New chemical system paves way for synthetic, CO2-reducing gasoline

New chemical system paves way for synthetic, CO2-reducing gasoline

Researchers have discovered an affordable, efficient method for reducing CO2 to carbon monoxide.

Developed by researchers at the Univ. of Illinois at Chicago, the new chemical system can efficiently perform the first step in the process of gasoline and other energy-rich products out of carbon dioxide, a major contributor to global warming. The “co-catalyst” system uses inexpensive, easy to fabricate carbon-based nanofiber materials to efficiently convert carbon dioxide to carbon monoxide, a useful starting-material for synthesizing fuels. The findings can be found online in the journal Nature Communications.

Amin Salehi-Khojin is a UIC professor of mechanical and industrial engineering and principal investigator on the study. “I believe this can open a new field for the design of inexpensive and efficient catalytic systems for the many researchers already working with these easily manipulated advanced carbon materials,” he said.

Researchers have spent decades trying to find an efficient, commercially viable way to chemically reduce, or lower the oxidation state, of carbon dioxide.

Although reducing carbon dioxide is a two-step process, chemists had commonly used a single catalyst, Salehi-Khojin said in a statement. He and his colleagues experimented with using different catalysts for each step. Previous experiments used silver for the final step in the reduction to carbon monoxide. Because silver is expensive, Salehi-Khojin and his colleagues set out to see if a relatively new class of metal-free catalysts – graphitic carbon structures doped with other reactive atoms – might work instead. It appears that they hit pay dirt.

Carbon nanofibers are a well-known structural material, which the team doped with nitrogen as a substitute for silver in to catalyse the second step. As it turns out, the nitrogen wasn’t the key to their success.

“It was the carbon atom sitting next to the dopant that was responsible,” said Mohammad Asadi, a UIC graduate student who is one of two first-authors of the study.

“We were very surprised at first,” Asadi says. As they continued to characterize the reaction it became clear not only that carbon was catalyzing the reaction, but that the co-catalyst system was more efficient than silver, “showing substantial synergistic effects.”

Bijandra Kumar, UIC research scholar and the other first-author of the paper, says the team “uncovered the hidden mechanism” of the co-catalyzed reaction, which has “opened up a lot of options for designing inexpensive and efficient catalyst system for carbon dioxide conversion.”

“Further, one can imagine that using atomically-thin, two-dimensional graphene nanosheets, which have extremely high surface area and can easily be designed with dopant atoms like nitrogen, we can develop even far more efficient catalyst systems,” Kumar says.

“If the reaction happened on the dopant, we would not have much freedom in terms of structure,” says Salehi-Khojin. In that case, little could be done to increase the efficiency or stability of the reaction.

But with the reaction happening on the carbon, “we have enormous freedom” to use these very advanced carbon materials to optimize the reaction, he says. The researchers hope that their research leads to commercially viable processes for the production of syngas and even gasoline from carbon dioxide.

At the scientific recording station in Mauna Loa, Earth’s CO2 concentration reached 0.04% or 400 ppm for the first time in May 2013, although this level had already been reached in the Arctic in June 2012. Sir Brian Hoskins of the Royal Society said that the 400ppm milestone should “jolt governments into action”. The potential for fuels made from CO2 to impact these numbers in a positive way is not yet known.

Be social, please share!

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail

Leave a Reply

Your email address will not be published. Required fields are marked *