New system to convert CO2 to methanol04/08/14Science & Technology
Global: Scientists have discovered a new catalytic system for converting carbon dioxide (CO2) to methanol, a key commodity used to create a wide range of industrial chemicals and fuels.
According to the researchers – from the US Department of Energy’s (DOE) Brookhaven National Laboratory, the University of Seville in Spain and the Central University of Venezuela – due to its significantly higher level of activity in comparison to other catalysts, the new system could make it easier to get normally unreactive CO2 to participate in these reactions
Brookhaven chemist Dr Jose Rodriguez, who led the research, said: “Developing an effective catalyst for synthesizing methanol from CO2 could greatly expand the use of this abundant gas as an economical feedstock.”
In the future, such catalysts could help mitigate the accumulation of CO2 by capturing it when it is emitted from methanol-powered combustion engines and fuel cells and recycling it to synthesise new fuel.
The team was particularly interested in exploring a catalyst composed of copper and ceria (cerium-oxide) nanoparticles, sometimes also mixed with titania, which they had previously found to have exceptional reactivity in a variety of reactions, with studies showing that the interfaces of the two types of nanoparticles is critical to the reactivity of the catalysts, with highly reactive sites forming at regions where the two phases meet.
To explore the reactivity of such dual particle catalytic systems in converting CO2 to methanol, the scientists used spectroscopic techniques to investigate the interaction of CO2 with plain copper, plain cerium-oxide and cerium-oxide/copper surfaces at a range of reaction temperatures and pressures.
Their studies revealed that the metal component of the catalysts could not carry out all the chemical steps necessary for the production of methanol alone. The most effective binding and activation of CO2 occurred at the interfaces between metal and oxide nanoparticles in the cerium-oxide/copper catalytic system.
Dr Jesus Graciani, from the University of Seville and first author on the paper, said: “The key active sites for the chemical transformations involved atoms from the metal [copper] and oxide [ceria or ceria/titania] phases.”
The resulting catalyst converts CO2 to methanol more than 1,000 times faster than plain copper particles and almost 90 times faster than a common copper/zinc-oxide catalyst currently in industrial use, thereby illustrating the substantial benefits that can be obtained by properly tuning the properties of a metal-oxide interface in catalysts for methanol synthesis.
The research has been published in the journal Science.