Copper foam turns CO2 into useful chemicals -ref Materials Today

A catalyst made from a foamy form of copper has vastly different electrochemical properties from catalysts made with smooth copper in reactions involving carbon dioxide, a new study shows. The research, by scientists in Brown University’s Center for the Capture and Conversion of CO2, suggests that copper foams could provide a new way of converting excess CO2 into useful industrial chemicals. For example a photo of Cu foam from ERG Materials and Aerospace is given as follows:

Example of Copper Properties 


“Copper has been studied for a long time as an electrocatalyst for CO2 reduction, and it’s the only metal shown to be able to reduce CO2 to useful hydrocarbons,” said Tayhas Palmore, professor of engineering and senior author of the new research. “There was some indication that if you roughen the surface of planar copper, it would create more active sites for reactions with CO2.”




'As levels of carbon dioxide in the atmosphere continue to rise, researchers are looking for ways to make use of it. One approach is to capture CO2 emitted from power plants and other facilities and use it as a carbon source to make industrial chemicals, most of which are currently made from fossil fuels. The problem is that CO2 is extremely stable, and reducing it to a reactive and useful form isn’t easy.


Now,copper foam, which has been developed only in the last few years, provided the surface roughness (and increased surface area?-reaction:chemical rate controlled or mass transfer controlled?) for which Palmore and her colleagues were looking. The foams are made by depositing copper on a surface in the presence of hydrogen and a strong electric current. Hydrogen bubbles cause the copper to be deposited in an arrangement of sponge-like pores and channels of varying sizes.'


'After depositing copper foams on an electrode, the researchers set up experiments to see what kinds of products would be produced in an electrochemical reaction with CO2 in water.'

The experiments showed that the copper foam converted CO2 into formic acid — a compound often used as a feedstock for microbes that produce biofuels — at a much greater efficiency than planar copper. The reaction also produced small amounts of propylene, a useful hydrocarbon that’s never been reported before in reactions involving copper.

“The product distribution was unique and very different from what had been reported with planar electrodes, which was a surprise,” Palmore said. “We’ve identified another parameter to consider in the electroreduction of CO2. It’s not just the kind of metal that’s responsible for the direction this chemistry goes, but also the architecture of the catalyst.”

'Now that it’s clear that architecture matters,  It’s likely, Palmore says, that pores of different depths or diameters will produce different compounds from a CO2 feedstock. Ultimately, it might be possible to tune the copper foam toward a specific desired compound.'


Copper foam turns CO2 into useful chemicals - Materials Today