduce the carbon footprint of the production methods and any resulting products.

If scientists follow these principles, we will be well on the way to a green graphene economy. Beloin-Saint-Pierre explains: “The more knowledge we have from our producers and stakeholders, the better we will be at improving methods and practices.”

Julio Gómez Cordón, Graphene Flagship Work Package Deputy for Production, comments: “Optimising production processes based on the life cycle assessment of graphene materials will allow for greener and more sustainable materials to be produced for industry. This study can help graphene producers to design and optimise their production methods. Combining safe-by-design production methods with life cycle assessments will be the tool of choice to convert different graphene materials into state-of-the-art products.”

Andrea C. Ferrari, Science and Technology Officer of the Graphene Flagship and Chair of its Management Panel, adds: “The Net Zero goals are central to the Graphene Flagship’s Technology and Innovation Roadmap. Life cycle assessment studies are crucial to driving forward environmentally sustainable production. This work sets out a clear path towards a green supply chain for graphene and layered materials, and will be useful for guiding their exploitation in an ever-growing industrial setting.”

References

Beloin-Saint-Pierre, D., Hischier, R. Towards a more environmentally sustainable production of graphene-based materials. Int J Life Cycle Assess 26, 327–343 (2021). https://doi.org/10.1007/s11367-020-01864-z