French researchers say that a mix of carbon dioxide and methane could be the perfect feedstock for high quality carbon nanomaterials.

These days, graphene seems to make most carbon news headlines, but there’s another carbon nanomaterial that’s long had a role in industry, but it’s not often discussed. Carbon black is mainly seen as a reinforcing filler for tires and other rubber goods, but it is increasingly being used as a pigment for printing inks, coatings, conductive packaging and plastics. Fulfilling these needs requires mass production of the material, usually through thermal decomposition or partial combustion of petroleum, coal oil or acetylene gas. But in a paper published in a recent issue of Carbon [DOI: 10.1016/j.carbon.2016.09.052], French researchers have shown that biogas could be a more sustainable option.

Biogas is a renewable energy source, generated by anaerobic digestion of food, animal waste, plant material and sewage. It’s made from a mixture of carbon dioxide and methane, but the ratio varies depending on the source. So, to explore the range of materials that could be made from biogas, the team used five mixes, varying CO2 concentration from 0.0 to 7.4 vol%, to produce their nanocarbons.

The resulting materials were heat-treated to purify them, and physicochemical characterisation confirmed that they’d produced highly-crystalline nano-graphitic sheets, exhibiting 20-30 layers, with a lateral size in the range of 30-80 nm. They then dispersed these materials in a solution of bile salt and water to make an ink, and used them to produce a series of conductive membranes. Electrical measurements on these membranes showed that in some cases, the resistivity was as low as 1 ?cm, putting these biogas-sourced inks in the range of high-quality conductive-grade carbon black.

Thanks to their sustainable feedstock, these nanocarbons certainly look to exhibit some advantages over commercially-available carbon black. Their well-defined structure suggests that they could be suitable for use as a reliable filler material, and, according to the researchers, their electrical performance “… opens the way to conductive coatings, electromagnetic shielding, and other conductivity related applications.”


F. Hof, K. Kampioti, K. Huang, C. Jaillet, A. Derre, P. Poulin, H. Yusof, T. White, K. Koziol, C. Paukner, A. Pénicaud, “Conductive inks of graphitic nanoparticles from a sustainable carbon feedstock” Carbon 111 (2017) 142-149 DOI: 10.1016/j.carbon.2016.09.052