Scalable Method for Porous Graphene Membranes for CO2 Capture

In a study published in Nature Chemical Engineering, researchers at EPFL developed a scalable method for producing porous graphene membranes that efficiently separate carbon dioxide.

The development could significantly reduce the cost and footprint of carbon capture technologies.

Capturing CO₂ from industrial emissions is essential in addressing climate change. However, current methods, such as chemical absorption, are both expensive and energy-intensive. Graphene, a thin, ultra-strong material, has long been considered a potential alternative for gas separation. However, producing large, efficient graphene membranes has been challenging.

Led by Professor Kumar Agrawal of the Gaznat Chair in Advanced Separations, researchers at EPFL have developed a scalable approach to create porous graphene membranes that selectively filter CO₂ from gas mixtures. This method reduces production costs while improving membrane quality and performance, which could facilitate real-world applications in carbon capture and other areas.

Graphene membranes can be engineered with specific pores that allow CO₂ to pass through while blocking larger molecules like nitrogen, making them ideal for gas separation. These properties make them suitable for capturing CO₂ emissions from power plants and industrial processes. However, producing these membranes at scale has been both difficult and costly.

Most existing techniques use expensive copper foils to produce high-quality graphene, and the delicate handling often results in fractures that compromise membrane performance. The challenge has been developing a cost-effective, consistent method for producing large, high-quality graphene membranes.

The EPFL team tackled these challenges by developing a method to grow high-quality graphene on low-cost copper foils, significantly reducing material costs. They also refined a chemical process using ozone (O₃) to etch microscopic pores into the graphene, enabling highly selective CO₂ filtration.

The researchers enhanced the interaction between the gas and graphene, resulting in uniform pore development across large areas. This is a crucial step toward making the technology commercially scalable.

To address the issue of membrane fragility, the team also developed a unique transfer method. Instead of floating the delicate graphene sheet onto a support, which often leads to cracks, they employed a direct transfer technique within the membrane module. This approach eliminates handling challenges and reduces failure rates to nearly zero.

Using this novel method, the researchers successfully created 50 cm² graphene membranes with near-perfect integrity, surpassing previous limitations. These membranes demonstrated strong gas permeance and CO₂ selectivity, effectively allowing CO₂ to pass through while blocking other gases.

Optimizing the oxidation process increased the density of CO₂-selective pores, further improving the membrane's performance. Computational models confirmed that increasing the gas flow over the membrane was key to achieving these results.

This development has the potential to significantly impact carbon capture technology. Traditional CO₂ capture methods rely on energy-intensive chemical processes, making them difficult and costly for widespread use. In contrast, graphene membranes require no heat input and operate through simple pressure-driven filtration, offering substantial energy savings.

Beyond carbon capture, this technology could be applied to separate other gases, such as hydrogen and oxygen. With its scalable manufacturing technique and low-cost components, this breakthrough brings graphene membranes closer to commercial viability.

GAZNAT, the Swiss Federal Office of Energy, Bridge (Proof of Concept), and the Canton of Valais funded the study.

Journal Reference:

Hao, J. et al. (2025) Scalable synthesis of CO₂-selective porous single-layer graphene membranes. Nature Chemical Engineering. doi.org/10.1038/s44286-025-00203-z