Turning Methane into Carbon Nanotubes and Hydrogen

A new study describes how methane can be transformed into hydrogen and high-performance carbon nanotube materials.

Researchers at the University of Cambridge report this transformation in Nature Energy, showing that hydrogen can be obtained with low CO₂ emissions and produce high-performance carbon nanotube (CNT) materials at the same time. These CNTs can serve as sustainable alternatives to CO₂-intensive materials like steel, aluminum, and copper. 

The advancement was developed by a collaborative team from the University of Cambridge and Stanford University, who have enhanced a continuous-flow reactor to improve its efficiency without sacrificing the quality of the versatile and high-value nanotubes.

Hydrogen is increasingly recognized as a sustainable fuel that can facilitate the decarbonization of industries that are challenging to electrify, such as aviation and shipping. The global production of hydrogen stands at 100 million metric tons annually, primarily serving as a feedstock for industrial processes like ammonia production, which is essential for artificial fertilizers.

This hydrogen generation is predominantly dependent on steam methane reforming of natural gas, a process that is highly CO₂-intensive and accounts for 2-3 % of global greenhouse gas emissions.

The researchers have introduced the technology that holds the promise of being scaled for practical applications, offering a pathway to generate sustainable fuel and materials through a single process. This innovation could serve as a pivotal step for methane pyrolysis, a method that transforms methane into turquoise hydrogen, yielding solid carbon and thereby preventing CO₂ emissions.

The continuous-flow reactor developed by the researchers employs a highly adaptable and scalable method known as floating catalyst chemical vapor deposition (FCCVD), which facilitates the continuous mass production of carbon nanotubes (CNTs) in the form of mats, fibers, and aerogels.

These CNT materials possess strength and lightness superior to steel, along with excellent electrical and thermal conductivity. This unique combination of characteristics positions them as viable alternatives to existing materials across various applications, including batteries and textiles.

It is important to note that the FCCVD process has traditionally consumed hydrogen rather than generating it.

We were able to overcome this problem by recycling gases inside our reactor in a multi-pass configuration, which allowed the production of hydrogen and CNTs at the same time.

Jack Peden, Study Co-Author and Ph.D. Student, Department of Engineering, University of Cambridge

“The nanotubes produced in the multi-pass reactor possessed similar properties to those made in a conventional reactor, with the efficiency being many times higher than the conventional one,” said Peden.

Peden said that meeting today’s hydrogen demand of around 100 million metric tonnes per year using methane pyrolysis would generate roughly 300 million metric tonnes of solid carbon annually. He explained that only a small number of materials are currently produced at comparable scales, most notably structural materials such as concrete, steel, and plastics.

As a result, he argued that scaling up methane pyrolysis in a meaningful way would require producing carbon materials suitable for similarly large-scale applications.

By capturing and recycling the gases within the reactor and optimizing the furnace design, we have significantly reduced the energy required to run the process.

James Elliott, Study Co-author, Department of Materials Science and Metallurgy, University of Cambridge

“The carbon nanomaterials produced already show promise in batteries and textiles, and could in future be used in lightweight composites, building materials, or high-voltage electrical cables. Because these materials have substantial economic value, their sale can offset operating costs, making methane pyrolysis a commercially competitive route to low-carbon hydrogen,” said Elliott.

Journal Reference:

Peden, J. et al. (2026). Production of hydrogen and carbon nanotubes from methane using a multi-pass floating catalyst chemical vapor deposition reactor with process gas recycling. Nature Energy. DOI: 10.1038/s41560-025-01925-3.