Researchers at the University of Minnesota Twin Cities discovered a new method by which a catalyst can be used to burn one molecule selectively in a mixture of hydrocarbons. This new method could help in the removal of pollutants and improve efficiency for industrial processes ranging from the production of fuels and medications to fertilizers and plastics.

The research is published in Science.

By using a bismuth oxide catalyst, the researchers can selectively burn one molecule in a mixture of combustibles. The researchers showed that you can effectively combust even small amounts of acetylene in mixtures with ethylene. Removing acetylene is a crucial process to prevent poisoning of polymerization catalysts, which is vital for the production of polyethylene plastics, a market that exceeds 120 million metric tons annually.

No one else has shown that you could combust one hydrocarbon present in low concentrations, in mixtures with others.

—Aditya Bhan, lead investigator

Conventionally, combustion processes are used to burn all hydrocarbon fuel mixtures at high temperatures to produce heat. The use of a catalyst allowed the researchers to tackle the challenge of burning one molecule but not the others. The bismuth oxide catalyst is unique as it provides its own oxygen during combustion, rather than using oxygen from an outside source, in a process called chemical looping.

We were able to take oxygen out of the catalyst and put it back in multiple times, where the catalyst changes slightly, but its reactivity is not impacted. Operating in this chemical looping mode avoids flammability concerns.

—Matthew Jacob, first author

Traditionally, eliminating small concentrations of contaminants is very challenging and energy-intensive, but this new method could provide a more energy-efficient alternative.

The researchers said the long-term impact could be high because catalysts are used in just about anything we touch in modern society—from production of fuels and medications to fertilizers and plastics. Understanding how molecules combust—and don’t combust—on catalyst surfaces is valuable for making fuels and plastics production more efficient.

This work was funded by the US Department of Energy, Office of Basic Energy Sciences. The work was completed in collaboration with the University of Minnesota Characterization Facility and the Minnesota Supercomputing Institute.

Resources

• Matthew Jacob et al., Selective chemical looping combustion of acetylene in ethylene-rich streams. Science 387, 744-749 (2025) doi: 10.1126/science.ads3181