Advanced BioFuels USA

(Michigan News)  Producing synthesis gas, a precursor of a variety of fuels and chemicals, no longer requires natural gas, coal or biomass —

Solar-powered synthesis gas could recycle carbon dioxide into fuels and useful chemicals, an international team of researchers has shown.

“If we can generate syngas from carbon dioxide utilizing only solar energy, we can use this as a precursor for methanol and other chemicals and fuels. This will significantly reduce overall CO2 emissions,” said Zetian Mi, professor of electrical and computer engineering at the University of Michigan, who led the study published in the Proceedings of the National Academy of Science.

Composed mainly of hydrogen and carbon monoxide with a little methane, syngas is commonly derived from fossil fuels with the help of electricity. In addition, toxic chemicals are often added to make the process more efficient.

“Our new process is actually pretty simple, but it’s exciting because it’s not toxic, it’s sustainable and it’s very cost effective,” said Roksana Rashid, first author of the study, who performed the experiments as a doctoral student in electrical and computer engineering at McGill University in Canada.

To create a process that uses only solar energy, Mi’s group overcame the difficulty of splitting carbon dioxide molecules, which are among the most stable in the universe. For this, they peppered a forest of semiconductor nanowires with nanoparticles. Those nanoparticles, made of gold coated with chromium oxide, attracted the carbon dioxide molecules and bent them, weakening the bonds between the carbon and oxygen.

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“What is surprising is the synergy between gold and chromium oxide to make the CO2 reduction to syngas efficient and tunable. That was not possible with a single metal catalyst,” Mi said. “This opens up many exciting opportunities that were not previously considered.”

Mi’s tunable syngas setup uses standard industrial manufacturing processes, and is scalable. While Rashid used distilled water in this experiment, seawater and other electrolyte solutions are also expected to work, and Mi has used them in related water-splitting studies.

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Mi’s next goal is to increase the efficiency of the device, which currently stands at 0.89%. When 10% of the light energy is converted to chemical energy, he hopes that the technology could see the technology be adopted for renewable energy, similar to solar cells. 

The project was supported through the Emission Reduction Alberta ERA, based at McGill University in Canada, former home of Mi.   READ MORE

 Tunable green syngas generation from CO2 and H2O with sunlight as the only energy input (DOI: 10.1073/pnas.2121174119)