A research team from Caltech and the UCLA Samueli School of Engineering has demonstrated a promising way to convert carbon dioxide into ethylene – a chemical used to produce plastics, solvents, cosmetics and other globally manufactured products.
The scientists developed nanoscale copper wires with specially shaped surfaces to catalyse a chemical reaction that reduces greenhouse gas emissions while generating ethylene. Computational studies of the reaction show the shaped catalysts favoured the production of ethylene over hydrogen or methane.
Yu-Huang, Professor of Materials Science and Engineering at UCLA, said, “Developing materials that can efficiently turn greenhouse gases into value-added fuels and chemical feedstocks is a critical step to mitigate global warning while turning away from extracting increasingly limited fossil fuels.”
William Goddard, Caltech’s Charles and Mary Ferkel Professor of Chemistry, added, “The idea of using copper to catalyse this reaction has been around for a long time, but the key is to accelerate that rate, so it is fast enough for industrial production.”
“This study shows a solid path towards that mark, with the potential to transform ethylene production into a greener industry using carbon dioxide that would otherwise end up in the atmosphere.”
Originally, using copper to kick start the carbon dioxide reduction into ethylene reaction suffered two problems. First, the initial chemical reaction also procured hydrogen and methane. Second, previous attempts that resulted in ethylene production did not last long.
To overcome those issues, the researchers focused on the design of the copper nanowires with high active steps – similar to a set of stairs arranged at atomic scale. Findings of this showed that the step pattern across the nanowire’s surfaces remained stable under the reaction conditions, something that is key to both the systems durability and selectivity in producing ethylene.
The team demonstrated a carbon dioxide-to-ethylene conversion rate of greater than 70%, much more efficient that pervious designs. The new system also ran for 200 hours with little change on conversion efficiency.