A Catalystic Shock

Scientists surprised by discovery that copper embedded in carbon nano-spikes can turn carbon dioxide into ethanol.

Researchers at Oak Ridge National Laboratory developed a catalyst—made of copper nanoparticles (seen as spheres) embedded in carbon nano-spikes—that can combine electrical energy and carbon dioxide to produce ethanol.

The Science

Cloudy or still days mean energy production drops at solar panels or wind farms. Scientists at Oak Ridge National Laboratory developed a new process that could change this situation. They found that tiny spikes of carbon combined with copper particles convert carbon dioxide into ethanol fuel. The catalysts take a waste product of coal used in power plants and other hydrocarbon combustion reactions, in the presence of electrical energy, and create liquid fuel. Their finding was a surprise. They had been studying only the first step of a reaction and realized the catalyst was orchestrating the entire reaction, converting dissolved carbon dioxide to ethanol with a 63 percent yield.

The Impact

The catalyst achieved unprecedented selectivity for ethanol in a complex reaction. This is noteworthy because the reaction typically yields several products in small amounts. Moreover, it showed that the catalyst’s nanometer-scale texture can control the outcome of chemical reactions. The discovery offers a strategy for making certain chemical reactions possible without using expensive or rare metal catalysts, such as platinum. It may offer a new route for storing—in the form of the chemical ethanol—electrical energy. This could benefit wind and solar stations that produce energy only when wind is blowing or sun is shining.

Summary

Researchers arranged common materials in a catalyst containing nano-spikes of carbon and nitrogen embedded with copper nanoparticles. When this catalyst was used to electrochemically reduce carbon dioxide—i.e., use electricity to convert a waste product of hydrocarbon combustion back into a hydrocarbon fuel—they were surprised they directly made ethanol, a more valuable fuel than the methanol that they anticipated. It turns out that active sites within these nanostructures work in tandem to complete a complex chemical reaction instead of the simpler reaction that was expected. At the same time, this nanocatalyst was highly selective, producing fewer byproducts than other catalysts. While the researchers have not fully determined the energy efficiency of the process, they showed that if 100 electrons were pushed across the catalyst and reacted, then 63 would be eventually stored as ethanol fuel. Or, 100 molecules of carbon dioxide would produce 84 carbon atoms in ethanol. Because these nanostructured catalysts employ low-cost materials and can run at room temperature, scaling the reaction for industrial applications is possible. One exciting prospect is chemically storing energy from renewable but intermittent power sources.

Contact

Adam Rondinone
Center for Nanophase Materials Sciences
Oak Ridge National Laboratory
rondinoneaj@ornl.gov  

Funding

This material is based upon work supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, and conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science user facility.

Publications

Y. Song, R. Peng, D.K. Hensley, P.V. Bonnesen, L. Liang, Z. Wu, H.M. Meyer, M. Chi, C. Ma, B.G. Sumpter, and A.J. Rondinone, “High-selectivity electrochemical conversion of CO2 to ethanol using a copper nanoparticle/N-doped graphene electrode.” ChemistrySelect 1(19), 6055-6061 (2016). [DOI: 10.1002/slct.201601169]

Related Links

Oak Ridge National Laboratory news release: Nano-spike catalysts convert carbon dioxide directly into ethanol
Popular Mechanics: Scientists Accidentally Discover Efficient Process to Turn CO2 into Ethanol
Popular Mechanics: Meet the Scientist Turning CO2 into Ethanol
Popular Science: Nanotech Wafer Turns Carbon Dioxide into Ethanol
PhysOrg: Nano-spike Catalysts Convert Carbon Dioxide Directly into Ethanol
Yahoo! News: Scientists Accidentally Found a Great New Way to Convert CO2 into Ethanol
Time: Scientists Accidentally Discover Method to Turn Carbon Dioxide into Ethanol
Road and Track: Scientists Accidentally Discover Way to Turn Car Emissions into Alcohol
Christian Science Monitor: Scientists – By Accident – Turn Carbon Dioxide into Ethanol Fuel
Motor Trend: Scientists Discover How to Make Ethanol out of Carbon Dioxide
Wired: Chemists Accidentally Turn Carbon Dioxide to Ethanol in Breakthrough Study
Radio Australia: Renewable Energy: Scientists Accidentally Turn Carbon Dioxide into Ethanol
Microscopy News blog: ORNL Team Uses Nano-Spike Catalysts to Turn Carbon Dioxide into Ethanol
Energy.gov website: Scientists Accidentally Turned CO2 into Ethanol
Smithsonian Magazine: Scientists Stumble on a New Way to Tackle Carbon Emissions: Turn It into Alcohol
R&D Magazine: Scientists Turn Carbon Dioxide into Alcohol with a Single Spark
MIT Technology Review: The Biggest Clean Energy Advances in 2016

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