Earth & Conservation

This Metal Can Convert Atmospheric CO2 Into Liquid Fuel

Scientists have found a way to use bismuth as a catalyst for the direct conversion of carbon dioxide.

Researchers at the University of Delaware have developed a process for converting carbon dioxide into liquid fuel using bismuth as a catalyst. | Evan Krape/University of Delaware
Researchers at the University of Delaware have developed a process for converting carbon dioxide into liquid fuel using bismuth as a catalyst. | Evan Krape/University of Delaware

What if we could reverse that the primary process that’s causing Earth’s climate to warm? Instead of pumping carbon dioxide into the atmosphere, what if we could convert carbon dioxide into fuels and useful industrial chemicals?

That's the idea behind an ongoing research initiative at the University of Delaware that represents a kind of radical recycling approach to the carbon dioxide problem. The idea of reclaiming and repurposing carbon dioxide isn't new — plenty of scientific institutions are dedicated to this particular puzzle. But the new UD technique conscripts a new ally to the cause: bismuth.

Joel Rosenthal and his team in UD's department of chemistry and biochemistry have discovered a previously unknown property in bismuth that they say could be a legitimate tool in the fight against global warming. By way of a chemical process known as “catalytic plasticity,” bismuth can be used to directly convert atmospheric CO2 into liquid fuels and industrial chemicals.

It works like this: When an electrical current is shot through bismuth in a bath of salt, the resulting chemical reaction can be manipulated in real time to convert adjacent CO2 into usable fuels such as gasoline or chemicals, according to the new research. Because the chemical reaction can be “tuned” on the fly, the technique could power scaled-up systems that suck CO2 from the atmosphere and pump out valuable chemicals on the other end.

“We’re working to push the boundaries of this idea,” Rosenthal said in a statement accompanying publication of the research. “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.”

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Rosenthal and bismuth are old acquaintances. His team previously published research showing that the metal could be used with certain salts to convert carbon dioxide to carbon monoxide, which can be used as a fuel. The new research takes the concept to another level entirely, suggesting that bismuth and salts can convert CO2 directly into liquid fuels.

The findings are reported in the journal ACS Catalysis, published by the American Chemical Society. Rosenthal and his team have also filed a patent on the process. The work was supported by the US Department of Energy and the Alfred P. Sloan Foundation.

While the bismuth technique is in the very early stages, Rosenthal believes the technology could eventually be combined with other renewable energy strategies to significantly reduce carbon dioxide levels in the atmosphere.

“This technology would allow us to make liquid fuels using renewable electricity from sunlight and wind,” he said. ”This, in turn, would decrease our need for conventional petroleum resources, resulting in fewer carbon dioxide emissions.”

We should probably get cracking. Carbon dioxide levels averaged 410 parts per million during the month of April. Prior to the Industrial Revolution, CO2 levels hadn't exceeded 300 ppm in the past 800,000 years, according to the Scripps Institution of Oceanography, which tracks atmospheric carbon dioxide concentrations.