A research team from Caltech and UCLA Samueli School of Engineering demonstrates a promising way to efficiently convert carbon dioxide to ethylene, an important chemical used in the production of plastics, solvents, cosmetics and other important products worldwide.
Scientists have developed nanoscale copper conductors with specially shaped surfaces to catalyze a chemical reaction that reduces greenhouse gas emissions while generating ethylene, a valuable chemical. Computational studies of the reaction show that the catalyst formed favors the production of ethylene on hydrogen or methane. A study detailing the advance was published in Natural catalysis.
“We are on the brink of fossil fuel depletion, along with global challenges related to climate change,” said Yu Huang, co-author of the study and professor of materials science and engineering at UCLA. “The development of materials that can effectively convert greenhouse gases into value-added fuels and chemical raw materials is a critical step in mitigating global warming, while diverting from the extraction of increasingly limited fossil fuels. This integrated experiment and theoretical analysis presents a sustainable path to carbon sequestration and utilization. “
Ethylene currently has a global annual production of 158 million tons. Much of this is converted to polyethylene, which is used in plastic packaging. Ethylene is processed by hydrocarbons, such as natural gas.
“The idea of using copper to catalyze this reaction has been around for a long time, but the key is to speed up so that it’s fast enough for industrial production,” said William A. Goddard III, co-author of the study, and Charles and Mary Ferkel of Caltech. , Professor of Chemistry, Materials Science and Applied Physics. “This study shows a solid path to this brand, with the potential to transform ethylene production into a greener CO2 which would otherwise enter the atmosphere. “
Use of copper to start carbon dioxide (CO2) reduction in ethylene reaction (C2З.4) suffered two strikes against him. First, the initial chemical reaction also produces hydrogen and methane – both undesirable in industrial production. Second, previous experiments leading to ethylene production did not last long, with conversion efficiency declining as the system continued to operate.
To overcome these two obstacles, the researchers focused on the design of copper nanowires with highly active “steps” – like a set of stairs arranged on an atomic scale. An intriguing finding from this joint study is that this step on the surfaces of the nanowires remains stable under the reaction conditions, contrary to the common belief that these high-energy characteristics will be smoothed out. This is the key to both the durability of the system and the selectivity in the production of ethylene instead of other end products.
The team demonstrated a degree of conversion of carbon dioxide to ethylene greater than 70%, much more efficient than previous projects, which gives at least 10% less under the same conditions. The new system operates for 200 hours, with a small change in conversion efficiency, a major advance for copper-based catalysts. In addition, a comprehensive understanding of the structure-function relationship illustrates a new perspective for the design of highly active and durable CO2 reduction catalyst in action.
Huang and Goddard have often been collaborators for many years, with Goddard’s research group focusing on the theoretical causes behind chemical reactions, while Huang’s group creating new materials and conducting experiments. The lead author of the article is Chungseok Choi, a graduate student in materials science and engineering at UCLA Samuel and a member of Huang’s laboratory.
Electrochemical reduction of carbon dioxide to ethanol
Chungseok Choi et al, Highly active and stable stepped Cu surface for improved electrochemical reduction of CO2 to C2H4, Natural catalysis (2020). DOI: 10.1038 / s41929-020-00504-x
Provided by the University of California, Los Angeles
Quote: Researchers find an effective way to convert carbon dioxide to ethylene (2020, September 17), extracted on September 17, 2020 from https://phys.org/news/2020-09-effective-pathway-carbon-dioxide -ethylene.html
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