December 3, 2013
Co-Catalyst System Could Help Encourage Synthetic Gasoline Production
redOrbit Staff & Wire Reports - Your Universe Online
Researchers have reportedly developed a novel chemical system that uses inexpensive and easy-to-fabricate carbon-based nanofiber materials that could prove promising in the development of synthetic gasoline.Writing in the online edition of the journal Nature Communications, University of Illinois at Chicago (UIC) mechanical and industrial engineering professor Amin Salehi-Khojin and his colleagues report that their system efficiently converts carbon dioxide to carbon monoxide, a useful staring material for syngas and other synthetic fuels.
“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,” Amin Salehi-Khojin said in a statement Monday. His team’s method represents a new approach to the long-standing search for a commercially viable way to chemically lower the oxidation rate of CO2.
Lowering or “reducing” carbon dioxide’s oxidation rate is a two-step process, but Salehi-Khojin pointed out that chemists typically used only one catalyst. However, he and his associates experimented with using different catalysts for both steps. Previously, they used an ionic liquid for the first step and silver for the final reduction to carbon monoxide – a process which was reportedly more efficient than single-catalyst carbon reduction systems.
However, the expense of silver led the investigators to try using graphitic carbon structures doped with other reactive atoms, a fairly new type of metal-free catalysts, instead. They first tried carbon nanofibers doped with nitrogen as the second-step catalyst. Usually, when carbon materials are used in this process, the doping atoms drive the reduction reaction, but in this case Salehi-Khojin’s found it was the carbon atom that was responsible.
According to Mohammad Asadi, a UIC graduate student and one of the first authors of the study, the researchers were initially surprised by the result. However, as they continued their research, they found that not only was the carbon catalyzing the reaction, but that it was doing so more efficiently than silver. In fact, Asadi said that it showed “substantial synergistic effects.”
Furthermore, the study authors “uncovered the hidden mechanism” of the co-catalyzed reaction, according to UIC researcher and first author Bijandra Kumar. Their work has “opened up a lot of options for designing inexpensive and efficient catalyst system for carbon dioxide conversion,” Kumar added. “Further, one can imagine that using atomically-thin, two-dimensional graphene nano-sheets, 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.”
Had the reaction occurred on the dopant, Salehi-Khojin said that the researchers would have limited freedom in terms of structure, because little could be done to increase the reaction’s efficiency or stability. However, since the reaction occurred on the carbon, it gave them a tremendous amount of freedom to optimize the reaction using advanced carbon materials. He hopes that his team’s findings will lead to new commercially viable processes for the production of syngas, and perhaps even one day will allow scientists to use carbon dioxide to create gasoline.