Scientists Use Bismuth to Convert CO2 into Liquid Fuels

At the University of Delaware, in Joel Rosenthal’s office sits a shining piece of metal on a table, which looks more like a thing from a wizard’s pocket.

Shiny silver in color with splashes of gold and shocks of pink, the metal is known as bismuth. At present, it is used for making products as varied as shotgun pellets to cosmetics and antacids, such as Pepto-Bismol.

However, Professor Rosenthal’s study has expanded bismuth’s repertoire — he has recognized a type of magic in the metal that could be just that which the doctor ordered for our planet, Earth.

He stated it can assist in reducing the increasing levels of carbon dioxide in the atmosphere and offer sustainable paths to synthesizing fuels.

Rosenthal and his colleagues from the UD’s Department of Chemistry and Biochemistry have found out that bismuth has a strange characteristic that can be exploited to save the environment; as a catalyst or chemical “spark” for transforming carbon dioxide (CO₂), which is a greenhouse gas, into industrial chemicals and liquid fuels.

The outcomes of the study have been described in ACS Catalysis, a journal published by the American Chemical Society. A patent on the study has also been filed by Rosenthal’s team.

“Catalytic plasticity” is the term used by Rosenthal to refer to bismuth’s distinctive capability. By applying an electrical current to a bismuth film placed in a bath of salty liquids that contains amidinium and imidazolium ions, he and his colleagues could “tune” the chemical reaction to transform CO₂ to formic acid or to a liquid fuel such as gasoline.

Formic acid is a precious chemical used in various industrial applications such as preserving livestock feed and human food, and producing artificial flavorings, rubber and leather, and perfumes.

Conventionally, it has been necessary for chemists to develop a new catalyst to initiate every distinctive chemical reaction they analyzed, from steps a to b, from b to c, and so on, stated Rosenthal, which renders this process—the use of one catalyst that can be tuned or customized to efficiently initiate various types of reactions—specifically innovative reactions.

Our new findings are important from a technological standpoint—we think this platform will allow renewable energy sources such as solar and wind to drive the direct production of liquid fuels. But more importantly, we believe this concept of ‘catalytic plasticity’ signals a potential paradigm shift, a new way to think about renewable energy conversion, fuel production and catalysis, in general.”

Professor Rosenthal, Lead Author

Rosenthal and his colleagues earlier demonstrated that it is possible to use bismuth films in combination with specific liquid salts as low-cost catalysts for transforming renewable energy and CO₂ to gaseous fuels like carbon monoxide. In this research, they discovered that it is possible to use the same materials in the presence of various salts to enable direct conversion of CO₂ into liquid fuels.

I’ve been fascinated by the field of catalysis for a long time. Thinking about how you can take something cheap and plentiful and convert it into something much more useful and valuable without having to dump a lot of extra energy into it has always captured my imagination.

There are philosophical parallels between catalysis and the goals of the ancient alchemists. Alchemy is a loaded word, but in some ways, what we are studying is like modern alchemy - efficiently transforming carbon dioxide to more valuable fuels and chemicals is akin to trying to convert lead to gold.”

Professor Rosenthal, Lead Author

So what is the effect of Rosenthal’s technology on prevalent CO₂ levels?

It’s hard to predict the direct impact on those levels,” he stated. “This technology would allow us to make liquid fuels using renewable electricity from sunlight and wind. This, in turn, would decrease our need for conventional petroleum resources, resulting in fewer carbon dioxide emissions.”

Professor Rosenthal, Lead Author

Last April saw the highest ever sustained CO₂ levels in the Earth’s atmosphere, surpassing 410 ppm for the entire month, as reported by scientists at Hawaii’s Mauna Loa Observatory.

Rosenthal has been striving to overcome this challenge for almost eight years and will continue forward.